大钢锭内部空洞锻合过程的数值模拟

本文采用实验和塑性有限元法模拟相结合的方法研究了大钢锭在锻造过程中内部空洞的锻合机制。结果表明，空洞的闭合度λ和空洞周围的最大压应变ε 1成线性关系。工具与坯料间的磨擦影响坯料内部的应力应变分布，但不改变λ和ε 1的线性关系。当用上下平砧拔长大钢锭时，使ε 1峰值到达坯料中心的最小砧宽比为0.51，最佳砧宽比为0.7。对于FM法拔长，最小砧宽比为0.4，最佳砧宽比为0.6。

NUMERICAL SIMULATION OF THE VOID CLOSING IN A LARGE INGOT DURING FORGING PROCESSES

Numerical simulation by finite element method and experimental investigation of the mechanism of void closing were carried out. It was found that the degree of closure λ, of a void is directly proportional to the maximum principal compressive strian ε1 arround the void. Contact friction between material and tool effects the distribution of stress and　strain states in the billet, but not the relationship ofλandε1. In the flat-die drawing　of a billet, the minimum ratio of die breadth to billet height which makes the top maximum compressive strain El to get at the billet center is 0.51. The optimum die breadth is0.7 of the billet height. For the FM method of drawing, the minimum die breadth is 0.4　of the billet height and the optimum is 0.6. The calculated results are. In good agreement　with experiment and now applied in industrial practice.