Welding method for an impeller

摘要

A welding method for an impeller (10) having a plurality of blades (13), a disc (11) and an exterior body including a shroud (12) welded to the plurality of blades (13), comprising the steps of:
a first step for forming a groove (14) having a prescribed depth and a prescribed width toward one of the blades (13) on a surface of the disc (11) or the exterior body, which is opposite to a surface against the blade abuts, emitting laser light (21) toward the bottom of the groove (14), and performing melt-through bead welding to bond the bottom (14a) of the groove (14) to an end of the blade (13) in such a way that a bead formed on the back of the disc (11) or the shroud (12) is curved with an inward depression; and
a second step for performing overlaying welding after completion of the first step by supplying a filler metal to a molten zone while the bottom of the groove is scanned with the laser light.