Laser beam welding of aluminum alloy 5754-O using a 3 kW Nd:YAG laser and fiber optic beam delivery

A program was conducted to evaluate laser beam welding of aluminum alloy 5754-O using a 3.0 kW Nd:YAG laser and fiber optic beam delivery. The alloy and laser system were chosen based on consideration for potential applications in the automotive industry. Process parameters were developed for producing autogenous, square-butt welds in 1.6 mm thickness. Metallographic analyses, mechanical property testing, and post weld formability testing were conducted to characterize joints produced under these conditions. Results of these evaluations indicate that the 3.0 kW Nd:YAG laser provides adequate power density and beam quality for welding of this thickness. Enhanced absorption associated with the Nd:YAG laser is believed to be responsible for improved stability of the weld pool and increased weld consistency. Results of tensile tests of the Nd:YAG laser beam welds provided over 90 percent of base metal strength and measurements of post process formability of the welds yielded approximately 70 percent of base metal formability.