两相区轧制后低碳中锰钢中残留奥氏体在单向拉伸过程中的演变行为

Retained austenite evolution behavior during unidirectional tension of low carbon medium manganese steel after intercritical rolling

通过对轧制后低碳中锰钢薄板在不同预拉伸变形量下的组织进行了分析,并研究了单向拉伸过程中残留奥氏体组织演变的规律。试验结果表明,残留奥氏体向马氏体的相变主要发生在局部塑性变形阶段即屈服阶段,屈服阶段结束后,组织中的残留奥氏体基本全部转变为马氏体,试样进入均匀塑性变形阶段。拉伸过程中位错在局部的大量堆积和逐步迁移,在宏观上表现为吕德斯带的产生和移动,导致局部区域组织中的残留奥氏体发生相变,并且这种现象大多是沿着轧制方向进行的,并不会重复发生。

Microstructure of a low carbon medium manganese steel after rolling under different pre-stretch amounts was analyzed,and the retained austenite evolution during unidirectional tension was investigated.The results show that transformation of retained austenite to martensite is mainly occurred in the yield stage with local plastic deformation,and is basically completed when the yield stage ends with the specimens getting into the uniform plastic deformation stage.A large number of dislocations are partially accumulated and migrated gradually during the tension,showing as the generation and migration of the Luders band macroscopically,and inducing the transformation of residual austenite to martensite in local microstructure.This phenomenon mostly occurs along the rolling direction and can’t occur repeatedly.