Invar钢多层摆动焊接过程的数值模拟

以19.05 mm厚Invar钢板作为研究对象，通过研究Invar钢的多层摆动焊接，得到多层摆动MIG焊焊缝。利用建模软件建立和实际焊缝一致的有限元模型并进行分析计算，得出焊接过程中温度场的变化过程，对瞬时温度场和焊接热循环曲线进行分析，得出焊接过程中试样整体温度场的变化过程。结果表明，焊接时间越长，焊接速度越慢，熔池尺寸越大；热循环曲线的斜率代表该点温度变化的速率，斜率越大，温度变化速率越快，相对的，热循环曲线随着热源靠近发生剧烈地变化，远离热源变化平缓；直线焊接的热循环曲线为一条平滑的曲线，摆动焊接的热循环曲线为一系列均匀摆动的折线，折线摆动的频率与焊枪摆动的频率一致。

Numerical simulation on multi-layer weave bead welding process of thick plate Invar steel

The 19.05 mm thick Invar steel plates were taken as the research object, which were joined by multi-layer weave bead welding experiments. The temperature field model is established by the finite element method. The transient temperature field and the welding thermal cycle curve are analyzed, and the change process of the whole temperature field of the sample during the welding process is obtained. The results show that the weld pool size becomes larger because of the increase of welding time and the slow welding speed. The thermal cycle curve near the center of heat source changes drastically, and the thermal cycle curve away from the center of heat source changes gently. The thermal cycling curve of straight welding is a smooth curve, and the thermal cycling curve of swing welding is a series of uniform broken lines. The frequency of the broken line is consistent with the frequency of the welding torch swing.