Exploring Manual Laser Oscillation Welding of Stainless Steel in Different Joint Configurations

In this work, we report on handheld laser welding of AISI 304 L stainless steel sheets and pipes using various joint configurations. Sheet welds were performed using butt, corner, “T”, lap, and edge joints with a 2 kW continuous-wave handheld laser welding system. AISI 304 filler wire with a diameter of 1 mm was employed during welding. The process was carried out manually by manoeuvring the welding torch along the joint, utilizing an oscillating beam at a constant speed. The effects of oscillation amplitude, oscillation frequency, and laser power on weld pool shape and penetration were investigated. Weld quality was evaluated through X-ray radiography, optical microscopy, tensile pull testing, and micro-hardness measurements. Porosity was observed in welds produced under argon shielding gas. In contrast, using high-purity nitrogen gas resulted in porosity-free welds. Tensile tests showed that welds made with nitrogen shielding sustained a peak load of 23 kN, 26 kN and 12 kN for butt, “T” and lap joint welds respectively before fracture, significantly outperforming those welded under argon. Microstructural analysis revealed a duplex structure, with ferrite as the minor phase distributed in various morphologies within the austenitic matrix. All standard joint configurations were successfully welded using the handheld laser welding system.