采用4 kW的光纤激光和MAG电弧复合焊接10 mm厚的Q345B钢, 研究工艺参数对焊缝气孔的影响, 如光丝间距、焊接电流、激光功率, 激光前后位置以及给激光单加保护气等; 观察和分析焊缝气孔的成形原因。结果表明, 焊缝气孔的存在影响因素复杂, 合理匹配的工艺参数能使气泡有时间和空间逃逸从而避免焊接气孔的存在; 光丝间距、焊接电流和激光功率等参数之间的匹配关系对焊缝气孔的产生有重要影响, 当激光功率为恒定值3.5 kW时, 焊接电流295 A, 光丝间距2 mm的焊缝无焊接气孔出现, 若拉大光丝间距, 焊接电流可以适当增大; 激光在后焊接熔深较大, 但对气孔的抑制作用不明显。

10 mm thick Q345B steel is welded by 4 kW fiber laser and MAG arc, The effects of process parameters on weld porosity such as laser-arc distance, welding current, laser power, the position of laser before and after, and the addition of shielding gas to the laser are studied, the forming cause of weld porosity are observed and analyzed. The results show that the influence factors of weld porosity are complex, the reasonable matching process parameters can make the bubble escape in time and space to avoid the existence of the weld porosity, the matching relation between the parameters such as laser-arc distance, welding current and laser power has an important influence on the formation of the weld porosity. When the laser power is a constant value of 3.5 kW, the welding current is 295 A, and the laser-arc distance is 2 mm, no weld porosity, if the laser-arc distance is increased, the welding the welding current can be increased appropriately. The weld penetration of the laser in the rear arc is large, but the inhibition effect on the weld porosity is not obvious.