ENGINEERING RESEARCH INSTITUTE THE UNIVERSITY OF MICHIGAN ANN ARBOR Final Report THE EFFECT OF MELTING AND CASTING ATMOSPHERES ON THE STRESS-RUPTURE PROPERTIES OF CAST NICKEL-BASE ALLOYS C. M. Hammond R. A. Flinn Project 2308 DEPARTMENT OF THE NAVY, BUREAU OF AERONAUTICS AIRBORNE EQUIPMENT DIVISION, INSTRUMENTS BRANCH (AE-43) CONTRACT NO. NOas 55-110-c WASHINGTON, D.C. January 1956

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN TABLE OF CONTENTS Page LIST OF TABLES iii LIST OF FIGURES iv SUMMARY v INTRODUCTION1 OBJECTIVE1 PROCEDURE 1 1. PRELIMINARY iEERIMENTS 2 a. Specimen Design 2 b. Gating Design 6 c. Pouring Temperatures 6 2. STANDARD PROCEDURES 8 a. Mold Preparation 8 b. Melting and Pouring 9 c. Chemical Analyses 14 d. Mechanical Testing 20 e. Metallography 21 DATA AND DISCUSSION OF RESULTS 21 1. GUY-TYPE ALLOY 21 Vacuum-Fusion Analyses-Nitrogen Effect 22 2. INCO-700-TYPE ALLOY 25 Vacuum-Fusion Analyses-Nitrogen Effect 25 3. GMR-235 -TYPE ALLOY 28 Vacuum-Fusion Analyses —Nitrogen Effect 28 GENERAL COMPARISON 28 CONCLUSIONS 0 FUTURE WORK 31 BIBLIOGRAPHY 31 APPENDICES 33-36 I____________________________ ii _

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN LIST OF TABLES Table Page I. Properties and Nominal Compositions of Three Promising Cast Nickel-Base Alloys 3 II. Pouring Temperatures of the Three Alloys Investigated 6 III. Raw Materials 10 IV. Chemical Analyses-Wide Range 15 V. Chemical Analyses-Narrow Range 16 VI. Analysis Range vs 100-Hour Rupture Life 20 VII. Effect of Melting and Casting Atmospheres upon 100-Hour Rupture Strength and Elongation of Guy-Type Alloy at 1500~F 22 VIII. Vacuum-Fusion Analyses for Nitrogen 24 IX. Effect of Melting and Casting Atmospheres upon 100-Hour Rupture Strength and Elongation of Inco-700-Type Alloy at 1500~F 25 X. Effect of Melting and Casting Atmospheres upon 100-Hour Rupture Strength and Elongation of GMR-235-Type Alloy at 1500~F 28 XI. Summary of Stress-Rupture Properties of the Three Alloys 30 iii

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN LIST OF FIGURES Figure Page 1. Cast stress-rupture specimen 4 2. Test-bar cooling curves 5 3. Investment process 8 4. Air and argon-protected melting equipment 12 5. Vacuum + argon melting equipment 13 6. Effect of melting and casting atmospheres upon stress-rupture properties of Guy-type alloy at 1500~F (wide analysis range) 17 7. Effect of melting and casting atmospheres upon stress-rupture properties of Guy-type alloy at 1500~F (narrow analysis range) 17 8. Effect of melting and casting atmospheres upon stress-rupture properties of Inco-700-type alloy at 1500~F (wide analysis range) 18 9. Effect of melting and casting atmospheres upon stress-rupture properties of Inco-700-type alloy at 1500~F (narrow analysis range) 18 10. Effect of melting and casting atmospheres upon stress-rupture properties of GMR-235-type alloy at 1500~F (wide analysis range) 19 11. Effect of melting and casting atmospheres upon stress-rupture properties of GMR-235-type alloy at 1500~F (narrow analysis range) 19 12. Microstructures of cast Guy-type alloy 23 13. M.crostructures of cast Inco-700-type alloy 26 14. Microstructures of Inco-700-type alloy after testing at 1500~F 27 15. Microstructtres of GMR-255-type alloy 29 iv

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN SUMMARY Improvement of cast heat-resistant alloys in the past has depended upon the investigation of new compositions. By contrast, this work is directed toward determining the effect of melting and casting atmospheres upon the properties of existing alloys. The following table of data, obtained for three promising nickel-base alloys, indicates that melting and casting atmospheres can be very important in influencing 100-hour rupture strength and elongation at 1500~F. This Investigation (Melted unl| Published Properties |der vacuum, poured under argon) Alloy Type 100-Hour Percent 100-Hour Percent Rupture Strength Elongation Rupture Strength Elongation __________psi __psi (100 hours) Guy 49,000 2-5 56,000 7-10 Inco 700 435,000* 10' * 42,000 21 GMR 235 39-40,000 6-10 42,000 14-19 ~*Solution treated and aged, all others as cast. The strength increases were most pronounced in the high-boron material Guy type, while improvements in ductility were apparent in all cases. The low nitrogen contents, produced by the vacuum-melting technique, may account for the superior strength and ductility. These data indicate further that the effects of melting and casting atmospheres are of different magnitudes for various alloys. The improvement in ductility of the Guy-type alloy by vacuum melting may have led to the enhanced strength by avoiding rupture in the second stage of creep which may occur in the brittle, air-melted material. v

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN INTRODUCTION As a result of the conversion to gas-turbine engines by the aircraft industry, alloys for better service at elevated temperatures have become essential. Since the rotor blades in these engines are subjected to the higheso temperatures and stresses, the materials used here are critical. Initially, these blades were made of cobalt-base alloys, but the scarcity and expense of cobalt has led to considerable research on nickel-base alloys. 2''3 Most of the effort in these researches has been concentrated on variations in chemical analyses correlated with changes in stress-rupture properties at 15000F. Most of the nickel-base alloys developed in this manner are titanium or aluminum bearing, or both. Since these elements are known to give casting difficulties through severe metal oxidation and gas solution during melting, it was questioned whether or not the published properties represented the true potential of these materials. Therefore, research concerning the effects of melting and casting atmospheres upon stress-rupture properties appeared necessary to parallel the investigations of compositional effects. OBJECTIVE The objective of this investigation, therefore, is to evaluate the effect of melting and casting atmospheres and other processing variables upon the room-temperature and stress-rupture properties of promising nickel-base alloys. This report is concerned chiefly with the effects of the atmosphere during melting and casting. PROCEDURE A literature survey indicated that the Guy,1 Inco 700,4 and GMR 2355 alloy types are the most promising nickel-base materials at present. The _________________________________ 1 _____________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN properties and chemical compositions of these alloys are shown in Table I. All three materials contain considerable percentages of titanium and aluminum and, therefore, as mentioned in the Introduction, melting and casting atmospheres should be significant in determining ultimate properties. The general procedure followed in this investigation is conveniently discussed under the following headings: 1. Preliminary Experiments a. Specimen design b. Gating design c. Pouring temperatures 2. Standard Procedures a. Mold preparation b. Melting and pouring c. Chemical analysis d. Mechanical testing e. Metallography 1. PRELIMINARY EXPERIMENTS Before entering the principal phases of the investigation, it was necessary to establish specimen design, gating design, and pouring practices which would produce acceptable properties, i.e., similar to present published results. a. Specimen Design.-It was feared that the present standard test bar (.250 diameter, 1-in, gage length) would contain excessive center-line shrinkage in the gage length. Accordingly, two other designs were developed (Fig. 1) which should allow better feeding from the riser. Length-Diameter Specimen Type Diameter Gage Length Ratio A.250 1.0 4:1 B.250.50 2:1 C.125.25 2:1 To provide a wide range of alloys for evaluation, X-40, GMR 255, and.50%-C steel were selected for the tests. Fortunately, the degree of directional solidification in the standard bar was sufficient to produce radio graphically sound bars in all cases. This bar was then used throughout the investigation. Occasional center-line microshrinkage, too fine to affect the radiographs,was encountered. The cooling curves of Fig. 2 indicate a gradient of 100~F/in. at the time of solidification, which is of course the time at which the demand for feed metal is most important. ----- -------------------— 2 -------------

