초록
An application of innovative laser+GMA hybrid welding process is presented for reducing bead humping defects in high speed welding and increasing side wall fusion in narrow groove welding without torch or wire oscillation. In this hybrid process, the laser heat input is applied adjacent to the weld pool at a relatively low power density to produce a wider, flatter weld bead. In bead on plate in sheet metal gauges, the hybrid process was able to produce hump-free welds from 70ipm (${\sim}1780mm/min$) to over 150ipm (${\sim}3810mm/min$) of the travel speed compared to the un-assisted GMAW process. A square-butt joint in 15mm A572 Gr50 steel welds was investigated. A square butt joint with a gap of 3.2mm was filled with 6 passes. Liquid Nitrogen calorimetry and innovative $CO_2$ laser reflective optics were also developed to demonstrate the concept of hybrid welding.