BTi-62421s钛合金板TIG焊温度及残余应力数值模拟

Numerical Simulation of Temperature and Residual Stress in TIG Welding of BTi-62421s Titanium Alloy Plate

以热弹塑性理论为基础、有限元分析为手段,分析了2 mm厚新型高温钛合金BTi-62421s板材在合理的钨极氩弧焊工艺焊接过程中温度及残余应力分布规律。结果表明:随着焊接电流的增大,焊缝及热影响区温度梯度、焊缝及热影响区的宽度增大,靠近焊缝的近热影响区温度范围在合金相变点以上,焊后快冷易形成马氏体组织;施焊面焊缝区横向和纵向残余应力为拉应力,热影响区为压应力,施焊背面焊缝区横向和纵向残余应力为压应力,热影响区为拉应力,焊接残余应力随焊接电流的增大而增大,纵向残余应力始终小于横向残余应力。

Based on thermal elastoplastic theory, the temperature and residual stress distributions in TIG welding of 2 mm-thick BTi-62421s titanium alloy plate were investigated by finite element analysis. The results show that the temperature gradient and width of the welded joints and heat-affected zones （HAZ） increase with the increasing of welding current. The temperature of HAZ near the joints is above the transformation temperature of the alloy, which leads to martensite formation during the quick cooling after welding. The transversal and longitudinal residual stresses in the joints and HAZ on the welding side are tensile stress and compressive stress respectively. However, the transversal and longitudinal residual stresses in the joints and. HAZ on the reverse welding side are compressive stress and tensile stress respectively. The residual stress increases with the increasing of welding current, and the value of longitudinal residual stress is always smaller than that of the transversal.