m m m TABLE I z PROPERTIES AND NOMINAL COMPOSITIONS OF THREE PROMISING CAST NICKEL-BASE ALLOYS m 100-Hour Alloy Type Rupture Strength Percent Elongation C Cr M Al Fe Ti B Co Cb I at 100 Hours Guyl 48-50,000 5-5.10 15 6.0 6.0 4.5 ---.50 -- 2.0 *Inco 7004 41-43,000 10.10 15 5.0 5.0.5 2.0 --- 28 -- Z GMR 255 58-40,000 6-10.15 15.5 5.25 35.0 10.0 2.0.075 -- - *Properties from wrought specimens, solution treated 2160~F/2 hours and air-cooled; aged at 1600~F/4 hours and air-cooled. O

UNJVERs\Tv OF MiCHIGA4 Z - - ____-__ 33.100 - | Sc^.C- I" __* YS FEB. 15, \955 WL 5.090 ____ — a -1.00 -i% -i.158 D- A. ___*ISS / 2 O 5 m.1./.o o &.49 BD. 9 TO ~ ~ ~ ~.:ALL TFVIEG I._ __,,,N. e \.. ATETML OF BaA 0IS 4 30E = -- 1 ALL, A,-.p..U..?...507 ) 1-125 < - F 53 ig T.PE 1A\ -.TPr^DAFgT C 2 DRAFT UNDERCUT To ROOT OF TREA.O A-40 BZLE- -.837 -375A-L-THvAO5 AR \ Z/T - I:;.C. EKcPT A ALLoW FOR'5~4QM m_ tI OF.010 >44./sY>.66 M.m.TDo. 17. M usr BE. ADED _ To ALL TH-READ 0\ME1s\o D, 2.259 mn MATERIAL 15 STE-E-L-,I UNLES OTHERWIe 5PECF-IFIE-D.251 ToLES.A.1.CEc 5.010 64. 0'~ ENDS OF PiVNs5 TAPEsEO —---— D SA.E1 AE 3 Rg.GA ULb P\<S. s / I -'~4C5 15 -- — FoR - ^ — -. ~505'5P!ThAE.1._.504 FO R.505 Sp-c^neNi ^TYPE "B" -.5" GAE- LE1iGTH Fig. 1. Cast stress-rupture specimen.

DOUBLE SIZE 2800 C z 28 GAUGE rn FPrT.-l07%RHLP. -Z \ ~~~~~~~~~~~THERMOCOUPLE ^^a ~*~= —- ( 2600 ^2400 I g - \ ^Y ^~~BOTTOM 12200- -. ^ ^ "m^ w 2000 0 1800 -' 40 80 120 160 200 240 280 320 3601 TIME- SEC Fig. 2. Test-bar cooling curves.

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN b. Gating Design.-A new gating system was designed for this investigation for several reasons. The majority of the present systems attempt to deliver molten metal at both ends of the vertically cast bar. It must be recognized that this procedure results in the turbulent meeting of two streams of hot metal in the test bar and can lead to unpredictable variations in drossing and variable thermal gradients during solidification. The principal reason advanced for this type of gating is "to avoid cold metal in the riser." By contrast, it is generally agreed that a minimum of turbulence is encountered with bottom gating. The General Motors research group5 has developed a rather elaborate design based on this principle. This mold design, however, still employs an auxiliary runner "to avoid cold riser metal." It was considered possible by the present investigators that with rapid bottom pouring, a simple bottom gating system might be used, and the design shown in Fig. 3b was developed. The quantitative data of Fig. 2 indicate that ideal directional solidification with equal feeding contributions from both ends of the testbar section is obtained with this new arrangement. It should be pointed out, furthermore, that all bars have the same cooling rate because of the symmetrical arrangement about the downsprue. This is not the case in a number of designs now in use in which the bars at interior and corner locations of the cluster have different cooling rates. c. Pouring Temperatures.-GMR 235 was used as a model to evaluate pouring-temperature effects. Preliminary tests indicated that the influence of temperature was small and that a statistical study of a large sample would be required. (This work is now in progress.) However, to allow the investigation to proceed to the more significant phases, a pouring temperature of 2850~ + 200F was used for GMR 235 in order to provide satisfactory fluidity and at the same time to insure good casting surfaces. Since it has been established that fluidity is a linear function of the superheat above the liquidus, the other alloys were poured at approximately the same degree of superheat as shown in Table II. These temperatures were maintained for all three TABLE II POURING TEMPERATURES OF THE THREE ALLOYS INVESTIGATED Alloy Type Liquidus Pouring Temperature Degree Superheat ~F OF Guy | 2520 2800 280 Inco 700 2530 2800 270 GMR 235 2520 l 2850 | 550 l 6

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN c Dipcoated cluster, d. Mold assembly. ~..e. Final casting... Fig. 5. Investment process. ^\- ____e______________. Final casting.

