超低碳含铌钢的块状相变及动力学  

Kinetics of massive transformation for an ultra-low carbon steel containing niobium

作　　者：陆恒昌[1] 胡春东 王存宇[1] 浦恩祥 刘剑辉[1] 董瀚[1,2] 

机构地区：[1]钢铁研究总院,北京100081 [2]上海大学材料科学与工程学院,上海200072

出　　处：《钢铁》2018年第2期50-54,共5页Iron and Steel

基　　金：国家重点研发计划资助项目(2016YFB0101605);国家自然科学基金资助项目(51474076)

摘　　要：为了探究一种超低碳含铌钢（0.002C-0.52Nb）的相变机制及动力学,采用热膨胀法研究其连续冷却转变行为,通过光学显微镜及扫描电镜观察组织转变特征及规律,并用改进的JMA方程计算相变界面移动速率。结果表明,试验钢在3~30℃/s冷速范围内的组织具有块状相变的特征,即新相铁素体晶界呈不规则的锯齿状,可以跨越原奥氏体晶界生长;相变动力学计算结果显示,同一冷速下的界面速率基本稳定,3、5、10、30℃/s对应的平均界面移动速率分别为（0.65、1、1.7、6.2）×10^（-5）m/s,相界面移动速率随冷速增加而提高,与冷速的增加比例基本相当,界面控制的动力学方程基本适用,铌溶质在一定程度上影响了相界移动速率。For investigating the transformation mechanism and kinetics of an ultra low-carbon high niobium steel（0.002 C-0.52 Nb）, the dilatometry was employed by continuous cooling process. The microstructure was observed by OM and SEM. A modified Johnson-Mehl-Avrami（JMA）kinetics model was used to calculated the migration velocities of the advancing interface.The results show that the transformation mechanism for various cooling rates is massive transformation. The massive ferrite is characterized by zigzag grain boundary and the product can across the initial austenite grain boundary. The calculated interphase velocity is approximately constant with a mean value of（0.65,1,1.7,6.2）×10^（-5） m/s for 3,5,10,30 ℃/s respectively,which is proportional to cooling rate,implying that the employed model is available to massive transformation of the investigated steel. The solute niobium seems to have some effects to decrease the interphase migration velocities compare to that reported in literatures.

关 键 词：块状相变 动力学 膨胀法 超低碳钢 

分 类 号：TG142.1[一般工业技术—材料科学与工程]