中文摘要：

根据建立的环形铸坯热辗扩成形刚塑性有限元模型和铸态42CrMo钢动态再结晶数学模型，基于DEFORM-3D软件平台，综合考虑了变形、传热和微观组织演变等因素，对辗扩过程中的变形和动态再结晶行为进行宏微观耦合模拟。结果表明：在环形铸坯热辗扩成形过程中，动态再结晶程度较低，等效应变和晶粒尺寸呈现环带状分布，环件的内外层等效应变大，动态再结晶晶粒尺寸和平均晶粒尺寸细小，变形量较小的环件中层晶粒尺寸相对粗大。

英文摘要：

The rigid-plastic finite element model of annular casting blank during hot roiling and dynamic recrystallization mathematical model of as-cast 42CrMo steel have been established. Based on DEFORM-3D software platform, considering the factors of deformation, hot transfer and microstructure evolution, the maro-micro coupling simulation of deformation and dynamic re-crystallization behavior during hot rolling have been studied. The results show that the degree of dynamic re-crystallization is lower. Besides, the equivalent strain and grain size of ring piece are in zonal distribution. The dynamic re-crystallization grain size and average grain size are fine in outer and inner layer of ring due to the large equivalent strain. The bulky grain has been existed in the middle layer of ring due to the small deformation.