ENGINEERING RESEARCH INSTITUTE THE UNIVERSITY OF MICHIGAN ANN ARBOR. MICH. REPORT ON PROPERTIES OF AN AST.M A106, GRADE B CARBON STEEL PIPE By R. Jackow ski J. W. Freeman Project 842 Report 214 August 23, 1957 T HE TIMKEN ROLLER BEARING COMPANY STEEL AND TUBE DIVISION CANTON, OHIO

PROPERTIES OF AN ASTM A106, GRADE B CARBON STEEL PIPE The investigation covered by this report was made to evaluate the tensile and rupture properties of ASTM-A106, Grade B, carbon steel pipe. It was carried out as the Timken Roller Bearing Company's contribution to a cooperative program of Petroleum and Chemical Panel of the ASTM-ASME Joint Committee on Effect of Temperature on the Properties of Metals. Several organizations evaluated typical samples of carbon steel in plate and pipe form to establish typical properties for carbon steel products. Stress-rupture properties were measured at 1000-F and short-time tensile properties at 80, 200, 400, 600a 800, and 1000~F SUMMARY The rupture strengths at 1000-F determined for the carbon steel pipe material were as follows: Stress (psi) for rupture in Y0- h I our...000hour 10,.....000..ho 100,00 ur 17,500 11,300 7,300 4,800 Tensile properties from 80' to 1000F are given in the text, The tensile and rupture properties were in general equal to or higher than the average values published for carbon steel. This is to be expected for as-rolled carbon steel made to coarse grained melting practice. As would be expected for steel made by this melting practice the tensile tests showed strain aging.

2, TEST MATERIALS The tensile specimens submitted for this investigation were taken from a section of a hot rolled carbon steel pipe, The pipe was 8-5/8-inches OD by 0. 906 inch in wall thickness. It had been manufactured from a heat made to coarse-grained melting practice by the National Tube Company. The pipe was reported to be ASTM - A106 Grade B pipe having the following reported compositions: Chemical Composition (Percent) C Mn P Si Cr Ni Mo 0.265 0.73 0.011 0.022 0. 20 0. 02 00 03 0.02 RESULTS AND DISCUSSION Stress-rupture tests were conducted at 1000 F, The data obtained are presented in Table I and shown as a stress-rupture time curve in Figure 1. The rupture strengths and elongation values at fracture established were as follows: Stress (psi) for rupture in Fracture Elongation (%) Io0-hour I -00o100our -.0 our 1 00hour 100hour ~ A:... ~...... X 17,500 11,300 7,300 55.0 55.0 The data were as consistent as would be expected for specimens cut from a large pipe, Time-elongation data were obtained for the longer time tests, These data are presented in the creep curves of Figure 2, The curves are in line with what is to be expected for the material. Duplicate tensile tests were run at 80, 200, 400~ 600', 800' and 1000'F The stress-strain curves obtained from the tensile tests are presented in Figures 3 and 4. The tensile properties derived from the tensile tests are tabulated in Table II. Figure 5 shows the effect of temperatures on the tensile properties,

3, Very sharp yield points were obtained in most of the tests up to 400~F, This prevented obtaining strain data to plot good stress-strain curves and only "drop-of-thebeam" yield strengths are reported in those cases, The higher tensile strength obtained from 400' to 600'F is in all probability due to strain aging during testing. Above 400'F the tensile strengths, offset yield strengths and the proportional limit decreased with temperature. The ductility of the carbon steel pipe decreased to a minimum at 400'F and than increases considerabley above 400~F. Metallographic examination of the original structure, Plate 1, shows a matrix of ferrite together with a fine lamellar pearlite, During prolonged rupture testing at 1000lF the pearlite underwent spheroidization as shown in Plate No. 2, Shown also in Plate 2 are the fracture and the surface adjacent the fracture, The tensile and rupture properties of the carbon steel pipe were in general equal to or slightly higher than average of most published data. This would be anticipated for material from as -rolled pipe, particularly when made to coarse grained practice. The coarse grained practice obviously left the material susceptible to strain aging,

TABLE I STRESS-RUPTURE DATA AT 1000F FOR ASTM A106, GRADE B CARBON STEEL PIPE Stress Rupture Time Elongation Reduction of (psi) (hours) (% in 2 in.) Area (%) 32,200 S.T. TT.T 57.0 80 7 18,000 85 55.0 77.7 15,000 251 54,0 75 6 2, 000 572 53.5 69.5 11,500 572 59.5 72.8 9,000 3171 45.0 61.5 * - Average of 2 tests

TABLE II TENSILE PROPERTIES OF ASTM A106, GRADE B CARBON STEEL PIPE Offset Tensile Yield Stress Temp. Strength (psi) Proportional Elongation Reduction of (~F) (ps i) si) (% in 2 in. ) Area (%) 80 72,500 38,500* - 35,000 34.5 60.5 80 70,750 35,600 37,200 29,000 33.0 60.0 Average 71, 625 37,050 37,200 32,000 33.8 60.3 200 66,500 36,000* -- 27,000 31.0 61. 5 200 67,750 39,250* -- 29,000 29.0 6 1.0 Average 67, 125 37,675 28,000 30.0 61.3 400 78,000 36,500* -- 26,000 20.0 52.0 400 76,750 36,000* -- 26,000 20.5 49.0 Average 77,375 36,250 26,000 20.3 50.5 600 74,000 28, 100 31,600 14,000 34.0 61.5 600 72,500 28,500 32,200 14,000 36.0 63.0 Average 73,250 28,300 31,900 14,000 35.0 62, 3 800 56,800 26,600 29,900 13,000 38.5 74.0 800 57,000 27,600 31, 100 13,000 34.,0 74.5 Average 56, 900 27,100 30,500 13,000 36.3 74.3 1000 32,400 19,700 22,400 8,000 50.0 79.5 1000 32,000 20, 000 22,200 8,000 64, 0 881.9 Average 32,200 19,850 22,300 8,000 57.0 80.7 * - Yield Point by drop of beam method.