基于数值模拟的钛合金锥形件激光辅助铲旋成形研究

Research on laser-assisted shovel spinning forming of titanium alloy conical parts based on numerical simulation

针对中部带法兰锥形件采用传统“锻造+机加工”制备时材料利用率低、强度及韧性不足的问题,提出采用激光辅助铲旋成形工艺来实现钛合金中部带法兰锥形件的完整近净成形。根据铲旋成形原理,选取合适的激光热源模型,并基于Simufact Forming软件平台建立激光辅助铲旋有限元模型,研究了铲旋成形过程中的中部法兰变形区温度、变形行为及等效塑性应力和等效塑性应变分布规律。结果表明,采用坯料整体预热+激光辅助补热的方式,可实现坯料基体表层温度高、内层温度低,既有利于表面金属材料铲旋成形出法兰,又可避免锥壁翘起;铲旋成形时变形区材料轴向流动较多,径向流动较少,法兰形状呈“倒水滴”状;旋轮接触区等效塑性应力值较大,但法兰主体部分等效塑性应力值较小且分布均匀;基体主要变形区等效塑性应变值最大,达9~11,沿厚度方向逐渐减小,具有局部大塑性变形且变形不均匀的特点。

Aiming at the problems of low material utilization,insufficient strength and toughness when the central flange conical parts were prepared by traditional‘forging+machining’,a laser-assisted shovel spinning forming process was proposed to realize the complete near-net forming of the central flange conical parts of titanium alloy.According to the principle of shovel spinning forming,a suitable laser heat source model was selected,and a laser-assisted shovel spinning finite element model was established based on the Simufact Forming software platform.The temperature,deformation behavior and equivalent plastic stress and equivalent plastic strain distribution of the central flange deformation zone during shovel spinning forming process were studied.The results show that the method of overall preheating+laser-assisted heating of the blank can achieve high temperature of the surface layer and low tem-perature of the inner layer of the blank matrix,which is not only beneficial to forming the flange of the surface metal material by shovel spinning,but also avoids the upheaval of the cone wall.The axial flow of the material in the deformation zone is more than that of the radial flow,and the shape of the flange is‘pour drop’.The equivalent plastic stress value of the contact area of the roller is large,but the equivalent plastic stress value of the main part of the flange is small and evenly distributed.The equivalent strain value of the main deformation zone of the matrix is the largest,reaching 9-11,and gradually decreases along the thickness direc-tion,which has the characteristics of local large plastic deformation and uneven deformation.