核压力容器用SA508Gr.4N钢加热过程中的奥氏体相变  

Austenite transformation of SA508Gr.4N steel for nuclear reactor pressure vessels during heating process

作　　者：刘宁[1,2] 刘正东[1,2] 何西扣[2] 杨志强[2] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《金属热处理》2017年第3期88-92,共5页Heat Treatment of Metals

基　　金：国家重点研发计划(2016YFB0300203)

摘　　要：采用Formastor-FⅡ型热膨胀装置测定了SA508Gr.4N钢在不同加热速率下连续奥氏体化过程的热膨胀曲线,研究了该钢的连续奥氏体化相变行为,发现当加热速率较低时,相变开始温度较低,且相变温度区间延长。建立了SA508Gr.4N钢奥氏体化相变的Johnson-Mehl-Avrami(J-M-A)方程,并根据试验数据拟合得出奥氏体化相变激活能Q约为1.151×10~6J/mol,J-M-A方程参数n=0.67,lnk_0=129.6。根据J-M-A动力学方程推导出不同温度下等温奥氏体相变动力学曲线,随着保温温度的升高,奥氏体化进程加快,奥氏体化相变速率增大。根据等温奥氏体相变动力学曲线获得了SA508Gr.4N钢的温度-时间-转变量曲线。The thermal expansion curves of austenitization of SA508 Gr. 4N steel under different heating rates were measured by using Formastor-F Ⅱ thermal expansion tester,and the continuous transformation of SA508 Gr. 4N steel was studied in the process. The critical temperature of transformation is found to drop and the temperature range is lengthened with the lower heating rate. The Johnson-Mehl-Avrami（ J-M-A） equation of the austenitization transformation is built,and the activation energy Q for austenitization and the parameters of the equation are obtained by fitting the experimental data,in which Q = 1. 151 × 10~6 J / mol,n = 0. 67,lnk_0= 129. 6. The kinetics curves for isothermal austenitization of SA508 Gr. 4N steel at different temperature could be deduced according to the J-M-A equation,indicating that the process of austenitization transformation speeded up with the increasing temperature. The temperature-time-transformation curves for austenitization of SA508 Gr. 4N steel are established according to the kinetics curves.

关 键 词：SA508Gr.4N钢 奥氏体化相变 热膨胀曲线 

分 类 号：TG111.5[金属学及工艺—物理冶金]