Extension of the process limits in laser beam welding of thick-walled components using the Laser Multi-Pass Narrow-Gap welding (Laser-MPNG) on the example of the nickel-based material Alloy 617 occ

The joining of thick-walled components using beam-based joining techniques is content of worldwide research and development activities, but has not yet been established in industry. State of the art to weld nickel super alloys is currently a TIG narrow-gap welding. The present paper is focusing on a new specific laser beam welding process, the so-called Laser Multi-Pass Narrow-Gap welding (Laser-MPNG). It first explains the process principle based on 2D beam oscillation, the use of fiber lasers and the multi-pass principle. The potential of the Laser-MPNG welding process is demonstrated using the technically significant nickel-based material Alloy 617 occ. As a result, it was possible for the first time to realize a weld with a wall thickness of 140 mm free of cracks or bonding defects. Promising results of creep and low-cycle fatigue tests are used to show the potential that Laser-MPNG welded joints would have for future industrial applications.