Patent ID: 8426766

Claim:
A welding method for forming an impeller having a plurality of blades, and an exterior body including a disk and a shroud, comprising the steps of: forming a groove having a groove bottom, a longitudinal direction, a prescribed depth and a prescribed width on the exterior body; locating the groove on a first surface of the exterior body, which exterior body first surface is opposite to a second surface of the exterior body and against which a blade of the plurality of blades abuts, emitting laser light toward the bottom of the groove; focusing the beam of the laser light having one of a thin rectangular and a long elliptical shape with a long side; scanning the focused beam of laser light a first time along a longitudinal direction of the groove; positioning the longer side of the focused beam of laser light one of parallel to and inclined at a prescribed angle with respect to the longitudinal direction of the groove; performing melt-through bead welding and forming a molten zone for bonding the bottom of the groove to an end of the blade; forming a bead on the second surface of the exterior body during the melt-through bead welding, the bead being curved with an inward depression; and performing overlaying welding after completing the melt-through bead welding by supplying a filler metal to the molten zone while scanning the bottom of the groove a second time with the focused beam of laser light.