作　　者： ; ; ;

机构地区： 东北大学材料与冶金学院轧制技术及连轧自动化国家重点实验室

出　　处： 《材料热处理学报》 2006年第2期59-62,共4页

摘　　要： 对AISI 4340钢在950-1150℃进行奥氏体化,以获得不同奥氏体晶粒度(AGS),研究了连续冷却时贝氏体转变动力学特征。AGS对贝氏体相变动力学有很大的影响,AGS越大,贝氏体相变起始温度Bs越高。对试样进行了透射电镜(TEM)分析,结果表明AlN、TiC等粒子在晶界的析出对贝氏体起始反应起到促进作用。而AGS对贝氏体反应结束温度Bf的影响就很小。转变速率随AGS变化的规律是,AGS越大,转变速率反而减小。所有试样的转变速率随贝氏体体积分数ξ变化明显,大致可分成快速增加、缓慢减小和快速减小三个阶段。 In order to study the kinetics of bainite continuous transformation, AISI 4340 steel was austenitized in a temperature range of 950～1150℃ to obtain different austenite grain sizes(AGS) and then step-cooled to room temperature.The results show that AGS has a great effect on bainite transformation kinetics.The larger the AGS,the higher the bainite start temperature(B_s).Transmission electron microscope(TEM) observation shows that the existence of particles such as AlN,TiC etc.on prior austenite grain boundaries promotes the start bainite transformation.The effect of AGS on bainite finish temperature(B_f) is not obvious.The other aspect of kinetics is bainite transformation rate,the higher the AGS,the lower the rate.The transformation rates of all specimens change obviously with increasing bainite volume fraction,and three stages can be found: the rapidly increasing stage,the slowly decreasing stage and the rapidly decreasing stage.

关 键 词： 奥氏体晶粒度 贝氏体 相变动力学 热膨胀实验 低合金钢

领　　域： [金属学及工艺] [金属学及工艺]