A friction stir welding tool comprises a cylindrical shank, a shoulder portion disposed at a distal end of the shank, a pin extending from the shoulder, a cutting insert mounted within a concave portion at the distal end of the shank, and a scribe cutter mounted at a distal end of the cutting insert. The cutting insert extends distally through a channel in the pine, and the scribe cutter extends from a distal end surface of the pin in an offset position. The distal end surface of the pin is perpendicular to a longitudinal axis of the shank.

A friction stir processing tool for friction stir processing includes a shoulder for pressing against a workpiece surface and a pin, which protrudes beyond the shoulder and can be driven to rotate, for plasticizing introduction into at least one workpiece to be processed. The shoulder has an interruption opening on a circumferential region, so that the shoulder is not led around the entire circumference of the pin.

A friction stir welding device and a friction stir welding method provide that an additional material is introduced into the gap between a rotating pin and a fixed shoulder. The pin and/or the shoulder includes a conveyor worm structure by which the additional material is transported to the workpiece.

A friction stir welding method for joining a pair of workpieces by friction stir welding with a friction stir welding tool, includes rotating the friction stir welding tool about an axis in a clockwise direction when a probe is viewed from a lower side of the probe, and contacting first and second faces of the probe of the friction stir welding tool with a portion to be joined of the workpieces with pressing a shoulder face of the friction stir welding tool onto surfaces of the workpieces, while the friction stir welding tool is being rotated. Plastic flow of the workpieces is guided by a spiral groove of the second face so as to be separated from the shoulder face in a direction of the axis.

A friction stir spot welding device includes a pin member, a shoulder member, a rotation driving unit, a tool driving unit, a position detector, and a controller, wherein the controller sets as reference position of the tip end surface of the pin member or shoulder member at a time point when the pin member tip end surface or shoulder member contacts an obverse surface of an object and controls the tool driving unit reducing a pressing force to the object by the pin member and pressing force to the object by the shoulder member in a next welding process, and/or controls the rotation driving unit reducing the pin member rotational speed and shoulder member rotational speed in the next welding process, in case where a first position is the position of the tip end surface of the pin member or the shoulder member is within a first region.

A bobbin tool is disclosed that includes a top shoulder, a bottom shoulder, and an axial pin that extends between the top and bottom shoulders. The bottom shoulder has an annular shoulder end surface, a back surface opposite the annular shoulder end surface, and a side surface that joins the annular shoulder end surface and the back surface. One or more and radially-extending blades may be disposed on the side surface of the bottom shoulder and/or one or more axially-extending blades may be disposed on the back surface. The one or more blades provide the bobbin tool with an ability to friction stir weld a variable thickness workpiece assembly, axially plunged through the workpiece assembly along an axis of rotation of the bobbin tool, and/or be extracted through the workpiece assembly along an axis of rotation of the bobbin tool.

A welding tool for joining at least two workpieces at a joining region by friction stir welding includes a tool pin arranged along one axis of the welding tool, for applying frictional heat to the workpieces. The welding tool also includes a shoulder surrounding the tool pin, for separating the joining region from the surrounding area. The shoulder is moveable essentially parallel to the axis of the welding tool.

The present invention provides a welding tool member for friction stir welding comprising a silicon nitride sintered body, wherein the silicon nitride sintered body includes an additive component other than silicon nitride in a content of 15% by mass or less, and the additive component includes three or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. It is preferable that the content of the additive component is 3% by mass or more and 12.5% by mass or less. It is also preferable that the additive component includes four or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. Due to above structure, there can be provided a welding tool member for friction stir welding having a high durability.

The present disclosure arranges a pair of friction stir welding tools including probes and fixed shoulders at corner portions between a first workpiece and a second workpiece. The friction stir welding tools are arranged so that regions where the probes are embedded in the respective the corner portions and stirred are positioned symmetrically with respect to the second workpiece. With this arrangement of the friction stir welding tools, the corner portions are friction stir welded simultaneously.

In the present disclosure, friction stir welding tools having probes and stationary shoulders are disposed at corners between a first workpiece and a second workpiece. A welding device main body includes axially perpendicular movement units for moving spindle units, which hold the respective friction stir welding tools on a frame, in directions perpendicular to rotary shafts of probes, and axial movement units for moving the spindle units in directions parallel to the rotary shafts of the probes.