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针对铸造镁合金的激光焊接气孔难题,以AZ91D铸造镁合金为主要材料,紧密围绕气孔产生的原因、影响因素及其控制开展研究。探讨了铸造镁合金激光焊接气孔产生的特点和机理;研究了自熔激光焊接气孔产生的原因及影响因素;研究了填充焊丝激光焊接对焊缝气孔的控制及不同对接间隙焊接的质量控制。研究结果表明:铸造镁合金的激光焊接稳定性和气孔率主要受母材微孔率影响。对于母材微孔率在1—3%的铸造镁合金,采用填充焊丝激光焊接技术,焊缝平均气孔率降低到0.31%;对于母材微孔率在6—10%的铸造镁合金,采用填充焊丝激光焊接技术,使焊缝平均气孔率由20%降低到3%,对接间隙0.4mm时可以进行正常的焊接。
Aiming at the problem of laser welding stomatal of casting magnesium alloy, AZ91D cast magnesium alloy was taken as the main material to closely study the causes, influencing factors and control of stomatal formation. The characteristics and mechanism of the stomatal formation in the laser welding of magnesium alloy were discussed. The causes and influencing factors of the stomatal formation in the laser welding of the self-fluxing laser were studied. The control of the stomatal of the weld and the quality control of the butting gap welding were studied. The results show that the laser welding stability and porosity of the cast magnesium alloy are mainly affected by the porosity of the base metal. For the cast magnesium alloy with base metal porosity of 1-3%, the average weld porosity porosity is reduced to 0.31% by using filler wire laser welding technology. For the cast magnesium alloy with 6-10% base metal porosity, Filler wire laser welding technology, so that the average porosity of the weld from 20% to 3%, docking gap 0.4mm can be normal welding.