A fixture design for controlling impact of the airflow on laser welding of galvanized steels

• Published in: Optics and laser technology 2025-02, Vol.181, p.111736, Article 111736
• Main Authors: Yang, Baixuan, Alkhafaji, Ahmed, Ma, Junjie, Wang, Hui-Ping, Carlson, Blair E, Tong, Wei
• Format: Article
• Language: English
• Subjects: Airflow; Fixture design; Galvanized steel; Laser welding; Weld quality
• ISSN: 0030-3992
• DOI: 10.1016/j.optlastec.2024.111736

[Display omitted] •The weld airflow study found that the external airflow exerted two major effects to the process: adding traction to the molten pool surface and bending the plasma plume.•Study of airflow in different directions with respect to weld direction found that the above two effects can be harmful to the process stability in the case of the airflow following the welding direction.•A novel weld fixture block was designed to minimize the negative impact of horizontal airflow while facilitating the positive effect for process stability. This paper examines the effects of horizontal airflow on laser welding of galvanized steels. A uniform laminar flow was delivered using a specially designed external airflow device, and its impact on vapor plume dynamics and keyhole behavior was analyzed with synchronized high-speed cameras. The analysis showed that, under Follow airflow conditions, penetration depth was notably reduced compared to Against conditions, with increased surface defects observed in galvanized steel. Keyhole instability, as observed in the frequency spectrum (≤500 Hz), was more pronounced under Follow conditions. Theoretical analysis identified two main effects: 1) Airflow in the Against condition helps maintain keyhole opening by dragging melt away, while in the Follow condition, it drags melt toward the keyhole, leading to shrinkage. 2) Airflow affects the plasma plume, with Follow conditions increasing laser energy attenuation and resulting in shallow penetration. A hollow rectangular block fixture was designed to shield the molten pool and keyhole region from airflow effects. CFD modeling and experiments with a 5 mm block demonstrated reduced airflow impacts, improved process stability, and defect-free welds in both bare and galvanized steel.