影响新型低碳马氏体合金钢奥氏体晶粒的因素

Factors affecting Austenite grain in a new low-carbon Martensitic steel

运用光学显微镜、扫描电镜、能谱分析手段系统研究了加热温度、保温时间及合金成分对20Si Mn3Ni A钢原始奥氏体晶粒尺寸的影响。结果表明,随加热温度升高,原始奥氏体晶粒尺寸逐渐增大,奥氏体晶粒长大速率与该温度下的保温时间大致呈抛物线变化;较高含量的Mn提高了Ti、V的碳氮化物的固溶度积,使得该钢在加热温度大于990℃时,晶粒明显长大,高温加热时不具有抗晶粒粗化能力。综合考虑晶粒大小和第二相颗粒(主要是碳氮化物)的影响,并通过测试淬火+回火后的力学性能,确定20Si Mn3Ni A钢合适的奥氏体化温度约为900℃。

Effect of heating temperature, holding time and alloying component on prior austenite size of 20SiMn3NiA steel had been studied by optical microscopy, scanning electron microscopy and energy spectrum analysis. The results show that the prior austenite size increases with increasing the heating temperature, and also under definite heating temperature, the relationship between the austenitic grain growth rate and the keeping time conforming to the parabola curve. The tested steel has no anti-coarsening ability beyond 990℃, which means high Mn content increase solubility of carbonitride of V and Ti. The appropriate austenitizing temperature of steel 20SiMn3NiA is determined as 900℃ by testing the mechanical properties after tempering and quenching experiments and considering the influence of grain size and second phase particles （mainly carbonitride）.