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN nickel-base alloys throughout the remainder of this investigation. It is recognized that further work to delineate the quantitative effects of pouring temperature, as well as the influence of melting and superheating periods, would be of value and this is now in progress. 2. STANDARD PROCEDURES While substantial changes in mold design were considered important as just described, a good commercial investment practice was adopted as standard. Accordingly, wax patterns and an ethyl-silicate-base investment were used. a. Mold Preparation.-This process (Fig. 3) consisted of making wax replicas of the desired final casting, assembling the wax replicas on a wax gating system, dipcoating the replicas with a thin coating of a fine silica slurry, enclosing the assembly in a flask, and finally pouring in the investment material. The mold was allowed to set up at room temperature prior to dewaxing and firing to provide proper green strength for handling. The wax replicas, in this case wax tensile bars, were made by injecting wax at 80~C into the die shown in Fig. 3a. These bars were then assembled into a cluster shown in Fig. 5b, which was then mounted on a wooden bottom board prior to dipcoating, (Fig. 3c). The dipcoat mixture is listed below: Dry materials: 200-mesh Si flour 10 lb FeO.25 lb Sodium fluoride 13.5 g Wet materials: Nalcoag 875 cc H20 675 cc Batch A: Wetanol 40 g H20 1000 cc Octyl alcohol 2 drops The dry materials were mixed thoroughly prior to addition of the wet materials. The Batch-A solution, the wetting agent, was added to the slurry ten minutes prior to dipcoating. To insure removal of adhering air bubbles from the dipcoated cluster, a low-velocity air stream was passed onto the cluster, breaking all bubbles. The dipcoating operation was completed by sprinkling the wet _________________________________ 8 _________________________________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN cluster with 40-mesh silica sand and allowing it to dry four hours prior to investing. The coarse 40-mesh silica sand insured good bonding with the backup investment mix. Before actually investing, the clusters were surrounded by a stainless-steel flask (Fig. 5d) and the assembly was made water tight by dipping it into wax. A paper extension was sealed to the flask to allow for settling during vibration. The investment mixture is summarized below: Refractory materials: 200-mesh Si flour 12.0% 40-80-mesh Si sand 23.5% G Grog 25 % P Grog 40 % MgO (powdered).4% Investment binder Ethyl Silicate 40 2996 cc Diluter (5% H20, 95% Symasol) 2385 cc Reactor (50% H20, 50% Symasol +.75% HC1) 619 cc 6000 cc The refractory materials were mixed thoroughly for 30 minutes in a cement mixer. In the preparation of the investment-binder solution, the diluter was added to the ethyl silicate and then the reactor added. The investment binder was added gradually to the refractory materials until the slurry was of the consistency of thin cement, approximately 110 cc/lb. This mixture was then removed from the mixer and poured into the flasks, which were vibrated during pouring. The vibration insured dense packing around the cluster. After approximately four hours at room temperature, the mold possessed enough green strength for handling, dewaxing, and firing. The temperature and time for dewaxing were approximately 2250F and three hours, respectively. The firing cycle was 16000F for approximately 10 hours. The dewaxing operation removed the bulk of the wax, while firing removed the remainder and preheated the mold to 1600F'. IThe fired molds were removed from the furnace just prior to pouring. The critical transformation of silica in the temperature range of 10000-1200~F prohibited cooling the molds below this range after firing. Storage, however, was easily accomplished before or after dewaxing, with the former preferred. Dimensions were held to +.0025 in. with this process. The final test-bar casting cluster is shown in Fig. 3e. b_. Melting and Pouring. — The melting and the pouring of the three experimental nickel-base alloy types, Guy, Inco 700, and GMR 235, were conducted under three atmospheric conditions: ------------------------— 9 —------------

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN (1) Air (2) Argon-protected (3) Vacuum + argon Melts were made of virgin metals, except as noted in the test. The metals and alloys used, their analyses, and suppliers are listed below in Table III. TABLE III RAW MATERIALS Material Analysis -Percent Supplier Ni (electrolytic) Ni+Co - 99.95; Fe -.01-.04; Inco C - trace; Si - trace. Cr (electrolytic) Cr - 99.3; Fe -.13; 02 -.50; Electromet H2 -.004; N2 -.02. Mo (chips) Mo - 99+. Climax Moly Al (piglets) Al - 99.99. Alcoa NiB Ni - 80.4; Al <.01; Fe - 1.73; C -.15; B - 17.39; Electromet Si -.51. FeCb Cb - 57.34; C -.25; Si - 7.8; Electromet Fe - balance. Ti (rod) C -.03; N -.023; Fe -.04; Titanium Metals Corp. Ti - balance. of America FeC (alloy) C - 4.22; Si -.28; Mn -.19; S - trace; P - trace; Univ. of Mich. foundry Fe - balance. Co Co - 99.,9 Belmont Smelting and Refining Works The crucible charge and order of additions were in general the same for all three types of atmospheres. The nickel, chromium, cobalt, molybdenum, and iron were charged to the crucible. The other alloying elements were added ___________________________ 10 _____________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN after melt down in the following order: aluminum, carbon, titanium or columbium, and boron. Nickel squares were charged with the aluminum and titanium additions to curb their violent exothermic reactions. Temperatures for air and argon melting were measured by a Pt - 10% Rh - Pt thermocouple enclosed by a fused-silica tube. Optical pyrometer measurements were used to follow temperatures in vacuum. Heating rates in air and argon were determined for each alloy at a constant kilowatt input. These rates were used to calculate the actual pouring temperature, since the thermocouple had to be removed to place the mold on the furnace. The time interval between the last temperature reading and pouring was exactly two minutes. Liquidus temperatures were determined for each alloy investigated. Any change in the general procedure outlined above is indicated in the sections dealing specifically with each melting atmosphere. (1) Air Atmosphere.-The roll-over induction furnace used both for air and argon melting is shown in Fig. 4a. The mold was clamped on top of the furnace and the assembly rolled 180~. The position of the mold when partially rolled is shown in Fig. 4b. With air melting, the crucible was uncovered, allowing the melt to be exposed to the air. When the heat was poured, the mold was clamped above the furnace and argon pressure was used in pouring. A pressure of five psig was applied after the mold had been rolled approximately 90~ of the 180~ total. (2) Argon-Protected Atmosphere.-The same procedure was followed in argon-protected melting as in air melting, except the melt surface was covered with a blanket of argon throughout the heat. The crucible was charged, covered with an asbestos gasket and refractory brick, and flushed with argon. A positive argon pressure was maintained within th e crucible during melting. Argon pressure was again used for pouring. (3) Vacuum + Argon Atmosphere.-Thee exterior of the vacuum melting unit and control panel is shown in Fig. 5a. The mold assembly within the shell, the crucible, addition buckets and dipper are shown in Fig. 5b. The pressure within the shell during actual melting was below five microns. The crucible was charged and the buckets filled with the alloy additions in the order previously outlined. The cover was closed and a vacuum of five microns or below was drawn. At this point the power was applied to the crucible. After melt down, the heat was held for 20 minutes at approximately 2700~F to allow refining to take place. After refinement, the alloy additions were made. Since a considerable decrease in mold temperature would occur if the mold were placed in the vacuum shell at the outset of the heat, it was left in the l~~~~~g..~~~h

melts. Capacity, 10 lb. mn rm I used for air and argon-protected procedure. Fig. 4. Air and argon-protected melting equipment. Z

