中文摘要：

基于DEFORM有限元软件二次开发建立了40Cr钢本构关系,建立了高颈法兰封闭轧制成形的刚塑性有限元模型。进行了轧制过程中高颈法兰微观组织演变的研究,预测其成形过程中动态再结晶晶粒尺寸、体积分数和再结晶体积分数以及平均晶粒尺寸大小的变化情况,阐明了轧制工艺参数对微观组织细化的影响规律。结果表明：内外径部分在轧制中最先发生动态再结晶,最终轧制法兰的晶粒度可由119μm细化到11.368μm,这对产品性能的提高有重大影响。

英文摘要：

40Cr steel constitutive relationship was established based on the secondary development of finite element software DEFORM. A rigid-plastic finite element model of high-neck flange closed rolling was established. The microstructure evolution of the high-neck flange during the process was researched. The dynamic recrystallization grain size and volume fraction, the recrystallization volume fraction and the average grain size during the forming process were predicted. Effects of rolling process parameters on microstructure refinement were expounded. The results show that： in the inner and outer diameter parts of the workpiece, dynamic recrystallization takes first place; the grain size of final rolling flange is refined from 119 μm to 11.368 μm, which has great influence on the improvement of product performance.