INTERNATIONAL COOPERATIVE RESEARCH PROGRAM ON TOOL WEAR L. V.oiLwel 1 J. C. Mazur This document is subject to special export controls and each transmittal to foreign governments or foreign nationals may be made only with prior approval of the Manufacturing Technology Divisions MATF, Air.-Force Materials Laboratory, Wright-Patterson Air Force Base, Ohio 45433.

FOREWORD This Final Technical Report covers all work performed under Contract AF 33(61.5)-2159 from 16 November 1964 to 15 November 1965. The manuscript was released by the authors on 28 September 1966 for publication as an RTD Technical Report. This contract with The University of Michigan, Ann Arbor, Michigan wa.s initiated under Manufacturing Methods Project 8-338, "Formulation of International Standards for Cutting Tool Performance." It was accomplished under the technical direction of Mr. Floyd L. Whitney, Advanced Fabrication Techniques Branch, Manufa-cturing Technology Division, AF Materials Labora-tory, WrightPatterson Air Force Base, Ohio. Professor L. V. Colwell of The University of Michigan, Department of Mecha.nical Engineering served as Project Director for all but a short portion of the project. He was followed by Professor J. C. Mazur who was responsible for technical direction of the laboratory program. Others who participated actively in the program and in the preparation of reports were Professor L. Jo Quackenbush and Mr. J. M. Hardy. The primary objective of the Air Force Manufacturing Methods Program is to develop, on a. timely ba.sis, manufacturing processes, techniques and equipment for use in economical production of USAF materials and components. This program encompasses the following technical areas: Rolled Sheet, Forgings, Extrusions, Castings, Fiber a.nd Powder Metallurgy, Component Fabrication, Joining, Forming, Material Removal, Fuels, Lubricants, Ceramics, Graphites, Nonmetallic Structural Materials, Solid State Devices, Passive Devices, and Thermionic Devices. Your comments are solicited on the potential utilization of the information contained herein as applied to your present or future production programs. Suggestions concerning additional Manufacturing Methods Development required on this or other subjects will be appreciated. This technical report has been reviewed and is approved. MELVIN E. FIELDS, Colonel, USAF Chief, Ma.nufacturing Technology Division Air Force Materials Laboratory ii

ABSTRACT This is the fourth and final. report of the series under this contract~ It includes coverage of forces and shear zone mechanics, wear of American and European carbide and high speed steel cutting tools, and accelerated tests for evaluating cutting performance. In addition, the report summarizes the objectives, experimental procedures, and related activities of the OECD/CIRP internationa.l cooperative research program in metal cutting as detailed in Interim Reports 1, 2, and 3o The program has shown that it is possible to work successfully among various laboratories and across interna.tional boundaries to achieve specific goals. The exchange of information has proved to be not only a. valuable check upon the repeatability and validity of results but has led to improvements in measuring techniques and associated instrumentation for more reliable and more consistent interpretations The results have helped to identify those areas which need more intensive studies for evaluation of causes and effects of metal cutting behavior. Phase II, a study of steels of different microstructures and properties, is an important next step in the expansion of the OECD/CIRP program. iii

TABLE OF CONTENTS Part Page I. FORCES AND SHEAR ZONE MECHANICS IN MACHINING XC45 STEEL 1 Summary 2 I. Justification of the Subgroup Activity 2 II. Research Program 3 A. Comparison of dynamometers 3 B. Some particulars of measurement 7 III Results of Tests on XC45 Steel 8 A, Corrections of the gross forces measured 8 Bo Peculiarities concerning cutting forces with high speed steel tools 18 IV. Conclusions 24 II. WEAR ON AMERICAN AND EUROPEAN CARBIDE TOOLS IN MACHINING XC45 STEEL 27 I. Tests Results With European Carbides 28 Ao Flank wear 28 B. Crater wear 34 II. Preliminary Tests With American Carbides 34 A. Cutting tools 34 Bo Cutting conditions and test procedures 37 C. Carbides with negative rake 37 D, Carbides with positive rake 47 Eo Negative ra.ke vs. positive rake angles 55:F Significance of crater wear measurements 56 IIIo WEAR ON AMERICAN AND EUROPEAN HIGH SPEED STEEL TOOLS IN MACHINING XC45 STEEL 57 I. European High Speed Steel Tools 58 A. Test procedure 58 B. Tool material 58 C. Test results 60 II. American High Speed Steel Tools 64 A. Tool materials 64 B. Test procedure 64 C, Test results 64 IV. ACCELERATED TESTS FOR RATING HIGH SPEED STEEL TOOLS 69 Io Geometrically Stepped Cutting Speeds 70 A. Introduction 70 v

TABLE OF CONTENTS (Continued) Part Page B Description of the method 71 C. Condition of test 72 D. Results 72 E. Conclusions 73 II. Continuously Variable Cutting Speeds 73 A. Theoretical relationships 76 B. Laboratory evaluation 77 C. Test results 77 D, Conclusions 79 III. Proposed Tests 80 V. SUMMARY OF HISTORY AND RESULTS OF INTERNATIONAL COOPERATIVE RESEARCH IN METAL CUTTING 81. Io Introduction 82 IIo International Cooperative Research Program on Tool Wear 83 A. Specific objectives and approach of the OECD 83 B. Work material 84 C. Cutting tools 85 D. Experimental program 94 E. Tool wear results 1.03 III. Additional OECD/CIRP Research in Metal Cutting 120 IV. Conclusions and Recommendations 1.24 APPENDIX. TABLE OF CONTENTS OF PREVIOUS INTERIM REPORTS 127 DISTRIBUTION LIST 129 vi

LIST OF ILLUSTRATIONS No. Page 1. Comparison of cutting forces determined by dynamometers at four laboratories. 4 2. Forces involved in cutting. 9 35 Force analysis proposed by Po Albrecht, Cincinnati Milling Machine Company. 10 4. P. Albrecht method for determining force components PI and P2 of Figure 3o 11 5. (a) Determination of the directions of the forces P and Q; (b) P-Q force diagram; (c) three dimensional plot showing dependence of cutting forces on cutting conditions. (P. Albrecht) 12-14 6. Tangential and lateral forces and cutting ratio as a. function of feed, showing linear force-feed behavior beyond critical feed (CIRP-OCDE)o 16 7. Tangential and lateral forces and cutting ratio under conditions (V > 15 m/min) which give nonlinear force-feed behavior beyond critical feed (CIRP-OCDE). 19 8. Specific volumetric cutting energy versus feed at various velocities for annealed XC45 steel (CIRP-OCDE). 21 9. Specific volumetric cutting energy versus feed at various velocities for hardened and tempered (700-760~C) XC45 steel (CIRP-OCDE) o 22 10. Comparison of cutting forces and cutting ratios under identical cutting conditions for semiorthogonal and pure orthogonal cuts (CIRP-OCDE) 23 11 Plots of average flank wear and crater ratio versus cutting time for European PiO and P30 carbide grades. 29 12o Crater profiles along line AA (identified in Fig. 13) from results at Aachen and The University of Michigan for cutting conditions listed in Figo l1bo 35 vii

LIST OF ILLUSTRATIONS (Continued) No. Page 13. Top view of tool face showing the paths of the traces made on a Proficorder to provide information for mapping crater profiles. 36 14. Mapping of crater on face of K68 carbide grade at cutting time of 2 min with negative rake and cutting conditions indicated. 39 15. Mapping of crater on face of K6 carbide grade under same conditions listed in Fig. 14. 40 16. Mapping of crater on face of K21 carbide grade under same conditions listed in Fig. 14. 41 17. Tool of Fig. 16 with crater at end of 4 min cutting time. 42 18. Mapping of crater on face of K2S carbide grade under same conditions listed in Fig. 14. 43 19. Tool of Fig. 18 with crater at end of 4 min cutting time. 44 20. Tool of Fig. 18 with crater at end of 8 min cutting time. 45 21. Crater profiles along line AA for negative rake tools in Figs. 14, 15, 16 and 18; cutting time, 2 min. 46 22. Crater profiles along line AA for 2, 4, and 8 min cutting times on K2S carbide. 46 23. Mapping of crater on face of K21 carbide grade at cutting time of 2 min with positive rake and cutting conditions indicated. 48 24. Mapping of crater on face of K5H carbide grade under same conditions listed in Fig. 23. 49 25. Mapping of crater on face of European P10 carbide grade under same conditions listed in Fig. 23. 50 26. Tool of Fig. 25 with crater at end of 4 min cutting time. 51 27. Mapping of crater on face of European P30 carbide grade at cutting time of 4 min with cutting conditions same as those listed in Fig. 23. 52 viii

LIST OF ILLUSTRATIONS (Continued) No. Page 28. Tool of Fig. 27 with crater at end of 8 min cutting time. 53 29. Crater profiles along line AA from Figs. 23 through 25 for positive rake carbides. 54 30. Representative crater wear patterns found in wear studies of various carbides; (a) typical of P10, (b) typical of P30, (c) typical of American grades to date. 54 31. Comparison of crater profiles along line AA for negative and positive rake tools. 55 32. Range of tool life among European EW9ColO H.S.S. tools prepared for cooperative study. 61 33. Flank wear and crater ratio vs. time for tools of Fig. 32. 62 34. Results of tool life tests at The University of Michigan with tools 11A14, 15, 16 and 20 of Fig. 32. 63 35. Results of tool life tests with American H.S.S. tools. 68 36. Correlation between rapid method and classic method of evaluation for 83 steels of different grades and of several thermal and/or mechanical treatments. 74 37. Correlation between rapid method and classic method of evaluation for seven steels using two incremental speed ratios. 75 38. Taper turning and facing results under test.conditions. Points are averages of a number of tests. 78 39. Locations from which both compression and tension specimens were taken for plasticity studies of XC45 work material. 86 40. Results of true stress-true strain behavior of XC45 steel. 87 41. Rockwell A hardness-Carbide P1O. 89 42. Rockwell A hardness-Carbide P30. 90 43. Density —Carbide PO1. 91 ix

LIST OF ILLUSTRATIONS (Continued) No. Page 44. Density-Carbide P30. 92 45. Method of identifying cutting edges of indexable carbide tool bits. 94 46. Method of machining test bar. 95 47. Typical test data sheet. 96 48. Angles of a cutting tool. 97 49. Identification of tool wear. 101 50. Typical plot of flank wear versus cutting time. 104 51. Typical plots of crater depth versus elapsed cutting time. 105 52. Typical plots of crater ratio versus cutting time. 106 53. Tool life plot based upon total tool travel or rubbing distance to reach a flank wear of 0.2 mm or a crater ratio of 0.2 at various velocities. 107 54. Tool life versus cutting velocity based upon different values of flank wear and crater ratio. 108 55. Tool life versus cutting velocity for two heats of XC45 steel. 109 56. Tool life versus cutting velocity for same two heats of XC45 steel of Fig. 55 but tool failure based upon crater ratio of 0.2. 110 57. Comparison of tool life results among nine laboratories when based upon flank wear of 0.2 mm with P30 carbide. 111 58. Comparison of tool life results among nine laboratories when based upon a crater ratio of 0.1 with P30 carbide. 112 59. Comparison of tool life results among nine laboratories when based upon a crater ratio of 0.1 with P10 carbide. 113 60. Comparison of tool life results among nine laboratories when based upon flank wear of 0.2 mm with PO1 carbide. 114.x

LIST OF ILLUSTRATIONS (Concluded) No. Page 61. Tests at The University of Michigan indicate that the method of holding and driving the workpiece has an influence on tool life criteria. 115 62. Variations in normal rake angle shown contradictory trends when V30 is based upon flank wear or crater ratio as failure criteria. 117 63. Optimum side cutting edge angle is also influenced by form of failure criterion, flank wear or crater ratio. 118 64. Photograph and schematic of tool wear in finish machining. 119 65. Crater on face of K68 carbide grade tool with negative rake at cutting time of 2 min under conditions listed. Differences in behavior of carbide grades are emphasized when results are compared with corresponding crater on K21 grade under identical conditions. 121 66. Crater on face of K21 grade carbide is much smaller and shallower than crater of K68 grade under identical conditions as shown in Fig. 65. 122 67. Results of tool life tests with American H.S.S. tools. 123 xi

LIST OF TABLES Table Page I. Results of Comparative Wear Tests 38 II. Chemical Composition of European High Speed Steel 59 III. Heat Treating Cycles for European H.S.S. Tools 59 IV. Identification of American High Speed Steel Tools 65 V. Heat Treating Cycles for American H.S.S. Tools 66 VI. Comparison of Actual vs. Predicted Tool Life Equations when Cylindrical Turning, Taper Turning and Facing 1045 H.R. Steel at Test Conditions 79 VII. Symbols and Dimensional Units 98 VIII. Outline of Standard Test Program 99 IX. Participating Laboratories and Equipment Used 102 xii

PAPRT I FORCES AND SHEAR ZONE MECHANICS IN MACHINING XC45 STEEL

Research on cutting forces and the mechanics of cutting has been the responsibility of a subgroup of the main OECD/CIRP committee under the chairmanship of Mr. M. F. Eugene of the French Central Armament Laboratories (LCA). Seven laboratories are participating in this work, including the Cincinnati Milling Machine Company and the Carnegie Institute of Technology in the United States. The results of the work done have been summarized by Mr. Eugene for presentation during the OECD/CIRP meetings in Paris, France in September, 1966. The following information is a translation of his Rapport Concernant Les Recherches Effectuees Au Sein Du Sous-Groupe "Efforts Et Mecanique De Coupe" (Report on the Research Done by the Subgroup "Mechanics of Cutting and Cutting Forces). SUMMARY In the first phase of this work, the methods of measurement employed have been investigated, certain tests have been standardized and, above all, the different dynamometers used have been compared. After comparing the results, it was decided to construct a standard dynamometer. A fundamental problem ha.s arisen in connection with the corrections to be applied to the forces as measured; two approaches have been followed and from these it has been possible to decide upon the best method of correcting the results obtained in future tests. Analysis of results obtained with the XC45 steel in different structural states has shown that there are two ways in which the cutting forces change in relation to feed, and these must serve as guidelines for future research. I. JUSTIFICATION OF THE SUBGROUP ACTIVITY When the work group was formed in 1961, a general program of the studies to be made was presented. Analytical parameters were to be studied in order to link them as precisely as possible to the behavior of the tools. This would make it possible to predict cutting behavior, and would be of immediate value for industrial usage in selecting the most economical cutting conditions. First, this program was to study all the grades of nonalloyed steels ranging from low carbon contents up to carbon contents of 0.8%, respectively, in different structural grades' However, after a. first important series of tests 2

on a C.45%o carbon steel, it has been decided that the tests would be run on steels alloyed with nickel-chromium and with chromium-molybdenum., which are commonly used in industry. The second goal was the comparison of the known theoretical. data on cutting, to define their region of validity, to complete the data, and to try to link the mechanical and. physical characteristics involved in the cutting to the characteristics measurable on the machined material, As an implicit consequence, the work material was studied as a function of strain rate and temperature, Such studies give some hope of finding new or better metallurgical solutions for either the work material or tool material. Due to the scope of such an undertaking, the tasks would necessarily have to be spread.. The assignment of the subgroup "Mechanics of Cutting and Cutting Forcess" is to take all the measurements pertinent to the cutting with precision, a.nd al.s to detect any peculiarity susceptible to provide complementary information appropriate to the perfection of our a.nalytical and technological. knowledge II, RESEARCH PROGRAM Before beginning the research program, it was necessary to compare the methods used. to measure cutting forces and chip thickness (needed for ca.lcula.tion of shear a.ngle), to calibrate and measure cutting temperatures, to find the real values of the feeds indicated by the machine used, and to find the a.ctua;. cutting speeds,, A. COMPARISON OF DYNAMOMETERS In the beginning, the results from four laboratories were comparedAa.,chen, Delft, Liege, and Paris. Each laboratory used its own dyna.m.ometer to machine a CK 53N steel, with a high speed steel tool. (rake angle = 53C and V = _.5 m/min = 49 fpm) and with a. carbide tool (rake a.ngle = 6" and. V 1.50 m/min = 492 fpm). These tests were run in orthogonal. section on rounds. The tangential. fcrce Fz and the la.teral force Fx were measured as a function of feed and. ra.nged from.100 to 900 kg (220 to 1980 'b) for which the dynamometers could be compared. Five successive tests were run for ea.ch cutting condition to determine a mredia.n val.ue, The agreement of the results obtained with the high speed steel. was relativel.y good with regard to the tangential for ce, but significa.nt, unacceptable deviat ions were observed when measuring the lateral force (Figure 1). The results with the ca.rbide tooli a.t high speeds showed dev'iations for 'both the tan

0 - 0 0 - A - - - — A +_.t - * -+ AACHEN DELFT LIEGE PARIS Tool material: Co 10 3 X^ n =0 15Xm/min =9 UP xd~ X9d' = 49.2 ft/min = X d Lbf Kgf 1540- oo I, 1320- 600 FZ f( I Lbf Kgf F ^ / ^ ^) 1~98 90 FX=f(s) 1100 500176 80 176 -~ 80 -880- 400 1 54- 70 -s ^ I ' ' I //^.1^~~ 0^ ^132 60 h / O660 -300-/ - O110 50 440 - 200 188 40 220 - 100 -66- 30 0- ~ s.mm 44 20-~ ~1 s.mm 0.2 0.4 0.6 0.8 0,2 0.4 0.6 08 12 O2 0.4 0.62 pT 1 r -1 ^ 1 T~ ~^ in x 10^ i~~ ~ ~ ~ ~ ~ ^ nxIO^ I I f nl I ' I ' I - ' I ' I ' inxl 0.78 1.56 2.34 3.12 0.78 1.56 2.34 3.12 FEED FEED Figure 1. Comparison of cutting forces determined by dynamometers at four laboratories.

