中文摘要：

基于DEFORM软件，建立了外台阶截面环件热辗扩有限元模型，模拟分析了材质为42CrMo钢的环形铸坯热辗扩过程。结果表明：在选定的热辗扩工艺参数下，辗扩后环件表面平整光滑，无凹坑缺陷，成圆规整；与成形辊接触的环件内外层金属的流动速度大于芯部的流动速度；与成形辊接触的环件内外层金属等效应变较芯部大；在辗扩过程中，环件芯部的温度下降始终较内外层平缓，内外层金属的温度呈锯齿状下降趋势。本文的研究对外台阶截面环形铸坯热辗扩成形工艺的设计、环件质量预测与控制具有指导意义。

英文摘要：

Based on the DEFORM software, the finite element model of hot rolling ring with stepped cross section has been established in the text. The hot ring rolling process of the 42CrMo annular casting blank has been simulated and analyzed. The results show that： under the selected hot rolling parameters, the ring is smooth and regular without pits on surface; the flow velocity of inner and outer metal which contacts with forming roller is larger than that of the core part; the equivalent strain of the inner and outer metal is larger than that of the core part; in the hot ring rolling process, the temperature drops of the core part metal is gentle than that of the inner and outer part, the trend of temperature drops of the inner and outer part metal is zigzagging. It has important significance for design of hot ring rolling for annular casting blank with stepped cross section, as well as forecasting and controlling the quality of ring.