镍基高温合金锥筒形件拉深旋压成形机理研究

Research on deep drawing spinning forming mechanism of conical-cylindrical part of Ni-based superalloy

针对镍基高温合金因加工硬化严重成形时极易产生破裂和起皱等典型缺陷的问题,以锥筒形壳体类零件为对象,提出了一种由锥形预制坯经过真空固溶处理后拉深旋压成形锥筒形件的方法,并对其成形机理进行了研究。基于Abaqus/Explicit平台,建立了锥筒形件拉深旋压有限元模型,分析了成形过程中的瞬态等效应力、等效塑性应变、切向应力、壁厚及三向应变分布规律。结果表明:在旋压成形过程中,最大瞬态等效应力位于旋轮接触区及附近区域、最大瞬态等效塑性应变位于坯料口部;瞬态切向压应力最大值位于旋轮接触区,而瞬态切向拉应力最大值位于旋轮接触区附近的两侧区域。筒形段中部壁厚减薄,而坯料口部壁厚增厚。旋压成形试验表明,锥形预制坯经拉深旋压后可获得壁厚均匀的锥筒形件。

For the problem that the nickel-based superalloy was prone to typical defects such as crack and wrinkle due to severe work hardening during forming,taking the conical-cylindrical part as the object,a method for deep drawing spinning the conical-cylindrical part from the conical pre-formed blank after vacuum solution treatment was proposed,and its forming mechanism was studied. Based on Abaqus/Explicit,a finite element model of deep drawing spinning for conical-cylindrical part was established,and the distribution laws of transient equivalent stress,equivalent plastic strain,tangential stress,wall thickness and triaxial strain in the forming process were analyzed respectively. The results show that the maximum transient equivalent stress occurs in the contact area of roller and its vicinity,and the maximum transient equivalent plastic strain occurs at the mouth of blank. Besides,the maximum value of transient tangential compressive stress is located in the contact area of roller,and the maximum value of transient tangential tensile stress is located on both sides of the contact zone for roller. Furthermore,the wall thickness in the middle part of cylindrical section reduces,and the wall thickness of the blank mouth increases. Finally,the spinning tests show that the conical-cylindrical part obtains uniform wall thickness by deep drawing spinning conical pre-formed blank.