奥氏体不锈钢的再结晶动力学

Dynamic Recrystallization Kinetics in Austenitic Stainless Steel

采用双道次压缩和应力松弛2种实验方法,研究了含铌奥氏体不锈钢347热变形后的再结晶动力学特征,确定了AVRAMI方程表达式,同时通过定量金相技术分析了对应2种实验方法的淬火试样中再结晶组织所占份数。比较不同实验方法所得结果可知:定量金相分析结果与应力松弛法结果较吻合,而与双道次压缩实验结果差异较大。仅进行1次应力松弛实验就可以得到一条再结晶率与时间的关系曲线,可大大减少实验量。

Double-hit compression and stress rdaxation tests were both employed to investigate the post-dynamic recrystallization kinetics in the hot deformed austenite stainless steel AISI 347 with a very high Nb content up to 7.2%. Quantitative metallographic measurements were also done on the interruptedly quenched specimens to follow the evolution of recrystallized microstructure and compare with the results obtained by the two thermomechanical techniques. Advantage and disadvantage of each technique of determing PDR kinetics were discussed. It was found that data derived from stress relaxation technique was in good agreement with the data obtained by quantitative metallographic measurements. Besides, stress relaxation technique has a clear advantage over double-hit compression due to its high efficiency since a stress relaxation curve can produce much larger amount of data for the curve of recrystallized fraction vs. time.