TRIP780及DP780钢成形性能的影响因素研究

Research on Factors Influenceing Formability of TRIP780 and DP780 Steels

通过单轴预应变拉伸试验、冲压成形试验、模拟分析,对TRIP780及DP780钢的力学性能与成形性能进行了研究,并对TRIP钢冲压成形过程中残留奥氏体的转变及对性能的影响进行了分析。结果表明:与DP780钢相比,TRIP780钢具有更好的塑性、强度及加工硬化性能,并且后者的应变硬化指数n值在5%~25%的应变阶段可以保持在0.2以上。TRIP效应能有效抑制预应变对应变硬化性能及塑性的消耗,从而使TRIP780钢具有更好的二次硬化性能。在冲压成形过程中,随着应变比的增加,应变状态更接近平面应变,残留奥氏体转变量逐渐增加。

Mechanical properties and formability of TRIP780 and DP780 steels were studied through uniaxial pre-strain tensile test,stamping forming test and simulation analysis.The transformation of retained austenite in TRIP steel during stamping process and its influence on properties were analyzed.The results showed that TRIP780 steel had better plasticity,higher strength and work hardening ability than DP780 steel,and the work hardening index of TRIP780 steel could be maintained above 0.2 in the strain stage of 5%to 25%.The TRIP effect could effectively inhibit the consumption of work hardening ability and plasticity caused by pre-strain,which made TRIP780 steel to have better secondary hardening ability.In the process of stamping,with the increase in strain ratio,the strain state was even closer to the plane strain and the transformation amount of retained austenite increased gradually.