钛合金弯管动态流量控制法挤压成形的模拟与实验研究

Numerical simulation and experimental study of titanium alloy bending tube extruded by dynamic flow control technique

通过有限元分析和实验研究动态流量控制法挤压钛合金弯管件。实验验证弯管的尺寸精度和挤压载荷。分析调控量对弯曲曲率的影响、速度场和温度场。结果表明:挤压载荷的峰值误差为14.51%,挤出的管材弯曲曲率误差为3.47%;在模具结构中,调控通道Ⅱ截面面积不变时,弯管曲率半径随调控通道Ⅰ有效截面面积的增大而增大;在定径带处的合金呈非均匀流动,弯管件内外弧面存在流速差是挤出弯曲件的原因;合金的流速在通过定径带时发生分流补偿,由调控通道Ⅱ进入定径带的合金流速反超辅助通道内的流速,在焊合腔内边缘处存在金属流动死区。在定径带区域温升明显,最大温升为134℃。

The dynamic flow control extrusion(DFCE)of titanium alloy bending tubes was examined in the present study using both the finite element analysis and the experimental approach.The finite element analysis was first validated qualitatively and quantitatively by the experimental data obtained from the DFCE process.The effects of the area of channel cross section on the radius of curvature were studied by the finite element analysis.The fields of velocity and temperature of workpiece were studied.The results show that the relative errors of extrusion load and radius of curvature are 14.51%and 3.47%,respectively.The finite element analysis reveals that radius of curvature increases with the increase of cross-sectional area of controlling channel-Ⅰ.The different cross-sectional area of controlling channel-ⅠandⅡis found to be one major reason for the extrusion of bending tube.The velocity of workpiece is inhomogeneous in circumferential of bearing zone.The velocity of alloy flowing through die bearing from controlling channel-Ⅱincreases rapidly than that from auxiliary channel.The temperature rise is obviously and the maximum value is 134℃.