为了解决镀锌钢板在激光焊接过程中由锌蒸气引发的焊接缺陷问题, 在小孔上方施加平吹辅助气流, 以维持小孔持续稳定张开并形成稳定的锌蒸气逸出通道; 研究了平吹气流量对镀锌钢板零间隙激光搭接焊缝成形质量及力学性能的影响, 通过焊接过程的实时监测和数值模拟分析了平吹气流对锌蒸气有效逸出的作用机理。结果表明, 对厚度为1 mm的DP590镀锌钢板进行零间隙激光搭接焊时, 平吹辅助气流能有效促进锌蒸气的逸出, 从而获得表面质量和力学性能较好的搭接接头。

To solve the problem of weld defects caused by zinc vapor in the process of laser welding of galvanized steel sheets, we adopt the laminar flow above a keyhole to keep the keyhole open continuously and form a stable zinc vapor venting channel. The effects of the laminar gas flow on weld forming quality and mechanical properties of gap-free laser lap welded joint of galvanized steel sheet are studied. The influencing mechanism of the laminar flow on the effective escape of zinc vapor is analyzed with the utilization of real-time monitoring and numerical simulation of the welding process. The results show that for gap-free laser lap welding of DP590 galvanized steel sheet with thickness of 1 mm, the laminar flow can effectively promote the escape of the zinc vapor, and thus a lap joint with excellent surface quality and mechanical properties is obtained.