焊接参数对TC4薄板焊接过程的影响

目的 揭示焊接参数对TC4薄板焊接过程中温度场、位移场及应力场的影响规律。方法 基于有限元(FEM)模拟方法，运用Fortran语言对焊接热源及焊接参数进行定义，以模拟不同焊接参数下TC4薄板的TIG对接焊过程。结果 在稳弧阶段，温度场为一组以焊接方向为长轴的椭圆，且存在温度梯度，随着焊接速度的增大，温度场峰值、温度场温度梯度、熔池宽度和熔池体积逐渐减小，而焊接效率和焊接电流对温度场的影响与焊接速度刚好相反;随着焊接速度的增大，薄板最大变形量逐渐减小，焊接角变形及挠度变形逐渐得到改善，而焊接效率和焊接电流对位移场的影响与焊接速度刚好相反。在稳弧阶段，焊缝位置的残余应力为拉应力，两侧为压应力，随着焊接速度和焊接电流的增大，纵向残余拉应力逐渐增大，焊缝处高应力集中区的宽度逐渐减小，而焊接效率对应力场的影响与焊接速度刚好相反。在高焊接速度、中等焊接效率、低焊接电流参数条件下，可获得熔池体积小及熔池宽度窄的焊缝，有利于减小焊后残余应力与变形。结论 上述研究结果可为TC4薄板的焊接过程提供一定的理论指导。

Effect of Welding Parameters on Welding Process of TC4 Thin Plates

The work aims to reveal the effect of welding parameters on the temperature field, displacement field, and stress field during the welding of TC4 thin plates. Based on the finite element (FEM) simulation method, Fortran language was used to define the welding heat sources and welding parameters, to simulate the TIG butt welding process of TC4 thin plates under different welding parameters. The temperature field during the stable arc stage was a set of ellipses with the welding direction as the major axis, and there was a temperature gradient. As the welding speed increased, the peak value of the temperature field, the temperature gradient of the temperature field, the width and volume of the molten pool gradually decreased; while the impact of welding efficiency and welding current on the temperature field was exactly opposite to that of the welding speed. As the welding speed increased, the maximum deformation of the thin plate gradually decreased, and the welding angular deformation and deflection deformation were gradually improved; while the effect of welding efficiency and welding current on the displacement field was exactly opposite to that of welding speed. During the stable arc stage, the residual stress at the weld position was tensile stress, with compressive stress on both sides. As the welding speed and welding current increased, the longitudinal residual tensile stress gradually increased, and the width of the high stress concentration zone at the weld gradually decreased; while the effect of welding efficiency on the stress field was exactly opposite to that of welding speed. Under high welding speed, medium welding efficiency, and low welding current parameters, a weld with a small pool volume and narrow pool width could be obtained, which was beneficial for reducing residual stress and deformation after welding. The above research results can provide certain theoretical guidance for the welding process of TC4 thin plates.