径压胀形中管材的填充性及成形性分析

通过对不锈钢管材径压胀形过程进行有限元数值模拟，对成形管材断面对角线长度变化趋势及壁厚分布规律进行了分析与比较，探讨了加载方式、管端约束条件（管端自由与管端固定）及摩擦条件对管材填充性及成形性的影响规律。结果表明，自由胀形直径或内压力越大，则管材的填充性越好，但成形性越差；管端固定时会使管材的填充性及成形性变差；摩擦使胀形管材断面形状不完全对称，且随着自由胀形直径或内压力的增大而显著。

Investigation on the Corner-filling Ability and Formability of Tube in Hydroforming with Radial Crushing

Based on the finite element simulation of tube-hydroforming process with radial crushing,the influence of loading path,constraint conditions of tube ends(fixed ends and free ends)and friction state upon the corner-filling ability and formability of stainless steel tube have been investigated by analyzing and comparing the maximum diagonal lengths in tube section and thickness distribution in deformed tube.The results show that a larger internal pressure or maximum diameter at free bulging stage increases the corner-filling ability while decreases the formability of the tube;moreover,fixed ends bring on poor corner-filling ability and formability.The existence of friction between the tube and dies results in a nonsymmetrical section which is more remarkable in larger internal pressure.