逆转变奥氏体对中Mn钢低温冲击断裂过程的影响  

Effect of reversed austenite on low temperature impact fracture process of medium Mn steel

作　　者：李敬[1] 杨跃辉[1] 张晓娟[1] 梁国俐[1] 苑少强[1] Li Jing;Yang Yuehui;Zhang Xiaojuan;Liang Guoli;Yuan Shaoqiang(Key Lab of Intelligent Equipment Digital Design and Process Simulation,Hebei Province,Tangshan University,Tangshan Hebei 063000,China)

机构地区：[1]唐山学院河北省智能装备数字化设计及过程仿真重点实验室,河北唐山063000

出　　处：《金属热处理》2021年第11期147-151,共5页Heat Treatment of Metals

基　　金：河北省高端钢铁冶金联合研究基金(E2019105101);唐山市科技计划(18130218a)。

摘　　要：对超低碳7%Mn钢进行了不同温度的回火处理,测定了组织中的逆转变奥氏体含量及其在-60、-100℃下的冲击吸收能量,并观察了冲击断口附近的显微组织,进而讨论了逆转变奥氏体含量及稳定性对试验钢低温冲击断裂过程的影响。结果表明:逆转变奥氏体对试验钢低温韧性的影响具有两面性,一方面能够通过相变缓解裂纹尖端的应力集中,改善钢的低温韧性,另一方面,当其稳定性较低时易于在应力作用下大量发生马氏体相变,导致钢低温韧性降低。冲击断口附近产生明显塑性变形的区域都较小,表明在冲击断裂过程中难以通过大范围的TRIP效应实现韧化。Ultra low carbon 7%Mn steel was tempered at different temperatures and the content of reversed austenite in the steel and the impact absorbed energy at-60℃and-100℃were measured,and the microstructure near impact fracture was observed,then the effects of content and stability of reversed austenite on low temperature impact fracture process of the tested steel were discussed.The results show that the effect of reversed austenite on low temperature toughness of the tested steel has pros and cons.It can alleviate the stress concentration at the crack tip and improve the low temperature toughness of the steel through phase transformation.On the other hand,when the stability of reversed austenite is lower,a large amount of reversed austenite can transform to martensite easily under stress,resulting in the reduction of low temperature toughness.The plastic deformation area near the impact fracture is small,which indicates that it is difficult to achieve toughening by a wide range TRIP effect during impact fracture.

关 键 词：逆转变奥氏体 中Mn钢 低温韧性 断裂机制 

分 类 号：TG142.1[一般工业技术—材料科学与工程]