The effects of short pulse laser surface cleaning on porosity formation and reduction in laser welding of aluminium alloy for automotive component manufacture

Laser welding of aluminium alloys typically results in porosity in the fusion zones, leading to poor mechanical and corrosion performances. Mechanical and chemical cleaning of surfaces has been used previously to remove contaminants for weld joint preparations. However, these methods are slow, ineff...

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Bibliographic Details
Published in:Optics and laser technology 2014-12, Vol.64, p.162-171
Main Authors: AlShaer, A.W., Li, L., Mistry, A.
Format: Article
Language:English
Subjects:
Aluminium alloy
Aluminum base alloys
Automotive engineering
Cleaning
Formations
Laser beam welding
Laser welding
Porosity
Reduction
Welded joints
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Summary:Laser welding of aluminium alloys typically results in porosity in the fusion zones, leading to poor mechanical and corrosion performances. Mechanical and chemical cleaning of surfaces has been used previously to remove contaminants for weld joint preparations. However, these methods are slow, ineffective (e.g. due to hydrogen trapping) or lead to environmental hazards. This paper reports the effects of short pulsed laser surface cleaning on porosity formation and reduction in laser welding of AC-170PX (AA6014) aluminium sheets (coated with Ti/Zr and lubricated using a dry lubricant AlO70) with two types of joints: fillet edge and flange couch, using an AA4043 filler wire for automotive component assembly. The effect of laser cleaning on porosity reduction during laser welding using a filler wire has not been reported before. In this work, porosity and weld fusion zone geometry were examined prior to and after laser cleaning. The nanosecond pulsed Nd:YAG laser cleaning was found to reduce porosity significantly in the weld fusion zones. For the fillet edge welds, porosity was reduced to less than 0.5% compared with 10–80% without laser cleaning. For flange couch welds, porosity was reduced to 0.23–0.8% with laser cleaning from 0.7% to 4.3% without laser cleaning. This has been found to be due to the elimination of contaminations and oxide layers that contribute to the porosity formation. The laser cleaning is based on thermal ablation. •This research focuses on porosity reduction in laser welding of aluminium alloy.•Weld quality was investigated for two joints, fillet edge and flange couch joints.•The effect of laser cleaning on porosity reduction after welding was investigated.•It was found that laser cleaning reduced porosity less than 1% in both joints.•Weld dimensions and strength were evaluated and discussed for both types of joints.
ISSN:0030-3992
1879-2545
DOI:10.1016/j.optlastec.2014.05.010