The study of laser bead-on-plate welding of nickel based superalloy Rene 77 using single mode high power fiber laser has been undertaken to determine the effect of process parameters, such as laser power, welding speed and laser beam defocusing, on the weld geometry and quality. Non-porous and crack-free welds can be achieved for a relatively wide range of fiber laser welding parameters. The welding speed has a major effect on the weld aspect ratio. The laser beam defocusing significantly affects the weld bead geometry, the stability of the keyhole and pore formation. The transition from keyhole mode to conduction mode welding occurs between focal point position +2.0 mm and +4.0 mm. The high porosity was observed at the focal point position of +2.0 mm. The heat input higher than18 J/mm results to hot cracking in the heat affected zone (HAZ). Moreover, it was found that the welds with the weld aspect ratio higher than 1.5 contain cracks, which propagate from the HAZ into the weld metal.

Date Published: 22 January 2013
PDF: 7 pages
Proc. SPIE 8703, Laser Technology 2012: Applications of Lasers, 87030Q (22 January 2013); doi: 10.1117/12.2013428

Published in SPIE Proceedings Vol. 8703:
Laser Technology 2012: Applications of Lasers
Wiesław L Woliński; Zdzisław Jankiewicz; Ryszard S. Romaniuk, Editor(s)