Method of manufacturing tubular body, by friction stir welding

Abstract

Method of manufacturing a tubular end product, wherein an aluminum plate is formed into a generally cylindrical body such that opposite end sections of the cylindrical body are flattened and butted together along a joint region extending parallel to an axis of the cylindrical body, and such that each of the opposite flattened end sections has a predetermined width L as measured normal to the joint region, and the opposite flattened end sections are joined together at the joint region, by a friction stir butt welding operation wherein a rotary tool having a circular shoulder surface and a probe extending from the shoulder surface is moved relative to the cylindrical body while the shoulder surface is in rubbing contact with the flattened end sections, with the probe being rotated with the rotary tool and inserted in the joint region. The width L of each flattened end section of the cylindrical body is determined so as to be not smaller than a radius r (mm) of the rotary tool when 2r/sin θ<R, and not smaller than the radius r plus 3 mm when 2r/sin θ≧R, wherein 'θ' and 'R' respectively represent an angle (°) of inclination of an axis of rotation of the rotary tool with respect to a normal to the surface of the joint region, and an outside radius (mm) of the desired tubular product.