重力对全位置TIG焊熔池温度场与流场影响的有限元分析

Effects of gravity on temperature field and fluid flow distribution of all-position TIG welding using finite element method

建立了全位置TIG焊接中平焊、45°下向焊、立焊下向焊的熔池温度场、流场数值计算模型,计算了不同焊接位置以及不同重力加速度值情况下熔池的温度场和流场,分析了重力方向和大小对熔池内流场和温度场的影响规律;发现重力方向对熔池内液态金属的流场、温度场影响明显,液态金属的流动影响温度场分布明显,重力大小对熔池流场的分布形态没有影响,但是对流动速度影响明显.得到的结论对于研究熔池失稳判定依据、指导设计全位置TIG焊乃至MAG焊工艺具有一定的参考价值.

Numerical model of temperature field and fluid flow field was built to study the effects of gravity on different welding positions and different gravity values. Temperature field and fluid flow field of flat position,45° position and 90° position with downward speed were calculated,respectively. The results showed that fluid flow of 90° position was far more intense than the one of flat position,which affected the temperature distribution and caused molten metal flowing downward. The presence of gravity had no influence on fluid flow distribution morphology,but affected the flowing speed significantly. Conclusions of this study can be used on the research of welding pool instability judgment basis and deciding parameters of all position TIG or MAG welding.