All-position welding is an important technology in energy sources, chemical, shipbuilding and other industries. When welding current is larger than 200 A, the molten metal tends to flow down due to the force of gravity. In order to ＂push＂ the molten metal into the weld, a new kind of U-frame excitation model, which could produce electromagnetic force to balance the gravity of the molten pool, was designed. The related parameters of the excitation model were simulated by Maxwell 3D, and the relationships between the parameters and the magnetic induction intensity were analyzed. Finally, the electromagnetic force in the molten pool was calculated, and the appropriate parameters of the U-frame excitation model were determined. The results of the simulation verify the feasibility of the all-position welding excitation model.
近年来,下向熔化极活性气体保护焊(Metal active gas,MAG)在石油化工、管道工程等工业中获得广泛应用,但是下向MAG焊中当焊接熔池体积增大时由于其所处空间位置受重力因素影响较大,易产生熔池失稳问题,影响到焊缝的良好成形。针对上述问题开展下向焊熔池力学行为分析和熔池成形的控制策略研究,提出一种对下向MAG焊接熔池施加高频交变磁场,利用该磁场的电涡流效应产生电涡流力来抵消熔池液态金属重力分量的方法,达到克服重力对熔池成形的不利影响。开展熔池外加高频交变磁场熔池内部电磁场、涡流场和电涡流力的数值模拟和分析。进行45°和90°下向焊试验,对上述理论分析进行试验验证,结果表明高频交变磁场对熔池流淌具有抑制作用,采用电涡流技术用于克服下向MAG焊中的熔池失稳方案是可行的。
