锻态42CrMoA钢热变形软化行为及微观组织演变研究  

Study on hot deformation softening behavior and microstructure evolution of forged 42CrMoA steel

作　　者：陈迎庆 段兴旺[1] 贾悦 车鑫 CHEN Ying-qing;DUAN Xing-wang;JIA Yue;CHE Xin(School of Material Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学材料科学与工程学院,山西太原030024

出　　处：《塑性工程学报》2025年第1期185-192,共8页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51775361)。

摘　　要：以锻态42CrMoA钢的热压缩实验为基础,利用光学显微镜(OM)、扫描电镜(SEM)和电子背散射衍射(EBSD)技术对微观组织进行观察和分析。结果表明:当动态再结晶(DRX)完全时,真应力-真应变曲线有明显的峰值应力和软化特征;当DRX不完全时,真应力-真应变曲线没有明显的峰值应力和软化特征。结合EBSD数据可知,母相奥氏体亚结构影响马氏体相变。变形温度越低,应变速率越高,快速冷却后微观组织的中间取向差角晶界(MMAGBs)的比例和平均局部应变越大。由母相奥氏体晶粒和SEM下的微观组织可知,快速冷却后得到的马氏体组织分布与母相奥氏体分布有关,当母相奥氏体晶粒分布均匀时,马氏体组织分布有序和均匀;当母相奥氏体晶粒分布不均匀时,马氏体组织分布无序和不均匀。The microstructure was observed and analyzed using optical microscope(OM),scanning electron microscope(SEM)and electron backscatter diffraction(EBSD)based on hot compression experiments of forged 42CrMoA steel.The results show that when dynamic recrystallisation(DRX)is complete,the true stress-true strain curves have obvious peak stress and softening characteristics;when DRX is incomplete,the true stress-true strain curves have no obvious peak stress and softening characteristics.Combined with EBSD data,it is shown that the martensite transformation is influenced by the substructure of the parent austenite.The lower the deformation temperature is,the higher the strain rate is,and the larger the proportion of middle misorientation angle grain boundaries(MMAGBs)and the average local strain of the microstructure are bigger after rapid cooling.According to the parent austenite grain and microstructure under SEM,the distribution of martensite structure obtained after rapid cooling is related to the distribution of parent austenite.When the parent austenite grain distribution is uniform,the martensite structure distribution is ordered and uniform.When the parent austenite grain distribution is nonuniform,the martensite structure distribution is disordered and nonuniform.

关 键 词：锻态42CrMoA钢 软化特征 中间取向差角晶界 平均局部应变 马氏体相变 

分 类 号：TG142.1[一般工业技术—材料科学与工程]