AACHEN DELPT LIEGE PARIS a- a A- - — A +- - ~ -- ~ Tool material: Carbide PO10 V = 150 m/min = 9dp -=492 ft/min = F~ B X= 9(f b- 6) X 9(f Lbf Kgf FX= f(s) 1320- 600 Lbf Kgf FZ f(s) L 38 4 / Ii30 140- - 1100- 500 / - it 264- 120 -/ 880 400 220 100 - ' 660 300 176 80 I' 132 -60 a, 440 200 /7jl~~ ~88 -40 220 -100 44- 20 o0 1 s.mm 0 -* ~1~ ' ^ 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 -nx12 -nx12 * ~ 1~I~ ~ -. I I ~ ~ inxIO I~,~I~, inxIO 0.78 1.56 2.34 3.12 0.78 1.56 234 3.12 3.9 FEED PEED Figure 1-Concluded

gential and lateral forces. The deviations for the lateral forces were particularly important. It was presured that the disparity of results could be produced by differences in the vibration behavior of the machines used in the different laboratories. It was decided that the tests would be rerun with the same dynamometers in one laboratory, Aachen, with sections taken from the same bar of CK 53N steel. The second series of tests confirmed the previous results, within a 5% margin of error. A third comparison was tried by locating the precise position of the tests in a given bar of annealed XC45 steel at a specific radius of the bar. The steel. used at Aachen was an extension of the same steel used at Paris at the same radius, with both high speed steel and carbide cutting tools. The differences in the forces Fz and Fx as measured for high speed steel tools in the two laboratories was of the order of 1o. The tests run with carbides showed a systematic variation of 5% for the tangential force and of 12.5% for the lateral force. A similar comparison between measurements a.t Paris and Delft showed variations of the same order of magnitude Two conclusions could be drawn from these experiments' I, In such comparisons, the homogeneity of the bars used has to be considered, not only along the length, but also in cross section. 2o The more pronounced variations of the results obtained at higher cutting speeds seem to be the consequence of the vibration behavior of the dynamometers used (natural frequency)o Because of these results, it has been decided to build a standard dynamometer, as proposed by the president of Group C (Dr Opitz). First, however, the mechanical and physical cha.racteristics of the dynamometers used at present had to be compared. Their natural frequency varied from 500 to 1.200 Hz. The committee in charge of choosing the standards decided that the standa.rd dynamometer shoul.d lo measure the three orthogonal cutting forces, Fx Fz and Fy; 2. have a sufficient sensitivity without, however, reaching load deformations capable of disturbing the cutting (deflection < 10 u); 3. have high natural frequencies, > 3000 Hz along the three directions; 4. be exempt from mutual interaction of the forces; 5 not be influenced by the temperature, either by means of a particular location of the measuring device in the instrument, or by means of cooling by a water circuit; 6

6. present a practical, integrated, and permanent arrangement for the measurement of cutting temperatures; 7. assure the best possible arrangement of the piece and the mandrel of the lathe; 8. be capable of use in cutting with fluid. A dynamometer following these conditions is being realized at Aachen; it is inspired by the principle of the dynamometer conceived at the Polytechnical Institute in Zurich which measures forces by means of a piezoelectric quartz crystal and provides a natural frequency definitely higher than 3000 Hz. B. SOME PARTICULARS OF MEASUREMENT To calculate shear angle of the chip and to determine the rate of deformation of the metal, it is necessary to get precise measurements of the chip thickness. The work group had to compare the methods used and to propose to the participating laboratories the method which is best adapted to the type of chip obtained. Five methods have been considered: the direct measurement of the thickness is not possible for all types of chips; the method of weighing a defined length of chip ha.s given the best results for chips that are slightly curled and helical; for chips of small length, tightly curled and spiraled, the preferred method is to use a planimeter on an enlarged photograph of a cross section. In the study of the forces involved in plastic deformation during cutting, the value of the rate of deformation is very important; tests have shown that a 5% relative error in this value ca.n induce a 15% corresponding error on the energy of deformation. The comparison between such tests and the phenomena observed during cutting shows that it is necessary to be extremely careful when measuring the cutting ratio. The measurements of the average temperatures at the tool-chip interface and the calibrations that they imply have also been considered. Recommendations have been made, particularly for calibration of the electromotive thermoelectric force of the two materials in contact. It is suggested not to weld nor braze the two elements, work material-tool material, but to clamp them. One of the advantages of this method is that it maintains a contact pressure between the two elements during the temperature increase. The heating must take place in a neutral atmosphere (cracked ammonia). These precautions make possible good reproducibility of the calibrations because constant contact of the hot joint is assured. 7

III. RESULTS OF TESTS ON XC45 STEEL A. CORRECTIONS OF THE GROSS FORCES MEASURED The first phase of the cooperative studies wa-s mainly concerned with the fundamental problem of the corrections to be made to the gross forces measured by the dynamometer. This would make possible more precise calculations of the forces and energies of the elastic and plastic deformation in chip formation, and of the forces and energies induced by the friction of the chip on the tool. It is known, for example, that at small feeds the disturbing forces induced by the presence of a built-up edge and by end shearing, can represent a very important part of the total cutting force, up to 50% at very low feeds. As reference, Figure 2 represents the distribution of the forces involved in the formation of a chip. Two methods for correcting forces have been considered: 1. the method proposed by P. Albrect (Cincinnati Milling), and; 2. the method of F. Eugene. The first method considers that two disturbing forces, P1 and P2, appear at the tool edge, and a principal force, Q, (Figure 3) appears on the rake face. In orthogonal cutting, the tangential force Fz = P1 + Qcos (TQ-y) and the lateral force Fx = P2 + Qsin (TQ-y). The values of P1 and P2 can be determined from a plot of forces Fz and Fx as a function of feed for a defined cutting speed (Figure 4). On these plots, a line is drawn parallel to the somewhat asymptotic part of each of the two curves. PI and P2 are represented, respectively, by the differences between the drawn lines and the plots of the measured gross forces. Mr. Albrecht finally uses the diagram of the tangential force, Fz, as a function of the lateral force, Fx, that synthesizes the method (Figure 5a). Figure 5b represents results obtained by Cincinnati Milling in machining annealed XC45 steel with a carbide tool; Q is practically proportional to the feed whereas P increases up to a, certain feed and then stays practically constant. By means of the results of the comparative tests, and having taken into account the intense formation of a built-up edge (Figure 5c), Mr. P. Albrecht of the Cincinnati Milling Machine Company laboratory, proposes the following formulas for calculation of Q1 and Q2: cos (Y-7Q) Q1 = Tbs sin ~ cos(0-y+TQ) 8

Forces involved in the cutting I. Forces produced by the shearing. 31. Friction forces. in. Forces produced by the loose edge. BT. Forces produced by the frontal friction. Y. Forces produced by the end shearing. Figure 2. Forces involved in cutting.

0f P. Figure 3. Force analysis proposed by P. Al t Cincinnati Milling Machine Copan.

FZ P 7 ~o~~ FX ~U). ~ ~~P2 Fe ed Figure 4. P. Albrecht method for determining force components P1 and P2 of Fig. 3.

Q FZ K-. I- \~ alncreasing F-x ----- — ~\ — -roadius, r "Increosing feed Figure 5a. Determination of the directions o the forces P and Q. 12

DIRECTION OF l_-TOOL FACE '\ T 120 FRICTION ANGLE ON CHIP-TOOL INTERFACE Kgf \ = IO FZ 20Q 30Q x \ ' =~, _Q=TOOL FACE FORCE Fx x 50- __ P= PLOWING FORCE +6 CHIP 200- P Figure 5b. P-Q force diagram. 13

THRUST FOR V>Tq FORCE vlow high Figure 5c. Three dimensional plot showing dependence of cutting forces on cutting conditions (P. Albrecht).

bs sin (x7Q) Q2 = bs sin 0 cos(-/+'TQ) where T is the shear strength of the machined material. From. this method of the interpretation of the forces, it follows that the coefficient of friction of the chip on the tool, To, is independent of the angle of the tool, whereas with the previous method of using gross forces, this coefficient wa.s observed to increase markedly when the tool rake angle is increased; this is a paradox difficult to accept. The Albrecht method of correction seems to be convenient mainly for cutting conditions compatible with the use of carbide tools. The second method [for correcting gross force measurements], used at the Laboratoire Central de l'Armement, is of interest mainly with respect to cutting conditions typical of high speed steel tools. The cooperative tests made on the XC45 steel, for semiorthogonal cutting rounds, as well a.s for pure orthogonal cutting on tubes, the simplest of cutting conditions, have produced initial. curves which look very characteristic (Figure 6) The diagram of the tangential force, Fz, and of the lateral force, Fx, a.s functions of feed for relatively low cutting speeds, shows for each of the forces considered, a curve segment with the parabolic appearance (a-b), followed by a, straight line segment (b-c); the junction of these two segments corresponds to a critical feed., Ac, and the straight line segment be goes through the origin, When machining a, given material at a. given cutting speed, the value of Ac tends to increase when tool rake angle increases. The parabolic curve sgement, ab, is the consequence of the disturbing forces due likely to the presence of a built-up edge or to frontal friction, The curve segment, bc, is representative of the forces produced by the shearing and rubbingo The critical point, Ac, indicates the cutting conditions for which the disturbing forces produced by the presence of a built-up edge become negligible with respect to the forces which arise from the ela.stic and plastic deformation of the metal during chip formation, and the friction force of the chip on the tool. These forces are proportional to the chip section, The same tests run at increasing speeds show that the critical feed, A,, decreases to finally reach a minimum value at a sufficient cutting speed, For a given tool geometry, the law of regression of Ac as a function of cutting speed, Vc, is of the form: -n Vc Ac = Constant

Annealed steel XC45 =250X=900 Vc=lOm/mn Tool EW 9 ColO Ibsf kgf C C 1540- 700 -0.6 o o / 1320- 600- -. -0.55 1100- 500- X w -0.5 0 c 880 400 — 0 LL 660- 300- FZ/ I 440 200 / 24020 10- //F // o s 0.5 Ac 1 1.3 ~\~\ ~ \~Ipr.020.040.052 FEED Figure 6. Tangentia~l and lateral forces and cutting ratio as a function of feed, showing linear force-feed behavior beyond critical feed (CIRP-OCDE). 16

The critical feed, Ac, and the exponent, n, vary with the chemical composition of the machined metal, its structural state, and the geometry of the tool.. On the other hand, the tests have shown that the critical feed corresponds to a, temperature on the chip-tool interface of about 450~C (8420F), and the presence of this temperature explains the increase of Ac with the tool rake angle; thus it can be postulated that Ac is a function of the feed. the cutting speed, and the temperature: A = f (sVcec) The comparison of critical feeds on the XC45 steel in four different structural states (annealed, overheated, hardened and tempered at 650~C, and hardened and tempered at oscillating temperature) shows that the critical feed., AC representative of the behavior of the built-up edge, is related to the resistance to decohesion, KUFo The forces Fz and Fx and the rate of deformation of the chip, C, are shown in Figure 6 as a, function of feed. The rate of deformation is the ratio of the thickness of the chip to the feed, so It is observed that this rate is maximum (minimum chip thickness) at the critical feed, Ac, and decreases more or less rapidly beyond this feed. It can be presumed that it is the consequence of the fictitious rake angle caused by the built-up edge which has its maximum volume for the critical feed, Ac. On the other hand, it has been observed that the critical feed, Ac, cor-:responds to the minimum value of the tangential. force considered as a function of the cutting speed. More complete observations remain to be made, incorporating the analyses made at Aachen and Cincinnati with different methodso Fragments of the built-up edge sloughed off by the chip are very small at feeds below the critical feed, but increase rapidly at feeds above critical, and even more rapidly at higher cutting speeds. This sloughing off has a, considerable influence on the friction between chip and tool. On the other hand, Aachen has shown an increase in frontal tool. wear as a result of sloughing off of built-up edge. It seems that this mode of removal must take place before the critical feed, Ac, is reached. However, more tests have to be made., The critical feed and its attendant factors have both an analytical and a practical significance. For example, the sloughing off of built-up edge which starts at AC and which effects the friction between chip a.nd tool., explains to a, I.arge extent the spread in behavior of the high speed steel tool.s. It is a. factor which will. have to be considered when testing the wear of such tools o 17

Figure 6 has shown that the variation of Fz and Fx is proportional to the feed at feeds greater than critical, and that curve segments be of blc1 pass through the origin by interpolation. Also, for feeds smaller than Ac, the measured forces are definitely higher than the forces read from the interpolated straight segments ob-obl. It is inferred that the lateral and tangential forces, after correction for the disturbing effects of the built-up edge, will be Fzl and Fxl for a feed sl. However, in the zone of influence of the built-up edge, the factor C is also influenced by the mode of machining (pure orthogonal cutting on a tube versus the semiorthogonal cutting on a solid piece). For the subsequent calculations of the shearing force, Fs, and of the lateral compression force, Fn, the corrected forces can be used only by taking into account a corresponding correction of the value of the contraction coefficient, C; in order to do that, an average value of C obtained at feeds beyond the critical, Ac, can be used but with a degree in uncertainty. In fact, it is more precise, when comparing the mechanical and physical characteristics of the work material to the cutting characteristics, to make these comparisons for feeds equal to or greater than Ac. In making these tests, the cutting is generally done on a solid piece; implicitly, a secondary shearing is produced at the end of the tool. This shearing affects the cutting forces in a. way that cannot be neglected. The comparisons between orthogonal cutting on solid rounds and orthogonal cutting on tubes in the machining of XC45 steel in four structural states has shown that for orthogonal cutting on tubes: 1. The tangential force, Fz, is appreciably reduced, from 5 to 17% according to the structure of the steel, the tool rake angle, and the cutting speed. It has not been possible to determine the respective influences of the three factors. 2. The reduction of tangential force is proportional to the feed. 3. The lateral force, Fx, is affected little if at all. 4. The contraction ratio of the chip (C) is often strongly reduced, which seems to indicate that the behavior of the built-up edge is a, function of the two cutting modes, but as yet it has not been possible to determine a law of connection between cause and effect. It seems useless to correct the cutting forces without taking into account the variations of the factor C with the machining mode. B. PECULIARITIES CONCERNING CUTTING FORCES WITH HIGH SPEED STEEL TOOLS Figure 7 shows variations of the forces Fz and Fx as a function of feed, and indicates a second peculiarity for cutting speeds greater than 15 m/min (49 fpm). Beyond feeds corresponding to Ac, the forces Fz and Fx increase 18

lbsf kgf C 1540- 700 0.6 1320- 600 — 0 32 0-0.55 o1100- 500-1 i / =a 880- 400 i 0 LL i 660 300- 440- 200 // ^220 1 1 ~00/ i / I' A cSI 1 fi,,, s.mm/t FEED FEED... g - ~ \ ~ ipr.020.040.052 Figure 7. Tangential and lateral forces and cutting ratio under conditions (V > 15 m/min) which give nonlinear force-feed behavior beyond critical feed (CIRP-OCDE). 19

proportionately to the feed up to feed, s1. At higher feeds, the increase in forces is not proportional to feedo This phenomena, is more pronounced if the forces are changed into specific volumetric cutting energy, Wc = Fz/sb, and if the values are plotted on logarithmic coordinates. Figure 8 shows the behavior of the annealed XC45 steel, but does not show the preceding phenomenon for cutting speeds of 10 to 20 m/min (33-65 fpm) for tool. rake angle = 20~. It begins at a cutting speed of 40 m/min (130 fpm). For 10 and 20 m/min, each curve is formed by a, sloping segment of a straight line which ends at the critical feed, Ac, and is followed by a horizontal segment of a. straight line indicating that beyond Ac, Wc is proportional to the feed. The slope of the first segment is the consequence of the disturbing forces caused by the presence of a built-up edge, relative values of which decrease with the feed according to an exponential law with respect to the forces which arise from elastic and plastic deformations and the friction of the chip on the tool. For the cutting speed of 40 m/min, the peculiarity observed from the feed s1 (Figure 7), starts by an upturning of the energy curve after a, rather small additional feed. Figure 9 shows the behavior of XC45 steel, hardened and tempered at temperatures oscillating from 7000 to 760~C (1292~-1400~F)o For a cutting speed of 10i m/min, a, first sloping segment ends at the critical feed, Ac; it is followed by a small horizontal segment; beyond the specific energy increases rather abruptly and then decreases. This corresponds to the peculiarity represented in Figure 7 (for a. cutting speed of 40 m/min)o By increasing the cutting speed, one increases the intensity of the phenomenon which has a strong tendency to appear a.s soon a.s the critical feed, peculiar to the cutting speed considered, is reachedo In the field affected by this phenomenon, the calculations of shear stress, T,9 show that this value is smaller than it is outside the field, the shear angle is decreased, and, consequently, chip cross section is appreciably increased. At the present time, there is no explanation for this phenomenon. It seems to be a, thermal phenomenon affecting the mechanical properties of the material2 probably before it passes into the shear plane. If this is true, the problem is relatively complex because the following factors come into play. the thermal energy caused by elastic and plastic deformations of the material along the shear plane; the rate at which heat is taken off by the chip and; the physical properties of the work material (conductivity, specific heat, density). In any case, it seems necessary to know, on the one hand, the temperature of the chip in the shear plane9 - that different researchers have tried to measure or to calcula~te, and, on the other hand, the variation of the mechanical properties of the machined material in terms of the temperature. We know that this va.riation is not uniform for certain properties, 20

Wc kgm/cm3 350 300 250 - 10 Vmn 200 mm/t 0.2 0.3 0.4 0.6 0.8 1 Peed I._I I I I I I ipr.008.012.016.024.032.04 Figure 8. Specific volumetric cutting energy versus feed at various velocities for annealed XC45 steel (CIRP-OCDE). 21

Kgm/cm3 Wc 300 Y 4, V ^Vc=25 /r 2 50 i \ =VI20 m/mn V ^ (= 15 m/m n Vc I m/mn 200 0.2 1 1 mm/t 0.2 0.3 0)6.008.012.024 ipr. Figure 9. Specific volumetric cutting energy versus feed at various velocities for hardened and tempered (700-760~C) XC45 steel (CIRP-OCDE). 22

Annealed steel XC45 Tool EW 9 ColO '=25s X=90~ X Semi-orthogonal cutting on rounds.. Pure orthogonal cutting on tube Ibsf kgf 'C - 1540- 700o0.6 / \. / 1320- 600 — \, 0.5 X 1 1 0 0 - 5 0 0- 1 ^ ^ ^ ^ ^ - - - ^ Z WL 880- 400-. 660- 300- A 440- 200 - 220- 100 | 0 0.5 1.3 ~: 80- FI ipr.020.040.052 FEED Figure 10. Comparison of cutting forces and cutting ratios under identical cutting conditions for semiorthogonal and pure orthogonal cuts (CIRP-OCDE). 23

The Laboratoire Central. de l'Armement has been interested in the angle of maximum deformation of the chip, 4e It seems that the theoretical maximum deformation obtained by a, geometrical type analysis does not always correspond to the maximum deformation observed in the type of chip which gives a builtup edge. Since this characteristic is so important in studies of plastic deformation of the chip, it seems useful to observe and measure it. Tests have led this same laboratory to believe that the shearing work, Ws, proceeding from the present classical theories, can be decomposed into work of elastic deformation, Wde, work of plastic deformation, Wdp, and the frictional work. Tests run on XC45 steel in four structural states at different cutting speeds, tool rake angles, and feeds (66 conditions) have shown a, satisfactory correlation between Ws and Wde + Wdp. This study will be foll.owed on the Ni-Cr and Cr-Mo steels by the participants of the work group [Phase II]. If this method is confirmed and completed, it will. have the advantage of making possible the comparison of what happens in cutting on the basis of measurable mechanical characteristics of the work material under consideration, independently of the cutting phenomenon. However, the problems due to friction will not be resolved. Analyses of plastic deformations made at the Laboratoire Central. de 1'Armament independently of elastic deformations on the XC45 steel show that the plasticity would be relatively little affected by the structural state in the four cases considered. IV. CONCLUSIONS For future fundamental analyses and correlation studies between the mechanical, and physical. properties of the machined material and the cutting characteristics, and. after having taken into account the observations made during the prelimina.ry study of the XC45 steel, and also the economical a.nd practical factors, it is advised~ A. For the tests at cutting speeds compatible with the use of high speed cutting tools. determine the critical feed, Ace according to the nature and the structure of the work material, the cutting speeds, and the tool rake angles for cutting a. solid bar (semiorthogonal cutting); and 2o use a, feed equal to or greater than Ac (previously determined) for turning on a tube (pure orthogonal cutting), to note all the fa.ctors, C and ec9 as well. as the angle of maximum deformation,, as observed on the longitudinal median pla.ne of the chip. 24

B. For tests at cutting speeds compatible with the use of carbide tools 1. run tests on a solid bar for feed greater than 0.2 mm/rev (0.008 ipr) and speeds greater than 50 m/min, the critical feed, Ac, being very small (< 0.2 mm/rev, built-up edge nonexistent). It will, however, be necessary to run a limited number of tests on a, tube to determine the corrections concerning the shearing on the end of the tool. It will be essential to determine the mechanical characteristics of the steels as a. function of the temperature for each structural state. 25

PART II WEAR ON AMERICAN AND EUROPEAN CARBIDE TOOLS IN MACHINING XC45 STEEL

This chapter covers two sections relative to carbide tool wear: (1) European carbides and influence of factors other than tool or work material properties, and (2) preliminary tests with American carbides. The two sections relate particularly to results from tests conducted at The University of Michigan. I. TESTS RESULTS WITH EUROPEAN CARBIDES Most of the results with European carbides, P10 and P30, were reported in Part I of Interim Report Noo 3. However, the tool wear behavior observed at The University of Michiga.n was unique among the results from seven other participating laboratories and merits additional mention. The results are compared in Figure 11. The dashed lines in Figure 11 represent the range of scatter or dispersion of flank wear and crater ratio measurements, for given cutting conditions, from European laboratories at Aachen, Delft, Liege, Munich, Zurich, LoC.Ao Paris, and T.oH Goteborgo The individual results were coordinated by Dr. H, Opitz of Aachen in a report dated August 6, 1964. Ranges in measurements of 3:1 or more are noted, but. with one exception (flank wear, Figure lie), no abnormal changes in wear rates occur with time. However, The University of Michigan results do show some contrasts which were repeatable. A. FLANK WEAR In normal test sequences, the workpiece is chucked at one end and supported by a. heavy duty live center at the other in keeping with recommended procedures. Under these conditions, flank wear correlates very well with European results at short cutting times, but increases very rapidly in latter stages, to cause early termination of the tests. A change to a carbide tipped dead center in the tailstock gave no improvement in flank wear behavior, However, when the work was turned between centers with a. live center in the tailstack flank wear values fell within the scatter band of European results, All other factors were held constant when work holding methods were altered. The variations in flank wear behavior point to some sort of instability or lack of rigidity in the system. They have important practical significance, for they show how widely results ca.n vary even though general cutting conditions remain the same. There must, of course, be a valid explanation. Subsequent inquiries have revealed that the lathe used in these tests was the only one in participating laboratories that was resting on vibration isolators and, therefore' not lagged to the floor. It is also housed in a, laboratory on a 28

CUTTING TIMfE, min. 2 4 6 8 l1 20 40 60 -- I I I II I I I I.......i I i. I i"r' ' I~~~_ Il~~~~~ ~Work Material: XC45 in m m Tool Material: Carbide 10 Size of Cut: 3X0.25mm -0.12X0.01 in2 Test No. 6.2; V=125 m/in.0 0.0160. -410 fpm - -FANK -VEAR Tool Geometry: FLANK -WEAR '9 ^ 6 6 0 70 90 0.Smm -9. ~ 0.032in o.oo0.003.20 / 20-.2 -,Rangefof |) /' /. 0.0028.06 Chuck-Live// ^ ^^ $~Center _____________ Z 2 4 6 8 lo 20 carbide grades. Dashed lines represent range of scatter of results from European lab University of Michigan results are indicated. 0.0008,.02. /-.02 '9 Figure 11. Plots of average flank wear and crater ratio versus cutting time for European PlO and P0O University of Michig rpean Res ul tsed. University of Michigan results are indicated.