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN a. Exterior of vacuum melting unit, showing control panel, melting shell, and vacuum pumps. b. Interior of vacuum shell, showing the induction furnace, mold, charging buckets, and dipper, Fig. 5- Vacuum + argon melting equipment. 13

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN firing furnace until after the alloy additions were made. To protect the melt from air contamination while the mold was inserted, an atmosphere of argon was introduced into the shell and the melting crucible covered. After insertion of the mold, another vacuum was applied and the heat was remelted and heated to the pouring temperature. This entire operation required 20-30 minutes. Argon was bled in during pouring. Heats R-108, R-109, R-114, R-115, and R-160 were poured in this manner. Even though the sprue temperature was apparently greater than 1200~F after this 20-30-minute period,.the actual mold-cavity temperature was unknown. A cooling curve from a mold preheated at 1600~F showed that after 30 minutes the mold-cavity temperature dropped to 9000F. Cooling curves of molds heated at 1800~ -indicated that eight minutes were available before the mold-cavity temperature fell to 1600~F. To meet this time requirement, the melt was kept liquid during the introduction of argon. The power was applied immediately after the mold was inserted and the cover closed. The vacuum was applied to the shell after the power was turned on and a pressure of 30 microns obtained. Argon pressure of one atmosphere was applied during pouring, as in the previous case. Heats R-175 and R-176 were made while using this procedure and a mold temperature of 16000F attained at pouring (eight minutes after mold withdrawal from the firing temperature of 1800~F). c. Chemical Analyses.-The majority of the chemical analyses listed in this report were performed by the J. H. Herron Co. in Cleveland, Ohio. The chemical ranges of the elements and the percentages charged for the alloys are listed in Table IV. Difficulties with Ti, Al, and B analyses arose early. Several checks of these elements were performed by the International Nickel Co.6 These analyses checks are listed in Appendices I-III. The validity of the low Al, Ti, and B analyses was questioned, especially with the charged percentages listed above. However, to check the effect of the analysis spread on the stress-rupture properties, the following analysis range was obtained by removing heats which greatly departed from nominal analyses. Figures 6, 8, and 10 contain all the heats made for the three alloy types. Their wide analysis range is listed in Table IV. Figures 7, 9, and 11 contain the heats with the narrow analysis range listed in Table V. The effect of the analysis spread upon 100-hcu- rupture strength is shown in Table VI. 14

m m TABLE IV m CHEMICAL ANALYSES -WIDE RANGE C Type C Cr Mo ~ Al Fe Ti B Co Cb Guy charged.10 13.5 7.0 7.0 4.5 ---.60 --- 2.0 Z Range.08-.26 12.83-15.35 4o42-5.87 4.33-7.31 43.56-6.94 ---.28-.48 --- 1.52-2.0 Inco 700 charged.10 15.5 3 2 53 5 5 2.0 --- 29 Range.09-.34 14.79-15.89 2.10-3.32 1.32-3.4.17-.99 1.30-3.3 -- 27.14-30.5 --- - GMR 255 charged.15 15.5 5.0 3.5 10.C 2.0.09 —. -- Range.15-.27 15.03-15.99 4.51-5.59 2.57-4.66 7.65-11.10 1.70-2.30.06-.12 — _< I z

m m m TABLE V CHEMICAL ANALYSES-NARROW RANGE Alloy Type C Cr Mo Al Fe Ti B Co Cb I Guy*.10-.15 13.08-15.35 4.42-5.87 5.50-6.80 4.64-6.94 ---.37-.48 -- 1.83-2.50 Inco 700**.12-.16 15.03-15.60 22.1 0-.05 1.62.90 —210 27.7-29. GMR 235***.15-.18 15.03-15.99 4.31-5.39 3.02-3.88 8.54-11.10 1.75-2.30.06-.10 --- -- m *Composed of heats R-98, R-119, R-88, R-98, and R-160. - **Composed of heats R-97, R-87, and R-109. ***Composed of heats R-116, R-50, R-84, R-108, and R-114. O I z

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN C Cr Mo Al Fe B Cb Analysis Range.08-.26 12.83-15.35 4.42-5.87 4.33-7.31 4.36-6.94.28-48 1.52-2.30 65 —----- - ^ L -^ gon ^ ^ —------------------------- 60 55______ _____i -___ 30 a 0 40 30 1 5 10 20 50 100 200 500 1000 TIME - HOURS R-88 0 R-89 0 R-157 - R-115 0 General Key R-96 l R-98 + R-160 + Melt Atmosphere: Air 0 RI.60 R-119~ +,~ R - 176 A~~Argon- Protected * R-60 + R-119 + R-176 - Vacuum +Argon o R-158 V R-59 Y R-159 6 R-156 1 Fig. 6. Effect of melting and casting atmospheres upon stress-rupture properties of Guy-type alloy at 1500~F (wide analysis range). C Cr Mo Al Fe B Cb Analysis Range.10-.15 13.08-15.35 4.42-5B7 5.50-6.80 4.64-6.94.37-48 1.83-2.30 65 i 55 --- 340 - - -- 35 30 5 10 20 50 100 200 500 1000 TIME HOURS R-88 0 R-98 + R-160 ~ General Key R-96 R R-119 + Melt Atmosphere:Air 0 Argon-Protected * Vacuum-Argon Fig. 7. Effect of melting and casting atmospheres upon stress-rupture properties of Guy-type alloy at 1500~F (narrow analysis range). 17

