A different materials joint structure includes: a thinned-plate shaped iron member and a thinned-plate shaped aluminum member integrally joined together. The iron member comprises two or more steel thinned plates stacked on each other and an electrodeposition coating is applied to the thinned plates so as to form electrodeposition coating films on surfaces of the thinned plates. The iron member and the aluminum member are then stacked on each other with stacked surfaces, and are joined together by friction stir welding tool inserted from an aluminum member side toward an iron member side in a direction perpendicular to the stacked surfaces.

There is provided a method for manufacturing a joined body using a rotary tool with a stirring pin to perform friction stirring on a composite body having a first surface and a second surface that is different from the first surface. In the composite body, metal members are combined together in a joined arrangement. The method includes the steps of: forming the composite body by combining the metal members in the arrangement; fixing the composite body in a state where the metal members are combined together; performing friction stir welding by inserting the stirring pin through the first surface into the composite body that has been fixed; rotating the fixed composite body such that the second surface is in a positional relationship to face the rotary tool; and performing friction stir welding by inserting the stirring pin through the second surface into the fixed composite body.

A method of friction stir processing (FSP) includes contacting a first workpiece with a FSP tool, where the first workpiece is a low-melting temperature metal or alloy and the FSP tool is a single-body FSP tool having a diamond working surface. The method also includes rotating the FSP tool in contact with the first workpiece at an interface and generating thermal energy at the interface to heat the first workpiece. The method further includes conducting thermal energy away from the interface with the FSP tool, and friction stirring the first workpiece at a temperature of the FSP tool below 800 C.

A friction stir welding device includes a pair of workpiece surface plates between which a gap extending along a welding line between workpieces is formed; a welding device body including a rotatable friction stir welding tool protruding upward from the gap; and a linear guide mechanism and a moving device for the welding device body. The moving device has a configuration in which a pair of pin racks extending in a direction along the gap are disposed at symmetrical positions on both sides in a width direction with a position immediately below a tool movement path of the friction stir welding tool as a symmetrical axis, and pin gears that individually mesh therewith are provided in the welding device body so as to be rotatably driven. Respective sets of a pin rack and a pin gear are alternately brought into a strong meshing state during the movement of the welding device body by causing the locations of pins and teeth thereof to deviate from each other by a half pitch.

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 joining method for joining a first metal member with a second metal member with use of a rotary tool having a stirring pin is provided. The joining method includes steps of: butting the first metal member with the second metal member to form a butted portion; arranging an auxiliary member to be in surface-contact with the first metal member or the second metal member; and frictional stirring the butted portion in which the rotating stirring pin is inserted from a front surface of the auxiliary member and the rotary tool is relatively moved in the butted portion to join the first metal member, the second metal member and the auxiliary member, in the state that only the stirring pin is brought in contact with the first metal member, the second metal member and the auxiliary member.

A friction spot joining device configured to carry out friction spot joining of a pair of plates includes an advance-retreat drive configured to advance and retreat a tool to/from the plates a rotation drive configured to rotate the tool, and a controller configured to control the advance-retreat drive and the rotation drive. The controller executes a joining control in which the tool is caused to give pressure to the plates while the tool is rotated so that the tool is pushed into the plates, and a separating control in which the tool is separated from the plates when an integrated value (P=I.sub.DT) calculated using a current value (I.sub.D) of the rotation drive during the joining control and a driving period of time (T) during the joining control is determined to be reached a target value.

A friction stir spot joining apparatus for spot-joining a pair of plate members by friction stirring with a tool's pin portion includes an advancing and retracting driving device configured to advance and retract the tool to and from plate members, a rotationally driving device configured to rotate the tool, and control device configured to control advancing and retracting driving device and rotationally driving device. The control device executes joining control of pushing pin portion into plate members while the tool is rotated and causing pin portion to pressurize plate members, and executes heat dissipation control of reducing at least one of a rotation speed and a tool's pressurization force more than in the joining control while tool is rotated and pin portion is kept pushed into plate members after joining control and separating tool from plate members after the pin portion's surface temperature becomes less than an oxidation onset temperature.

A friction stir welding equipment according to an embodiment includes a spindle unit, a holder, and a moving part; the spindle unit is capable of rotating a tool; the holder is connectable to the tool via a radial bearing and is capable of holding at least one of a side surface of a processing member or a rim of an upper surface of the processing member; and the moving part is capable of changing relative positions of the tool and the holder with respect to the processing member.

A tool holder of a machine tool, in which the machine tool includes a spindle head and a spindle supported by the spindle head, includes: a shank portion attached to the spindle; a rotary portion integrally provided to the shank portion and to which a welding tool (processing tool) used for friction stir welding is attachable; a bearing mechanism (bearing) supporting the rotary portion so that the rotary portion is rotatable; and a bearing holder holding the bearing mechanism, in which the bearing holder is disposed facing the spindle head and is capable of transmitting a load applied to the bearing mechanism to the spindle head.