Influences of Tensile Rate Control Modes and Tensile Rate on Strength Test Results of Cold Rolled Sheet

Tensile comparison test was done to cold rolled galvanized steel sheet on different tensile rate control modes and tensile rate according to GB/T 228.1-2010, and the influences of strain rate, crosshead separation rate and stress rate on test results of proof strength of non-proportional Rp0.2, lower yield strength ReL and tensile strength Rm of cold rolled sheet were studied. The results show that the tensile test results on strain rate control mode were more stable than those on the other two rate control modes, and it could reduce the tensile test results uncertainty to minimum. The test results stability with strain rate of 0.000 25 s-1 was close to that with stress rate of 40-50 MPa · s-1. Under different tensile rate control mode, raising strain rate, crosshead separation rate or stress rate, the tested Rp0.2 and ReL would increase, but Rm basically was in steady state.