A friction stir spot welding method performs friction stir spot welding of a pair of workpieces having a coating film formed on at least one welding surface by using a refill friction stir spot welding device including rotary tools. The method includes removing the coating film by plunging a distal end of the shoulder member into one workpiece up to a position closer to the surface than the welding surface, while rotating the shoulder member as a rotary tool around the axis, and rotating the shoulder member in a state in which the surface of one of the pair of workpieces, with the welding surfaces being overlaid on each other, is pressed by the end face of the clamp member and performing friction stir spot welding of the pair of workpieces after the coating film removal by using the pin member and the shoulder member as rotary tools.

A friction stir spot welder includes a controller configured to: drive a rotary actuator and an advancement/withdrawal actuator to cause a pin to press workpieces while rotating; after the pressing, drive the rotary actuator and the advancement/withdrawal actuator to cause the pin and a shoulder to press the workpieces while rotating; and after the pressing, drive the rotary actuator and the advancement/withdrawal actuator to cause the pin and/or the shoulder to plunge into a weld region of the workpieces while rotating and stir the weld region to weld the workpieces together.

A friction stir spot welding apparatus including a controller that (A) operates a rotary driver and a tool driver such that a pin and a shoulder are brought into contact with a welded workpiece; (B) operates, after the (A), the rotary driver and the tool driver such that the pin separates from the welded workpiece; and (C) operates, after the (B), the rotary driver and the tool driver such that the pin advances toward the welded workpiece. The controller controls the tool driver such that pressing force applied to the welded workpiece from the pin and the shoulder in the (C) is smaller than that in the (B) and/or controls the rotary driver such that rotational frequencies of the pin and the shoulder in the (C) are lower than those in the (B).

Provided are a friction stir welding apparatus and a friction stir welding method capable of highly accurate position control in a Z-axis direction (vertical direction) of a joining tool when a joint target member is subjected to friction stir welding by the friction stir welding apparatus. The friction stir welding apparatus includes a joining tool which consists of a shoulder portion and a probe portion and is inserted into a joint target member to rotate, a joining head which holds the joining tool, an apparatus body which holds the joining head, rotates the joining tool, and moves the joining tool, and a control device which controls an operation of the joining tool, in which the control device has a reference setting mode where a correction reference used for correction of misalignment in the Z-axis direction of the joining tool which occurs when the joint target member is joined by the joining tool is set in a stage before the joining tool is inserted into the joint target member, a joining mode where the joining tool is inserted into the joint target member and the joint target member is joined, and a correction mode where an amount of position fluctuation of a tip of the joining tool with respect to the correction reference which occurs when the joining tool joins the joint target member is measured and correction is performed when the amount of position fluctuation exceeds a predetermined threshold value.

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.

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).

A double-head double-sided high-efficiency friction stir welding device includes a base (1), a pair of columns (2) arranged on the base (1), an upper beam (3), at least one worktable connected with a horizontal surface of the base (1), vision sensors (7) mounted on the upper head (5) and the lower head (6) and used for identifying the weld, and a CNC controller (8) used for controlling operations of the gantry, the upper head (5), the lower head (6), the worktable and the vision sensors (7).

A spot welding apparatus which performs spot welding of a plurality of plate materials which are lapped to each other, comprises a displacement driving unit which displaces lapped portions of the plurality of plate materials and a tool relatively to each other; a rotation driving unit which rotates the tool; and a controller which controls the displacement driving unit and the rotation driving unit so that the tool is plunged into the lapped portions in a state in which the tool is rotated to perform friction stir spot welding. The controller controls the displacement driving unit so that at least one friction stir spot weld is formed in a region of the lapped portions which is between a plurality of resistance spot welds formed by resistance spot welding.

A friction stir welding apparatus and method maintains a depth of a welded part constant without varying a depth-direction position of a welding tool leading end part relative to welded members. A control device controls an operation of the friction stir welding apparatus, and a holder unit is connected to a swing mechanism unit via a revolving mechanism section, and a welding tool is held to the holder unit. The control device has a first welding mode in which friction stir welding is performed on the basis of a welding condition signal for deciding a welding condition of the welding tool, a swing control signal for controlling the swing mechanism unit, a first hold position decision signal, and a second welding mode in which friction stir welding is performed on the basis of the welding condition signal, the swing control signal, and a second hold position decision signal.