SA508-3钢保温过程奥氏体晶粒长大规律研究

Austenite Grain Growth of SA508-3 Steel in Heating Process

锻造时需要确定始锻温度及控制锻造时的晶粒度。利用箱式电阻炉进行一系列保温实验,研究了核电压力容器材料SA508-3奥氏体不锈钢在不同保温温度和保温时间下的奥氏体晶粒长大规律。结果表明:当保温时间一定时,奥氏体晶粒随保温温度的升高呈指数关系长大。当保温温度超过1200℃时,奥氏体晶粒尺寸急剧增大,晶粒明显粗化。根据实验结果建立了奥氏体晶粒长大规律的数学模型,为确定SA508-3钢始锻温度提供了微观组织判断依据。

To determine the initial forging temperature and control grain size after forging, the austenite grain growth behavior of SA508-3 steel was studied systematically based on series of isothermal experiments in box resistance furnace at different heating temperature and holding time. The results indicate that austenite grain tends to grow up at an exponential relationship with the increase of heating temperature at a certain holding time. The austenite grain grows up sharply and becomes coarse obviously when heating temperature is higher than 1200℃. A mathematical model is established based on the experimental data to predict the austenite grain growth law, which can provide microstrueture judgment for the initial forging temperature.