Magna International Inc.
Method of Laser Beam Localized-Coating

Abstract:

A process is described for laser welding a sheet metal workpiece having an anti-corrosion pre-coat material on at least one major surface thereof. The sheet metal workpiece is arranged such that first and second side edges are in contact with one another and the coated major surface faces outwardly. A first laser beam having a first beam spot-size is used to form a laser weld joint between the first and second side edges. A second laser beam having a second beam spot-size larger than the first beam spot-size is then scanned along the laser weld joint and is tilted in a tilt direction parallel to the scanning direction to produce an elongated beam spot. During the scanning, a flow of a powdered anti-corrosion surface layer material is directed toward a portion of the laser weld joint that is being irradiated by the second laser beam. The second laser beam melts the material, which forms a layer adhering to the laser weld joint.