对汽车用电镀锌IF钢板进行不同拉伸温度和应变速率下的单向拉伸试验,研究了应力-应变曲线随拉伸温度、应变速率的变化规律,分析了拉伸温度和应变速率对该钢力学性能的影响和应变速率敏感指数随拉伸温度的变化规律.结果表明:IF钢单向拉伸应力随拉伸温度的升高而减小,随应变速率的增加而增大;屈强比随拉伸温度升高而呈向上开口的抛物线,临界温度约为120 ℃;不同应变速率下的硬化指数随拉伸温度的变化规律不尽相同;断裂伸长率随拉伸温度和应变速率的变化不大;力学性能的临界温度在100~120 ℃,但应变速率敏感指数在60 ℃时最大;此外其温度敏感性系数随应变速率的增加而增大.

Unidirectional tensile tests of the auto-use electrolytic zinc IF steel plate were carried out at various temperatures and strain rates.Change of the stress-strain curves with the change of tensile temperature and strain rate was studied.Influences of tensile temperature and strain rate on the mechanical properties were discussed,and the variation of coefficient of strain rate sensitivity with the tensile temperature was analyzed.The results show that uniaxile tensile stress of the IF steel decreased with increasing the tensile temperature,while increased with increasing the tensile rate.Yield-strength ratio had an upward parabola tendency with increasing the temperature and its critical temperature was about 120 ℃.The hardening exponent showed different variation with the increasing temperature at different strain rates.Elongation at rupture changed little with the variation of the temperature and strain rate.And the critical temperature of the mechanical properties was between 100 and 120 ℃,while the maximum coefficient of the strain rate sensitivity was obtained at 60 ℃.Furthermore,the coefficient of the temperature sensitivity increased with increasing the strain rate.