驱动辊转速对铸态42CrMo钢环件热辗轧微观组织的影响规律

环形铸柸微观组织的演变规律及合理控制是环类零件铸辗复合成形新技术发展面临的主要瓶颈问题.驱动辊转速是影响铸坯材料再结晶行为及组织状态的关键因素之一.本文基于ABAQUS平台,建立了42CrMo铸坯环件热辗轧的宏微观有限元模型,模拟揭示了环形铸坯材料的动态再结晶行为,阐明了驱动辊转速对再结晶晶粒尺寸及其分布的影响规律与机制.结果表明:铸坯材料动态再结晶百分数在环件内、外层高而使晶粒细化,而在环件中间层低导致粗品；驱动辊转速增大,铸坯材料动态再结晶百分数增加,轧制环件的平均晶粒尺寸减小；驱动辊转速对平均晶粒尺寸分布的均匀性影响不大.

Effects of rotational speed of driving roll on microstructure evolution during hot ring rolling of as-cast 42CrMo steel

The evolution rules and reasonable regulation of the microstructure of the as-cast ring blank material is the main bottleneck question for the development of the new casting-rolling composite forming technology.The rotational speed of the main roll is one of the key factors influencing the recrystallization behavior and microstructure of the as-cast ring blank material.In this paper,we first established a coupled macro-micro FE model of hot ring rolling for as-cast 42CrMo steel under ABAQUS software environment,then numerically revealed dynamic recrystallization(DRX) behavior of as-cast ring blank material,and lastly clarified the effect rules and mechanism of the rotational speed of the main roll on grain size and its distribution.The results show that:(1) The DRX percentages is high in the inner and outer layers of the ring leading to refined grain while relatively low in the middle layer of the ring resulting in coarse grain;(2) the DRX percentage increases while the average grain size decreases with the increase of the rotational speed of the main roll;and(3) the rotation speed of the main roll has negligible effect on the uniformity of the distribution of the average grain size.