【摘要】 在MMS-300热力模拟机上,利用膨胀法结合金相-硬度法,建立新开发的高速列车焊接构架用Mn-Cu-Ti-Nb低碳钢未变形和变形奥氏体的连续冷却转变曲线,研究了形变和冷却速度对试验钢γ→α相变行为及显微组织的影响。结果表明:随着冷却速率的增加,铁素体转变开始温度降低,铁素体晶粒得到细化,同时还促进了贝氏体相变。变形一方面促进了铁素体相变,细化铁素体晶粒;另一方面又抑制了贝氏体相变,使贝氏体含量降低,硬度降低。更多还原

【Abstract】 By dilatometric change combined with microstructure and hardness measurement,austenite CCT diagrams for non-predeformation and deformation process for low carbon Mn-Cu-Ti-Nb steel used in the bogie frame of high-speed trains were established by MMS-200 thermal mechanical simulator.The effects of predeformation and cooling rate on γ→α transformation behavior and microstructure were studied.The results show that the ferrite transformation temperature is lowed and the grain size is refined with increasing of cooling rate,and the bainite transformation is also accelerated.On the one hand,the deformation can promote ferrite transformation and refine the ferrite grains,and on the other hand,can restrain bainite transformation and the volume fraction of bainite and hardness are decreased.更多还原