齿轮坯模锻成形表面缺陷分析

采用刚塑性有限元方法，从变形体与模具型腔表面的动态识别出发，提出了处理变形体与模具型腔表面接触和脱离的算法．并将此算法用于成形过程的表面缺陷预测．通过对不同坯料高径比和不同摩擦条件下齿轮坯模锻成形过程的对比模拟，跟踪描述了其各种表面缺陷的形成过程，分析了缺陷形成的原因．定量地给出了不产生类似表面缺陷的极限工艺范围．该极限工艺范围将对合理制订金属塑性成形工艺提供重要的理论依据．

Defect Analysis in a Semi Finished Gear Forging Process by Finite Element Method

Based on a rigid plastic finite element method, a contacting and separating algorithm between deforming body and die surfaces is proposed to deal with the distinguishing problem between deforming body and die surfaces. Using this algorithm, the surface defect in metal forming process can be predicted. The material flow pattern of semi finished gear forging process with different frictions and ratios of height to radius is analyzed in detail. Also, the initiation of surface defect in semi finished gear forging process is analyzed by simulating the surface defect forming process. Meanwhile, the reasonable forging critical diagram of semi finished gear forging is given. This critical diagram is very useful for prevention of surface defects in metal forming process.