Welding method

A method of manufacturing an aircraft component, comprising the steps of

• (a) providing two or more metal work-pieces, each work-piece having a least cross-sectional dimension of 50 mm or greater;
• (b) friction stir welding at least one region of each of said two or more work-pieces thereby producing a friction stir welded region extending from the exterior surface of the work-piece into the work-piece by a first distance greater than 10 mm, the friction stir welded region having a grain structure that is finer than the grain structure of the work-piece outside that region,
• (c) skimming the friction stir welded region of each of said two or more work-pieces to produce a substantially flat surface,
• (d) arranging said two or more work-pieces so that the substantially flat surface of each of said two or more work-pieces resulting from step (c) abuts the substantially flat surface of another of said two or more work-pieces resulting from step (c),
• (e) fusion welding the abutting substantially flat surfaces, thereby joining the work-pieces together to form a block of metal, the fusion welding causing material in the friction stir welded region of each work-piece to melt to a second distance extending into the work-piece, the second distance being less than the first distance such that a fusion welding region of the work-pieces that melts during fusion welding is encompassed within the friction stir welded regions of the work-pieces, and
• (f) after step (e), machining metal away from the block of metal to form an aircraft component.

A method of joining two metal work-pieces, the method comprising:

• providing two metal work-pieces, each work-piece presenting at least one face defining a plane;
• preparing the work-pieces by applying a friction stir welding process on the at least one face of each work-piece, the friction stir welding process defining a friction stir welded region extending a first distance into the work-piece from the plane of the at least one face, the friction stir welded region having a grain structure that is finer than the grain structure of the work-piece outside the friction stir welded region;
• arranging the work-pieces so that the at least one face of one work-piece abuts the at least one face of the other work-piece at a butt joint;
• and then
• welding the two work-pieces together at the butt joint with a fusion welding process wherein a portion of the friction stir welded region of each work-piece is melted, thereby defining a melted region extending into each work-piece a second distance from the plane of the at least one face of each work-piece, and wherein the first distance is greater than the second distance such that the melted region is encompassed within the friction stir welded regions of the work-pieces and so that a remaining portion of the friction stir welded region of each work-piece is sandwiched between the melted region and the portion of the work-piece outside the friction stir welded region.