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN C Cr Mo Al Fe Ti Co Analysis Range.09-.34 14.79-15.89 2.10-3.32 1.32-3.40.17-.99 1.30-3.30 2714-30.5 60 — 55 | —~~~~ 3 —------ — rgo n 30 3_ 5_ CO). 35 5 10 20 50 100 200 500 1000 TIME HOURS R-87 0 R-86 * R-109 General Key R-95 <( R-97 + Melt Atmosphere: Air 0 R-61' R-117 — Argon Protected 0 Vacuum+ Argon o R-58 Y Fig. 8. Effect of melting and casting atmospheres upon stress-rupture properties of Inco-700-type alloy at 1500~F (wide analysis range). C Cr Mo Al Fe Ti Co Analysis Range.12-.16 1503-15.60 2.10-3.03 2.90-3.52.37-.69 1.65-2.10 27.7-29.0 450 ~5M Air A 35 Argon-Protected 0 prs 5 10 20 50 100 200 500 1000 TIME- HOURS R-87 0 R-97 R R-109 3 General Key Melt Atmosphere: Air 0 Argon-Protected * Vacuum + Argon c Fig. 9. Effect of melting and casting atmospheres upon stress-rupture properties of Inco-700-type alloy at 1500~F (narrow analysis range). _______________________ 8 ____________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN C Cr Mo Al Fe Ti B Analysis Range.15-.27 1503-15.99 4.31-5.39 2.37-4.66 7.65-11.10 1.90-2.30.06-.12 50MEHOURS'R-84 R-85 * R-108 General Key ArgonProtected 40o 0 35 49 30 R 5 10 20 50 100 200 500 1000 TIME - HOURS R-84 0 R-85 ~ R-108 ( General Key R-100 ( R-99 # R-14 4 Melt Atmosphere: Air 0 R-43 " R-116 + R-175 +Argon- Protected * R~~-113 R-II~~6 -4-+ R-175 +Vacuum+ Argon ) R-50 R-49 ) R- 120 Fig. 10. Effect of melting and casting atmospheres upon stress-rupture properties of GMR-235-type alloy at 1500~F (wide analysis range). C Cr Ma Al Fe Ti B Analysis Range.15-.13 15.03-15.99 4.31-5.39 3.02-3.88 &54-11.10 1.75-2.30.06-.10 60 6 — 4-rgon-pr" _____oo__-_3 55 4 —-te35 1 5 10 20 50 100 200 500 1000 TIME HOURS R-116 R-50 R-108 0 General Key R-84 0 R-114 < Melt Atmosphere:Air 0 Argon-Protected ~ Vacuum +Argon Fig. 11. Effect of melting and casting atmospheres upon stress-rupture properties of GMR-255-type alloy at 15000F (narrow analysis range). 19

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN TABLE VI ANALYSIS RANGE VS 100-HOUR RUPTURE LIFE 100-Hour Rupture Life Alloy Type Analysis Range Air Argon-Protected Vacuum + Argon wide 43,000 41,000 57,000 Guy narrow 45,000 44,000 58,000 wide 37,000 43,000 44,000 Inco 70 narrow 41,000 45,000 44,000 wide 41,000 42,000 42,000 GMR 239 GMR 2narrow 41,000 4,000 42,000 It is evident from the above table that compositional variations, to the extent given in this report, have little effect upon 100-hour rupture strengths of the three alloys. Some small changes occur in the slopes of the stressrupture lines. d. Mechanical Testing.-To evaluate the effect of melting and casting atmospheres upon ambient- and elevated-temperature properties, the following were used as indices: Ambient-Temperature Properties Elevated-Temperature Properties (1) Tensile strength (1) Stress-rupture strengths at varying (2) Yield strength (.2% offset) rupture times (5) Rc hardness (2) Percent elongation (4) Percent elongation (3) Percent reduction of area (5) Percent reduction of area Before testing, each specimen was radiographed and visually inspected for any flaws. Only specimens which were radiographically sound and which possessed good surface quality were submitted. The room-temperature and stress-rupture tests were performed at The University of Michigan by the staff of Prof. J. W. Freeman, using well-established techniques. The general procedure for room-temperature testing was as follows: (1) the load was applied hydraulically (2) strain measurements were recorded by a Martens-type extensometer system. 20

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN Stress-rupture testing was conducted as follows: (1) three covered thermocouples were tied to the specimen along its gage length (2) the specimen was placed in a cold furnace and brought to temperature at no load (3) the specimen was loaded when the temperature distribution along the gage length was within + 5~F (at 1500~F). e. Metallography.-All metallographic specimens were taken transversely from the center of the gage length. The specimens were mounted in bakelite, ground on dry emery papers, and polished on a diamond lap. Electrolytic etching was performed in a solution composed of 5% hydrofluoric acid, 10% glycerine, and 85% absolute alcohol. Vacuum-fusion analyses of representative heats of the three alloys melted and cast under the three atmospheres were performed with the National Research Vacuum-Fusion Apparatus at the University. Nitrogen, hydrogen, and oxygen contents were determined. DATA AND DISCUSSION OF RESULTS The effects of melting and casting atmospheres upon the properties of the Guy-, Inco-700-, and GMR-2355 types of alloys are illustrated in Figs. 6-11 and Appendices I-IV. In the following section the results for each alloy will first be discussed separately, followed by a general comparison. The discussion covers only the elevated-temperature properties because of their importance in design variation with atmosphere. The ambient-temperature properties for all alloys are summarized in Appendix IV. No atmosphere effect is evident. 1. GUY-TYPE ALLOY The effect of melting atmospheres upon the stress-rupture properties of this alloy is shown in Figs. 6 and 7 and Appendix I. In the case of the Guy-type, the elevated-temperature elongation and strength level are raised considerably by vacuum + argon melting, as shown in Table VII. A separate curve is drawn for the argon-protected heat, R-98 in Figs. 6 and 7 because large amounts of a foreign phase appeared in the microstructure. This foreign "white phase" is illustrated in Fig 12c, and minor ____________________________ 21

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN TABLE VII EFFECT OF MELTING AND CASTING ATMOSPHERES UPON 100-HOUR RUPTURE STRENGTH AND ELONGATION OF GUY-TYPE ALLOY AT 1500~F Atmosphere 100-Hour Rupture Strength Percent Elongation at 100-hour ________ psi Rupture Air 42,000 3 Argon-protected 41,000 1-3 Vacuum + argon 56,000 7-10 amounts were also observed in the following heats only: R-119 (57), R-60 (5%), and R-89 (1%). In general, these heats exhibit stress-rupture properties below average for their specific melting conditions. A survey of the analyses does not indicate any correlation with chemical composition. Apparently, the appearance of this phase is undesirable for high-temperature strength. No optical microstructural changes are evident in the vacuum + argon melted heats to explain the increase in rupture strength or elongation, The structure of this alloy is shown in Fig. 12a. General precipitation occurs throughout the matrix, as shown in Fig. 12b. Vacuum-Fusion Analyses -Nitrogen Effect Vacuum + argon melting and casting decrease the amount of nitrogen in the metal compared with air or argon-protected atmospheres, as shown in Table VIII. Apparently, nitrogen may be involved in explaining the marked increases in elongation and strength at 1500~F. The difference in nitrogen evolved at the 1550~C and 1850~C temperatures is of interest. Since 1850~C is necessary to decompose TiN or CbN, the difference between the 1850~ and 1550~C analyses may indicate the nitrogen combined in this manner. It is interesting to note that the ratio of nitrogen evolved at 15500C to that evolved at 18500C is comparable for all atmospheres. Work is in progress to investigate the effect of deliberate nitrogen additions to vacuum-melted material. 22

ENGINEERING RESEARCH INSTITUTE ~ UNIVERSITY OF MICHIGAN'.';:. C'C~~~~~~~~~~~~~~. Kv* 7:" ^> * 6"r,^^fi,, a. General structure of Guy-type b. Matrix structure of Guy-type alloy. alloy. Heat R-88: air atmosphere. Heat R-88: air atmosphere. Fine precipitate in matrix is Nir (ATi). ------------------- 5_-.. C. Unidentified whit.p in-. test-bar gage length).

