Deep section welding with high brightness lasers

Experiments using high average power (HAP) diode-pumped solid state lasers (DPSSL), reveal cross-section welds appearing more like an electron beam weld than traditional kilowatt class CO2 or fiber-delivered, lamp-pumped Nd:YAG welds. Because of the high beam quality, focus lenses were utilized with unusually large F# values and working distances while maintaining a sufficiently small spot size required to exceed the 1, 000, 000 watts/cm(2) key-holing threshold power density. Weld experiments were conducted on 20mm and 65mm structural steel plates with a TRW HAP laser. Since the resultant welds were very narrow and deep, a method of wearing was implemented to widen the fusion zone. With only 4500 watts of average power delivered to the workpiece, full penetration, 65mm butt welds were completed in a single pass.