摘要
用高温金相显微镜观察了低碳钢 (2 0及 15CrMo钢 )在真空加热时奥氏体晶粒长大现象 ,绘制了它们的长大动力学曲线。试验结果表明 :两种钢的奥氏体晶粒长大规律非常类似 ,但其急剧长大温度 (TG)有显著差别 :即 2 0钢的TG 为 85 0～ 10 0 0℃ ,而 15CrMo钢为 10 0 0～ 12 0 0℃ ,并且在 110 0℃明显地观察到该钢奥氏体晶粒的恒温长大现象。试样冷却时未观察到 2 0钢中析出先共析铁素体及随后珠光体形成的动态过程 ,却看到了15CrMo钢条块状贝氏体的转变过程中引起的表面浮凸现象。研究了两种钢经真空热处理后的室温组织。
By means of high temperature microscope the phenomenon of austenitic grain growth in the low carbon steels(20 and 15CrMo) when heated in vacuum is observed,and its dynamic curves have been also graphied.Experimental results show that the law of austenitic grain growth for two kinds of low carbon steels are similar,their temperatures of austenitic grain rapid( T G) growth are very different,that means:850～1 000 ℃ for 20 steel,1 000～1 200 ℃ for 15CrMo steel,and the isothermal growth phenomenon is obviously observed at 1 100 ℃.The kinetic processes of pre-eutectoid ferrite precipitation and the pearlite formation from austenite of 20 steel can’t be observed when cooled in furnace .With respect to 15CrMo steel,the reliefs on the specimen surface caused by the formation of needle bainite during cooling have been observed.The microstructures at room temperature are also studied.
出处
《金属制品》
2003年第4期43-47,共5页
Metal Products