CUTTING TITE, min. 2 4 6 8 10 20 _ I I~'i' ' I~1~'l'\~'1I J ' I........ 1 i 1' 1111 ~ 1~ I ~ Work rlterial: XC 5 inL I I Tool M erial: Ca ide P30 -6o60~~~~~~ F | OSize of Cut 3 0.25 mm 0) 01. x 0.01 in___________________________ Test No, 6.2; V= SO m/min= 52 fpm Tool Geetry.0160 -.40 FLANK YEAR + 6.40 + 6 0 70 90 0.8 mm -.0024 0.032 in 7 7 1 ~/ / 7/ ~ I/ m // ^ o.oolo -0i ^ 0.00214.06 /*,.06 ^ 0.0016.Oh -/ 7 U of M CRATER RATIO 0.0008 - 02 -0 chuck-live center - 02 - chuck-dead center I......I...... I I jj_ I I I I 1 2 4 6 8 10 20 CUTTING TIME, min. Figure 11-Continued

in mm - Vork kMaterial: XC 4 Tool Material: Carbi e P10 0.02140-.60- Size of Cut: 3 x C.2 mm2 0.12 0.01 in _____________________ Test No. 14.2; V= 12 m/min= 141 fpm 0.0160 -.40 Tool Geometry: oC _l,-2^ ^.-^-. ^ - Raige 6 6 0 70 0 0.8 mm 0.032 n 0.0080.20 0.00o40.10 ~ i18 74E ~ ~ 0.002i4.06 w o.6 7 */ / CRATER RATIO 101, ~ ~ 0 0.0016.04 - e / of (j) chu k-live center () ^,^'* A ** ^ ^ bet een centers, live oooo8.02 / /0 _/ @0 /~~~~/ 2 4 6 810 20 40 6080100 200 CUTTING TILE, min. Figure 11-Continued

CUTTING TIt;E, min. 2 4 6 8 10 20 40 60 80 100 200 _ I I r I I n I I I I m mI I I I Work Material XC45 Tool Material ~ Carbide P10 in mm Size of Cut: 3X0.25mm2 =0.12X0.0 in2 rest NO. 14.; 0.0160.4o V=160 1/min Range of European =525 ipm Results Tool Geometry 6 6070 90 0.8mm 0.032in 0.0080.20- /., -,20 UofM Chuck Live Center *, moooo.10 7 \pq~~t 100 A'J A // / ~ 0.0016 04 /A O./ / ~~~0 / / 0.0008 -.02 FLANK ' / TER -ATIO b^ <^^^& ^ / / - /_ 3 ^/ / A/ 2 T 6 8 10 20 O 60 80 CUTTING TIME, min. Figure 11-Continued

CUTTING TIME, min. 2 4 6 8 o10 20 4h Work Mater al: XC 45 Tool Iater al: Carbid PO10 ~~~~~in I~mm~~ ~SizeofCu 3 x 0.~ mm2 in^~~~~~~~ "~~~~~~~ ^~ o 0.12 x 0.01 in2 Tost No, 31T — - 3~-V- 20 /min — 6& 6 ~pm ~~~~0.0160.-40~~ E Tool Geome ry: 0.0160 )-.h0~ Q / O og P FIANK WVEAR 6 6 0 70 9) 0.8mm 0.032 in 0,0080 2- 0 /~ -- 0 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^~~ f I /~ ^^// -4.7~~~~~~~~~ / /.7~~~~a-4 ^ / / P 00040.10 ~ // pq 1-100.,.7 ^ > / ~~~~ / -^ / S I 0.0024.06 7 (.) 0 /.06 010016 - - - " '-~ 0/ CRAT RATIO ^ 0.0016.0)-.O+ / ^ ~~~~~~~~~~~~~~~~~~~~~U of M~ 0*0008 ~.02 0 0.0008- 002^ ^ ^^ Ochuc -live center.0 7/ t - chuc -dead center 7^~~~ *betw en centers, live 2 4 6 8 10 20 hO CUTTING TIME, min. Figure Il-Concluded

first floor level. In contrast, European lathes were not only lagged solidly, but most of them were set at ground level on one meter thick concrete bases. B. CRATER WEAR Crater ratios (the depth of the deepest part of the crater, KT, over the distance from the deepest part of the crater to the existing cutting edge, KM) were not as sensitive to the factors which influenced flank wear, and University results, for the most part, correlated very well with the results from other laboratories. However, Figure llb shows that the ratios for the P30 carbide at a velocity of 525 fpm were substantially lower. That this behavior is other than coincidental is substantiated by the results shown in Figure 12. The curves represent crater profiles along the line AA, as identified in Figure 139 and compare the size and shape of the crater resulting from identical tests at The University of Michigan and Aachen laboratories~ The Aachen results were taken from the previously mentioned report by Dr. Opitz. Unfortunately, this was the only common cutting condition for which representative crater information was available, and it is not known just how typical these results are. The University results, however, were repeatable. The fact that there are differences in behavior, makes it imperative that answers be resolved if there is to be complete faith in interchangeability of information. The various factors involved should and will be investigated to greater depth as the OECD/CIRP cooperative program continueso II. PRELIMINARY TESTS WITH AMERICAN CARBIDES Complete investigations with American carbide tools are scheduled for later phases of the tool wear program. However, a few grades have been used in an introductory series to observe patterns of tool wear behavior, and to provide some -tie-in" with the wealth of European information already available for the XC45 work material. Other than the carbides, the methods and techniques of investigation were those of the main cooperative wear program. A. CUTTING TOOLS The cutting tools for this investigation were provided by Kennametal, Inc. for both positive and negative rake angles in all standard carbide grades. However, only the grades listed below were on hand at the time of the initial test series Conversion to equivalent grades among various manufacturers is always dangerous, but Table A-III in Interim Report No. I lists the PlO and P03 European carbides a.s most nearly equivalent in composition to Kennametal grades KSH and K2S, respectively. All tools were of the same size and shape, and the same tool holders were used for both foreign and domestic carbides 34

Univ. of Mich. O A 0F7 - F 7 AX 0 A__ /________ C /.702.0-4 ~, i.002-.08 results at Aachen Aachnd The University of ihin for uttin onditions \ /4 LU /.004 CARBILE P30 0.02.04.06.08 DISTANCE FROM ORIGINAL CUTTING EDGE, in Figure 12. Crater profiles along line AA (identified in Fig. 13) from results at Aachen and The University of Michigan for cutting conditions listed in Fig. llb. 35

.150" Line of Tukon Indentations fnr Reference.002-.003".....I ', —. --.o015" 1 l ~:.. ~ ^ - ^ ~ <>l I. '- ~~^."' < >. < A A; ~ ' _ _ ^ / -Line of Traces Crater <~ >\ _ _.015" Apart.015" TOOL _ Figure 13. Top view of tool face showing the paths of the traces made on a. Proficorder to provide information for mapping crater profiles. Original traces through Tukon indentations before cutting maintained original distance to cutting edge. Single traces along line AA were used to plot crater profile normal to the cutting edge, as in Fig. 21. 36

Rake Kennametal Carbide Grade Angle K2S K5H K6 K21 K68 Negative X X X X Positive X X B. CUTTING CONDITIONS AND TEST PROCEDURES For comparative purposes, cutting conditions were held constant for all. carbide grades and for both negative and positive rake angles. The conditions are indicated in Table I, and they are the same as those listed in Figures lib and Ild for the European carbides. Flank wear, crater ratio, and particularly crater profile served as a basis for comparison. Crater profiles were determined from multiple traces in the tool face on a micrometrical "Proficorder" along the paths illustrated in Figure 13. Points at several. levels of depth were located on each trace and plotted to give the crater profiles in Figures 14 through 30. The Tukon hardness indentations shown in Figure 13, and original traces along the paths before cutting, served as references for the crater measurements. More direct comparisons among various carbides were made by plotting the crater depth variations along the line.AA as identified in Figure 13. This is the same location and path used to determine crater ratio. Flank wear and crater ratio are listed in Table I for all. tools, including the European grades. Cutting times a.re all relatively short in this exploratory investigation, with only three tools carried as long as 8 min. However, there are meaningful differences in behavior. Crater widths vary by almost 4:1, and crater depths vary by more than 50:0. among the grades at 2 min cutting times. Crater width is as much a.s 8 times the feed rate. These data. should become more meaningful a.s data for other carbide grades are added. Co CARBIDES WITH NEGATIVE RAKE The crater profiles shown in Figures 14 through 20, and the results listed in Table I verify clearly that there are two distinct classes of carbides among the four grades tested. The K6 and K68 grades are of a similar class, and both show wide, relatively deep craters and high flank wear at the end of two minutes cutting time. In contrast, the K2S and K21 grades have narrow, shallow craters and relatively low flank wear. The relative depths of the craters are shown more convincingly in Figure 21. 37

TABLE I. RESULTS OF COMPARATIVE WEAR TESTS Work Material: XC45 Steel, Heat No. 0656 Size of Cut: 3 x 0.25 mm2 0.12 x 0.010 in.2 Cutting Velocity: 160 m/min = 525 fpm Flank Wear, VB Crater Ratio,KT/KM Tool Carbtide 2~ Q ~ ~ ~g~8 Tool Geometry No, Grade a y \ X m r min min min min min min Al K2S.0033".0048".0072".025.046 082 6 -6 -6 70 90 0 0.032" A271 K212.0028".0032".015.022 A91 K6.0080" o096 A151 K68 00099".122 0.8mm A658 K21.0027".023 6 6 0 70 90 A558 K5H.0013".0075 589 PlO.001".001 8".0081.8 013 610 P30.0022".0037".0044".019 034.068 38

CRATER DEPTH " V~- 0.0 u in. Oum Ii\ I* - 1,600 in. 40) m *- 3,200 /4in. 80r m I- 4,800 a 0 in. 120U[m Cutting Time: 2 min. Work Material: XC 45 (0656) - -t t-? -__ __ - __ __ Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in2 ___ - _ __ __ _ _ - ______ -Cutting Velocity: 160 m/min = 525 fpm. __ ___7___ ~Tool Material: K68 Carbide 15".005" TOOL GEOMETRY 6 6 6 0 9 _____ _____ ______....),0.0321 SCALE 5081 Figure 14. Mapping of crater on face of K68 carbide grade at cutting time of 2 min with negative rake and cutting conditions indicated. 39

CRATER DEPTH ~ - 0.0,uin. OGim A- 800 /sin. 20Am P -~X TT1 rrr T 0 Tn - 1,600 A.in. 407m B]- 2,400 ain. 6o0j4.m A- 3,1200 Ain. 80/m ~ -~Cutting Time: 2 min. I \ YEl LE / Work Material: XC h5 (0656) Size of Cut: 3 x 0.25 mm 2 0.12 x 0.01 in Cutting Velocity: 160 m/min. 525 fpm. 0 5 " Tool Material: K6Carbide.00 5 TOOL GEOMETRY -. e r8mm 6 6 6 670 90.32i SCALE 50 1 Figure 15. Mapping of crater on face of K6 carbide grade under same conditions listed in Fig. 14. 40

/CRATER DEPTH?- 0.0,in. O4 m - 100 in. 2.5 Tm _ -Ii:_~~ ~ ~ ~ - r 200 Jin. 5um Cutting Time: 2 min. ~__- ^ - ~ Z ~ ~ __ ---__ _ ~Work Material: XC 45 (0656) Size of Cut: 3 x 0.25 mm2 ~- ~ -,l~ --- —-~~~~~, -0.12 x 0.01 in2 Cutting Velocity: 160 m/min. n -___<^~,-2^~~ ~~~~~~~ - -~525 fpm. Tool Material: K21 Carbide TOOL GEOMETRY o( \ \ K C r SCALE 508 1 Figure 16. Mapping of crater on face of K21 carbide grade under same conditions listed in Fig. 14. 4h

CRATER DEPTH - 0.0,A4in. 0/m [,I~,;02; t t ] Ei - 100 1in. 2.5 m - - - ~ ~- ~ ~~~- - - A- 300 j0in. 7.5,A4m X- 400, in. 10, m Cutting Time: 4 min. Work Material: XC 45 (0656) I- A ~ - - — ~~ t Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in2 ~~I- I - - -~~ ~ ~~ t ~t Cutting Velocity: 160 m/min = 525 fpm. ___a- __ -__ _ Tool Material: K21 Carbide - ~ 4,, TOOL GEOMETRY r.8mm 6 -6 -6 70 90.032 SCALE 50 1 Figure 17. Tool of Fig. 16 with crater at end of 4 min cutting time. 42

CRATER DEPTH o - 0.0 }4in. O0m A- 200 4in. 5A4m ~ - ~ -~ X- 400 /M in. 10m ) - 600,4in. 15 4m ~~ ~^ -~ ~-~- ~~~~~~~~~ Cutting Time: 2 min. Work Material: XC 45 (0656) Size of Cut: 3 x 0.25 m2 0.1p x. 0.01 in2 Cutting'Velocity: 160 m/min 525 fpm..~^ ~-~ ~ ~ ~~~ ~ ~ ---. -.,. 17-.Tool Material: K2S:Carbiae TOOL GEOMETRY =E E A ( r SCALE 50 1 Figure 18. Mapping of crater on face of K2S carbide grade under same conditions listed in Fig. 14. EN~~~ll~~tl? U ^

CRATER DEPTH *- 0.0 Ain. OAm A- 200 t4 in. 5/m 0- 400 #in. 10,P m \ - 600,min. 15pm A - 800 A4in. 20lm Cutting Time: 4 min. Work Material: XC 45 (0656) Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in Cutting Velocity: 160 m/min =.525 fpm. r016 Tool Material: K2S Carbide TOOL GEOMETRY 6 -6 -6 70 90.8mm 32in SCALE 508 1 Figure 19. Tool of Fig. 18 with crater at end of 4 min cutting time. 44

l RATER DEPTH I - 0.0,in. O. m X- 400 /in. 10,m Cutting Time: 8 min.. few ~~p H * _ 1 4 {-~ - Work Material: XC 45 (0656).\.. A, //- 8 / Size of Cut 3 x 0.25 mm2 0.12 x 001 in I, / ~ ~ -1,600LCutIting Velocity: 160 m/in = 525 fpm. / 4 ~^ Tool Material: K2S Carbide TOOL GEOMETRY (X | Y E r 6 - 6 - 6 70 90.8mm 032in SCALE 50s1 Figure 20. Tool of Fig. 18 with crater at end of 8 min cutting time....

K21 K2S.002 \ K6. 0O.004 \ / \,-~ K68 Negative Rake *. 2 min..006... 0.020.040.060.080 DISTANCE FROM ORIGINAL CUTTING EDGE- i Figure 21. Crater profiles along line AA for negative rake tools in Figs. 14, 15, 16 and 18; cutting time, 2 minutes. 2 min. 0 ^Q o4^ ^~ 4 min..00 8 min. Negative Rake.004 I.. 0.020.040.060.080 DISTANCE FROM ORIGINAL CUTTING EDGE- in Figure 22. Crater profiles along line AA for 2, 4, and 8 minute cutting times on K2S carbide. Results from Figs. 18, 19 and 20. 46

The progress of wear with time may be observed for the K21 and K2S grades in Figures 16 and 17, and Figures 18, 19, and 20, respectively. Figure 22 compares the crater profiles at 2-, 4-, and 8-min intervals for the K2S carbide along the path, AA. These show a typical effect in that the deepest part of the crater moves away from the cutting edge as the crater increases in size. The differences between the two classes of carbides are quite evident. However, cutting times are short, and any attempt to evaluate the performance of carbides in any one class would be mere speculation, even though one grade may have more wear than another. However, the crater profiles reveal some differences between them which may or may not be significant in time. For example, the K6 carbide has a crater only 2/3 as deep as the K68 grade, but it has a. broader band of wear at the nose and gives evidence of some grooving at the depth-of-cut line, where the crater wear is very abrupt. The K21 grade has the least wear of the four carbides, but there is a potential source of trouble, as Figures 16 and 17 show a. groove or rut at the nose which has a tendency to be as deep as the crater itself. A groove also exists on the K2S carbide, but the groove is shallower than the crater. In either case, the wear is still very small D. CARBIDES WITH POSITIVE RAKE Flank wear and crater ratio results with positive rake angles are listed in Table I, and the crater profiles are shown in Figures 23 through 28. Crater profiles along line AA are compared in Figure 29o The P10 and K5H carbides show the least wear, while the K21 grade shows the most. Wear magnitudes are all quite small, however. Even though cutting time is short and wear is in its early stages, there are two observations which relate to wear behavior among the carbides: (1) variations in crater shape, and (2) size and location of crater and its relationship to crater ratio. The first of these is substantiated by observations made during the tool life tests on European carbides, where craters were observed at regular intervals of time for as long as two hours of cutting. Almost without exception, the P10 and P30 carbides developed the two distinct crater shapes illustrated in Figure 30 (a.) and (b), respectively, and indicative of the crater profiles in Figures 25 through 28. The crater on the P30 grade was very uniform and parallel to the cutting edge along its full length. At advanced stages of wear, however, the crater approached the shape of Figure 30 (c). All of the American carbides tested to date have shown craters typical of the sketch in (c) to at least some degree. The second observation concerns the relationship between the craters and the flank wear and crater ratio results on carbides P10 and K5H. The results in Table I show virtually identical values for flank wear and crater ratio on the two materials. However, Figures 24, 25, and 29 show a. difference in the 47

_P - - \ - - | - - ||.-CRATER DEPTH - 0.0 in. 0 /qm - 100/Pin. 2.$,m __ c S ___ ~__ X- 400in. 10IOm rI,r/ ' 7 *- 500o in. 12. 1n A A. I I 71 I i ]Cutting Time: 2 min. Work Material: XC45(0656) ~-~S - |^ -~- -~ ~ ~~ Size of Cut: 3x0.25 mmp 0.12x0.01in2 - - ~-~ ^-<)~~~~~~~~~- -Cutting Velocity:,/\t~~~~ ( | A160 m/min = 525 fpm ~~^ 1^ X n TdTool Material: I- - ~~~~~~~-~-~-~~~ K21 Carbide.005" TOOL GEOMETRY oc K r 0.. 8;m 6 6 o 70 90 032i SCALE 50 1 Figure 23. Mapping of crater on face of K21 carbide grade at cutting time of 2 min with positive rake and cutting conditions indicated. 48

(_ J[^___________ \ 1 CRATER DEPTH, * 00/in. O ^_.- 50 / in. 1.2am - - - -1 ____ - mEl- lOOin. 2.5m l ~- 150A/in. 3.8Vm A __ ~_ ~ ~- ~. A Cutting Time: 2 min.._....- - - +- -- +- +_ _ Work Material: XC4 (0656) 2 l:^ ~~~~~~Size of Cut: 3x0.25 mm 2 I... - L L _~1_L-~L~ ____0.12x0.01 in - ( Cutting Velocity: 160 m/min - 525 fpm I~\~ 11; Sr X X - TTool Material: IL __T. J T~. K5H Carbide.015",005'o TOOL GEOMETRY 6 6 0 70 190 321i SCALE 50 1 Figure 24. Mapping of crater on face of K5H carbide grade under same conditions listed in Fig. 23. 49

