The static recrystallization softening behavior by two⁃pass compression test of Mn18Cr18N retaining ring steel were investigated on a Gleeble 1500D thermo⁃simulation machine. Effect of deformation temperature, strain rate, deformation degree and initial austenite grain size on the static recrystallization microstructure was analyzed. The softening fraction of static recrystallization was determined using the 2% stress offset method and it was modified with the metallographical observation. Then static recrystallization kinetic model was established and the activation energy for static recrystallization is determined as 249. 3 kJ/mol. The results show that the shape of static recrystallization softening curves of Mn18Cr18N steel is sigmoidal and obeys the Avrami law. The volume fraction of static recrystallization increases with the longer holding time, and the higher the hot deformation temperature is, the higher the volume fraction of static recrystallization also becomes. At the lower temperature and smaller deformation degree, the incubation time is longer and static recovery occurs. There is a good agreement between the predicted value and experimental results, which provides a reliable model of hot upsetting simulation for retaining ring steel.%在Gleeble－1500D热模拟机上，采用双道次热压缩试验研究Mn18Cr18N护环钢高温变形后不同停留时间内的静态软化行为，分析热变形温度、应变速率、变形程度以及初始奥氏体晶粒对静态再结晶行为的影响．通过应力补偿法计算静态再结晶软化率，并结合金相组织作了修正．建立其静态再结晶动力学模型，获得静态再结晶激活能249．3 kJ／mol．研究表明：Mn18Cr18N钢静态再结晶软化曲线呈“S”形，符合Avrami方程．静态再结晶体积分数随着停留时间延长而增加，热变形温度越高，静态再结晶分数越大，而在较低温度和较小变形程度时，孕育时间较长，主要发生静态回复，将静态再结晶动力学模型的预测结果与实测值进行比较，二者吻合较好，为护环钢后续热镦粗工艺模拟提供更为详尽的模型．
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