塑料模具钢镦粗过程内部空洞缺陷的有限元模拟

利用JmatPro软件模拟计算718类塑料模具钢(3Cr2MnNiMo)热物性参数。应用ABAQUS有限元模拟软件建立模具钢镦粗过程中孔洞模型,模拟不同压下率条件下孔洞的闭合规律。模拟结果表明:孔洞闭合分为开始闭合、闭合加速和闭合减速3个阶段;孔洞闭合的2个主要影响因素为孔洞表面等效应变ε_e、静水压力与等效应力之比σ_m/σ_e;随着孔洞所处位置不同,孔洞闭合度不同,根本原因为孔洞所处位置的等效应变不同。所得结果对于塑料模具钢实际锻造生产过程具有指导意义。

FEM simulation of inner void defects in plastic die steel during upsetting process

To simulate the closure of void defects in plastic die steel with different reduction rate, the model of upsetting process was established based on the finite element software ABAQUS. Before establishment of the model, the thermophysical parameters of 718 plastic die steels (3Cr2MnNiMo) were simulated by JmatPro software. The simulation results indicate that the closure of the void defect is divided into three stages：start stage, acceleration stage and deceleration stage. Two main influencing factors of the closure for a void defect are found to be equivalent strain εe and the ratio of the hydrostatic pressure to the equivalent stress of the void surface σm/σe. The closure degree changed with the location of void defects along axis height of cylinder, which is mainly attributed to the difference of equivalent strain to which the voids are subjected. The simulation results provide guidance for practical forging process of plastic die steel.