PCRATER DEPTH 0- 0.O/in.. 0..m 1- 50 /,in. 1.2/Am - lo00in. 2.5Am I 1 I I I 1A Al *i 2 Cutting Time: 2 mn. t.-.. ~ -~ — t-_ ~ Work Material: xc45 (0656) /E-l- iyi ~~- ~~~__ --- —. ~~~ Size of Cut:,*.~ 3 x 0.25 mm2 -.~~~I-... -~ —~~ ~-~- ~__0.12 x 0.01 in2 Cutting Velocity* r -t - - - ~- - r-~ - - -r 160 m/mir =.525 tpm i l^~~!_~~ _~ Tool Material: L~ 1 V L P10 Carbide.005" TOOL GEOMETRY 0.8mm 6 6 0o 70 90.032i SCALE 508 1 Figure 25. Mapping of crater on face of European P10 carbide grade under same conditions listed in Fig. 23. 5o

CRATER DEPTH o0- O.O 'in. OIm m 5~ 0 /4in. 1.2kAm r. 1 ___ _ __ _ ____ __ _Sm- 5lOO1 in. 2. m l- 2004/in. $vm A.....i A Cutting Time 4L min. -r^"L~~~ ~~ - Work Material: x045 (0o66) Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in2 Cutting,Velcity:. 160 m/min = 5e25 fpm Tool Materiall PIO Carbide!.005" TOOL GEOMETRY I_..i...r 0:8mm 6 6 0_ 70 90.032L1 SCALE 508'1 Figure 26. Tool of Fig. 25 with crater at end of 4 min cutting time. 51

j -\~-.-/f l/^ ^ CRATER DEPTH O- O. O/in. O m - 200/i(in. 5A/m X- L400/in. 10 'm ~~ - } -~ - rr- 0oo,'in. l2.^$ Cutting Time 4 min. -- ^ — ~~~ t~ T ---- — ~~ Work Material: xc45 (0656) "1- T;^ TII Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in2 I I IF_- -- -I - ~ Cutting Velocity: xj^^ S T T^~~ 160 m/min = 525 fpm ~~ --- -- t- ~ ~ — X t t-~~~~~~ Tool Materiial: ~ 0.'1 P30 Carbide.005" TOOL GEOMETRY CTcu (~8.m 6 6 0 70 90 32i SCALE 50)'1 Figure 27. Mapping of crater on face of European P30 carbide grade at cutting time of 4 min with cutting conditions same as those listed in Fig. 23. 52

/ y -- ^^^~~~~ CRATER DEPTH ~- 0.0in. 0/om 200 /in. 5,m ~"". l "" _ _ _ X:- 400 0 Iin. 10Am 0- 1000 in.. 253/m ](, iiP a F Tw r r Cutting Time,: 8min. -1 -~~- ~~ ~~~~~~-~~joo Work Material: XC45(0656) Size of Cut: 3 x 0C25 mm2 - _ _0.12 x 0.01 in Cutting Velocity: - 160 mi/min = '525 fpm Tool M'ater - al: ' QX1 5 P30 earbidd __.... _005" TOOL GEOMETRY.... I 1........ [ r 0 70 90.2 SCALE 50S1 Figure 28. Tool of Fig. 27 with crater at end of 8 min cutting time. 51

K5H C K21 a.0~002 _~ ~Positive Rakes ~.002 2 min. 0.020.040.060 DISTANCE FROM ORIGINAL CUTTING EDGE- in Figure 29. Crater profiles along line AA from Figs. 23 through 25 for positive rake carbides. * \I. (a) (b) (c) Figure 30. Representative crater wear patterns found in wear studies of various carbides; (a) typical of P1O, (b) typical of P30, (c) typical of American grades to date. 54

depth and location of the crater. The actual maximum crater depths along line AA were 190 [ in. and 120 p in. for the K5H and PlO, respectively, but the distances from the maximum depth locations to the existing cutting edges also differed by the same proportion. Therefore, the crater ratios were still similar. Whether these relationships between the crater and crater ratio are typical or merely coincidental is not known at this time because of the limited experience in the use of crater ratio as a criterion of tool life. In the previously cited example, illustrated in Figure 12, the smaller craters were accompanied by lower crater ratios. However, these were related to the same cutting tool material. If the same crater ratio can represent different crater conditions, particularly when, say different carbides are compared, what does it imply? The answer to this question is undoubtedly of more importance in relating wear phenomena than in practical application to determination of tool life. The significance of these measurements and observations is covered briefly in a closing section. E. NEGATIVE RAKE VS. POSITIVE RAKE ANGLES Only one carbide, K21, was common to both negative and positive rake angle tools. As a result, the information is not very conclusive. However, the positive rake tool showed a wider and deeper crater, as indicated in Figure 31, and more edge wear around the nose. There was no difference in flank wear. C ~I ~~/- Neg. Rake Pos. Rake K21,002~ 2 min. C lI. | I I 0.020.040.060 DISTANCE FROM ORIGINAL CUTTING EDGE-in Figure 31. Comparison of crater profiles along line AA for negative and positive rake tools. 55

F. SIGNIFICANCE OF CRATER WEAR MEASUREMENTS Tracing and plotting of crater profiles is a. tedious and time consuming task. Therefore, if the time is to be well spent, the results themselves must serve a useful purpose. The most logical and the most important purpose is to contribute information which may be used to develop a general relationship between wear behavior and various metal cutting parameters. Tool wear is an extremely complex phenomena. It is complex because it is related to a number of simultaneous causes which a.re themselves affected by cutting conditions and which, in turn, influence wear rates. The investigation of cutting temperatures, particularly temperature distributions at the tool-chip interface, will play a prominent role in the study of wear behavior. This will lead to improved efficiencies, not only in cutting processes, but in tool materials as metallurgists learn more and more about the kind of properties that are required. If cutting temperatures influence the rate of wear, it follows that temperature distributions will influence the pattern of wear. Therefore, the shape, size, and depth variations of the crater, and the location of critical depth regions with respect to cutting conditions, provide useful information for correlated studies. 56

PART III WEAR ON AMERICAN AND EUROPEAN HIGH SPEED STEEL TOOLS IN MACHINING XC45 STEEL

I. EUROPEAN HIGH SPEED STEEL TOOLS Of the many phases included in the OECD/CIRP international cooperative program, investigations of tool wear and tool life with European high speed steel cutting tools have proved to be the least successful. Large and inconsistent variations in results have been the rule rather than the exception, not only among participating laboratories, but from test to test in individual laboratories. Consequently, only limited progress has been made. Most of the blame for the inconsistent results has fallen upon the high speed steel selected for these investigations. Some remedial measures have been taken, but results are still not acceptable. A. TEST PROCEDURE Test procedures are identical to those used in the carbide tests. Total failure often served as the criterion for tool life, but flank wear values of 0.2 and 0.4 mm (.008 in.-.016 in.) and crater ratios of 0.1 and 0.2 were used when possible. B. TOOL MATERIAL The tool material selected for this program is a. cobalt' grade EW9ColO (German designation) high speed steel with the chemical analysis shown in Table II, and the heat treatment indicated in Table III. The finished tools were 23.5 mm (0.94 in.) square by 145 mm (5.8 in.) long overall, with a H.S.S. section 35 mm (1.4 in.) long butt welded to a regular steel shank. The JessopSaville works in Sheffield, England made the steel, and the Rohn works in Sassenheim, Netherlands made the tools and carried out the heat treatment. Professor Pekelharing of the Technological University of Delft wags responsible for carrying out the coordinated effort. The information in this section is taken from his report "The Manufacture and Testing of Butt-Welded H.S.S. Tools for CIRP Group "C," July, 1963. A great deal of effort went into the production of the tools. Ingots, billets, and bars were all marked and related. Inclusions, grain size, and carbide distribution were observed, and only those bars which fulfilled all of the requirements were selected for final processing. However, variations were still apparent, for the tools gave very erratic results. Variations of 25:1 were encountered in tool life tests at given cutting conditions.

TABLE II. CHEMICAL COMPOSITION OF EUROPEAN HIGH SPEED STEEL Chemical Composition, % GRADE (German) C Mn Si S P Ni Cr W V Co Mo EW9 ColO 1.3. 0.0 0..009 0.014 0.16 4,54 9.65 3.58 10.10 4.00 TABLE III. HEAT TREATING CYCLES FOR EUROPEAN H.S.S. TOOLS Treatment Temperature and Time Preheat Up to 450~C(842~F) for 1 hr 1st Salt Bath 850-o900C(15620-16520F) for 4 min 2nd Salt Bath 1200~C(2192~F) for 4 min Salt Quench 550~C(1022~F) for 4 min and air cool Multiple Temper 5900C(10940F) Tempering Time, hr 1 + 1 2 2 Hardness, Rc 64.5 - 65 59

After the large dispersions were reported, the "Metal Cutting" committee of CIRP decided to make 20 solid tools to eliminate any possible effects of welding, and to modify heat treatment slightly to improve carbide distribution for more homogeneous structures. One of these changes was to raise the austenitizing temperature to 1220~C (22280F). Information is not available on other changes made, but results were not improved appreciably. C. TEST RESULTS Figures 32 and 33 represent sample results of typical behavior encountered in the high speed steel investigations. These were compiled at the Aachen and Liege laboratories from tests on the 20 revised tools. The tool identification numbers 11Al through 11A20 are code numbers to relate the tool to the ingot and billet from which it came: 11 = Ingot No. 11 A = Billet No. 1 1-20 = position of tool along bar, starting at the bottom Figure 32 shows a variation in tool life among the tools from 12.5 min to more than 80 min at which point four tools had not yet failed. There is no prominent correlation evident between tool life and Vickers hardness. Figure 33 shows little if any correlation between tool life and flank wear or crater ratio. The dashed lines represent the range of values among all tools. Other results not included, show that relative tool lives are unpredictable among the tools, as complete reversals in position can occur. Four of the tools, lllA14, 15, 16 and 20 were eventually sent to The University of Michigan. The results of tool life tests based upon complete failure are shown in Figure 34. There is much less dispersion than what these same tools show in Figure 32, and what is more the relative results were better, with tool 1A16 giving consistently the best performance. One factor which must play at least some part in the inconsistent behavior of these tools is the tool shape, itself, and in turn, its effect upon chip flow. The chip wa.s continuous from beginning to end of cut, tended to curl around itself and the tool, and required constant attendance to keep the tool free. In a test with American H.S.S. tools, in which the same tool shape was retained, the chip wa.s allowed to take its own course as it wound around the tool, and the tool failed in less than a minute. When the test was repeated and the chip carried off continuously with care, the tool life was 5.5 and 6.5 min in two attempts. 60

Tool Material: EW9 ColO Work Material: CK 53 I Size of Cut: 3 x 0.2 mm 2 0.12 x 0.008 in Cutting Velocity: 44m/min = 144 fpm Tool Geometry: C4 6 300 90 87 0.5mm E 0.020 E 29 0 0 co 0< io) Q*7 r^Mir r- rH rH r j=~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~NO 9 cf-rK rH H H H >9 HH rH rH lH H H1 ^ ~~~~ ~ ~~~~~ H~i HH i^ HH rH H Z T9H 4 C)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^940- ~~~~~~T H OL~~~~~~~~O W I H 92 10 20 30 40 50 60 70 80 TOOL LIFE, min Figure 32. Range of tool life among European EW9ColO H.S.S. tools prepared for coopera.tive study.

aa:n-IT'J T00o JO aw-mI q. SanTeA aq'eDopu sasso o 'slTooq — I'6 uo q.U9anamsea9T Jo saSu'sx qua9saLctdax sauTI paqs(C[ 'T JO SToo0. OJ U.s-oq. oSA o-.q.'x * a:q-.Ba;: pus a.eaB 9 U',' '61" aa nBTL u!w -1 3f11 9NUlLn) 001 08 09 0* O 01 8 ' t.Z0'0 OO / ), ouIVM ^3i v~o ^^^ -90'0, 80'0 ^ 0+ 0 + +/ sI'0o 3r.g > '11 + -~Z i80 0 i +$ / -0-o',Zoo'X 7 - o~' noto' / /^ - or 0o,00'

TOOL MATERIAL: EW9 Co 10 WORK MATERIAL: XC45 (06(8) SIZE OF CUT: 3 x 0.2 mm 0.12 x 0.008 in2 TOOL GEOMETRY NOSE RADIUS=Q.5 mm=.20 in v=44 m/min C r =144 fpm ^ ^5` 40 6 mtn0.020 in 6 032 $U 9084 1.Omm=0.040 in S ~ S 30 NOSE RADIUS=1.0 mm=.040 in w U. j^~~~~ ~~V= 50m/min 20 - =164 fpm 0 V=50 m/min =164 fpmr 10 V=57.5 m/min =188 fpm ___________ _ _I________________________n i IIA16 146165 20 14(151620 14151620 TOOL NO. 11A16 Figure 34. Results of tool life tests at The University of Michigan with tools llAi, 15, 16 and 20 of Fig. 32.

II. AMERICAN HIGH SPEED STEEL TOOLS Partly because of the difficulty experienced by preselecting a single European H.S.S. grade, and partly because there was knowledge to be gained by using more than one composition, four American H.S.S. grades were selected for study. Testing has been confined to conventional tool life tests, with total tool failure as the criterion for tool life. General test procedures have been followed, except that flank wear and crater wear measurements were not made. A. TOOL MATERIALS The tools were provided by the Latrobe Steel Compa.ny in standard 1/2 in. square tool bits. The identifications, chemical analyses, and heat treating cycles are tabulated in Tables IV and V. In every grade, the tools represent the product of a single bar of steel to minimize the influence of minor variations in chemistry or mill processing. All tools were checked for hardness and found to be within the desired limits indicated in Table V. Two cobalt grades are included, although neither is directly comparable to the European steel. It may be of interest to note that the greatest apparent difference in heat treatment for the American and European tools is in tempering temperature and time. B. TEST PROCEDURE Tools were mounted in a 15~ solid block tool holder set at 900 to the work axis. Test bars were held in a chuck at one end and supported by a live center at the other. The tool shape and the size of cut were the same as those used with the European H.S.S. tools. They remained constant for all grades in the standard tests. El.a.sped cutting time to total failure determined tool life. C. TEST RESULTS The test results are plotted in Figure 35. First it is interesting to note that the differences among all tools in Fig. 35 (c) are no more than 20%, and usually less, with respect to cutting velocity for a given tool life. This includes the European EW9ColO grade. Also of interest, is the fact that the cobalt grades gave the most erratic behavior, which, of course, is in keeping with the experience on the EW9ColO material. However, a. change in side cutting edge angle on the Dynacut tool (which had the greatest dispersion of results with the standard tool shape) not only reduced scatter, but modified the form of tool failure from the nose of the tool to the flank. Results are plotted in Figure 35 (b). Attempts to reduce scatter of results by reducing side rake angle were not effective. 64

TABLE IV. IDENTIFICATION OF AMERICAN HIGH SPEED STEEL TOOLS Quan- Tools Latrobe Grade AISI Chemical Composition, ^ Latro'be Grade~~ -~ tity Numberss** Type C Si Mn W Cr Mo V Co S 30 69- 98 Electrite Double Six XL M-2 0,84 0.31 0.25 6.50 4.07 5.04 179 - 0.012 30 99-128 Electrite Crusader M-3 1.21 0.25 0.26 553 4.13 i.18 0.012 31 1" 31 Electrite Dynacut M-43 1.17 0.37 0.27 2.40 3.74 7.60 1.57 7.75 0.018 37 32- 68 Electrite Super Cobalt T-5 0.85 0.23 0.33 18V43 4.18 0.74 1.94 7.97 0.017 *Supplied by Latrobe Steel Company **Inclusive \31

TABLE V. HEAT TREATING CYCLES FOR AMERICAN H.S.S. TOOLS* Electrite Electrite Electrite Electrite Treatment Double Six Crusader Dynacut Super Cobalt M-2 M-3 M-43 T-5 Preheat (Salt) 15500F 1550 F 1550F 1550~F Austenitize (Salt) 2220~F 2220~F 2175 F 2300~F Salt Quench 10500F 1050~F 1050~F 1050F Air Cool 125 ~F 125 F 125 F 125 F Multiple Temper 1025~F 1025~F 1000~F 1025~F Tempering Time, hr 2+2 2+2 2+2+2 2+2 Hardness Aim, Rc 64-66 65-67 68-70 64-66 Supplied by Latrobe Steel Company 66

The results seem to imply that the behavior of the cobalt grades is due to other than normal wear processes. These grades are sensitive to vibrations, particularly when less-than-optimum tool shapes are used. Future studies should include investigations of tool shape and its influence on the relative behavior of these tools. 67

6 Tool Material: Latrobe H.S.S. as indicated 60 Work Material: XC45 (0648 Double six Size of Cut: 3 x 0.2 mm 2 1 ousi Double six (M-2) 0.12 x 0.008 in Csa 40 Tool Geometry: 0,30,6,6,6,0,0.5 mm 40 o Dbnacut 0.020 in. Super Cobalt ~bEW9 Co 10 30 ~Dynacut (M-43) CrusaderI (M3)^ ~with side cutting \ ~Crusader (M-3) \ edge angle = 150 20- 20 2DC 0 l8 8 U. Ia C31~\ L~ -I oo II i L 44 I 4 4 4 Dynacut (M-43) e I~~~~~~~~~~I J2 C1 t 2 ~~~~~~~' SuperCobalt (T-\) 2 I I I I I 100 200 100 200 100 200 CUTTING VELOCITY-fpm CUTTING VELOCITY- fpm CUTTING VELOCITY-fpm Figure 35. Results of tool life tests with America.n H.S.S. tools.

