氩氢保护下GMAW电弧特性的数值分析

Numerical Analysis of GMAW Arc Characteristics with Ar-H_2 as Shielding Gas

以氩氢混合保护气GMAW焊接电弧为研究对象,依据流体动力学和电磁学理论构建了电弧的数学模型。使用有限元分析软件进行了热、电磁和流场的耦合计算,研究了二维稳态轴对称氩氢混合保护气下的GMAW焊接电弧形态,得到了Ar:H_2=3:1(摩尔比)混合气体保护下不同工艺参数焊接电弧的温度场、速度场、压力场和电势的分布特征,并与纯氩保护下GMAW焊接电弧特征进行对比。结果表明,加入氢气作为保护气体,电弧最高温度、速度、压力和电势都明显提高。另外,与纯氩相比,弧柱的高温区在中心轴线处更集中,且焊接电弧能量密度更高。

Taking GMAW （gas metal arc welding） arc with Ar-H2 shielding gas as the object, a mathematical model of the arc based on the fluids dynamics and electromagnetics theories was developed. The coupling calculation of heat, electromagnetic and flow field was carded out by using the finite element analysis sottware, and the GMAW arc shape with Ar-H2 shielding gas under the two-dimensional steady and axisymmetric state was studied. The distributions of temperature, velocity, pressure and electric potential of welding arc with different process parameters under the protection of Ar：H2=3：1 （mole ratio） mixed gas were obtained, and the GMAW welding arc characteristics were compared with that under the protection of pure argon. The results show that with the addition of hydrogen as shielding gas, the arc temperature, velocity, pressure and electric potential obviously increase. In addition, compared with pure argofi as the shielding gas, the high temperature zone of arc column in central axis is more concentrated and the energy density of the welding arc is higher.