双弧脉冲MIG焊耦合电弧特性的数值模拟研究

针对双弧脉冲MIG焊热源稳定性差的问题，本文对双弧脉冲MIG焊耦合电弧进行瞬态数值模拟，分析了不同脉冲电流参数下耦合电弧形态、温度和压力的分布及变化规律。研究表明：耦合电弧呈驼峰状，脉冲电流发生跳变时，耦合电弧伸展或收缩，并逐渐稳定，峰值电流越小，越快达到稳定；增大脉冲电流，耦合电弧温度和电弧压力随之升高；保持总电流不变，减小主弧电流，增大旁弧电流，主弧温度和电弧压力减小，旁弧温度和电弧压力增大，当旁弧电流足够大时，耦合电弧温度和电弧压力呈双峰分布。数值模拟结果与双弧脉冲MIG焊工艺实验结果吻合良好，模拟结果对调控双弧脉冲MIG焊脉冲电流参数，改善其耦合电弧稳定性及工艺性能具有重要意义。

Numerical simulation of coupled arc characteristics in dual-arc pulse MIG welding

In view of the poor stability of the heat source of dual-arc pulse MIG welding, the transient numerical simulation of the coupled arc of dual-arc pulse MIG welding was carried out, and the distribution and change law of the shape, temperature, and pressure of coupled arc under different pulse current parameters were analyzed. Results show that the coupled arc was humped. When the pulse current jumped, the coupled arc expanded or contracted and gradually stabilized; the smaller the peak current was, the faster it reached stability. With the increase in pulse current, the coupled arc temperature and arc pressure increased. When the total current was remained unchanged, reducing the main arc current and increasing the side arc current caused the decrease in the main arc temperature and arc pressure, and the increase in the side arc temperature and arc pressure. When the side arc current was large enough, the coupled arc temperature and arc pressure showed a bimodal distribution. The numerical simulation results were in good agreement with the experimental results of the dual-arc pulse MIG welding process. The numerical simulation results are of great significance to regulate the pulse current parameters of dual-arc pulse MIG welding and improve its coupled arc stability and process performance.