PART IV ACCELERATED TESTS FOR RATING HIGH SPEED STEEL TOOLS

Almost without exception, the most useful machinability data which are currently available have come from long extended laboratory evaluations, or have resulted from long experience in the observation of on-the-job performance. The desirability of a short time test procedure which would provide a. valid machinability evaluation is, therefore, self-evident. Some preliminary studies of a short time technique were to have been included for high speed steel tools in this phase of the international cooperative research program, but the problems encountered in the high speed steel program in general made it advisable to postpone this series until the problems are resolved. However, the groundwork for the accelerated test program has been laid by previous investigations in Europe and The University of Michigan. Two techniques are described. Both involve a variation in cutting velocity, but one technique uses a. stepped variation in geometric progression, while the other employs a. continuously varying velocity. I. GEOMETRICALLY STEPPED CUTTING SPEEDS This technique is being used by Professor E. Bodart of the University of Liege. The following information is a translated version of his paper "Correlation des Resultats entre une Methode Rapide de Mesure de l'Usinabilite et les Essais de Longue Duree" (Correlation of Results Between a Rapid Method of Measuring Machinability and Tests of Long Duration) which appeared in CIRPAnnals of February, 1963 (Volume X). A. INTRODUCTION For given cutting conditions (tool material, tool geometry, work material, chip geometry) the durability of the cutting tool can be represented by V60, the cutting speed for which the tool ha.s a. life of 60 min. The Taylor relation is VTn = C. For given cutting conditions, tests are run at different cutting speeds, and the time to total tool failure is recorded. In this manner several tests, 7 or 8 for example, are run at different speeds. Tool lives fall, generally, between 8 to 80 min. This classical method of determining V60 is very reliable, and is little influenced by local variations in work material characteristics; on the other hand, it is rather long and laborious, and it requires several tools and a fairly large quantity of steel. Several researchers have tried to find more rapid methods of measuring V60. The method used here simulates the wear that the tool would have undergone in a normal test. 70

B. DESCRIPTION OF THE METHOD The method consists of making cylindrical turnings with the same tool at cutting speeds increasing discontinuously following a geometric progression with a ratio 1:1.12; therefore, the cutting spends are stepped according to a normal series (Renard series) with a ratio 1: EO. An initial cutting speed, Vo, definitely smaller than the cutting speed V60, is selected. This cutting speed, Vo, is used for 0.2 min, then a cutting speed V1 = V0 x 1.12 is used for 0.2 min, and so on, up to a cutting speed Vk = V0 x (1.12)k, for which the tool fails in less than 0.2 min. Therefore. the tool fails after having been used for: 0.2 min at the cutting speed, Vo, 0.2 min at the cutting speed, V1, 0.2 min at the cutting speed, V2, and Tk min at the cutting speed, Vk. The deterioration (wear) of the tool during these different periods has to be taken into account. To this end, the following hypothesis is made: Let Tkl be the cutting time which, for the cutting speed Vk would correspond to 0.2 min of cutting at the cutting speed Vk-l (respectively, the cutting time T1, for the speed Vk, would correspond to 0.2 min of cutting at the speed V1). Assuming that the relation VT = C can be used, we have: Ve-1(0~)n I Vn Vkl1 (0.2) Vk(Tkl) V1 (0.2)n = V(Tl) VnVkT for which (0.2 (T ) (0.2)n v(T 1.12 k k-l V k 1.1(0.2)n V (T )n Knowing the value of the exponent n (let n = 0.08), it is deduced that: T = 0.0475 min k-l Tk-2 0.0113 min T - 0.0026 min k-3 0.0614 min Therefore, the calculated times [equivalent times at speed Vk] Tk_l, Tk2,..., are added to the time Tk, which is found experimentally at the speed 71

Vk. Times smaller than.001 min are disregarded. It is sufficient to add 0.06 min to the time Tk, providing that tool failure occurs during the fourth period or a following period. The first periods during which the tool is used correspond to very small equivalent times T1, T2,..., that have little bearing on the value to be added to the experimentally determined time Tk. However, these first periods are rather important, it is during this time that the tool adapts itself to the cutting conditions. Therefore, an initial cutting speed must be chosen such that tool failure will occur after at least 9 or 10 speed increments. For certain grades of steel and certain machining conditions, V60 is known in advance within 15% margin of error; therefore a starting speed can be determined accurately to allow 10 steps to failure. The initial speed would be equal to 0.4 x V60. C. CONDITIONS OF TEST The adopted criterion for tool life is V60 (cutting speed for which the tool has a life of 60 min). The tests have been run in dry turning at a depth of cut of 2 mm (0.080'in) and a feed of 0.2 mm/rev (0.008 ipr). The tool geometry is as follows: a Y7 X E r 8~ 27~ 00 600 900 0.5 mm = 0.020" The tool material is 18-4-1 high speed steel. D. RESULTS' The method was first used on 83 steels of different grades and of several thermal and/or mechanical treatments. The 18-4-1 high speed steel tools were taken from the same heat (lot B1) for which the values of V60 and n(n = 0.08) had been determined by the classic long time test. These tests gave the following relationship between V60 classic and V60 rapid: Vo0 classic = (V60 rapid + 1.0) x 1.029 with a standard error a equal to + 8,10% (see Figure 36) The same rapid method was used on 7 steels with different machinabilities (V60 ranging from 35 m/min to 113 m/min). These were machined with 18-4-1 high speed steel tools from the same heat (lot B2) for which the values of V60 and n (n = 0.05) were known. These tests gave the following relationship: 72

VQ0 classic = (V60 rapid - 0.7) x 0.928 with a standard error a equal to + 3.20o (see Figure 37) The rapid test was also used to determine the machinability of a C30 m steel. With n = 0.065, the V60 rapid is 3.9% smaller than V60 based upon long time tests; the standard error, a, is ~ 7.75%. In order to run these rapid tests, the lathe must have stepped speeds in the ratio of 1:1.12, or must be equipped with a variable speed drive. Such lathes are not normally used in workships, but there are lathes in which spindle speed is graduated in a geometric progression with a ratio of i:l'0 or 1:1.26. A lathe with the 1:1.26 ratio was used with 6 of the 7 steels previously reported in Figure 37 for a. ratio of 1:1.12. These were machined with the same lot of tools, and it is noted, in Figure 37 that similar results are achieved with either speed ratio. E. CONCLUSIONS There is generally good correlation between the classic long time method and the rapid method, but there are exceptions. However, it presents a definite practical interest for: a. A rapid evaluation of machinability, allowing the most favorable cutting conditions, b. a test of practical acceptance, and c. the rapid examination of a large number of steels. II. CONTINUOUSLY VARIABLE CUTTING SPEEDS This particular technique probes into relationships between cylindrical turning, or the classic method of evaluation, and taper turning and facing. The following information is taken from work performed at The University of Michigan, including ASME paper 62-WA-281, "Tool Life for Cuts Wherein the Cutting Speed Varies During the Cut," by Professors L. V. Colwell and J. C. Mazur. 73

* Average of three tests x Single test result fpm m/min 459.2 - 140...... /x _ / 393.6- 120 -~~~ ~ 328 - 100 0 0" 262.4 80 /1 196.8- 60 ~ ~x~..~ Xx x 131.2- 40 / / 65.6 - 20 ~~~~, / 0 20 40 60 80 100 1'20 140 m/min 0 65.6 131.2 196.8 262.4 328 393.6 459.2 f pm V60 Classic Method Figure 36. Correlation between rapid method and classic method of evaluation for 83 steels of different grades and of several thermal and/or mechanical treatments. 74

Ratio * 1.26 + 1.12 fpm m/min 459.2 140 /+ 328- 100 392.6 - 120 / =<.~~~~~~~~~~~~~ m /min =~ / 0o 262.4 80.6 131.2 196.8 262.4 328 393.6 459.2 131.2 40~-_ A6. __ __ __ / / / / 0 / 0 20 40 60 80 100 120 140 n /min 0 65.6 131.2 196.8 262.4 328 393.6 459.2 V60 Classic Method Figure 37. Correlation between rapid method and classic method of evaluation for seven steels using two incremental speed ratios. 75

A. THEORETICAL RELATIONSHIPS The initial theoretical concept is based upon the assumption that the life of a cutting tool is dissipated linearly with cutting time. This implies, for example, that a tool could be used for say 50% of the tool life at a velocity of V1, 25% of the tool life at a velocity V2, and the tool would then fail after cutting for 25o of the tool life at another velocity V3. Therefore, AT1 AT2 AT Ai ~+ ~+ +... =1 or - 1 T1 T2 T3 Ti When the velocity varies uniformly as in taper turning or facing at a constant RPM, the time intervals would be infinitely small and the relationship would be expressed as: tf f dt= 1 (1) T o where dt = differential of elapsed time during cutting T = total tool life corresponding to cylindrical turning tf = actual elapsed cutting time to total tool failure From Taylors equation, VTn = C, 1 1 Cn C n C T- - (2) V 2JRN For taper turning, 12 (R-Ro) cot e t = Nf 12 cot e dR and dt = ( ) Nf where R = radius of workpiece at certain interval, ft Ro= radius at beginning of cut, ft N = spindle RPM f = feed rate, ipr e = 1/2 included ta.per angle t = cutting time at given point. 76

After substitution of Eqs. (2) and (3), integration of Eq. (1) from Ro to Rf, the radius at failure, yields the following derived expression for taper turning: l+n Fn-1 1 NR 1-n L= 1+n 1-n (4) 2 \12n cot / Equation (4) applies to facing when cot 0 = 1. [Note: Ro does not appear in the final equation because in the integration the term Ro exp (n+l/n) is << Rf exp (n+l/n) and can be neglected.] B. LABORATORY EVALUATION To evaluate the concepts of the preceding section, tool life tests in cylindrical turning, taper turning, and facing were performed at the following conditions: work material: 1045 H.R. steel tool material: T-1 H.S.S. tool geometry: 0, 22, 6, 6, 6, 0, 0.020 in. feed 0.0115 ipr depth of cut: 0.040 in. In each case, tools were run to complete failure in a continuous cut. Facing started from a hole diameter of 1.25 in. Tapers were 3 in./ft, with initial diameters as low as 1 in. Maximum work diameter was 8 in. C. TEST RESULTS The average values of as many as 10 tool life tests at each spindle speed are plotted on logarithmic coordinates in Figure 38 for both taper turning and facing. It is seen that the results can be represented by an equation of the form m NRf = Kt ( where "m" is the absolute slope of the line. Equation (5) and Eq. (4) have the same format. Therefore, for taper turning, l+n m = l-n 77

400 FACING:300 -,~_~ a. 150 2 TAPER TURNING NR.2.3. 100 60 0.1 0.2 0.3 0.4 RADIUS AT FAILURE-FEET Figure 38. Taper turning and facing results under test conditions. Points are averages of a number of tests. Taper 3 in/ft. 78

fn ( l+n l-n ant 2 12n cot Consequently, it is possible to predict "m" and "Kt" for taper turning if "n" and "C" are known from Taylors equation for cylindrical turning; or, Taylor's expression can be derived if the taper turning equation is known. The same holds true for facing as well. Table VI shows the comparison between actual results determined by experiment, and the corresponding equation for each operation as predicted from the results of the other two. TABLE VI. COMPARISON OF ACTUAL VS. PREDICTED TOOL LIFE EQUATIONS WHEN CYLINDRICAL TURNING, TAPER TURNING, AND FACING 1045 H.R. STEEL AT TEST CONDITIONS Directly Equations as Predicted from Results of: Operation from Cylindrical Taper Facing Experiment Turning Turning Cylindrical VT010=05 VT5=20 4 VTVT.083=198 Turning Taper NR21=23 NR1.22=23 NR 8=24 Turning Facing NR1.18=29 NR1.22-29 NR1.21=29 Undoubtedly, within the range of cutting conditions used, the correlation between actual and predicted values is very good. Other tests indicate that the correlation holds for wide feed ranges and for several other materials which were available. However, additional studies are required to evaluate the technique as a short time test. D. CONCLUSIONS a. Cutting behavior is predictable wherein the velocity varies during the cut. b. Theoretical equations based upon the assumption that tool life is dissipated linearly with time appear to give good correlation among cylindrical turning, taper turning, and facing results. c. The results indicate common dependency of all three types of operations on the same differential equation. 79

III. PROPOSED TESTS The accelerated test program is set up to be carried out on a LeBlond tapeturn lathe. The unique capability of a numerically controlled lathe adds convenience and versatility to the various techniques. The increasing velocity techniques will be used in the formal program, but it is also desirable to know whether the temperature increase associated with progressively increasing feed rates at constant speed will accomplish the same result. It is feasible that this approach might yield confident evaluation in substantially shorter time than the conventional Taylor tool life test. The increments of feed rate are small enough to produce a smoother transition of temperature during a test cycle, in contrast to the somewhat coarser steps of cutting speed reported by the European laboratories. One disadvantage of using taper turning and facing for continuously varying cutting velocity is that both operations become less accurate as the diameters of the workpieces decrease. Consequently, the unique capability of a numerically controlled lathe for programming increasing spindle speeds and increasing feed rates offers a facility for overcoming the problems peculiar to both techniques. Preliminary tests have given repeatable information, 80

PART V SUMMARY OF HISTORY AND RESULTS OF INTERNATIONAL COOPERATIVE RESEARCH IN METAL CUTTING

I. INTRODUCTION This project constitutes a segment of participation on the part of the United States in an international cooperative research program in metal cutting. The program has the political support of the Organization for Economic Cooperation and Development (OECD), and is under the technical guidance and direction of a committee of "experts" from the International Institution for Production Engineering Research (CIRP). It has been underway for approximately four years and has developed a significant body of information on the machining of normalized plain carbon steel. The CIRP believes that scientific explanations can be found for operator skills and proposes to find them so a.s to relieve mankind of the need to relearn the same skills with each succeeding generation. Further, it believes that a scientifically based technology such as can be developed from finding these explanations is the only means through which modern high speed digital computers, numerical control, and adaptive control can achieve their full potential for increasing needed productivity. This is its objective. Eleven of the twenty-two member countries of the OECD are engaged in various phases of study including surface finish, forces and energy, mechanics of cutting, cutting temperatures, and tool wear in addition to detailed analyses of the work and tool material. The OECD/CIRP activity is expected to continue for an extended period, and will cover several work materials and several processes. This particular contract was set up essentially to participate in that part of the OECD/CIRP program devoted to the wear of sintered carbide and high speed steel cutting tools in turning. It covers substantially only European tools and a European source of normalized 1045 steel as the work material. However, several commercial grades of American H.S.S. and carbide tools have been introduced to provide a link with the main body of information being developed by the international program, and to investigate laboratory techniques and analytical procedures for producing technological information of use to American industry. In addition to the substantial support provided by the United States Air Force through the medium of this contract, the Latrobe Steel Company and Kennamental, Inc. are cooperating by providing cutting tools, technical assistance, and the analytical ca.pabilities of their own laboratories. The Micrometrical. Division of Bendix Corporation supplied use of a Proficorder for tool wear measurements. It is only through such voluntary cooperation within each country that the OECD hopes to broaden and extend the total program to a successful conclusion. 82

II. INTERNATIONAL COOPERATIVE RESEARCH PROGRAM ON TOOL WEAR A SPECIFIC OBJECTIVES AND APPROACH OF THE OECD The planners of the overall program recognized that the same problems which beset early attempts at international cooperation in chemistry, physics, metallurgy, electronics, and other branches of science would also have to be overcome in this venture. They realized also that no plan can successfully anticipate the nature of all the results to be expected from a thoroughly fundamental research program. Consequently, the initial stages of the plan consisted of a simple and cautious beginningo It was decided to start with a simple, common work material. and conventional tool materials in simple lathe turningo The guiding objective was a. high degree of uniformity. Therefore, the tools and the work material were to be acquired from single sources and evaluated as to uniformity. Further, the test protocol or analytical procedure was specified in substantial detail. The laboratory program was divided into two parts, the Standard Program and the Main Program. The Standard Program was to be carried out by all laboratories so a.s to get an indication of the dispersion that still persisted among laboratories despite rigid standardization of materials and practices. It was intended also as a means toward correction of unusual or unexpectedly large deviations from a common average. The Main Program wa.s to be shared cooperatively, but with sufficient duplication for a check on resultso The initial plan was scheduled in three phases: Phase 0. Procurement and standardization Phase 1. Comparative study of one steel by all participating laboratories to test and correct the proposed analytical and experimental methods in order to assure agreement among laboratories Phase 2. Study of steels of different microstructures and properties. Phase 0 of the program was carried out during 1961 and 1962. This involved the selection, manufacture and evaluation of the initial work and tool materials, the development of standard test methods, the comparison of tool dynamometer calibrations, and the development of a detailed program of the tests and studies to be conducted by each laboratory. Phase 1 was initiated early in 1963 when the work and tool materials were ready for delivery. Phase 2 materials a.re in preparation. A very important part of the cooperative effort has been the semiannual meeting of the OECD/CIRP coordinating committeeo The oral discussions have 83

helped to discover unusual or unexpected results which otherwise might not be reported and yet which may constitute new and rewarding directions for further research. Thus in the initial phases and in subsequent phases yet unplanned, the OECD/CIRP program can be expected not only to yield useful technological information but also to: 1. discover new directions for basic research 2. develop better analytical techniques and equipment and 3. make significant progress toward universally dependable procedures and standards which can be applied internationally. B. WORK MATERIAL The work material selected is a. normalized XC45 plain carbon steel, which corresponds to an AISI 1045. It was electric furnace melted and continuously cast in 100 mm (4 in.) diameter bars by the French firm, "Societe des Aciers Fins de l'Est." The compositions of two heats cast for the OECD/CIRP studies are as follows: Heat C Si Mn S P Ni Cr Mo Co No. Z0648 0.445 0.35 0.73 o0.008 0.015 0.09 0.09 Trace 0.043 zo656 0.440 0.41 0.71 0.010 0.015 0.09 0.08 - 0.046 The bars were sprayed with aluminum to protect them from excessive oxidation and decarburization during heat treatment. They were heat treated in an automatic oil furnace for 45 min at a temperature of 8700C, furnace cooled to 8000C, then further cooled by moving air to 500C in another 45 min. Typical strength properties are: Ultima.te Yield Ave rage Heat Strength, Strength, El Hardness No. kg/mm (psi) kg/mm (psi) __Vickers zo648 74 47.2 20 195 (105,300) (67,000) zo~66 -73.7 48.2 1 (104,500) (68,;00) 84

Extensive macro-and microanalyses of the structures showed Heat No. Z0648 to have a slightly more banded and coarser structure than Heat No. Z0656, However, the structures were fairly uniform and the differences were very small. On the basis of these analyses, it was determined that a "clean-up" cut of no less than 1 mm (0.040 in.) depth be taken to remove surface variations, and that cutting be stopped at a bar diameter of approximately 2 in. to stay within a uniform structure. Studies of plasticity and related properties of both heats are being carried out at the Chalmers Technical University in Goteborg, Sweden. Figure 39 shows the location of test specimens used to determine the true stresses and strains plotted in Figure 40. Professor Olav Svahn concludes that: lo The material in the center zone, 1, is harder than the rest. 2. Zones 2, 3, and 4 correspond fairly well. 3. Zone 4 has the least scatter while zone 3 has the largest scatter, probably due to the history of the material. 4. The curves have approximately the same slope and are parallel. The results from both heats are in excellent agreement. These results will become part of a larger body of information on these and other materials and will be analyzed for any possible correlation between material properties a.nd tool wear behavior. C. CUTTING TOOLS 1. European Carbide Tools The carbide tools selected for the OECD/CIRP study were ISO grades P10 and P30. These have the following nominal chemical compositions: ISO Source Source Composition, % Source Grade Grade WC TiC TaC - CbC Co PiO Soderfors N-16 71 12 12.5 4 5 P30 Widia TT 30 82 8 10

Original Diameter of XC45 / Location Work Material 1\ U / Number 15 (a) 16 *^.. ^.~ /^ ~ __ ~, ---Zone Number Original Diameter /Zone Num of XC45 Work Material (b) Figure 39. Locations from which both compression and tension specimens were taken for plasticity studies of XC45 work ma.terial. 86

kc kt 110 kplmm 2 --- - 100 90 -/x x 80 ^^^^^Cr(~~~~ ~~~~5~~~Material: XC45 Steel Heat No. Z 0648 70 -a) 60 -~ 00 3~~5 /^ ~ Zone I medellinle Zone 2 x Tension 40 Zone 3 A Zone 4 o 30 Compression 20 10 -0 O 10 0.20 0.30 0.40 0.50 0.60 0.70 True Strain Figure 40. Results of true stress-true strain behavior of XC45 steel.

