Investigation of the Significant Properties and Characteristics of Cold Worked Steels
CASE INST OF TECH CLEVELAND OH METALS RESEARCH LAB
Cold working tubes of AISI 1040 and 8630 steels by amounts up to 65 per cent reduction in area brought about a rise in tensile strength from about 85,000 psi to approximately 125,000 psi with a decrease in ductility contraction in area of only 10 per cent 65 to approximately 55 per cent. Moreover, the tubes at this high reduction were not notch sensitive, as measured by the concentric static notch tensile test. The dependence of tensile strength on amount of cold work was found to be almost linear within the ranges studied, but discontinuous as the mode of cold work changed from drawing tension to rocking compression. The dependence of tensile ductility on amount of cold work was again almost linear for drawn tubes up to 25 per cent reduction. However, tubes rocked to reductions of 51 and 65 per cent showed ductilities which were almost independent of the amount of cold work. Cold work by drawing appeared to be much more effective in raising the strength and reducing ductility than that by rocking for the same amount of cold reduction. Thermal stress relieving had little effect on the tensile properties of the drawn tubes 10 and 25 per cent reductions, but the tensile strengths of the rocked tubes 51 and 65 per cent reductions were slightly lowered and their ductilities were somewhat increased by the thermal stress relieving.