采用SYSWELD软件对Q345低合金钢板的匙孔型钨极气保焊（keyhole gas tungsten arc welding，K-TIG）焊接过程进行了模拟，选用了3种形式的组合热源对K-TIG焊接过程的温度场进行数值模拟，并与实际焊缝轮廓进行对比，发现采用上半部分双椭球热源和下半部分3D高斯热源的组合热源所得温度场与实际情况较为相似.并通过K-TIG焊接数值模拟，分别研究板厚、间隙和焊接速度对K-TIG焊接接头变形和应力的影响.结果表明，减小焊接板厚有利于减小焊后z向变形和横向残余应力，留出适当的间隙有利于减小焊后残余应力，增大焊接速度有利于减小焊后变形，但不利于控制焊后残余应力.
Keyhole gas tungsten arc welding (K-TIG) process of Q345 low alloy steel plates was simulated by SYSWELD software. The temperature field of K-TIG welding process was simulated with three different combined heat sources, and compared with actual weld profile obtained by experiment. It was found that the temperature field obtained by the combination of double ellipsoid heat source on the upper half and 3D Gaussian heat source on the lower half was similar to the actual situation. The effects of plate thickness, gap and welding speed on the deformation and stress of K-TIG welded joints were investigated by K-TIG welding numerical simulation. The results indicate that reducing the thickness of weld plates is beneficial to reducing Z-direction deformation and transverse residual stress, leaving appropriate gap is beneficial to reducing residual stress, increasing welding speed is beneficial to reducing deformation after welding, but is not beneficial to controlling residual stress after welding.
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