热变形对35CrMo钢淬火马氏体晶体学特征的影响

Influence of hot deformation on crystallographic characteristics of quenched martensite for 35CrMo steel

通过热压缩实验获得不同应变下35CrMo钢的淬火马氏体组织。基于电子背散射衍射(EBSD)测试技术研究了热变形对35CrMo钢淬火马氏体晶体学特征的影响,重点分析了不同变形量下奥氏体晶粒尺寸及马氏体变体组合特征的变化。研究结果表明:多轮动态再结晶的出现造成了高温真应力-真应变曲线的多峰变化,且第1轮动态再结晶明显细化了奥氏体晶粒。原始奥氏体的晶粒取向决定了淬火后马氏体变体的类型,且淬火马氏体变体的组合方式均为密排面组合。不同变形量下淬火马氏体变体间的取向差集中在50°~60°范围内,可通过引入大角度晶界来细化晶粒。

The quenched martensite structure of 35CrMo steel under different strains was obtained by hot compression test.Then,the influences of hot deformation on the crystallographic characteristics of quenched martensite for 35CrMo steel were investigated based on electron backscatter diffraction(EBSD)test technique,and the changes of austenite grain size and combination characteristics of martensitic variants under different deformation amounts were analyzed.The research results show that the occurrence of dynamic crystallization with multiple rounds results in multimodal changes of the true stress-true strain curve at high temperature,and the first round of dynamic crystallization significantly refines the austenite grains.The grain orientation of original austenite determines the type of martensitic variants after quenching,and the combination pattern of quenched martensitic variants is close-packed plane combination.In addition,the orientation difference between the quenched martensite variants under different deformation amounts is concentrated in the range of 50°-60°,and the grains can be refined by introducing large-angle grain boundaries.