A method of performing friction stir spot welding of a plurality of steel plates, includes the steps of: friction stirring a spot welding portion of the plurality of steel plates by pressing a tool against the spot welding portion while rotating the tool, to plasticize the spot welding portion by friction heat; cooling the spot welding portion to cause martensitic transformation to occur in the spot welding portion, after the step of friction stirring the spot welding portion; and tempering the spot welding portion by the friction heat by re-pressing the tool against the spot welding portion while rotating the tool, after the step of cooling the spot welding portion.

A tool for friction stir welding includes a tool part, a shank part and a cap part. The tool part and the shank part have a hexagonal frustum-shaped concave section and a hexagonal frustum-shaped convex section to enable movement of the tool part with respect to the shank part in a direction parallel to an axis of rotation while movement of the tool part with respect to the shank part in a direction around the axis of rotation is restricted, by the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section of the tool part and the shank part are fitted to each other. After the hexagonal frustum-shaped concave section and the hexagonal frustum-shaped convex section are fitted to each other, by the tool part and the shank part being covered by the cap part, the tool part is fixed to the shank part.

The friction stir welding tool member according to the present invention is made of a ceramic member in which a shoulder portion and a probe portion are integrally formed, wherein a root portion of the probe portion and an end portion of the shoulder portion have a curved surface shape; and the friction stir welding tool member has a ratio (R1/D) of 0.02 or more and 0.20 or less when a curvature radius of the end portion of the shoulder portion is defined as R1 (mm) and an outer diameter of the shoulder portion is defined as D (mm). In addition, the ceramic member is preferably made of a silicon nitride sintered body having a Vickers hardness of 1400 HV1 or more. According to the above-described configuration, a friction stir welding tool member having excellent durability can be provided.

A friction stir welding (FSW) tool includes a head, a tool holder and a body between the head and the tool holder and attached to the head and the tool holder. The body may include a plurality of cooling fins. An interior of the body may include a pressure sensor, a temperature sensor, a torque sensor, and a communication node in electronic communication with the pressure sensor, the temperature sensor, and the torque sensor. The communication node may be in Bluetooth communication with a computing device.

A friction stir welding tool includes a housing and a stir pin. The housing includes a first surface, a housing hole formed in the housing and having a housing hole opening on the first surface, and a discharge hole through which the housing hole is in communication with an outside of the housing. The stir pin includes a pin holder and a pin body. The pin holder has a first end portion and a second end portion. The first end portion is configured to be connected to a rotation spindle. The pin body is provided in the housing hole, is detachably attached to the second end portion, and is rotatable together with the pin holder around the rotation axis. The pin body includes a stir portion that protrudes from the first surface via the housing hole opening.

Solid-state joining of preformed features, such as bosses, flanges, gaskets, centralizers and other features to substrates or cast parts by a solid-state additive manufacturing process is disclosed. Joining can be between same or different materials using same, similar or dissimilar filler material than the materials of the feature and the part that need to be joined.

The invention relates to a method and a device for the residue-free friction stir welding of workpieces with different thicknesses, having the following method steps: a) two workpieces (6) to be welded are mounted such that the workpieces can be approached by a holding bell (3) for the friction stir welding tool and the drive head (2) thereof, b) after the welding device is started up, a welding pin tip (5) is immersed into the plastified material of the two workpieces (6) to be connected, wherein a welding shoe (4) is used which has a trapezoidal structure that extends in the diagonal direction of the welding shoe (4) for receiving the welding pin tip (5), and a circular opening (14) is mounted in a web with a smoothing surface (13) which has a front edge (12) that is part of a stepped Spahn guide stage (11), c) in order to improve the method, a welding shoe (4) is used in which the stepped Spahn guide stage (11) has material conducting channels on the front edge (12).

The friction stir welding tool member according to the present invention is made of a silicon nitride sintered body, wherein the silicon nitride sintered body contains 15% by mass or less of additive components except silicon nitride in such a manner that the additive components include at least one element selected from lanthanoid elements and at least one element selected from Mg, Ti, Hf, and Mo. In addition, it is preferable that the additive components further include at least one element selected from Al, Si, and C. According to the above-described configuration, a friction stir welding tool member having an excellent durability can be provided.

Embodiments can include a self-reacting friction stir weld (“FSW”) tool. The device can be configured to be portable and produce full penetration welds in situ. The FSW tool can include a system that cuts out a portion of the structure surrounding a defective portion of the structure. A work-piece can be inserted within the removed portion and friction stir welded to the structure via the FSW tool. A superior repair as compared to merely welding the defect can be achieved by replacing a portion of the structure surrounding the defect as opposed to merely welding the defect (e.g., the crack). A controlled geometric shaped weld beam can be generated for the interface between the work-piece and the structure, which may led to a stronger, more reliable weld.

A friction stir spot welding method includes a welding step of forming a build-up portion on a workpiece by friction-stirring the workpiece, using a pin and a shoulder, while pressing a surface of the workpiece with an end face of a clamp, and filling a portion of the workpiece being softened in a chamber portion of the clamp by press-fitting at least one of the pin and the shoulder into a plastic flow portion of the workpiece. and the friction stir spot welding method further includes a pressing step of pressing a surface of at least one of a region of the build-up portion, which is frictionally stirred by the shoulder, and an adjacent region of the build-up portion against the end face of the clamp with the pin and the shoulder retracted into an accommodation space.