Development of ultra deep penetration welding with 10 kW fiber laser

Abstract

Wine-cup weld bead geometry with excessive wide bead surface is apt to form for high-power high-brightness laser welding in range of low welding speeds (lower than 1 m/min), as a result, the decrease in welding speed induces considerable increase in bead width, but only slight increase in penetration depth. This paper presents a method for enlarging and deepening the keyhole opening and suppressing the plume/plasma by using a gas jet nozzle, to get ultra deep penetration in high power fiber laser welding. With two high-speed CMOS cameras and X-ray transmission apparatus, the behaviors of the keyhole, the melt flow and the plume were observed. The influence of the gas jet parameters and welding conditions on the weld bead geometry was investigated. The results showed that in laser welding of thick section stainless steel, the penetration depth was increased from 18.2 mm to 24.5mm in the conditions of the laser power of 10 kW and the welding speed of 0.3 m/min.Wine-cup weld bead geometry with excessive wide bead surface is apt to form for high-power high-brightness laser welding in range of low welding speeds (lower than 1 m/min), as a result, the decrease in welding speed induces considerable increase in bead width, but only slight increase in penetration depth. This paper presents a method for enlarging and deepening the keyhole opening and suppressing the plume/plasma by using a gas jet nozzle, to get ultra deep penetration in high power fiber laser welding. With two high-speed CMOS cameras and X-ray transmission apparatus, the behaviors of the keyhole, the melt flow and the plume were observed. The influence of the gas jet parameters and welding conditions on the weld bead geometry was investigated. The results showed that in laser welding of thick section stainless steel, the penetration depth was increased from 18.2 mm to 24.5mm in the conditions of the laser power of 10 kW and the welding speed of 0.3 m/min.