The tools were 1/2 in. square by 3/16 in. thick by 1/32 in. nose radius indexible or throw-away tips, precision ground on all surfaces for both 6~ positive and 6~ negative rake tool holders. Each tool was assigned an identification number, and each tool was checked for hardness and for density to determine the degree of uniformity. The results of tests carried out at the Technical University in Aachen, Germany on the initial order of 1144 tools, Figures 41 through 44, indicate that the tools are uniform with little scatter or dispersion for either hardness or density. Evaluations performed at The University of Michigan on additional tools agreed very favorably. The Rockwell A hardness scale was selected over the Vickers test after consideration of results and various advantages and dis-advantages of both methods. Five tool tips from each grade were selected on a sampling basis (guided however, by the extremes and averages for both hardness and density) for electron microscope investigation of microstructure. It was found that the microstructures of both carbide P10 and carbide P30 are substantially uniform, although within individual tool tips there are occasional tungsten carbide grains as large as 5.0 u. The average grain diameter varies between 1.5 and 2.0 p in the P10 grade, while carbide P30 has a slightly smaller average grain size ranging from 1.2 to 1.5 u. All tools with especially high densities were shown to exhibit larger structural and hardness differences. These tips were removed from the study program. 2. European High Speed Steel Tools The original high speed selected for the cooperative program is a high cobalt composition known as EW9ColO. It was made by the Jessop-Saville Works in Sheffield, England and processed by the Rohn Works in Sassenheim, Netherlands. It has the following composition: ~~______Grade _Chemical Composition, % C Mn Si S P Ni Cr W V Co Mo EW9ColO 1.3 0.33 0.30 0.009 0.014 0.16 4.54 9.65 3.58 10.10 4.00 Rockwell C hardness is 64-65 The tools themselves are a nominal 1 in. square by 6 in. long. The first tools had approximately a 1.5 in. length of high speed steel but welded to a regular steel shank. Later tools were solid high speed steel. 88

200 AVERAGE = 91.135 DEVIATION =~ 0.095 150 - C) Ct 10 LJ m CD Z 50 -11 40 128 20 155 17 00000 00 ROCKWELL "A" a 8 to ~ c, HARDNESS d o 5 Figure 41. Rockwell A hardness-Carbide P1O. 89

200 AVERAGE x = 90.05 DEVIATION s=~o0.1l 150 V) rrO 100 O O 9o 0 50 - 1 3 1 8 3711121316944 to (D 0 0 0 N rO) 0)0 0i oi 7 ai 6 0 0 d 00 0000(30 00) 0)0) ROCKWELL "iP' Figure h2. Rockwell A hardness-~Carbide P0. 90

300 AVERAGE = 11.67g/cm3 DEVIATION s= 0.04g/cm3 a 200 LL 0 (r z 100 2 0 2 7 14128184282 00 1 0 100 n O eo o un o 100 LO 0 U_ ) 0 iL 0 UF) 0 U) 0 0 LO. LOO o.- l. OD OD (' J o DENSITY, Gm/Cm3 Figure 43. Density —Carbide P10. 91

350 AVERAGE x= 13.232 g/cm DEVIATION s= 0.035g/cm3 300 -250 O) a. F-200 - LL 0 3, n 150 z 100 50 82 336 149 14 6 0 0 L 0 U 0 cu cd ro rO r rO ro ro ro r DENSITY, Gm/Cm3 Figure 44. Density —Carbide P30. 92

Although cutting tools were made only from those bars which fulfilled all of the requirements with respect to inclusions, grain size, and carbide distribution, the high speed steel phase of the cooperative program has been plagued by large discrepancies in results. Resolving these differences may require some program changes. 3. American Cutting Tools Investigations with American cutting tool' materials have been exploratory or introductory in nature in this phase of the cooperative program. A number of different materials grades will be evaluated before more extensive studies get underway. The carbide cutting tools were provided by Kennametal, Inc. in all commercial grades for positive and negative rake angles. The following grades were on hand for this study: Rake Kennametal Carbide Grade Angle K2S K5H K6 K21 K68 Negative X X X X Positive X X The shape and size are identical to the European grades. High speed steel tools were provided by the Latrobe Steel Company in standard 1/2 in. square tool bits in four grades: Latrobe Grade AISI Type Hardness, Rc Electrite Double Six XL M-2 64-66 Electrite Crusader M-3 65-67 Electrite Dynacut M-43 68-70 Electrite Super Cobalt T-5 64-66 In every grade, the tools on hand represent the product of a single bar of steel to minimize the influence of minor variations in chemistry or mill processing. 93

D. EXPERIMENTAL PROGRAM Details of the pain for the experimental program on wear of carbide tools were issued by Dr. Opitz of the Technical University of Aachen, Germany in January, 1965. A very similar plan governing the conduct of high speed steel tool life tests was published by Professor Bodart of the University of Liege, Belgium in February, 1963. The purpose of both plans is to provide a base for all tests to guarantee and prove conformance of all participating laboratories in measuring wear and conducting the metal cutting tests uniformly. Every phase of the program is spelled out in a rigorous format. Each combination of tool material, tool geometry, and size of cut is specified by a test number, and definite cutting velocities are specified for each test. Other details of the program range from the proper identification of tools and cutting edges, a.s in Figure 45, and the proper method of machining a test!___ 2 5__ 6 6 3 C3 4 I~13 8 7 Figure 45. Method of identifying cutting edges of indexable carbide tool bits. bar, as illustrated in Figure 46, to proper recording procedures and wear measuring techniques to yield the data indicated on the typical test data sheet shown in Figure 47. The various symbols and dimensional units used in the program are identified in Table VII. Tool angles are identified in Figure 48. The total program consists of two parts, the Standard Program and the Main Program. The Standard Program (Table VIII) was to be conducted by all participating laboratories so that data from different sources could be compared and evaluated for scatter, reproducibility and proper application of techniques, and instrumentation. These evaluations served as a. basis for discussing and setting up the Main Program which wa.s an extension of the format in Table VIII. In reality, the Standard Program served as a, clearing house to trouble shoot various problems which arose during the exchange of information among the various laboratories. Once reliability was established, the Main Program was shared among the participants. 94

L = 20-24 inches - I.) I______ L 2) 1 F L L/2 3-.) 4. ) Figure 46. Method of machining test bar. 95

CIRP - OECD Test Data Test Nr.: Group C for Tool Wear Measurement in Turning Paper Nr.: Laboratory: Test Engineer: aaterial: Tool Material: Charge No.: Tool No.: Bar No.: Tool- c r X x e r Geometric Machined one utting Speed v = m/min Lathe: ip Cross-Section=b.s= mm2 Theor. Chip Thickness hl: Remarks: Run T Clearance Face _Rake Race Cutting Ratio min B VBmax KS KT KM KT/KM KB Weight Length _0-2mm 10"2mm 102mm um ulm mm g mm 2 4 ~=== 3 8 4 12,5 _______ ______[__ 5 126_______ 6 20 _______ 7 25 __ _____ 31,5 = 9 40 ____ _ 10 50_ _ _U__ 63 _______ _____ ' 1_ 2 80 13. - 100 i4 12'5 ________ 15 160 ________________ 16 200 _______ _________ 18 ~ ~' I ~. I Remarks: Date Signature: Figure 47. Typical test data sheet. 96

+L I \+1 4 Nomenclature rake angle r inclination angle relief angle, end relief angle side cutting edge angle s nose angle E nose radius r Figure 48. Angles of a cutting tool. 97

TABLE VII. SYMBOLS AND DIMENSIONAL UNITS Spe c ification Symbol Dimens ion width of wearland VB mm depth of crater KT m width of crater KB mm shift of cutting edge KS Jm distance between cutting edge and deepest point of crater KM um width of cra.ter lip KL um feed s mm/r depth of cut b mm. cutting speed v m/min revolutions per minute n i/min dia.meter d mm. cutting ratio c nose radius ^- r mm radius of cutting edge ri p.m roughness Rt; Ra; CLA p.m 98

TABLE VIII. OUTLINE OF STANDARD TEST PROGRAM Tool Geometry Cutting Conditions Test Tool eNot Material X- " - r, Feed, Depth of Cut, Cutting Speed, m/min Noo Material a 7 A X E m/ mm mm/r mm 2.1 P30 6~ 6~ 0" 700 90~ 0,8 0,25 63-80 -100-125160-200 2c2 F30 6~ 6~ 0~ 70o 90~ 0,8 05 3 80-12-160 70.1 P30 6~ -6~ 6~0 700 90~ 0,8,25 80-125 6.2 P30 6~ 6~ 0~ 700 90~ 0,8 0,25 3 100-160200* 10ol PlO 6~ 6~ 0~ 700 90 0,8 0o25 3 100-160-200-20 10.2 PlO 60 60 0~ 70~ 90~ 0,8 0,5 3 125-200 15.1 PlO 6 ~ -6 -6 70 90~ 0,8 0.25 3 125-200 0o 114,2 PlO 6 6~ 0 700 90o 0,8 0,25 3 125-200* With chipbreaker.

Most of the format outlined in the test program fulfills the requisites of any good test procedure. However, wear measurements and tool life criteria differ substantially from those in common use in the United States. American practice is to rely almost exclusively on flank wear as a criterion of failure on carbide tools, and total failure on high speed steel tools. Crater wear is often observed, but not formally considered. The international cooperative program on tool wear employs both flank and crater wear to evaluate tool behavior. The important measurements are identified in Figure 49. 1. Wear Measurements Use of the crater a.s a criterion of failure requires that a trace be made of the crater profile, from which the deepest part of the crater, KT, and the distance from this deepest part to the existing cutting edge at the time, KM, can be determined. The ratio of KT/KM is a measure of effective crater wearo A Tukon hardness indentation outside of the expected wear band serves as a reference and assures that the trace can be made through the same point with little error. The following recommended criteria. represent tool failure: VB = 0.2 mm (.008 ino) and K = 0.2 or VB = 0.4 mm (.016 in ) and K = 0.1 where VB = flank wear and K = crater ratio, KT/KM. The two sets of criteria reflect situations when either flank wear or crater wear predominates. Methods used to measure the crater include both tracer and optical techniques. Table IX lists the various laboratories which participated in formal attempts to determine the degree of reliability or repeatability of tool wear measurements with various instruments. In general, the repeatability is good. However, practically every laboratory showed excessive deviation from the mean in at least one of the measurements indicated in Figure 49. It is estimated that some of the dispersion is due to human judgment. The rest is due to the equipment itself. A tentative conclusion is that equipment using physical contact with diamonds or similar devices may be responsible for some of the larger deviations. Burrs and other hazards are more easily recognized by optical means. Included angles of styli also tend to mask boundaries such as cutting edges or crater edges. Care is required in interpretation of the measurement. 100

VB Tukon Indentotion Section a-a as = 0.125 in. _ u Ii ---c of*e Figure 49. Identification of tool wear. 101

TABLE IX. PARTICIPATING LABORATORIES AND EQUIPMENT USED Tool Laboratory Equipment No. 1 Delft (Netherlands) A, B, VB' KB, KL: toolmakers' microscope amplification 30x KM, KT; Talysurf amplification: vertical 200x; horizontal 20x 2a Aachen (Germany) A, B, VG', KB, KL: toolmakers' microscope A, KB, KM, KL, KT: Leitz-Forster 2b London First reading 2c London One day later 3a Kapfenberg (Austria) KT: Leitz-Forster all other sizes: Stereo microscope with ocular micrometer magnification rx and for KL lOOx 3b Aachen Same as 2b 4 Zurich Schmaltz-lightsection microscope on a SIP universal measuring machine MU 214 B 5a Chippendale (Austria) Light section microscope of own design 5b Chippendale Profile projection method 7 Goteborg (Sweden) Talysurf and toolmakers' microscope 8 Leige A, B, VB', KB, KL: toolmakers' microscope KT: Forster-Leitz 9a Manchester (England) Microscope 9b Manchester Talysurf 9c Manchester Talysurf and microscope, readings one month later 10 Saint-Ouen B, VB': SIP measuring machine MU 214 B other sizes: Perthometer lla Arcueil (France) SIP measuring machine MU 214 B llb Arcueil A, B, VB', KB, KL: toolmakers' microscope magnification 13x; KT, KM: Schmaltz light section microscope 12a Torino (Italy) SIP measuring machine MU 214 B 12b (Torino A, B: optical comparator Microtechnica magnification O5x; VB', KB, KM, KL, KT: optical micrometer (Galileo) magnification 5Ox 12c Michigan (U of M) Toolmakers' microscope 12d Michigan Proficorder 15 Kapfenberg Same as 3 16a Delft Same as 1 16b Pittsburgh (Carnegie Tech.) Profile recorder and measuring microscope 102

E, TOOL WEAR RESULTS 1. Carbide Tools a, Effect of Cutting Velocity Figures 50, 51, and 52 are concerned directly with the typical wear criteria upon which tool life determinations are based. They show the orderliness of flank wear, crater depth, and crater ratio as wear parameters. The large asterisk at the end of four of the five plots indicates that the tool was unusable for further testing, Typical tool life-cutting speed plots from the flank wear and crater ratio determinations are shown in Figures 53 through 60. Figure 53 is a tool life plot based upon total tool travel or rubbing distance rather than cutting time. It shows a, typical difference between the two curves, which implies that some cutting conditions will encounter catastrophic failure due to crater wear while others will be due to flank wear, However, Figure 54 shows that the difference in tool life as a, result of using either flank wear or crater wear as the criterion of failure are somewhat arbitrary depending upon the actual limiting values selected in each case. One set of curves representing the higher cutting speeds and longer tool lives is based upon a flank wear of 0.3 mm (0,012 in.) and a crater ratio of 0.2. The other set at lower cutting speed is based upon a flank wear of 0.2 mm (0.008 in,) and a crater ratio of 0.1. In both cases, the results are nearly equal, but the crater wear becomes dominant at higher cutting speeds. Appropriate values of both these criteria differ among work materials and vary with the type of operation. Consequently, it seems appropriate to reserve judgment on the proper limiting value until more information of this type is available. Another interesting comparison in the use of either flank wear or crater ratio as the criterion of tool failure is shown in Figures 55 and 56, which represent the results of tool life tests on the two heats of XC45 work material prepared for the international study. Figure 55, based upon a limiting flank wear of 0.2 mm (0.008 in.), shows no significant difference between the two heats. However, there is an appreciable difference when the crater wear characteristics are compared, as in Figure 56. The reasons for the differences in sensitivity of these parameters are not adequately understood at this time and will require further study. Comparisons of results among participating laboratories are summarized in Figures 57 through 60. It is evident that there is scatter of the order of at least two to one in most of the data, but it is also evident that crater wear gives more consistent results than flank wear particularly on the PlO carbide material, This is especially true of the results found at The University of Michigan as covered in Part II of this report Figure 61 shows that 103

,020 0,5.016 0.4.012 1 0.3.^~ /^ ^ ^^ /~e.X/.. LrqO 08 0.2 SYM I I MM| /r '/ /" A. *.....250 820 -— 004J~~. 0,~200 651 -,004 01 0 x.... ---.../60 525 j e........0. 125 410 C.^^' f ' o!...../0.100 328 +........80 262 IN. |.......6 3 207.002 -- " 2 5 10 20 50 100 200 300 ELAPSED CUTTING TIME, T(MIN) WORK MATERIAL: XC 45 HEAT ZC656 WORKING DIA.: 96-48 mm TOOL GEOMETRY 4-2 in C L TOOL MATERIAL: CARBIDE P30 6'1 6 17dl9] 0.8 mm 0.032 in SIZE OF CUT: b x s= 3 x0.25 mm = 0.12 x 0.0 in2 TEST NO. 2.1b Figure 50. Typical plot of flank wear versus cutting time. The large asterisk at end of curve indicates that tool was unsuitable for further testing.

240 200 i I / // / I J SYMBOL SPEED Q::00 m/mln fpm L 8 4. 250 820 8-.... A~-.200 656 680 / /. 160 525 20 / / 1..... ---.100 328 4I0&,,/ /8 26 I 0 10 20 30 40 50 100 150 200 ELAPSED CUTTING TIME, T(MIN) WORK MATERIAL: XC45 HEAT: Z0656 WORKING DIAMETERS: 96-48 mm 2-4 in TOL GEOMETRY TOOL MATERIAL: CARBIDE P30 6 6 j 70 908 mm TEST NO. 2.1 b 0032 in SIZE OF CUT: 3 x.25mm' 0.12 x 0.01 inZ Figure 51. Typical plots of crater depth versus elapsed cutting time. The depth represents a maximum depth along a prescribed path normal to the cutting edge.

0.3 — 4.. x I, / 02/ / / YMO so /+250250 820 w A^ /~*~.....200 656! 0.05 x-.~/60 525 ~It ~ *-..... 125 410 0 0.04 o --- — ~~ fo0 328 ^ /^ ^ +/" 0*. ~~~~~~~6 3 207 C/~ 'X+ 2 5 10 20 50 100 200 300 ELAPSED CUTTING TIME,T(MIN.) WORK MATERIAL: XC45 TOOL GEOMETRY HEAT: Z0656 WORKING DIAMETERS 6 T 1790 0.8 mm 96-46mm or4-2mn 0.032 in TOOL MATERIAL: CARBIDE P30 TEST NO. 2.lb SIZE OF CUT? 3x0.25 mm 0.12 x 0.01 in Figure 52. Typical plots of crater ratio versus cutting time. Values of 0.1 or 0.2 serve as tool failure criteria.

33330 -1000 ft \ \ 16660 500- \ VB=0.2rn \ K=0.2.j 6666 200 0 - 3333 1000 1666 -500 1 I 50 100 rr'min 200 300 I i JI I I fi 166 333 ftrnin 666 1000 CUTTING SPEED, V TOOL MATERIAL: CARBIDE P 30 HEAT: Z0656 WORKING DIAMETER: 96 -48mm or 4 -2in TOOL GEOMETRY WORK MATERIAL: XC45 6 16 170190108 mm TEST NO. 2.1b 0.032 in SIZE OF CUT: 3x.25mmL 0.12 x 0.01 int Figure 53. Tool life plot based upon total tool travel or rubbing distance to reach a, flank wear of 0.2 mm or a. crater ratio of 0.2 at various velocities. 107

200 \\ min 100 \ \ VB = 0.2 mm \ VBO0.3mm 50 \\' K -O. mm 0 K =0.2 mm 40 30 F-. \20 10 _ 50 mlnin I 00 200 300 167 333 666 1000 ft/min CUTTING SPEED, V WORK^~~~ AT TOOL GEOMETRY WORK MATERIAL: XC 45 TOOL GEOMETRY HEAT:Z0656 61610170900.8m WORKING DIAMETER 0.032 in 96 -4 8 mm or 4-2 in TOOL MATERIAL: CARBIDE P30 TEST NO 2.1b SIZE OF CUT: 3x0.25mmL =0.120 x0-010 in Figure 54. ''ool life versus cutting velocity based upon different values of fla.nk wear and crater ra.tio. 108

200 min 100 50\ o-.Z0656 50 - x. Z0648 40 30 E20 _ x,, 10 5 _ 3 50 m/hnn I 00 200 300 167 333 666 1000 ft/min CUTTING SPEED, V TOOL GEOMETRY WORK MATERIAL: XC 45 L HEAT:Z0648/Z0656 61 6 o7r0.8mm WORKING DIAMETER 0.032 in 96 -4 8 mm or 4-2 in TOOL MATERIAL: CARBIDE P30 TEST NO 2.1 o/b SIZE OF CUT: 3x0.25mmz 0-120 x0-010 inz Figure 55. Tool life versus cutting velocity for two heats of XC45 steel. Tool failure based upon flank wear of 0.2 mm. 109

200 min 100 50 ~ \\ 40 30 Z0648 \Z0656 "J20 w.4 5 a 50 mAtnn 100 200 300 167 333 666 1 00 ft/min CUTTING SPEED, V TOOL GEOMETRY WORK MATERIAL: XC 45 L w [ ~ I ' II r HEAT:Z0648/Z0656 66 0 6|06mm WORKING DIAMETER 0.032 in 96 -4 8 mm or 4-2 in TOOL MATERIAL: CARBIDE P30 TEST NO 2.1 a/b SIZE OF CUT: 3xO25mm2 ~0-120 x 0010 inz Figure 56. Tool life versus cutting velocity for same two heats of XC45 steel of Fig. 55 but tool failure based upon crater ratio of 0.2. Difference between the two heats of steel are more pronounced. 110

TOOL LIFE vs CUTTING SPEED WORK MATERIAL; XC 45 TOOL MATERIAL: CARBIDE P30 SIZE OF CUT: 3x0.25mmt -0.12 xO.Oin2 TEST NO. 6.2 TOOL GEOMETRY 200 - 0l l?[ ~EI r 6 6 06 7090 0.8m.032n +\ X AACHEN 100.y + DELFT Y' LIEGE A MUNICH * ZURICH I Is~ \ ~a~o L.C.A. PARIS c 50 o GOTEBORG oYx A MANCHESTER ~ \ r~T~~v MICHIGAN 20 o j o O 10 3 I 50 100 200 m/min. 500 167 333 667 fpm 1667 CUTTING SPEED, V Figure 57. Comparison of tool life results among nine laboratories when based upon flank wear of 0.2 mm with P30 carbide. 111

TOOL LIFE vs CUTTING SPEED WORK MATERIAL' XC 45 TOOL MATERIAL: CARBIDE P30 SIZE OF CUT: 3x0.25mm' =0.12 xO.OIin2 TEST NO. 6.2 TOOL GEOMETRY 200 6 6 06 70 90 0.8m.032n X AACHEN 100 -+ DELFT *~~Y LIEGE a MUNICH \ ZURICH \ L.C.A. PARIS 50- \ GOTEBORG MANCHESTER U r+v4 v MICHIGAN 20 Av V t \ Ul + o\. \ 0\ r 1 _ II oY 5 \ 3 50 1)00 200 m/min. 5(X 167 333 667 fpm 1667 CUTTING SPEED, V Figure 58. Comparison of tool life results among nine laboratories when ba.sed upon a crater ratio of 0.1 with P30 carbide. 112

