Laser welding of refractory metals

Welding of thick section refractory metals is difficult with conventional arc processes but can be accommodated with high-intensity-beam sources such as the electron or laser beam. High-laser-beam irradiance is necessary to achieve deep penetration of refractory metals. Consequently, a focused beam of high power and beam quality is required. A 500 W diode pumped Nd:YAG was used to perform bead-on-plate tests on 2 mm sheets of rhenium and tungsten. The welds were sectioned and analyzed for profile and porosity. Results indicate the difficulty in using high-irradiance beams to weld rhenium and tungsten. Microhardness measurements indicate no significant decrease in hardness in the fusion zone. However, the presence of cracks tended to produce a slight decrease in the hardness measurements.