m TABLE VIII Z VACUUM-FUSION ANALYSES FOR NITROGEN Melting and Crucible Percent N2 at 1850~C Alloy Heat Alloy HeaCasting Temperature minus Percent of 1850~C Nitrogen Type No. rEvolved at 1550C m eAtmosphere 1550~C 185O0C Percent N2 1550C at 15500C Guy R-96 Air.0442.0154? I R-98 Argon-protected.0098 _ R-115 Vacuum + argon.0010.0021.0011 52. Z R-160 Vacuum + argon.0029 -- R-176 Vacuum + argon ---.0036 Inco R-95 Air.0108 --- 700 R-117 Argon-protected.0045.0113.0068 60. R-109 Vacuum + argon.0010.0018.0008 44. C GMR R-120 Air.0043.0258.0215 83. 235 R-99 Argon-protected.0055 ---- R-108 Vacuum + argon.0006.0025.0019 76. R-175 Vacuum + argon ----.0041 Oxygen was.0003-.02% and hydrogen.0000oooo8-.o0004 at 1850~C. No consistent variation with type of melting was obtained. The role of dross in the case of oxygen and of storage time of the samples in the case of hydrogen can affect the results seriously. Z

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN 2. INCO-700-TYPE ALLOY The effect of melting atmospheres upon the elevated temperature properties of this alloy is shown in Figs. 8 and 9 and in Appendix II. Vacuum + argon melting and casting atmospheres exert a significant effect upon elevated-temperature ductility and improve strength somewhat as shown in Table IX. TABLE IX EFFECT OF MELTING AND CASTING ATMOSPHERES UPON 100-HOUR RUPTURE STRENGTH AND ELONGATION OF INCO-700-TYPE ALLOY AT 1500~F 100-Hour Rupture Strength Percent Elongation Range Atmosphere Atmosphere psi at 100 Hours Air 37,000 2-4 Argon-protected 42,000 3-4 Vacuum + argon 42,000 21 Optical microstructural examinations give no clues to the reasons for strength or ductility variations with melting and casting atmospheres. The general cast microstructure of the Inco-700 type is shown in Fig. 13a. Figure 13b shows in detail the primary precipitate. This precipitate is probably chromium carbide with dissolved molybdenum and titanium. Figure 14a shows the structure of this alloy after testing at 1500~F. This precipitation around existing phases is typical of all air and argon heats. Figure 14b shows the structure of the vacuum + argon melted Inco-700-type alloy after testing. A radical change has occurred as a result of testing. Vacuum-Fusion Analyses -Nitrogen Effect The vacuum-fusion analyses for Inco-700-type alloys shown in Table VIII show that vacuum + argon melting produces the lowest nitrogen content. ____________________________ 25 ___________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN - * T'YV'~ V * ^. i A — A^ f, ^ A.-< /, ^. 6' (. 1- \ V.^*' ^;/- * -' >, \ ^-'/- - ~' >'' ~ -' ".~- \ C';' \ ~ ~ *..; (-' *...-,.\ " l' " \ \ ^' -' Y.. C Pt~ * -,. *''.. * -; *t.- f I.,1 100X a. General structure of cast Inco-700-type alloy. Heat R-86' argon-protected atmosphere. - 9 0~' -J ^o b. Detail of precipi~tate in cast Inco-700 —typ& al~loy. Heat R-86: argon-protected atmosphere. Fig. 115. Microstructures of cast Inco-700-type alloy; electrolytic etch, 5%HF, lc~ glycerine, and 85% alcohol (specimens from center of test-bar gage length). _ _ _ _ _ _ __ j26 _

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN ti, - -. -.^,~~~~~~~~b I21'p j k.~4_ 500X a. Precipitation around primary precipitate after testing. Typical of heats melted under air and argon-protected atmospheres. Heat R-86: argon-protected atmosphere. i / r -'^ i-~ —;. *i/'.' *~ 500X "b. Structure of vacuum + argon melted Inco-700-type alloy after testing. Heat R -109: vacuum + argon atmosphere. 4-~~~~~~~~*~ ~~~~~~~~~~~~~~ f N* b. Structure of vacuum + argon melted Tnco-700-type a~lloy after testing. Heat B-109: vacuum + argon atmosphere. Fig. l4- Microstructures of Inco-700-type alloy after testing at 15000F; electrolytic etch, 5% HF, 10^ glycerine, and 85% alcohol (specimens from center of test-bar gage length). 27

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN 3. GMR-235-TYPE ALLOY Elongation at 15000F is strongly affected by melting and casting atmospheres, as indicated in Table X and in Figs. 10 and 11 and Appendix III. TABLE X EFFECT OF MELTING AND CASTING ATMOSPHERES UPON 100-HOUR RUPTURE STRENGTH AND ELONGATION OF GMR-235-TYPE ALLOY AT 1500~F 100-Hour Rupture Strength Percent Elongation Range Atmosphere___ l _____psi at 100 Hours Air 41,000 6-9 Argon-protected 41,000 3-7 Vacuum + argon 42,000 14-19 Examination using the light microscope does not explain variations. Figure 15a shows the general microstructure of this alloy. Inclusion clusters are evident. At higher magnifications (Fig. 15b), some of the primary precipitate appears as a eutectic. General precipitation within the matrix is obvious in this figure. The eutectic is apparently Ni-B or Ni-B-C, since in the Inco-700type alloy, which has similar chemistry except for boron, no eutectic appears. A similar eutectic also appears in boron steels. The inclusion clusters are titanium carbonitrides.7 In Fig. 15b, general precipitation is evident in the matrix. This phase is Ni3(AlTi).8 Vacuum-Fusion Analyses-Nitrogen Effect The vacuum-fusion analyses for the GMR-235-type alloy, shown in Table VIII, indicate that the increase in elongation at 15000F by vacuum + argon melting could result from differences in gas content. GENERAL COMPARISON The data just discussed may be summarized best by Table XI. ___________________________ 28 _____l________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN. /,'~'''/a';.' I. i j -'- j l',- K' i'- -; ^ > * /' 5'. 4;. -. ^' "1 /. ^J~e,~~.... 10OX a. General structure of cast GMR-235-type alloy. Heat R-85: argon protected atmosphere. Clusters of inclusions are TiN + TiC. Eutectic is Ni-B-C.'" " b. e Heat R-85: argon-protected atmosphere. Fig. 15. Microstructures of GMR-25 -type alloy; electrolytic etch, 5% HF, 10% glycerine, and 85% alcohol (specimens from center of test-bar gage length). - 29