TOOL LIFE vs CUTTING SPEED WORK MATERIAL: XC 45 TOOL MATERIAL: CARBIDE PIO SIZE OF CUT: 3xO.25mm2 = 0.12x.1O in~ 1000 TEST NO. 14.2 TOOL GEOMETRY ) ol (1 tI^otVI Abe,, r 6 6 170 190 0.8mm.032in x AACHEN 500 + DELFT Y LIEGE A MUNICH ^(O)(\ '* ZURICH 0 L.C.A. PARIS | Q\#0 GOTEBORG 0 ^ * dA MANCHESTER -200 (vj V MICHIGAN W v\ r^ ' i00 - \ ~..., ~ I \ - 120 p ot ^ Ar.; 0 - 50 too 200o~ (....'. 50 /00 200 m/mm 500 167 333 667 fpm 1667 CUTTING SPEED, V Figure f59. Comparison of tool life results among\nine laboratories when based upon a crater ratio of 0.1 with P10 carbide. 113 115

TOOL LIFE vs CUTTING SPEED WORK MATERIAL: XC 45 TOOL MATERIAL' CARBIDE PIO SIZE OF CUT: 3xO.25mm2 0.12xO.01 inm 1000 TEST NO.14.2 TOOL GEOMETRY?. ''1I -IA.b? I r 61 61 0170 9010.8mm.032in x AACHEN 500 (a) + DELFT Y LIEGE a MUNICH cf.~ \ ~ * ~~ ZURICH ~ \c:' ~o~0 L.C.A. PARIS ao + 0 GOTEBORG co 200 \ *A MANCHESTER 200 V MICHIGAN o IY() lo) o Y 50 X (x) 5) 20 + 10 I 50 100 200 m/mmin 500 167 333 667 fpm 1667 CUTTING SPEED, V Figure 60. Comparison of tool life results among nine laboratories when ba.sed upon flank wear of 0.2 mm with PlO carbide. 114

CUTTING TIME, min. 2 U 6 8 10 20 h0 Work Mater al: XC 45 Tool Mater al: Carbid PO10 ~~~~~~~~~~in mm ~Size of Cu 3x0. r mm2 in^~~~~~~~~ '~~~~~~-~ rm 0. 12 x 0.01 in2 ~_ Tes-t No,1 2i-~V" 200 m/min* 6Y6 ~pm ~~~~~~~~^o.ol6o.h *Tool Geometry: 0.0160 )-.UO- ~ / 'd P FLANK WEAR 6 6 0 70 9 0.8mm 0,032 in 0,0080 i-0- __ - /.10 7 // ^^-/ \.J1..06~ 0,002~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ e O~ ~ ~~~~~~~~~~~~~~~~01 o.ooo -.io ~"___' //~ *. —~ + ^ ~ 71.0 0 0.0024 -,06 X. 0 i I ^ ^_____________y'___________^ ^_____________________. --- —-- *~~~ CRATE RATIO H 1 0,0016.0o -* *.o -O + 7 / I 7 ^. U of M 0,0008 ~ 02 0 ~~~~~0.0008 - ~~.02^~,~ 7~ 070chuc -live center. 7'/~ ~I-~- chuc -dead center 7/~~ *^~~betw en centers, live 2 4 6 8 10 20 hO CUTTING TIME, min. Figure 61. Tests at The University of Michigan indicate that the method of holding and driving the workpiece has an influence on tool life criteria. The effect is greater upon flank wear than upon crater ratio.

the method of holding and driving the workpiece had a great influence on flank wear, but seemed to have little effect on crater wear, or at least, on crater ratio. Some of the observations made at the University indicate that a given crater ratio is not always indicative of the actual size of the crater. b, Effect of Tool Geometry and Feed Figures 62 and 63 demonstrate typical opposite trends with regard to optimum or best normal rake angle, y, and best side cutting edge angle, X, depending upon whether flank wear or crater wear is used as the criterion for the end of useful tool life. The results are for the P30 carbide, but similar results were noted for the P10 material, The data are significant, for they indicate that tool geometry may be a more important factor in carbide tool wear than is generally understood. Obviously the presence of such contradictary guide lines requires more research not only to provide a broader base for making proper selections of tool sha.pe, but for determining the causes. Cutting temperature distributions, development of crater and flank profiles, and shape of the cross section of the chips would provide valuable contributions if documented and analyzed during the entire useful life of the cutting tools. co Nose and Groove Wear Wear along the cutting edge and nose of turning tools is an important factor in the determination of surface quality; particularly in finish operations. The University of Delft, under the direction of Professor Pekelharing, has specialized in studying the problems of finish machining, and has developed special techniques in which the consequences of nose wear and groove wear may be adequately observed. The progression of wear with time can be studied from a. single picture made by superimposing a series of photographs from consecutive time intervals one upon the other as illustrated in Figure 64. Nose wear and groove wear are defined as N and G, respectively. Professor Pekelha.ring's technique makes no attempt to explain the causes of nose and groove wear, but it does provide an interesting study of the effect of tool wear upon the surface roughness of the workpiece and the interaction of this resulting roughness pattern on the tool configuration, Results with carbide tools indicate that nose wear increases continuously with time, as would be expected. However, groove wear can actually decrease during longer cutting times after reaching a peak value in earlier stages. It was found that the grooves have a pitch equal to the feed. d. American Carbides The tests with American carbide tool materials are covered in Part II of this reporto The initial emphasis has been placed on extensive description 116

V vsS l lltllr wWORK MATERIAL: XC45 6s lo j l7O 0.8mm TOOL MATERIAL: CARBIDE P30 0.032 in SIZE OF CUT' 3xiV/armm2,0.12 x 0.01 In TEST NO 2.1,2,3 3.1,2 ti c~ o,400 120 =6\ S fpm 333- 100 I(3n m/ n SsIO 267 80 ~ 233 0.25,5 mm/U.8 i I, I 0.01.02 ipr.032 FEED, S I 400r 120 fp 6 ' 333 100 -n =0 =(m, n I m/n min 267 80 200 60 0.25.5 mm/U.8 0.1.02.032 FEED, S Figure 62. Variations in normal rake angle shown contra.dictory trends when V30 is ba.sed upon flank wear or crater ratio as failure criteria. 117

VvsS I r1h l ^18 lgIr WORK MATERIAL: XC45 6 6 0 pO0.8mm TOOL MATERIAL: CARBIDE P30 0.032in SIZE OF CUT' 3xfVarcmma 0.12 x 0.01 In;F^~~ ~~TEST NO 2.,,3/4.1,23/5.1,2 4i,=50'\ 20 ^=-70o I K a) 333 100 c3/ mmn 8 267 80- 70 ____________________________ 233 T O 0.25.5 mm/U.8 0.01.02 ipr.032 FEED, S 0 c 400 120 it x 5 f9( 333 100 ^ I /nMl/n ne IK 267 80.200 60 0.25.5 mm/U.8 i I.......I I i ".01.02.r.032 FEED, S Figure 63. Optimum side cutting edge angle is also influenced by form of failure criterion, flank wear or crater ratio. 118

bs o caI -f 125 X MAGNIFICATION G __. i Figure 64. Photograph and schematic of tool wear in finish machining. 119

of crater wear. Entire craters are traced at given time intervals, and the results are plotted to give crater profiles a.s in Figures 65 and 66. As these figures indicate. this has been found, to provide a very sensitive indication of differences among carbide grades. It is contemplated that this technique will be extended to cover all carbide grades for at least short time intervals at the OECD/CIRP cutting conditions. This will provide not only an indication of differences among the grades, but will establish a "tie-in" with the wealth of information available from the main program. 2. High Speed Steel Tools The high speed steel program with the European EW9ColO tool material ha.s been pla.gued by extreme dispersion reported by virtually all participating laboratories. The problem ha.s not yet been resolved to full satisfaction. Opinions of various investigators have focused attention on tool composition, heat treatment, grinding practice, and standardized cutting conditions. On the basis of tests at The University of Michigan with carefully prepared tools, there is evidence to support the claim that the high cobalt content of the EW9 -ColO steel is a possible case of difficulties both in grinding and in relation to the OECD/CIRP test conditions. Figure 67 gives the tool life results (based on total failure) on four American grades and the Eurooean grade of high speed steel. It is noted that the greatest dispersion in results among the American tools occurred with the two grades which have high cobalt contents (~ 8%). On the other hand, these same tools were capable of slightly higher velocities for given tool lives. Excessive dispersion of results was not experienced with the EW9ColO grade, but in fairness to European results, only a limited number of tests were made. It compared very favorably with the best of the four American grades. The high speed steel program is covered in more detail in Part III of this report. III. ADDITIONAL OECD/CIRP RESEARCH IN METAL CUTTING Although the tool wear program has received the greatest participation, there are a number of laboratories including those at the Carnegie Institute of Technology and the Cincinnati Milling Machine Company that are engaged in other phases of a.ctivity-Mechanics of Cutting and Cutting Forces, Machined Surfaces, Metallurgical Properties of Machined Steel, and Statistical Programming among others. When available, many of the reports covering the results of work accomplished have been included either in close association with the tool wear results or as separate sections. 120

CRATER DEPTH ~- 0.0 m in. O~ m - 1,600o # in. 40, m - 3,200 / in. 80J m A- 4,800 A4in. 120l m Cutting Time: 2 min. Work Material: XC 45 (0656) ~ —l - -- ~ --- - - + -___ Size of Cut: 3 x 0.25 mm2 0.12 x 0.01 in2 I-1~ ~ e ~ Cutting Velocity: 160 m/min = 525 fpm. ______ ____ Tool Material: K68 Carbide ^~T^r T v~ T ~- 15". ilTOOL G EOMETR TOOL GEOMETRY 6 -6 0. r 6 -6 -6 70 90 0.8mm:.032i SCALE 50 1 Figure 65. Crater on face of K68 carbide grade tool with negative rake a.t cutting time of 2 min under conditions listed. Differences in behavior of carbide grades are emphasized when results are compared with corresponding crater on K21 grade under identical conditions. 121

CRATER DEPTH - 0.0, in. O, m I - Z100 4in. 2.5kam [~ — - ---------- A - 200 i in. 5Am TII~ \g X1 T T 1 CtCutting Time: 2 min. ~~ - _-_<_.....~ —.~ Work Material: XC 45 (0656) I ISll11 L 1 _ 2 L~~~~ ~Size of Cut: 3 x 0.25 mm2,~- - --------— ~~~~ ~~ 0.12 x 0.01 in Cutting Velocity: 160 m/min. ~~ ---- --— _- 525 fpm. Tool Material: K21 Carbide __ --- - _. O^/T r-r~~~r TOOL GEOMETRY IX I A j 6+ 6 -6 - 70 90 SCALE 50 Figure 66. Crater on face of K21 grade carbide is much smaller and shallower than cra.ter of K68 grade under identica.l conditions as shown in Fig. 65. 122

60 Tool Material: Latrobe H.S.S. as indicated 60 Work Material: XC45 (06L8 Double six Size of Cut: 3 x 0.2 mm 2 Crusader Double six (M-2) 0.12 x 0.008 in 40 Tool Geometry: 0,30,6,6,6,0,0.5 mm 40 Dynacut 0.020 in..^p^ ^^^ 1 *EW9 Co 10 30 Dynacut (M-43) with side cutting \ Crusader (M-3) edge angle = 150 20 2 20 2I 0 *g 1 1 8 U. 8 6 G16 16 ^ I \ \ I * o1 1 t \ ~ ^ 4 4~ I1 4 t ^ 1^^~~4Dynacut (M-43) III 2^^ t ~20 ^' ^^ Super Cobalt (T-5) 2 100 200 100 200 100 200 CUTTIN__ VE_ TY_ fpm CUTTING VELOCITY- fpm CUTTING VELOCITY-fpm Figure 67. Results of tool life tests with American H.S.S. tools.

Part I of this report presents a summary of work completed on forces a.nd shear zone mechanics as compiled by Mr. Eugene of the French Central Armament Laboratories (LCA), chairman of the subgroup on "Mechanics of Cutting and Cutting Forces" Some interesting work has also been performed by Professor Pekelharing at the University of Delft in which he investigates the effect of built-up edge (BUE) on surface finish in an attempt to determine the cutting conditions for obtaining the best possible surface finish on the XC45 work material. Professor Pekelharing concludes that the best cutting condition is one in which the cutting speed is high enough to eliminate BUE, and that this cutting speed decreases as feed increases. It is affected, however, by work material and tool material properties. More complete information on surface quality will soon be available from other laboratories as well. One important aspect of the overall cooperative research program is that with proper guidance, proper distribution of work activity, and free and complete exchange of information through reports and scheduled group meetings, the quantity and quality of work done cannot be achieved by any other mea.ns. The future of metal, cutting research promises to take on more meaning after the first phase of the OECD/CIRP program. IV. CONCLUSIONS AND RECOMMENDATIONS Based upon the work done in The University of Michigan laboratories, and the exchange of information among all. laboratories, the following conclusions are those of the authors of this report and not necessarily those of the OECD/ CIRP committee: 1. It is possible to obtain reasonable agreement across international boundaries as to the machining characteristics of tools and work materials when both are adequately defined and analytical procedures are specified and controlled and test equipment is carefully compared 2, The international cooperative research approach will: a, discover new directions for basic research; b. develop better analytical techniques and equipment, and; co make significant progress toward universally depenable procedures and standards which can be applied internationally. 3. The American practice of basing the life of carbide tools only upon flank wea.r is suspect for many applications. 124

4. Tool geometry may be a more important factor in influencing the wear of cutting tools than is generally understood. The combined use of flank wear and crater wear to study causes and effects of metal cutting behavior has considerable merit. For these and other reasons that can be drawn from the results of this study, it is recommended; 1, that the cooperative program be extended to cover other work materials and microstructures as is contemplated in Phase II; 2. that efforts be made to explore a broader range of tool properties and tool shapes; 3o that more exhaustive and correlated analyses be made of the effects of cutting time upon: (a) flank wear, (b) crater wear9 (c) cutting forces, (d) cutting temperatures and their distribution, (e) cutting ratio, (f) shape of chip cross section, (g) shape of the crater3 and (h) degree and frequency of chips segmentation~ There is a, pronounced lack of information of this type which could help to evaluate performance in adaptive control systems, and which could guide metallurgists in developing better tool materials for unique combinations of workpiece composition and microstructure 125

APFENDIX TABLE OF CONTENTS OF PREVIOUS INTERIM REPORTS

INTERIM REPORT NO. 1 I. Introduction II. Program Objectives III. Experimental Procedure Appendix I. Tabular Information on American and European Tool Materials Appendix II. Conversion Between Metric and Inch Systems INTERIM REPORT NO. 2 I. Evaluation of Carbide Tools P10 and P30 II. Structural Analysis of XC45 Work Material INTERIM REPORT NO. 3 I. Wear on European Carbides in Machining XC45 Steel II. Repeatibility of Wear Measurements Between Laboratories III. Influence of Speed and Feed on Forces, Finish, and Built-Up Edge IV. A New Method for Studying Tool Wear in Finish Machining V. Plasticity Study of XC45 Work Material 128

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DISTRIBUTION LIST (Continued) Scientific & Technical Informa.tion Air University Library Facility Maxwell AFB, Alabama Attn Technical Library RQT-16448 Hq USAF (AFXSAI) P.O, Box 5700 Air Battle Analysis Center Bethesda, Maryland 20014 Deputy Director of Plans for War Plans National Academy of Sciences Directorate of Plans, DCS/P&O National Research Council Washington, DoC. 20330 Materials Advisory Board 2101 Constitution Ave., NoW. Washington, D C. 20418 Other Adamas Carbide Corporation AVCO Corporation Market and Passaic Streets Lycoming Division Kenilworth, New Jersey 07033 Main Street Attn~ H.So Kalish, Director Stratford, Connecticut Research and Development Attn: Superintendent Manufacturing and Engineering Aerojet-General Corporation P.Oo Box 296 Battelle Memoria.l Institute Azusa, California 505 King Avenue Attns K. F Mundt Columbus, Ohio 43201 Vice President of Manufacturing Attn: Mr. Francis W. Bougler, Chief Metalworking Research Div. AiResearch Manufacturing Company 9851 Sepulveda Boulevard Bell Aerosystems Company Los Angeles, California 90009 Niagara Falls Airport Attn: Technical Library Buffalo 5, New York Attn~ Library Alfred University College of Ceramics Bendix Corporation Alfred, New York Research Laboratories Division Attnn Dr, Philip H. Crayton Southfield, Michigan Attn~ Ronald M. Centner Allegheny Ludlum Steel Corporation Research Center The Boeing Company, Headquarters Breckenridge, Pennsylvania PoOo Box 3707 Attn: Po R. Borneman Seattle 24, Washington Chief Resea.rch Metallurgist Attn B. K. Bucey, Director Research and Development 131

DISTRIBFTION LIST (Continued) Carborundum Company Crucible Steel Company of America P.O. Box 337 P.O, Box 7257 Niagara Falls, New York Pittsburgh 13, Pennsylvania Attn: Dr E. Dow Whitney Attn: E. J. Dulia, Manager Product Research Carnegie Institute of Technology Pittsburgh 13, Pennsylvania Curtiss-Wright Corporation Attn: Dr. M. Co Shaw, Head Metals Process Division Department of Mechanical P.O. Box 13 Engineering Buffalo, New York Attn: R. A. Kaprelian Chicago Latrobe General Manager 411 W. Ontario Avenue Chicago 10, Illinois Douglas Aircraft Company, Inc. Attn. D. Jo Kallio, Chief Engineer 3555 Lakewood Boulevard Long Beach 8, California Cincinnati Milling & Grinding Machines Attn: 0. L, Rumble, Tooling 4701 Marburg Avenue Manager Cincinnati9 Ohio 45209 Attno Dr, Mo Eugene Merchant Douglas Aircraft Company, Inco 3855 Lakewood Boulevard Cincinnati Milling & Grinding Machines Long Beach 8, California 4701 Marburg Avenue Attn: J. S. Sempres Cincinnati, Ohio 45209 Production Development Attn: Gerald W. Long Manager Production Development Department Firth Sterling, Inc. Carbide Division Cincinnati Milling & Grinding Machines 3115 Forbes Avenue 4701 Marburg Avenue Pittsburgh, Pennsylvania 15230 Cincinnati, Ohio 45209 Attn: To G. Barnes, Vice President Attn~ Dr. Richard L, Kegg Physical Research Department Fairchild Stratos Corporation Aircraft and Missiles Division Cleveland Twist Drill Company Hagerstown 10, Maryland 1.242 E 49th Street Attn: L. B. Carroll, Manager Cleveland. Ohio 44101 Tool Manufacturing and Design Attn: C, W. Clark, Vice President Attn: A. D. Jairett, Manager Manufacturing and Engineering Tool Manufacturing and Design Cleveland Twist Drill Company Firth Loach Metals, Inc. 1242 E 49th Street Buttermilk Hollow Road Cleveland, Ohio 44101 McKeesport, Pennsylvania Atrtn: R. D. Lesher, Research Engineer Attn: Wo J. Loren, President Research Laboratory Depto 106 132

DISTRIBUTION LIST (Continued) Ford Motor Company Goodyear Aerospace Corporation 20000 Rotunda Drive Tool Research and Development Dearborn, Michigan Akron 15, Ohio Attn~ Dr. Vo F. Zackay, Director Attn: R. J. Moldovon Research and Engineering Center Greenfield Tap & Die Company Sanderson Street Ford Motor Company Greenfield, Massachusetts 20000 Rotunda Drive Attn: So Sinclair, Director of Dearborn, Michigan Research Engineering Attn: Dr. M. Huminik Department Research and Engineering Center Grumman Aircraft Engineering Corporation Ford Motor Company Bethpage, L.I., New York 20000 Rotunda Drive Attn: Wo Jo Hoffman, Vice President Dearborn, Michigan Manufacturing Engineers Attn~ Scientific Laboratory Ceramics and Glass Department Grumman Aircraft Engineering Corporation General Dynamics/Astronautics Bethpage, L.I. New York San Diego 12, California Attn: Mrs, Sara T, Moxley Attn: D. Weisinger Director Technical Info File, P1. 12 General Dynamics/Ft. Worth Grants Lane Heald Machine Company Fto Worth, Texas 10 New Bond Street Attn: Fo A. Fuhrer, Chief Worcester 6, Massachusetts Manufacturing Engineering Attn: Dro R. SO Hahn Research Engineer General Electric Company Large Jet Engine Department Hughes Aircraft Company Cincinnati, Ohio 45215 Florence and Teals Attn: Guy Bellows, Manager Culver City, California Manufacturing Engineering Attn: Library Research Laboratory IIT Research Institute General Electric Company 10 W, 35th Street 1 River Road Chicago, Illinois 60616 Schenectady 5, New York Attn: Fo C. Holtz, Attn: Dr. W. W. Gilbert, Manager Attn: Dr, No Parikh, Director Machine Division Metals Research Division General Motors Corporation Kennametal, Inc. General Motors Technology Center 700 Lloyd Avenue Detroit, Michigan Latrobe, Pennsylvania Attn. Ho D. Hall, Director Attn: W. Lo Kennecott Manufacturing Development Vice President 133

