低功率脉冲激光诱导电弧复合仰焊工艺适应性研究

采用低功率脉冲激光诱导MAG电弧复合焊接工艺，开展了X70管线钢仰焊工艺适应性研究。焊接试验结果显示，单MAG热源采用210 A电流能够获得成形良好的焊接接头，但工艺参数敏感，电弧电流变化易产生缺陷；加入激光后，电弧电流参数区间可拓展至180～230 A，在抑制内凹缺陷的同时，可提高对错边的工艺适应性。焊接接头拉伸和背弯试验表明，无论复合焊接接头是否存在内凹缺陷，均具备与母材相当的拉伸强度，内凹缺陷使接头的最大完全载荷大幅度降低。仰焊熔池受力分析表明，仰焊焊缝成形主要受重力影响，激光热源提供竖直向上的分力大于其热输入带来的重力，有利于扩大参数适应区间，增加背部余高。

Study on Process Adaptability of Low-power Pulsed Laser Induced Arc Hybrid Welding in Overhead Position

The adaptability of X70 pipeline steel overhead welding process was studied by using low-power pulsed laser induced MAG arc hybrid welding process. The test results show that a single MAG heat source with 210 A current can obtain a well formed welded joint, but the process parameters are sensitive and the change of arc current is easy to produce defects. After adding laser, the arc current parameter range can be extended to 180~230 A, which can suppress concave defects and improve the process adaptability to misalignment. The tensile and back bending tests show that the tensile strength of the hybrid welded joint with or without concave defects is equivalent to that of the base metal, and the maximum complete load of the welded joint with concave defects is greatly reduced. The stress analysis shows that the weld formation of overhead welding is mainly affected by gravity. The vertical component force provided by the laser heat source is greater than the gravity brought by its heat input, which is conducive to expanding the parameter adaptation range and increasing the back reinforcement.