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN TABLE XI SUMMARY OF STRESS-RUPTURE PROPERTIES OF THE THREE ALLOYS This Investigation Published Atmosphere Alloy Type Properties Argon- Vacuum Air Ai Protected + Argon 100-hour rupture strength (psi) 49,0001 42,000 41,000 56,000 Guy Percent elongation (100 hours) 2-51 3 1-3 7-10 100-hour rupture strength (psi) *43,0004 37,000 43,000 42,000 Inco 700 Percent elongation (100 hours) 10* 2-4 3-4 21 100-hour rupture strength (psi) 37-40,0005 41,000 41,000 42,000 GMR 235 Percent elongation (100 hours) 6-10 6-9 3-7 14-19 *Solution treated and aged. CONCLUSIONS 1. In all three alloy types, melting under vacuum and casting under argon atmospheres improves ductility two- to tenfold under stress-rupture test conditions at 1500~F. 2. Stress-rupture strength at 1500~F is improved in the Guy-type alloy by 38% and in the Inco-700 type by 13% with the argon + vacuum melting technique compared with air melting. No change occurs in the GMR-235 type. 3. The air-melted and argon-protected heats contain from five to ten times the nitrogen of the vacuum + argon heats. 30

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN FUTURE WORK Additional research may profitably include the following: 1. Investigation of the effect of pouring temperature and pressure upon elevated-temperature properties of the three alloys. 2. Effect of grain size upon ambient- and elevated-temperature properties. 3. Effect of nucleation upon elevated-temperature properties of the three alloys. 4. Effect of nitrogen additions to vacuum-melted, Guy-type alloy to determine the atmosphere effect. 5. Evaluation of properties after solution treatment and aging to produce uniform structures. 6. Exploration of the effect of higher stress-rupture test temperatures. 7. Examination of vacuum- and air-melted heats with the electron microscope to explore differences in structure. BIBLIOGRAPHY 1. Guy, A. G., "Nickel-Base Alloys for High Temperature Applications," Trans. A.S.M., 41:125-40 (1949). 2. Kinsey, H. V., and Stewart, M. T., "Nickel-Aluminum-Molybdenum Alloys for Service at High Temperatures," Trans. A.S.M., 43:193-223 (1951). 3. Pfeil, L. B., Allen, N. P., and Conway, C. G., "Nickel-Chromium-Titanium Alloys of the Nimonic 80 Type," Iron and Steel Institute, Symposium on High Temperature Steels and Alloys for Gas Turbines, 1951, pp. 37-45. 4. Lyman, T. (editor), Metals Handbook 1954 Supplement, A.S.M., 1954, p. 47. 5- McCullough, D. C., Webbere, F. J., and Thomson, R. F., "Improving Investment Casting Quality," Am. Foundryman, April, 1955, pp. 56-61. 6. "Methods for Chemical Analysis of Nickel and High Nickel Alloys," Technical Bulletin T-36, International Nickel Co. 31

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN BIBLIOGRAPHY (Concluded) 7. Hanne-Rothery, W. R., Raynor, G. V., and Little, A. T., "On the Carbide and Nitride Particles in Titanium Steels," J. Iron and Steel, CXLV, 129-41 (1942). 8. Nordheim, R., and Grant, N. J., "Aging Characteristics of Nickel-Chromium Alloys Hardened with Titanium and Aluminum," Trans. J. Metals, 6:211-18 (1954). 32

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN APPENDIX I EFFECT OF ATMOSPHERE ON STRESS-RUPTURE PROPERTIES OF GUY-TYPE ALLOY AT 1500~F Heat Atm Chemical Composition(l) R(10) Rupture Percent Percent C Cr Mo Al Fe Ti B Co Cb B.T. A.T. Life (Hours) Elongation(2) R.A. (3) R-59 Argon.26 14.o4 4.78 6.12 5.96 -.32 - 1.99 58.5 51 55,000 643 (4) 35,000 508(4)(5) 35,000 547(4) - - 55,000 385 2 2 R-89 Argon.13 14.63 5.3 7.31 4.51 -.31 - 1.89 36 40 50,000 9.0 2 4 45,000 24(6) 1 - 37,000 115 1 3 R-98(8) Argon.12 15.35 5.50 6.14 5.45 -.44 3.68 2.22 43 44 39,000 4.3 2 2 35,000 14 2 4 R-119(8) Argon.11 13.08 4.42 5.77 6.94 -.38 - 2.30 39 31.5 46,000 62 3 4 40,000 188 4 5 57,000 240 5 5 R-60 Air.26 13.75 4.99 4.33 5.91 -.50 - 1.52 37 30 35,000 544 5 6 35,000 485 5 7 55,000 511 6 9 35,000 189(6) 4 4 R-88 Air.12 13.99 5.87 6.80 4.64 -.42 - 1.97 38.5 33 50,000 18 <1 <1 47,000 43 2 2 45,000 83(7) 3 3 42,000 155 3 4 R-96(8) Air.15 14.17 4.84 5.91 4.86 -.-7 4.24 1.83 42 29 45,000.33(6) 1 3 45,000 111 3 4 42,000 345 4 8 R-115 Vacuum.20 12.83 5.54 6.54 5.40 -.35 - 1.96 - - 6,o000 77 7 17 6.42(9).60(9) 55,000 210 6 9 50,000 273(6) 9.0 15 R-160 Vacuum.10 13.44 5.56 5.50 5.06 -.48 - 2.06 - - 65,000 13.2 3.0 6.5 58,ooo 80.5 10 15 54,000 132 8 11 R-176* Vacuum - - 60,000 70 4.0 5.0 55,000 131 7.0 8.0 50,000 178 5.0 6.5 R-156* Argon 40,000 199 3 3 45,000 145 1.0 1.0 R-157* Argon 45,000 79 2 2.5 40,000 168 2.0 2.5 R-158* Air 45,000 10.2(6) 40,000 117 3 4 R-159 Air.08 13.10 5.71 6.04 4.36 -.28 - 1.86 45,000 102 2 1.5 (1) Balance Ni. (2) Percent elongation in one inch measured after fracture. (3) Percent R.A. measured after fracture. (4) Test discontinued after stated number of hours. (5) Overheated to 1800~F after 508 hours. (6) Casting defect in fracture. (7) Broke in fillet. (8) Ti and Al analyzed by specifications in the Analysis Manual of the International Nickel Co.6 (9) Analysis checks performed by the International Nickel Co. (10) B.T., A.T. - before testing, after testing. * Analyses not completed. 33

