Provided is a double-side friction stir welding method of metal sheets or metal plates to each other, and a double-side friction stir device for performing the double-side friction stir welding. According to the present invention, a pair of rotating tools facing each other is respectively arranged on a top-surface side and a bottom-surface side of a butted portion or an overlapping portion, which comprises a joint portion of two metal sheets or two metal plates, the pair of rotating tools is moved in a welding direction while being rotated at the butted portion or the overlapping portion, and while the metal sheets or the metal plates are softened by frictional heat generated between the rotating tools and the metal sheets or the metal plates, softened parts are stirred by the rotating tools to produce a plastic flow to join the metal sheets or the metal plates to each other.

This disclosure relates to a two-piece friction stir welding (FSW) tool insert. The tool insert has a longitudinal axis of rotation and comprises a stirring pin and an annular shoulder coaxially mounted about the stirring pin. The stirring pin and annular shoulder each comprise polycrystalline cubic boron nitride. The annular shoulder is a thin disc with a thickness of 1 to 12 mm and the shoulder comprises a tapered, central aperture, through which the stirring pin protrudes.

A friction stir welding device includes: a probe capable of pressing a welding target part of a workpiece while rotating; a shoulder externally surrounding an outside of the probe, on a plane intersecting a rotation axis of the probe; a shoulder attachment member provided with the shoulder; and a flow path formed at a contact part between the shoulder and the shoulder attachment member and adapted to allow a cooling medium to flow therethrough.

Provided is a method for manufacturing a liquid-cooled jacket, to reduce the size of a recessed groove on a surface of a metal member and also to reduce roughness of an abutted surface. The method includes: a placing step of placing a jacket body and a sealing body, a first main joining step of performing friction stirring by moving a main joining rotary tool around along a first abutted portion, and a second main joining step of performing friction stirring by moving the main joining rotary tool around along a second abutted portion. The main joining rotary tool has a base-end-side pin and a tip-end-side pin. A taper angle of the base-end-side pin is grater than a taper angle of the tip-end-side pin and a stairs-like pin step portion is formed on an outer circumferential surface of the tip-end-side pin.

A method for manufacturing a liquid-cooling jacket (1) where heat transfer fluid flows in a hollow part (14) defined by a jacket body (2) and a sealing body (3) includes: an overlapping process in which the sealing body (3) is placed on an end surface (11a) of a peripheral wall part (11) in such a way that the end surface (11a) and a back surface of the sealing body (3) are overlapped each other to form a first overlapped part (H1); and a primary joining process in which primary joining is performed by friction stirring in such a way that a rotary tool (FD) is moved once around a recessed part (13) along the first overlapped part (H1). In the primary joining process, in a state where a base side pin of the rotary tool (FD) is in contact with the sealing body (3), a flat surface of the base (tip) side pin is brought in contact with only the sealing body (3), and a tip of a projection projecting from the flat surface is inserted more deeply than the first overlapped part (H1) to join the first overlapped part (H1).

The present invention is characterized by including a primary joining process to perform friction stirring to a first butted portion by moving a stirring pin one round around a sealing body with a predetermined depth along a set moving route set at an inner position relative to an outer peripheral side face in a state that only the stirring pin of a rotary tool being rotated is inserted into the sealing body and that an outer face of the stirring pin is slightly in contact with a step side face of a peripheral wall step portion. In the primary joining process, after only the stirring pin being rotated is inserted into a starting position set at a position on an inner side relative to the set moving route, the stirring pin is gradually inserted to the predetermined depth while an axis of the rotary tool is moved to a position on the set moving route.

A bonding device for joining together a first member (3), an intermediate member (4), and a second member (3) which are layered as a laminated assembly includes a probe (12, 41), an anvil (11, 11b, 11c, 11d), a shoulder member (13,13a, 61,64,68), a drive mechanism (14) configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line, and an electric power supply (15) electrically connected to the anvil and the shoulder member to conduct electric current through the laminated assembly via the anvil and the shoulder member.

Provided is a joining method that can prevent a plastic flowing material from flowing out from a butt section and that can reduce the thickness and weight of metal members. The joining method is for joining a first metal member and a second metal member by using a rotary tool comprising a stirring pin, and is characterized in that: the stirring pin comprises a flat surface perpendicular to the rotation axis of the rotary tool and comprises a protruding section protruding from the flat face; and in a friction stirring step, the flat surface is brought into contact with the first metal member and the second metal member, and a front end face of the protruding section is inserted deeper than an upper overlapping section to join an upper front butt section and the upper overlapping section.

A friction stir welding tool member according to the present embodiment has a shoulder portion and a probe portion concentrically projecting from an upper surface of the shoulder portion. The shoulder portion includes a curved surface processed portion that is curved to have a curved shape on an outer peripheral edge of the shoulder portion. A space occupancy occupied by the two-dimensional space in which neither the shoulder portion nor the probe portion exists is in a range of 30% to 70%, the space occupancy being determined based on a projection drawing of a side surface region surrounded from a tip of the probe portion to the curved surface processed portion of the shoulder portion.

An object of the present invention is to provide a joining method by which metal members can be suitably joined to each other. The present invention is characterized by including a friction stirring process in which the first metal member, the second metal member, and the auxiliary member are joined to one another by moving the rotary tool along the inner corner portion in a state where the tip side pin which is being rotated is inserted into the inner corner portion, is in contact with the first metal member, the second metal member, and the auxiliary member, and an outer circumferential face of the base side pin is pressed against the auxiliary member.