The correlation of laser weld plasma and its cross-sectional geometry Available to Purchase

The cross-sectional geometry of a laser weld is important to its formability. In the previous research [1], 20% total concavity was determined critical to the fracture mode of a laser weld under the Erickson formability test. When the total concavity of a laser weld of galvanized low carbon steel sheets is less than 20% of the thinner gauge thickness, the fracture is expected to be located outside of the weld. In this research, the relationship between plasma radiation and weld cross-sectional geometry has been studied. Galvanized low carbon steel sheets of different gauges were butt-welded together using an 6 kW CO₂ laser in the continuous mode. Two bandwidths of radiation were detected, blue and infrared. The results of this research showed that low plasma light intensity tended to be related to the formation of a concave weld while high plasma light to the formation of a convex weld. The blue and infrared plasma radiation showed similar correlation to the cross-sectional geometry of a weld.