变形速度对TRIP钢冲压成形性的影响

在TRIP钢相变动力学模型的基础上,推导了残余奥氏体体积比变化速率与变形速度的关系,详细分析了变形模式和变形速度对残余奥氏体转变的影响规律,讨论了相变诱发塑性效应对TRIP钢冲压成形性的作用机理,并通过圆筒件拉深成形试验,验证了不同变形速度下TRIP钢的成形性。结果表明,残余奥氏体体积比变化速率随变形速度的增加而增加;变形速度和变形模式对相变诱发塑性效应的发挥影响较大,变形过快导致后续变形所需塑性补充不足;TRIP钢良好塑性得以发挥,必须具有合适的变形条件。

Influence of deformation rate on formability of TRIP sheet steel

On the basis of transformation dynamics mechanics model of TRIP steels,expression-describing relationship between transformation velocity of retained austenite and deformation rate is proposed.Influence of deformation mode and deformation rate on martensite transformation is analyzed in detail.And mechanism of transformation-induced plasticity effect on formability for TRIP steels is discussed.Then experiments of cup deep drawn under different velocity are carried out and formability is analyzed.It indicated that transformation rate increases with deformation rate and deformation rate is very important for TRIP effect to bring into play.Fast deformation could result in plasticity supply falling short for further deformation.Only under appropriate deformation mode and suitable deformation rate could the good ductility be made full use of.