光纤激光焊接铝合金离焦量对焊缝成形的影响

Effect of Defocusing Amount on Weld Shapingin Fiber Laser Welding of Aluminum Alloy

采用高功率光纤激光对3mm厚铝合金进行焊接实验,系统研究了离焦量对焊缝熔池形貌、熔深、熔宽、底部驼峰及深宽比、宽度比例系数的影响。结果表明,随着离焦量的增加,焊接模式由深熔焊转变为热导焊,熔宽变化不明显,底部驼峰高度和宽度比例系数降低;用高功率光纤激光焊接时,通过减小负离焦量或改变为正离焦的方式能降低焊缝塌陷程度与底部驼峰高度;用较低功率光纤激光焊接时,通过增大负离焦量或减小正离焦量的方式能增大背面熔宽。

The high power fiber laser is used to conduct a welding experiment on 3 mm thick aluminum alloy, and the effects of the defocusing amount on the morphology, penetration depth, penetration width, root humps, aspect ratios, and width ratio coefficient of weld pools are systematically investigated. The results show that, with the increase of the defocusing amount, the welding mode is transformed from the deep-penetration welding to heatconduction one, the weld width does not change obviously, the root hump height and the width ratio coefficient decrease; with the high power fiber laser, the degree of welding bead subsidence and the height of root humps can be reduced by cutting back the negative defocusing amount or transforming into positive defocus; with the low power fiber laser, the back weld width could be increased by strengthening the negative defocusing amount or reducing the positive defocusing amount.