基于多场耦合有限元法的大规格电镦成形工艺优化

Optimization of large size electrical upsetting forming process based on multi-field coupling finite element method

为了分析电镦成形过程中缺陷的形成过程,基于MSC.Marc平台建立了多场耦合的有限元分析模型。通过数值模拟和生产实践得出产生波浪缺陷的主要原因有两方面:一是在预热阶段大电流的作用下,随温度升高,趋肤效应明显,形成椭圆柱体,这种现象在后面的电镦成形过程中逐步放大,从而形成波浪缺陷;二是电镦过程中峰值电流大、温度较高,且峰值电流在靠中、后阶段,硬化不明显,导致波浪缺陷。随后,通过无级电流变化的模式调节不同阶段的电流,成功避免了电镦过程中的波浪缺陷。最后,通过在MSC.Marc软件中开发电流子程序,建立了电流多节点闭环控制的数值模拟优化方法,并在实践生产中得到验证。

To analyze the forming process of defects in electrical upsetting process,a multi-field coupling finite element analysis model was established based on MSC.Marc platform.Through numerial simulation and production practice,it is concluded that there are two main reasons for the appearance of wave defects.The first one is the obvious skin effect with the increase of temperature under the action of large current in preheating stage,an elliptical cylinder is formed.This phenomenon gradually enlarges in the later electrical upsetting,thus the wave defects are formed.The second one is that the peak current is large,the temperature is high,and the peak current is in the middle and later stages during the electric upsetting process,the hardening is not obvious,which leads to wave defects.Subsequently,the wave defects in the electrical upsetting process is successfully avoided by adjusting the current at different stages through the mode of stepless current change.Finally,by developing the current subroutine in MSC.Marc software,a numerical simulation optimization method for current multi-node closed-loop control was established,which was verified in practice.