线能量对TC4钛合金激光焊接残余应力和变形的影响

利用有限元分析和实验测试，研究了TC4钛合金平板激光焊接线能量对变形和残余应力的影响规律，并通过焊缝金相实验分析了线能量与焊接残余应力和变形的内在关系。结果表明：钛合金激光焊接产生的纵向残余拉伸应力约700MPa～850MPa，而横向残余拉伸应力只有50MPa～80MPa。激光焊接线能量增加时，纵向残余应力拉伸区域变宽，峰值应力降低，而横向残余应力随线能量的增加而升高。在临界焊透规范以上焊接时，角变形随线能量的增大而减小，但横向收缩变形增大。试件被完全穿透焊接时，线能量对角变形的影响作用降低。

Effects of Heat Input on Laser Welding Residual Stress and Distortion of TC4 Titanium Alloy

The effects of heat input on the laser beam welding residual stress and distortion of TC4 titanium alloy were investigated by finite element analysis and experimental tests. The internal relationships of residual stress, deformation and heat input were further investigated by the metallographic section of weld. The results showed that the tensile stresses produced in the longitudinal direction of welded joints were about 700 MPa-850 MPa, but only 50 MPa-80 MPa for the transverse tensile stresses. The tensile region of longitudinal residual stress was widened and the stress peak was decreased, but the magnitude of transverse tensile stress was increased when the heat input increasing. At the same time, the angular distortion was decreased and the transverse shrinkage deformation was increased when welding at above a critical specification. As the welding specimens were fully penetrated, the effects of heat input on the angular distortion were decreased.