等温条件下非等截面钛合金型材热拉弯材料流动仿真研究

Simulation study on hot stretch bending material flow of non-uniform section titanium alloy extrusions under isothermal conditions

通过高温单向拉伸试验,获得了TC4钛合金挤压型材在700℃不同应变速率下的拉伸性能,并基于ABAQUS平台建立了带加强筋的U形截面钛合金热拉弯有限元仿真模型。研究了沿弧长方向挤压型材带筋和非带筋截面上的应力、应变变化规律和筋附近的材料流动行为。结果表明:挤压型材沿弧长方向由外侧向内侧应力逐渐减小,拉应力逐渐转变为压应力;加强筋处有较大的应力梯度,筋条顶部为压应力,底部为拉应力;在距离加强筋30 mm范围内应力有较大变化;仿真结果可为后续非等截面钛合金挤压型材精确拉弯成形、辅助加热装置设计和模具设计提供工艺指导。

The tensile properties of TC4 titanium alloy extrusions at 700℃and different strain rates were obtained by the high temperature uniaxial tensile tests.Based on ABAQUS software,a finite element simulation model of U-shaped section with strengthening rib was established.The changes law of stress and strain on the reinforced and non-reinforced sections of the extrusions along the arc length and the material flow behavior near the ribs were studied.The results show that the stress of extrusions decreases gradually from the outside to the inside along the arc length and the tensile stress gradually turns to compressive stress.There is a large stress gradient at the strengthening rib,and it is compressive stress at the top of the rib and tensile stress at the bottom.The stress changes greatly within 30 mm from the strengthening rib.The simulation results can provide technical guidance for the subsequent precise stretch bending forming of the nonuniform section titanium alloy extrusion,auxiliary heating device design and mold design.