APPENDIX II EFFECT OF ATMOSPHERE ON STRESS RUPTURE PROPERTIES OF INCO-700-TYPE ALLOY AT 1500~F rf Z Ha Atm | - Chemical Composition (1) Rc(9) Rupture Percent Percent Heat Atm C Cr Mo A Fe Ti ___B Co _Cb B.T. A.T. Stress Life (Hours) Elongation(2) R.A.(3) Z R-58 Argon.34 15.)9 2.43 2.56.6o 3.11 - 2.4 - 5 31 5,000 40 5 35,000 544(4) - - 55,000 474 4 3 Z 35,000 50(4) - - R-16 Argon.27 15.13 5.0) 5.4.17 1.55 - 3 -.52 47,500 7 3 6 45,000 75 3 3 r 40,000 123 3 8 F 35,00o 261 3 4 R-97 Ar-on.12 15.50 2. 1.52.9 1.50 - 2.50 - 51 29 50,000 595 6 a-97 Ar|on ] ] ]31 29 50,000 39 3 6 5.52(- 2.06( ) 45,000 152 4 7 42,000 122 3 2 39,000 319 5 7 R-117(7) Argon.15 15.32 5.52 2.15.99 2.11 - 50.02 - - 5.5 42,000 60 3 2 58,000 175 3 7 34,000 4o0 3 5 -61 Air.25 14.79 2 2.12.6o 5.5 - 27.14 - 51 55 5,000 571() - - 35,000 545(4)- -r 55,000 523(4) - 55,000 693 7 18 R-87 Air.16 15.6 5.05 2.90.57 1.65 - 27.7 - 31 30 45,000 12 4 5 42,000 355 2 3 40,000 173 2 3 58,000 114(5) - - R-95 Air.09 15.35 2.49 1.49.69 1.55 - 30.50 - 27 31 41,000 8(6) 3 4 38,000 32 2 35 35,000 882 2-2 32,000 147 4 5 R-109 Vacuum.15 15.03 2.10 1.32.6o 1.73 - 29.0 - 55 57 50,000 24 48 3.17(8) 2.10(8) 45,000 73 21 25 "l 41,000 166 4 4 (1) Balance Ni. (2) Percent elongation in one inch measured after fracture. " (3) Percent R.A. measured after fracture. (4) Test discontinued after stated number of hours. (5) Inclusion in fracture. (6) Probable defect in fracture. Z (7) Ti and Al analyzed by specifications in the Analysis Manual of the International Nickel Co.6 (8) Analysis checks performed by the International Nickel Co. (9) B.T., A.T. - before testing, after testing.

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN APPENDIX III EFFECT OF ATMOSPHERE ON STRESS RUPTURE PROPERTIES OF GMR-235-TYPE ALLOY AT 1500~F Chemical Co position(l) Rc,(11) Se Rupture Percent Percent Heat Atm C Cr Mo Al Fe Ti B Co Cb B.T. A.T. ess Life (Hours) Elongation(2) R.A.(3) R-49 Argon.18 15.33 5.10 2.89 8.37 2.26.11 30 29 35,000 366 6 9 35,000 177 5 11 35,000 382 6 9 R-85 Argon.16 15.18 4.83 4.66 8.45 1.70.11 - 25 45,000 40 4 4 42,000 72 5 10 40,000 113(4) 7 13 38,000 13(5) - - R-99(9) Argon.17 15.27 4.98 2.95 10.91 1.90.08 32 34.5 45,000 55 6 14 3.62(10).12(10) 40,000 119 35 55,000 510 18 21 R-116(9) Argon.17 15.43 4.31 3.24 10.51 2.17.07 - - 32 33 45,000 61 6 11 40,000 223 11 11 R-43 Air.17 15.34 4.71 5.12 7.65 2.26.12 - - 50 - 35,000 597 9 14 55,000 317 10 16 35,000 334 13 15 R-50 Air.18 15.99 5.39 3.34 8.54 2.27.0 - - 51 51.5 55,000 516 7 14 35,000 46o 5 8 355,000 599 7 8 55,000 456 5 14 R-84 Air.16 15.64 4.46 3.88 10.44 1.75.1- 45,000 17 1 4 42,000 49(6) 2 8 40,000 137 6 13 36,ooo.5(7) 1 2 R-100(9) Air.15 15.11 5.06 2.61 11.01 1.90.07 - - 52 27 45,000 63 7 15 40,000 177 9 15 56,000 347 11 21 R-120(9) Air.27 15.43 4.38 2.37 10.41 2.05.06 52.8 52.5 45,000 78 7 11 42,000 122 9 13 33,000 235 3 8 R-108(9) Vacuum.16 15.03 5.26 3.01 10.91 2.15.06 30.5 30 45,000 72 19 22 3.02(10).066(10) 37,200 260(8) 19 31 R-114 Vacuum.15 14.98 5.06 3.76 11.10 2.30.06 - - 26 32 45,000 49 18 25 40,000 94 14 40 37,000 16o 12 27 32,000 429 15 25 R-175 Vacuum - _ 40,000 136 13 24 45,000 96.5 17 29 (1) Balance Ni. (2) Percent elongation in one inch measured after fracture. (3) Percent R.A. measured after fracture. (4) Broke in gage mark. (5) Blow hole in fracture. (6) Broke near fillet. (7) Fracture shows casting defect. (8) Stripped out of adapter after 175 hours, brought back up under load. (9) Ti and Al analyzed by specifications in the Analysis Manual of the International Nickel Co.6 (10) Analysis checks performed by the International Nickel Co. (11) B.T., A.T. - before testing, after testing. ~~__~~_______________3_ 55 __________

ENGINEERING RESEARCH INSTITUTE * UNIVERSITY OF MICHIGAN APPENDIX IV AMBIENT-TEMPERATURE PROPERTIES OF GMR-235-, INCO-700-, AND GUY-TYPE ALLOYS Alloy Heat m (1) Tensile Yield Percent Percent Type cea Strength Strength(4) Elongation R.A. GMR-235 R-10 Argon 33 114,000 98,000 4 5.5 R-14 Argon - 96,300 96,300(3) 2 0 R-99 Argon 32 116,000 99,000 3 5 R-116 Argon 32 122,300 - 4 4 R-120 Air 33 110,000 97,000 2 3.5 R-100 Air 32 100,000 100,000(3) 2 2.5 R-108 Vacuum 31 106,000 95,500 3 6 R-114 Vacuum 26 97,000 85,000 3 6 Inco-700 R-117 Argon - 91,700 - 5 8 R-58 Argon 31 118,000 104,500 4 4 R-86 Argon 33 111,000 102,000 3 4 R-97 Argon 31 110,500 99,000 4 8.5 R-61 Air 31 90,500 90,000 2 7.5 R-95 Air 27 106,000 97,000 4 9 R-109 Vacuum 33 109,000 95,000 6 13 Guy Type R-98 Argon 43 104,000 104,000(3) 1 - R-119 Argon 39 127,000 127,000(3) 1 R-88 Air 39 106,800(2) 106,800(3) R-96 Air 42 130,100 122,000 2 1 R-115 Vacuum - 138,000 118,000 2 1 (1) Average of three readings. (2) Defect in fracture. (3) Tensile strength same as yield strength. (4).2 percent offset. 36