Bead Morphologies and Formation Mechanism of Oscillating Laser‐Arc Hybrid Welding Under Joint Gap Conditions

ABSTRACT Oscillating laser‐arc hybrid welding (OLAHW) integrates synergistic heat sources and a stirring effect from its high‐frequency oscillating beam, offering significant advantages in weld structure and adaptability. However, its broader industrial adoption is hindered by molten pool instability, collapse, and weld failure, especially when confronted with fluctuating gap conditions. To address these challenges and illuminate the welding instability mechanisms of OLAHW under gap variations, this study utilizes an experimental platform. Using a combination of experimental research and theoretical modeling, we investigated the effects of process parameters—laser power, welding speed, and scanning diameter—on weld appearance under different gap conditions. Furthermore, by analyzing the energy distribution and the force analysis of the molten pool root, we established a parameter normalization model and an equivalent force model of the molten pool. Based on this, the coupling regulation mechanism of “gap‐energy‐force” was clarified. The results show that dynamic regulation of laser power, welding speed, and scanning diameter can effectively suppress the melt pool instability caused by gap fluctuation, thus improving the weld appearance. This work provides a theoretical basis for real‐time parameter optimization of industrial welding.