SURFACE TREATMENT METHOD FOR ALUMINUM ALLOY MATERIAL FRICTIONALLY STIR-WELDED

• Main Author: KUMAGAI MASAKI
• Format: Patent
• Language: English
• Published: 26.07.2012
• Subjects: APPARATUS THEREFOR; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; PERFORMING OPERATIONS; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To prevent generation of a difference in tint between a portion corresponding to the stirred part of the aluminum alloy material and a portion corresponding to the peripheral portion of the stirred part in a coating deposited on the surface layer part of an aluminum alloy material frictionally stir-welded through anodic oxidization treatment.SOLUTION: By formation of the surface friction stir layer 8 by applying surface friction stirring with a columnar pin-less rotary tool 11, of which the edge face has a recessed part 11' formed having a shape of concave curvature, to a stirred part 6, which is formed by friction stir welding of a lid member 2 and a side member 3 of the aluminum alloy material and to a peripheral portion 7 of the same, within the range in which the tint difference is not to be generated, even when thereafter grinding the surfaces of the two corresponding portions and subjecting them to an anodic oxidation treatment to form a coating 9, the difference in distribution state of second-phase particles between the two portions is made smaller and uniformed, so that generation of a difference in tint on the coating is prevented.