中文摘要：

在920~650℃、变形量60%、应变率分别为0.01、0.1、1、10 s-1时,进行了45钢的热模拟压缩实验。利用金相和SEM组织观察研究了变形过程中组织演变规律。结果表明：中碳钢过冷奥氏体组织转变中的动态相变和珠光体的球化对变形温度和变形速率的要求不同,变形温度对铁素体析出含量有较大影响,随着变形温度的降低,铁素体析出含量增加,但随着变形速率的增加,变形温度对于铁素体析出效果减弱。当变形温度为800℃时,中碳钢组织中开始析出形变诱导铁素体;当变形温度低到750℃时,中碳钢组织开始发生动态珠光体转变。

英文摘要：

When deformation was 60% at 920-650℃ and strain rate was 0.01,0.1,1,10 s-1respectively, the hot compression simulation experiment of the 45 steel was carried out. The microstructure evolution of the steel in deformation process was investigated by metallography microstructure observation and SEM microstructure observation. The results show that dynamic phase transition and pearlite spheroidization demand different deformation temperature and deformation rate in medium carbon steel undercooled austenite transformation. Deformation temperature has a great influence on ferrite precipitation. With deformation temperature decreasing, ferrite precipitation content increases. But with the increasing strain rate, effect of deformation temperature on ferrite precipitation will be weakened. When the deformation temperature is 800℃,medium carbon steel microstructure begins to precipitate the ferrite induced by deformation. When the deformation temperature decreases to 750℃, medium carbon steel microstructure begins to dynamic pearlite transform.