Some examples include welding a first workpiece to a second workpiece. For instance, the first workpiece may be secured adjacent to the second workpiece. At least one of the first workpiece or the second workpiece includes a channel or a portion of a channel in a respective surface such that a complete channel is presented when the first workpiece and the second workpiece are secured adjacent to each other. A rotating tip of a welding tool is inserted into the complete channel for welding the first workpiece to the second workpiece. A surface burr resulting from the welding is located within the complete channel.

Pin tool assemblies for friction stir welding and apparatus and methods that include the pin tool assemblies. The pin tool assemblies include an outer member, an inner member, and a stop. The outer member includes an inner surface that defines an elongate internal cavity and an external shoulder that includes an opening to the elongate internal cavity. The inner member includes a welding end, extends at least partially within the elongate internal cavity, and projects from the opening such that the welding end is external the elongate internal cavity. The pin tool assembly is configured to permit motion of the inner member relative to the outer member. The stop defines a plurality of stop configurations. Each of the stop configurations restricts motion of the inner member relative to the outer member in a stop direction to define a corresponding stop distance between the welding end and the external shoulder.

In a double-acting friction stir spot welding device or a double-acting friction stir spot welding method, a pin member and a cylindrical shoulder member that rotates around the axis of the pin member are used as rotary tools, and a clamp member that has a cylindrical shape positioned so as to surround the outside of the shoulder member and is configured to press a workpiece from an obverse surface with an annular pressing surface of the distal end is used as a holding jig. The clamp member has an inclined surface that is adjacent to the inner edge portion of the pressing surface and inclined so as to reduce the inner diameter of the clamp member toward the back side as viewed from the pressing surface.

Pin tool assemblies for friction stir welding and apparatus and methods that include the pin tool assemblies. The pin tool assemblies include an outer member, an inner member, and a stop. The outer member includes an inner surface that defines an elongate internal cavity and an external shoulder that includes an opening to the elongate internal cavity. The inner member includes a welding end, extends at least partially within the elongate internal cavity, and projects from the opening such that the welding end is external the elongate internal cavity. The pin tool assembly is configured to permit motion of the inner member relative to the outer member. The stop defines a plurality of stop configurations. Each of the stop configurations restricts motion of the inner member relative to the outer member in a stop direction to define a corresponding stop distance between the welding end and the external shoulder.

A method for manufacturing a hollow container with use of a rotary tool including a tapered stirring pin, including: preparing a first metal member, a second metal member, and an auxiliary member; butting the first metal member and the second metal member to face with each other, the auxiliary member is interposed between the first metal member and the second metal member; and joining the first metal member with the second metal member via the auxiliary member. The first and second metal members, and the auxiliary member are made of aluminum or an aluminum alloy, and the first and second metal members have higher hardness than the auxiliary member. At least one of the first and second metal members has an inclined surface inclined outward, and the auxiliary member has an inclined surface, tapered from the external surface toward an internal surface, on at least one of the side surfaces.

A method for manufacturing a liquid-cooled jacket includes: preparing, as well as a jacket body having a bottom, a peripheral wall and a seal body having a first substrate formed of a first metal, a second substrate formed of a second metal so as to have a peripheral edge of the first substrate exposed, and a plurality of fins; arranging an overlaid portion formed with an end face of the peripheral wall overlaid with a rear face of the first substrate; and joining by friction stir the overlaid portion by moving a joining rotary tool along the overlaid portion relatively in a state where a stirring pin of the joining rotary tool is contacted with only the first substrate or with both the first substrate and the peripheral wall.

Disclosed is a method for making polystyrene foam which utilizes one or more atmospheric gases, particularly CO.sub.2, as the blowing agent in combination with a polymer processing aid (PPA), typically an ester that is relatively non-volatile at the extrusion temperature range. The blowing agent and the PPA may both be introduced into the molten thermoplastic polystyrene resin or the PPA may be incorporated in the solid source polystyrene resins. The resulting foam will be substantially free of residual blowing agent and dimensionally stable at ambient temperatures.

A technique for joining parts of incompatible metals involves cold spraying a 150-900 micron thick layer of a metal compatible with the second part onto the first part, and friction stir joining the parts by lap welding while keeping a tool of the FSJ tool at least 300 microns away from the first part (less layer) throughout the joining, to avoid damaging the cold spray to first part interface, and formation of intermetallics. Improved fatigue resistance is shown. A sealant can advantageously further improve fatigue resistance.

A friction stir welding method of welding first and second members to each other by rotating and pressing a friction stir tool into butt surfaces of the first and second members and moving the friction stir tool while rotating the friction stir tool, includes: a butt process of abutting the first and second members on each other, and abutting a side surface of a third member on side surfaces of the first and second members; an offset process of making a rotation center of the friction stir tool coincide with a position offset from the butt surfaces, and moving the friction stir tool to reach an inside of the third member; and a welding process of making the rotation center coincide with the butt surfaces, and moving the friction stir tool to reach the inside of the third member.

A method for friction welding, the method comprising: locating a first workpiece in a recess or aperture of a first tool; bringing a weld face of the first and a weld face of a second workpiece into frictional engagement; and moving the first tool and the second workpiece relative to one another.