DISTRIBUTION LIST (Continued) Kearney & Trecker Corporation Purdue University 11000 Theodore Trecker Way Lafayette, Indiana Milwaukee, Wisconsin Attn: Professor 0. D. Lascoe Attn: W. C. Beverung Industrial Engineering Assistant Sales Manager Rohr Aircraft Corporation Landis Tool Company P.O. Box 878 Waynesboro, Pennsylvania Chula Vista, California Attn: H. E. Balsiger, Chief Attn: B. F. Raynes Engineer Executive Vice President Latrobe Steel Company Ryan Aeronautical Company Latrobe, Pennsylvania 3701 Harbor Drive Attn: C. R. Wendell, Manager San Diego 12, California Metallurgical Services and Attn: J. P. Orr Tool Steels Sandia Corporation LTV-Vought Aeronautics Division Sandia Base P.O. Box 5907 Alburquerque, New Mexico Dallas, Texas 75222 Attn: E. P. Quigley, Supervisor Attn: W. W. Wood Manufacturing Processes Development Division 2565 Lockheed Aircraft Corporation California Division Society of Carbide Engineers 2555 N. Hollywood Way 718 Finley Road Burbank, California Lombard, Illinois Attn: Robert L. Vaughn Attn: William Pelger Lockheed Aircraft Corporation Solar Aircraft Company 86 S. Cobb Drive Facilities Division Marietta, Georgia San Diego 12, California Attn: W. P. Frech Attn: J. A. Logan, Manager Manufacturing Engineering Thompson-Ramo-Wooldridge, Inc. The Marquardt Corporation 2355 Euclid Avenue 16555 Saticoy Street Cleveland 17, Ohio Van Nuys, California Attn: E. J. Hayes Attn: Director of Manufacturing Tungsten Alloy Manufacturing The Martin Company Company Baltimore 3, Maryland 65-67 Colden Street Attn: Chief Librarian ~Newark, New Jersey Engineering Library 134

DISTRIBUTION LIST (Continued) Union Twist Drill Company Professor Nathan H. Cook Research and Development Department Room 35-132 Monroe Street Massachusetts Institute of Technology Athol, Massachusetts 77 Massachusetts Avenue Cambridge, Massachusetts United Aircraft Corporation 400 Main Street McDonnell Aircraft Corporation E. Hartford 8, Connecticut P.O. Box 51.6 St. Louis 66, Missouri Sikorsky Aircraft Division Attn: A. F. Hartwig United Aircraft Corporation Chief Industrial Engineer N. Main Street Stratford, Connecticut McDonnell Aircraft Corporation Attn: A. Sperber PO. Box 516 St. Louis 66, Missouri United Greenfield Corporation Attn: Central Files Department 110 411 W. Ontario Chicago 11, Illinois Metcut Research Associates, Inc. Attn: Woodrow Tichy, Vice President 3980 Rosslyn Drive Cincinnati, Ohio 45209 University of California Attn: Dro Michael Field, President Los Angeles, California Attn: Professor M. Ao Simon Mr. Leslie L. Gould, Staff Metallurgist University of California Materials Advisory Board Los Angeles, California National Academy of Science Attn: Reno Cole 2101 Constitution Avenue, N. W. Washington, D. C. 20418 University of California Bancroft Way National Science Foundation Berkeley 8, California Office of International Science Attn: Professor E. G. Thomsen Activities Industrial Engineering Washington, D. C. 20550 Attn: Dr. Philip W. Hemily University of Cincinnati Deputy Head Cincinnati, Ohio Attn: Professor L. Doty National Science Foundation Mathematics Department Office of International Science Activities Professor Walter Backofen Washington, D. C. 20550 Department of Metallurgy Attn: Mr. Ray W. Mayhew, Head Massachusetts Institute of Technology International Organizations 77 Massachusetts Avenue Staff Cambridge, Massachusetts 135

DISTRIBUTION LIST (Continued) National Science Foundation Pratt & Whitney Aircraft Company, Inc, Office of International Science East Hartford 8, Connecticut Activities Attn: Rr A. Foisie, Product Washington, D. C. 20550 Engineering Attn: Mr. Paul A. Roessler Attn: R. Stoner, Supervisor Staff Associate Methods Development Section International Organizations Staff University of Cincinnati Cincinnati, Ohio National Twist Drill. Company Attn: Professor Hans Ernst 6841 N. Rochester Road Rochester, Michigan University of Cincinnati Attn: C, J. Oxford Cincinnati, Ohio Director of Research Attn: Dr. Jo R. Lemon Engineering College North American Aviation, Inc. Rocketdyne Division University of Cincinnati 6633 Canoga Avenue Cincinnati, Ohio Canoga Park, California Attn: Dr. I. Morse Attn: Jce Foreman Engineering College Attn: E. Co Haynie, D/520 University of Cincinnati North American Aviation, Inc. Cincinnati, Ohio Space and Information Systems Attn: Dr. Frank Tse Division 12214 Lakewood Boulevard University of Dayton Downey, California Research Institute Attn; L. E. Gatzek, D/098 Dayton, Ohio 45409 Attn: Go J. Roth Northrop Corporation Norair Division University of Denver 1001 W. Broadway Denver Research Institute Hawthorne, California Denver 10, Colorado Attn: V. L. Boland Attn: Robert Venuti, Asst. Dir. Attn: R. R. Nolan Attn: Dr. D. Klodt Research Metallurgist Pennsylvania State University 207 Old Main Building University of Illinois University Park, Pennsylvania Department of Mechanical Engineering Attn: Professor A. 0. Schmidt Urbana, Illinois Industrial Engineering Attn: Professor K. J. Trigger 156

DISTRIBUTION LIST (Continued) University of Illinois Carmet Company Department of Mechanical Engineering 1515 Jarvis Avenue Urbana, Illinois Ferndale, Michigan 48220 Attn: Dr. Bo F. Von Turkovich Attn: C. H. Toensing, Director Technical Services University of Wisconsin Madison, Wisconsin VR/Wesson Company Attn: Professor Jo C. Bollinger 800 Market Street Waukegan, Illinois 60086 Valeron Corporation Attn: R. Lo Brogan, Vice President Valenite Metals Division 31100 Stephenson Highway Newcomer Products, Inc, Madison Heights, Michigan P.O. Box 272 Latrobe, Pennsylvania 15650 Dr. L. C. Hamaker Attn: J. Kozusko Vice President of Technology Vanadium-Alloys Steel Company Vermont American Corporation Latrobe, Pennsylvania 500 East Main Street Louisville 2, Kentucky Vascoloy-Ramet Corporation Attn: John D. Knox, Manager 800 Market Street Multi Metals Division Waukegan, Illinois Attn. Dr. D. H. Driggs Metal Carbides Corporation 6001 Southern Boulevard Vitro Corporation of America Youngstown, Ohio 44512 Chemistry and Arc Department Attn: R. T. Beeghly 200 Pleasa.nt Valley Way West Orange, New Jersey Sandvik Steel, Inc. Attn. Martin Ortner, Director 1702 Nevins Road Fair Lawn, New Jersey Wendt-Sonis Company Attn: D. Po Cameron 10th and Collier Streets Hanniba.l Missouri Morse Twist Drill & Machine Co, Attn~ To Vo Hilt, General Manager Attn' John Jo Hayes New Bedford, Massa.chusetts Weldon Tool Company 3000 Woodhill Road National Lead Co. of Ohio Cleveland 14, Ohio Attn: Mr. W. E. Stephens Attn: W. C. Bergstrom Box 39158 Cincinnati, Ohio 45239 Adamas Carbide Corporation Kenilworth, New Jersey 07033 Metal Cutting Tool Institute Attno E. L. Dreyer, President Attn: Perry Lo Houser, Pres. Chrysler Building 405 Lexington Avenue New York, N. Y. 10017 137

DISTRIBUTION LIST (Continued) New Hampshire Ball Bearings, Inc. Crucible Steel Co. of America Attn: W. M. Ware Research Librarian Engineering Department 234 Atwood Street Peterborough, New Hampshire Pittsburgh, Pennsylvania. 15213 Gleason Works Corning Glass Works Attn: Harry J. Hart, Mgr. Attn: Jon D. Lowry Research & Development Trans. Prod. Dept. 1000 University Avenue Corning, New York Rochester 3, New York California Institute of Technology General Electric Company Attn: Aeronautics Library Attn: Leola Michaels, Librarian 1201 E. California Street Metallurgical Products Department Pasadena, California 91109 Box 237 Detroit, Michigan 48232 Jones & Lamson Machine Co. Attn: N. R. Heald Giddings & Lewis Machine Tool Co. 160 Clinton Street Attn: Mr. E. J. Kaiser, V.P. Engrg. Springfield, Vermont 142 Doty Street Fond du Lac, Wisconsin 54935 Brush Beryllium Company Attn: John Estess, Product Mgr. Firth Sterling, Inc. 17876 St. Clair Avenue Attn: M. L. Backstrom Cleveland, Ohio 44110 3113 Forbes Avenue Pittsburgh, Pennsylvania 15230 Lehigh University Attn: Dr. Richard M. Spriggs Ex-Cell-O Corporation Materials Research Center Attn: Library Bethlehem, Pennsylvania 18015 1200 Oakman Blvd. Detroit, Michigan Federal-Mogul-Bower-Bearings, Inc. Attn: David W. Lannin Kearney & Trecker Corporation 11021 Shoemaker Avenue Attn: O. B. Mohr Detroit, Michigan 48213 6800 W. National Avenue Milwaukee, Wisconsin E. I. DuPont de Nemours & Co. Central Research Dept. Cornell Aeronautical Laboratory, Inc. Experimental Station Attn: Library Wilmington 98, Delaware P. O. Box 235 Buffalo, New York Brown & Sharpe Mfg. Company Attn: C. Sharpe, Director R8& Centerdale 11, Rhode Island 138

DISTRIBUTION LIST (Continued) Allison Division United Shoe Machinery Corporation General Motors Corporation Attn: Bruce F. Paul Attn: Library Balch Street P.O. Box 894 Beverly, Massachusetts Indianapolis 6, Indiana Union Carbide Corporation Western Gear Corporation Stellite Division Precision Products Div. Attn: E. E. Jenkins Attn: Eo T. Bergquist, Tech. Div. Kokomo, Indiana 46901 P O, Box 192 Lynwood, California United States Steel Corporation Attn: Thos. J. Woeber, Warner & Swasey Company Marketing Research Attn: Robert T. Hook Machinery & Allied Industries 5701 Carnegie Avenue Five Gateway Center Cleveland, Ohio Pittsburgh, Pennsylvania 15230 University of Washington Union Carbide Corporation Attn: T.S. Shelvin Linde Division Ceramic Engrgo Division Attn: John Fo Pelton, Mgr. Seattle, Washington Flame Plating Dept. P.O. Box 24184 Nuclear Metals Indianapolis, Indiana 46224 Division of Textron, Inc. Attn: Martin R. Lee Union Carbide Corporation West Concord, Massachusetts 01781 Nuclear Division Attn: Co Scott The Norton Company P O. Box Y-12 Attn, Dr. L. P. Tarasov N. Oakridge, Tennessee 37830 Research & Development Worcester 6, Massachusetts Sundstrand Machine Tool Company Attn: H. Ro Leber Nuclear Metals Newburg Road Division of Textron, Inc. Belvidere Illinois Attn, James G. Hunt Staff Ceramist Syracuse University Research Inst. West Concord, Massachusetts 01781 Metallurgical Research Laboratory Bldg. D6, Collendale Campus University of Alabama Syracuse 10, New York Attn Dr. Chass. HoT. Wilkins Dept, of Metallurgical Engrg. Sun Oil Company Tuscaloose, Alabama Attn: Paul E. Hagstrom Research & Development Marcus Hook, Pennsylvania 139

DISTRIBUTION LIST (Concluded) Republic Steel Corporation Sperry Gyroscope Company Research Center - Library Attn: G. B. Achtmeyer 6801 Brecksville Road Mail Station 2T117 Cleveland, Ohio 44131 Great Neck, New York 11020 Sikorsky Aircraft Division Stanford Research Institute United Aircraft Corporation Department of Metallurgy Attn: Library Menlo Park, California N. Main Street Stratford, Connecticut Overseas Co A. Gladman R. We ill Division of Applied Physics Ingenieur Militaire en Chef National Standards Laboratory Laboratorie Central de l'Armement University Grounds Arcueil (Seine) City Road Paris, France Chippendale - N S.W., Australia Professor F. Koenigsberger E. Bodart The Manchester College of Science Professor a l'Universite de Liege and Technology Institut de Mecanique Sackville Street 75 rue du Val-Benoit Manchester 1. England Liege Belgium Dr. Ing. M. Pesante Fo Eugene Chef du Service des Recherches RIV Ingenieur Militarie en Chef Officine di Villar Perosa Institut Superiour des Materia.ux et de Via, Nizza 148 la Construction Mecanique Torino, Italy Paris, France Professor Ir. A. J. Pekilharing Monsieur Po Nicola.u Laboratorium voor Werkplaatstechniek CIRP Secretariate Generale Technische Hogeschool 44 rue de Rennes Leeghwaterstraat 3 Paris VI, France Delft, The Netherlands J, Pomey Olov Svahn Directeru Scientifique de la, Regie Professor, Doctor of Technology Nationale Chalmers Tekniska Hogskola des Usiness Renault Gibraltargatan 5M 8 Avenue Emile Zola Goteborg S, Sweden Boulohur-Be llaneourt ( Seine ) Paris, France 1.40

Unclassified Security Classification DOCUMENT CONTROL DATA - R&D (Security claeificatton of title, body of abstract and Indexing annotation must be entered when the overall report is clastlfied) 1. ORIGINATING ACTIVITY (Corporate author) Za. REPORT SECURITY C LASSIFICATION The University of Michigan Unclassified Department of Mechanical Engineering 2b GROUP Ann Arbor, Michigan 48105 3. REPORT TITLE INTERNATIONAL COOPERATIVE RESEARCH PROGRAM ON TOOL WEAR 4. DESCRIPTIVE NOTES (Type of report and Inclulive datei) Final Report, 16 November 1964 - 15 November 1965 S. AUTHOR(S) (L.st name. tirat name, initial) Colwell, L. V., Mazur, J. C., Quackenbush, L. J., Hardy, J. M. 6. REPORT DATE 7a. TOTAL NO. OF PAGES 7b. NO. OF REFS December 1966 128 None 8a. CONTRACT OR GRANT NO. 9a. ORIOINATOR'S REPORT NUMBER(S) AF 33(615)-2159 06926-4-F b. PROJECT NO. MM Project Nr. 8-338 _ c. S. OTHER R PORT NO(S) (Any other numbere that may be asasined Chie report) d. AFML-TR-66-387 10. A VA IL ABILITY/LIMITATION NOTICES Qualified requesters may obtain copies of this report from DDC. I1. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY Air Force Materials Laboratory Research and Technology Division Wright-Patterson Air Force Base, Ohio 13. ABSTRACT This is the fourth and final report of the series under this contract. It includes coverage of forces and shear zone mechanics, wear of American and European carbide and high speed steel cutting tools, and accelerated tests for evaluating cutting performance. In addition, the report summarizes the objectives, experimental procedures, and related activities of the OECD/CIRP international cooperative research program in metal cutting as detailed in Interim Reports 1, 2, and 3. The program has shown that it is possible to work successfully among various laboratories and across international boundaries to achieve specific goals. The exchange of information has proved to be not only a valuable check upon the repeatability and validity of results, but has led to improvements in measuring techniques and associated instrumentation for more reliable and more consistent interpretations. The results have helped to identify those areas which need more intensive studies for evaluation of causes and effects of metal cutting behavior. Phase II, a study of steels of different microstructures and properties, is an important next step in the expansion of the OECD/CIRP program. DD o., JAN 1473 Unclassified Security Classification

Unclassified Security Classification 14~ LINK A LINK B LINK C KEY WORDS ROLE WT ROLE WT ROLE wT Wear, Cutting Tools, Measurement INSTRUCTIONS 1. ORIGINATING ACTIVITY: Enter the name and address imposed by security classification, using standard statements of the contractor, subcontractor, grantee, Department of De- such as: fense activity or other organization (corporate author) issuing (1) "Qualified requesters may obtain copies of this the report. report from DDC " 2a. REPORT SECURITY CLASSIFICATION: Enter the. over (2) "Foreign announcement and dissemination of this all security classification of the report. Indicate whether report by DDC is not authorized" "Restricted Data" is included. Marking is to be in accord-a o ance with appropriate security regulations. (3) "U. S. Government agencies may obtain copies of this report directly from DDC. Other qualified DDC 2b. GROUP: Automatic downgrading is specified in DoD Di- ss shall request through rective 5200. 10 and Armed Forces Industrial Manual. Enter the group number. Also, when applicable, show that optional. markings have been used for Group 3 and Group 4 as author- (4) U. S. military agencies may obtain copies of this ized. report directly from DDC Other qualified users 3. REPORT TITLE: Enter the complete report title in all shall request through capital letters. Titles in all cases should be unclassified, If a meaningful title cannot be selected without classifica- tion, show title classification in all capitals in parenthesis (5) "All distribution of this report is controlled. Qualimmediately following the title. ified DDC users shall request through 4. DESCRIPTIVE NOTES: If appropriate, enter the type of.___b,I report, e.g., interim, progress, summary, annual, or final. If the report has been furnished to the Office of Technical Give the inclusive dates when a specific reporting period s Services, Department of Commerce, for sale to the public, indicovered. cate this fact and enter the price, if known. 5. AUTHOR(S): Enter the name(s) of author(s) as shown on 11. SUPPLEMENTARY NOTES: Use for additional explanaor in the report. Enter last name, first name, middle initial tory notes. If military, show rank and branch of service. The name of the principal author is an absolute minimum requirement. 12. SPONSORING MILITARY ACTIVITY: Enter the name of the departmental project office or laboratory sponsoring (pay6. REPORT DATl Enter the date of the report as day, ing for) the research and development. Include address. month, year; or month, year. If more than one date appears on the report, use date of publication. 13. ABSTRACT: Enter an abstract giving a brief and factual summary of the document indicative of the report, even though 7a. TOTAL NUMBER OF PAGES: The total page count it may also appear elsewhere in the body of the technical reshould follow normal pagination procedures, i.e., enter the port. If additional space is required, a continuation sheet shall number of pages containing information. be attached. 7b. NUMBER OF REFERENCES: Enter the total number of It is highly desirable that the abstract of classified reports references cited in the report. be unclassified. Each paragraph of the abstract shall end with 8a. CONTRACT OR GRANT NUMBER: If appropriate, enter an indication of the military security classification of the inthe applicable number of the contract or grant under which formation in the paragraph, represented as (TS). (S). (C). or (u) the report was written. There is no limitation on the length of the abstract. How8b, 8c, & 8d. PROJECT NUMBER: Enter the appropriate ever, the suggested length is from 150 to 225 words. military department identification, such as project number, 14. K subprojecnumber, ystem numbers task number et. KEY WORDS: Key words are technically meaningful terms subproject number, system numbers, task number, etc. subprojec ' systemnumbers,. ts nbor short phrases that characterize a report and may be used as 9a. ORIGINATOR'S REPORT NUMBER(S): Enter the offi- index entries for cataloging the report. Key words must be cial report number by which the document will be identified selected so that no security classification is required. Identiand controlled by the originating activity. This number must fiers, such as equipment model designation, trade name, military be unique to this report. project code name, geographic location, may be used as key 96. OTHER REPORT NUMBER(S): If the report has been words but will be followed by an indication of technical conassigned any other repcrt numbers (either by the o riginks, rules, and weights is optional. or by the sponsor), also enter this number(s). 10. AVAILABILITY/LIMITATION NOTICES: Enter any limitations on further dissemination of the report, other than those Unclassified Security Classification

UNIVERSITY OF MICHIGAN 3 9015 02651 5109