中文摘要：

针对钻杆接头挤压缩口成形过程中产生连皮四周出现缺肉及折叠缺陷的现象,采用三维有限元模拟软件Derform-3D,对整个缩口过程及成形影响因素进行了模拟分析,发现缺陷的产生主要是由反挤压与缩口同时进行时成形件底部金属复杂流动引起的。通过对冲头形状、凹模型腔及摩擦系数等成形影响因素分析,确定出缩短冲头长度、适当增大冲头直径、凹模变锥角并底部加台、减小摩擦系数等解决措施,并通过实验得到合格的产品。

英文摘要：

Aiming at the defect of enfold and the shortage of material around web in the forming process of necking for drill pipe joint,the finite element software Derorm-3D was employed to simulate the whole process and the shape factors of necking.The results show that the defect is mainly caused by complex metal flow at the bottom of formed parts when backward extrusion and necking at the same time.Through the analysis of forming factors including punch shape,matrix cavity and friction coefficient,the solutions were determined,such as shortening the length of the punch,increasing the punch diameter,changing cone angle of the concave die,increasing the table at the bottom of concave die and reducing the friction coefficient.Finally,the qualified workpiece is produced.