氧元素分布模式与AA-TIG焊熔池形貌的数值模拟

文中结合电弧辅助活性TIG焊熔池氧元素分布的试验研究结果,提出焊接熔池表面氧元素分别与熔池表面温度和位置相关两种分布模式,建立了更完善的电弧辅助活性TIG焊熔池模型,求解结果与已有的试验结果和理论研究吻合良好. 结合求解结果,利用格拉晓夫数G_r,磁雷诺数R_m和表面张力雷诺数M_a分析了浮力、电磁力和表面张力的相对作用大小; 利用Peclet数分析了熔池热对流和热传导的相对强弱. 结果表明,电弧辅助活性TIG 焊熔池表面张力作用远大于电磁力和浮力,并决定熔池流动形式;熔池热对流主导熔池的传热过程,揭示了不锈钢活性TIG焊活性元素决定深而窄的熔池形貌的内在本质.

Oxygen distribution and numerical simulation of weld pool profiles during arc assisted activating TIG welding

In arc assisted activating TIG welding, the base metal is pre-melted by assisting arc with mixture of argon and oxygen to form an oxide layer, and TIG welding is then carried out, so the weld penetration increases significantly. In this paper, two distribution modes of oxygen on the surface of weld pool was proposed based on experimental measurements, and a more complete model of weld pool in AA-TIG welding was developed. The computed results agreed well with the experimental data and existing theoretical results. Combined with the computed results, Grashof number Gr, magnetic Reynolds number Mm and surface tension Reynolds number Ma were employed to investigate the relative importance of buoyance, Lorentz force and surface tension. Peclet number was use to distinguish the relative intensity of heat convection and heat conduction in the weld pool. The results reveal that the surface tension controlled the flow type of weld pool, and the heat convection determined the heat transfer in weld pool. The relationship between the activating elements and weld penetration during A-TIG welding was clarified.