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Engineering Research Institute

THE UNIVERSITY OF MICHIGAN Ann Arbor. Mich.

REPOBT ON

PEOPERTIES OF AN ASTM A 106, GRADE B CARBON STEEL PIPE

By

R„ Jackowski J* W. Freeman

August 23, 1957

Project 842 Report 214

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^ 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#, 6〇〇0, 800and1000°F»

SUMMARY

The rupture strengths at 1OOO0F determined for the carbon steel pipe material were as follows:

Stress (psi) for rupture in________________________________________________________________________ .

T〇Q^!liour            ldOQ-hour                        〇b(3»liour                  !()0» d()〇^hour~，

17,500               11,300                7,300                     4,800

Tensile properties from 80# to 1000*F 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.

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„9〇6 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 • Al〇6 Grade B pipe having the following reported compositions:

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 (%)

166-liour """"10bO-Kour           16> dod^hour             100-tiour                                 lbOO-hour

17,500            11,300            7,300                    55.0                  55s0

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°y 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.

Very sharp yield points were obtained in most of the tests up to 400°F(6 This prevented obtaining strain data to plot good stress-strain curves and only ndrop-of-the- beamM yield strengths are reported in those cases.

The higher tensile strength obtained from 400* to 6〇0*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 1000#F 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 aging0

A106, GRADE B

氺

STRESS-RUPTURE DATA AT 1000*F FOR ASTM

CARBON STEEL PIPE

Reduction of Area (%)

80.7

77.7             75.6

69.5             72s8

Average of 2 tests

61.5