多楔异速轧制25CrMo4实心车轴仿真结果分析

Simulation results analysis of multi-wedge differential speed rolling for 25CrMo4 solid axle

基于DEFORM-3D二次开发写入多元非线性回归硬化模型,通过高温拉伸实验确定Cockroft-Latham断裂模型参数,对25CrMo4复杂实心车轴在轧制速度比为1.0、1.15、1.25和1.5的同径同速和异速轧制工艺下的成形进行有限元仿真。对同速和异速轧制后所得的复杂车轴的轧制外形、轧制力、流动速度场、塑性损伤和等效应力应变等情况进行分析,从而探究异速轧制对车轴成形的影响。结果表明,异速轧制可提高材料的成形性,有益于变形深入心部,异速轧制力小于同速轧制;异速轧制对轧件的上下对称表面的搓轧作用不同,使得速度略大的一面损伤略大;在异速轧制的过程中,附加剪应力降低了摩擦对轧件的阻碍作用,使得等效应力低于同速轧制。

Based on the secondary development of DEFORM-3D,the multivariate nonlinear regression hardening model was written,and the parameters of Cockroft-Latham fracture model were determined by high temperature tensile experiments.The forming of 25CrMo4 complex solid axle with different rolling speed ratios of 1.0,1.15,1.25 and 1.5 was simulated by finite element method.The rolling shape,rolling force,flow velocity field,plastic damage and equivalent stress and strain of the complex axle obtained after same and differential speed rolling were analyzed,and the effects of differential speed rolling on axle forming were explored.The results show that the formability of the material can be improved by differential speed rolling,and it is beneficial for the deformation deep into the center.The differential speed rolling force is less than that of same speed rolling.The cross shear rolling effect on the upper and lower symmetrical surfaces of the rolled piece is different,and the side with larger speed has a little more damage.The hindering effect of friction on the rolled piece is reduced by additional shear stress in differential speed rolling,and the equivalent stress is lower than that of the same speed rolling.