热机械控制工艺对高铝低硅相变诱发塑性钢组织性能的影响

摘要

Effect of thermomechanical controlled processing on the microstructure and mechanical properties of high Al-low Si transformation induced plasticity steel was investigated by isothermal holding after hot roll-ing. The results have shown that the microstructures of the present steels consist of polygonal ferrite,granular bainite and retained austenite. As deformed,strain of retained austenite induces transformation of martensite. Those transformations induce plasticity,which occur to both steels,so that excellent mechanical properties of both steels can be obtained. Al additions in Steel B increase the stacking fault energy. The width of an ex-tended dislocation in the fcc crystal structure become smaller. The formation of the stacking faults becomes more difficult.γ→ε transformation is strongly suppressed,resulting in the retention of significant amount of retained austenite in Steel B,and therefore more quantities of granular bainite. The mechanical properties of Steel B are higher than those of Steel A due to TRIP effect of retained austenite.%通过热轧后等温保温实验,研究了热机械控制工艺( TMCP)对高铝低硅相变诱发塑性钢组织性能的影响。结果表明,二种实验钢显微组织均由铁素体,贝氏体和残余奥氏体组成,变形时,残余奥氏体因应变诱导马氏体相变,相变诱发塑性,获得了良好的力学性能。 B钢中添加A1增加了奥氏体的堆垛层错能,降低了扩展位错的宽度,不易形成层错。由于γ→ε转变被抑制而造成B钢中更多奥氏体的残留,最终导致贝氏体量更多。由于残余奥氏体的TRIP效应,B钢力学性能优于A钢。