Song, L. and Zhang, P. and Li, Z. and Feng, J. and Li, J. and Huang, Y. and Fang, C. (2026) Effects of heat source arrangements on arc behavior and keyhole stability in Laser-Arc hybrid welding of 12-mm-thick AH36 steel. Optics and Laser Technology, 197: 114758. ISSN 0030-3992
Full text not available from this repository.Abstract
Laser–Arc Hybrid Welding (LAHW) critically depends on the guiding mode that sets the spatiotemporal sequence of the heat sources. Yet, how the guiding mode governs keyhole stability, the physical core of process robustness, remains poorly understood. Using AH36 high-strength steel plates of 12 mm thickness, we systematically compare Arc-Leading (A-L) and Laser-Leading (L-A) modes by combining side-view high-speed imaging (10,000 fps) with synchronous electrical measurements. We show that the two modes establish distinct bidirectional couplings between the electrically driven arc stability and the mechanically driven keyhole stability. In the A-L mode, the leading arc first forms a wide, high-temperature molten pool that buffers droplet momentum and suppresses high-frequency keyhole oscillations. After a short free-growth period (∼0.8 ms), the arc is captured and locked by the laser-formed keyhole, eliminating deflection and markedly increasing arc stiffness. In contrast, the L-A mode lacks such buffering; droplets directly impinge on the rear keyhole wall, periodically inducing partial collapses and a keyhole reconstruction period that is ≈1.8 × that of the A-L mode. Macroscopically, the A-L mode achieves a stable root at a gap of 0.6 mm, whereas the L-A mode requires 0.8 mm to suppress humping. These results reveal mode-specific feedback loops—virtuous in A-L and self-exciting in L-A—and provide a mechanistic basis for widening the robust process window in industrial LAHW.