基于动态再结晶仿真的40Cr轴锻件锻透性研究

合理的拔长工艺可有效利用动态再结晶机制对大型轴类锻件充分改性.建立宏微观耦合仿真模型,对Φ300 mm×4000 mm的轴锻件的拔长过程进行数值模拟,综合考虑了变形、热传导、变形生热、摩擦生热、动态再结晶等多个因素.分析发现在下压的第2圈即累计压下率约为9%时,材料达到了临界应变条件而发生动态再结晶;随着压下率的增加,动态再结晶体积分数升高;当压下率达到约30%时,随材料心部有67%的区域充分改性;拔长后约60%的区域动态再结晶晶粒尺寸低于100μm,晶粒细化.

Research on Forging Penetration Efficiency of 40Cr Axial Forging by Simulation of Dynamic Recrystallization

The property of heavy axial forgings cau be modified by reasonable drawing process with the advantage of dynamic recrystallization.In view of formation,heat transfer,heating generation,dynamic recrystallization,a macro-micro coupled process was set up,and the drawing process of Φ300mm×4000mm axial forging was simulated.It is found that when the cumulative reduction ratio reaches 9% in the second round,the dynamic recrystallization occurs in the material as it reaches a critical strain condition.With the increase of reduction ratio,the volume fraction of dynamic recrystallization increases.When the cumulative reduction ratio reaches 30%,about 67% of the inner region of the axial forging is modified fully.After the drawing process,the dynamic recrystallization grain size in 60% of the cross-section area is less than 100 μm and the grains get refined.