Si对中锰钢淬火配分组织和性能的影响

Effects of Si on the Microstructure and Mechanical Property of Medium Mn Steel Treated by Quenching and Partitioning Process

将20Mn5钢和20Mn5Si2钢进行淬火和配分(Q&P)工艺处理,用扫描电镜观测其微观组织,用X射线法测量残余奥氏体量,研究了Si对其微观组织和力学性能的影响。结果表明,试验钢中的奥氏体含量明显高于传统的TRIP钢和Q&P工艺处理钢;在相同Q&P工艺条件下,20Mn5Si2钢比20Mn5有较多的残余奥氏体,析出物数量较少。同时,20Mn5Si2钢具有较低的屈服强度、较高的抗拉强度和达到28 GPa%的强塑积。Si的添加提高了中锰钢中残余奥氏体量,这种奥氏体在拉伸变形过程中的TRIP效应是产生较高抗拉强度高和延伸率的主要原因。

Effects of Si on the microstructure and mechanical property of 20Mn5 steel and 20Mn5Si2 steel processed by quenching and partitioning （Q＆P） were investigated. The microstructure characterization and austenite fraction measurement were carried out using scanning electron microscopy and x-rays diffraction. It was found that there is much more austenite fraction in the studied medium manganese steels than that of conventional TRIP steels and steels treated by Q＆;P process; and under same experi- mental condition, the austenite fraction in 20Mn5Si2 is significantly higher and fewer precipitated carbides than that in 20Mn5 steel. It was proposed that the larger fractioned austenite in Si-medium Mn steel results in the much lower yield stress and much higher product of tensile strength to elongation than that of the medium Mn steel without Si both processed by quenching and partitioning.