中文摘要：

通过实验和有限元模拟的方法,研究了薄壁微小型铜管无芯模钢球旋压缩径过程中,铜管的成形特征和应力应变分布。结果表明,随着进给比的增加,已成形表面依次出现金属切向堆积和表面波纹等现象,缩径后铜管壁厚随之增加。旋压缩径后铜管金相组织呈现明显的分层现象,内层稀疏,外层致密,且外表面由于金属流动形成剧烈变形层。等效应力应变均大致呈层状分布,三向主应力均在钢球与铜管接触处达到压应力最大值。

英文摘要：

The forming process of mandreless ball neck-spinning on miniature copper tube is studied based on the simulation and experimental results,and the forming characteristics,metal flow rule,and stress–strain distribution are analyzed： 1） The wall-thickness of formed part increases as the axial feed rate increases,and tangential built-up of metal and surface waves occur on the formed surface in turn.2） The metallurgical structure of formed part shows lamination that the inner is sparse while the outer is dense,and a severe deformed layer is shaped on external surface due to the metal tangential flow.3） The equivalent stress and strain are arranged in layers in the axial direction,and three principal stresses reach the peak value of compressive stress at the contact site of balls and copper tube.