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通过电弧模型与熔池模型耦合数值模拟,研究了氩弧和氦弧特性及其对SUS304不锈钢钨极惰性气体保护(TIG)焊熔池形貌的影响.通过比较氩弧和氦弧的温度轮廓线以及阳极表面电流密度和热流密度分布发现,氦弧的径向距离比氩弧收缩明显,导致更多热量传递给阳极.模拟了氩弧和氦弧下浮力、电磁力、表面张力和气体剪切力分别对熔池形貌的影响.结果表明:不论是在氩弧还是在氦弧下,熔池中表面张力是影响熔池形貌的最主要驱动力.在氩弧下,影响熔池形貌的另一个重要的驱动力是气体剪切力,而氦弧下则是电磁力.由于电磁力引起的内对流运动增加了熔深,从而导致相同氧含量时氦弧下的熔深和焊缝深宽比要高于氩弧下的熔深和焊缝深宽比.随着氧含量的增加,氩弧和氦弧下的焊缝深宽比均先增加而后保持不变.焊缝深宽比的模拟结果与实验结果符合较好.
The effects of argon arc and helium arc on the weld pool morphology of SUS304 stainless steel Tungsten Inert Gas (TIG) weld were studied by numerical simulation of arc model and weld pool model. By comparing the temperature profiles of argon arc and helium arc It is found that the radial distance of helium arc is more obvious than that of argon arc, which leads to more heat transfer to the anode. The buoyancy, electromagnetic force, surface tension and gas shear under argon arc and helium arc are simulated. The results show that the surface tension in the weld pool is the most important driving force affecting the shape of the weld pool in both argon arc and helium arc, Another important driving force of the morphology is the gas shear force, which is the electromagnetic force under the helium arc. The penetration due to the electromagnetic force increases the penetration depth, resulting in the penetration of the helium arc at the same oxygen content and The aspect ratio of the weld is higher than the penetration depth and the aspect ratio of the weld under the argon arc.With the increase of the oxygen content, the aspect ratio of the weld under the argon arc and the helium arc first increases and then remains unchanged. Aspect ratio simulation results are in good agreement with the experimental results.