The method includes a step of preparing a first member made of a first metal and a second member made of a second metal having a smaller deformation resistance than the first metal, and a step of joining the first member and the second member. The step of joining includes a step of heating the first member and the second member by relatively rotating the first member and the second member, while pressing the first member and the second member against each other, without changing a relative positional relationship therebetween, and a step of cooling the first member and the second member heated, while being pressed against each other. In a first contact surface which is a surface of the first member coming into contact with the second member, a recess is formed so as to include a region intersecting the axis of rotation.

A friction stir welding apparatus that includes a rotary tool and a heating device. The heating device is placed in front of the rotary tool to heat steel sheets that are used as a workpiece. The rotary tool is moved in the welding direction so that steel sheet is softened by frictional heat. Additionally, the surface temperature, the area, and the position of the heated region during the heating process are strictly controlled. The heating of the steel sheets by the welding apparatus provides sufficient strength and good welding workability by advantageously eliminating plastic flow defects generated due to insufficient heating of workpieces.

A joining method is capable of suitably joining metal members of different kinds. The joining method includes a step of preparing a first metal member having a first upper surface, a first lower surface and a first inclined surface connecting the first upper surface and the first lower surface, and a second metal member having a second upper surface, a second lower surface and a second inclined surface connecting the second upper surface and the second lower surface. The second metal member has a higher melting temperature than the first metal member. A butting interface is formed by butting the first inclined surface and the second inclined surface. The first and second metal members are joined by moving a rotary tool along the butting interface while the rotary tool is inserted from the first upper surface and a stirring pin is in contact with the first metal member.

Additive manufacturing systems and methods are disclosed. A housing includes a passageway having first and second open ends. A material is fed through the passageway and exits its second open end. A friction stir weld (FSW) bobbin pin tool is mounted in the housing with a radial edge of the pin tool's annular volume disposed adjacent to the second open end of the passageway. The annular volume is adapted to receive a substrate. The FSW bobbin pin tool is operable to be rotated so that the substrate and the material exiting the second open end of the passageway are plasticized in the annular volume for deposition onto the substrate.

A friction stir joining device includes a tool, a rotary driver, a linear-movement driver, and a control device. The control device is adapted to (A) dispose so that a first member opposes to the tool, and the first member, a second member and a third member are located in this order, (B) control the linear-movement driver and the rotary driver so that a tip-end part of the tool presses a joined part of a to-be-joined object while the tool is rotated, (C) control the linear-movement driver and the rotary driver so that the third member softened extends above an upper surface of the second member, and the tip-end part of the tool reaches a first position, and (D) control the linear-movement driver and the rotary driver so that the tool is drawn out from the joined part while the tool is rotated.

A friction stir spot welding apparatus includes a pin member formed in a solid cylindrical shape, a shoulder member formed in a hollow cylindrical shape, the pin member being inserted in the shoulder member, a rotary actuator that rotates the pin member and the shoulder member on an axis that is in agreement with an axial center of the pin member, and a linear actuator that linearly moves each of the pin member and the shoulder member along the axis. A tip-end part of the shoulder member is formed in a tapered shape.

A friction stir welding tool for a machine tool having a frame and a spindle rotatable relative to the frame. The friction stir welding tool includes a pin, a shoulder, and a drive shaft connectable to the spindle to set the pin and shoulder in rotational motion about a rotation axis, wherein the shoulder is rotatable relative to the pin about the rotation axis. To obtain different speeds of the pin and shoulder in a simple and robust manner, a planetary transmission having a ring gear, a planet carrier, and a sun gear is connected to the drive shaft, pin, and shoulder. The pin or the shoulder is connected to the planet carrier so that the pin and shoulder are set in rotation about the rotation axis at different rotational speeds, but in the same rotation direction, by driving the drive shaft by the spindle.

A subframe structure for a front of the vehicle includes a front subframe made of steel and a rear subframe made of a light metal. The front subframe comprises left and right side members extending in approximately parallel with each other and including flange sections, the rear subframe comprises left and right rear side sections including flange sections, and a rear cross section connecting the left and right rear side sections. The left and right rear side sections are stacked on the left and right side members, and the flange section are joined together so as to define left and right closed sections, therebetween, and the left and right side members are further fastened to the left and right rear side sections by bolts extending through the left and right closed sections.

A system and method for making adjustments to output effort from a spindle driver using a multi-stage nested control loop of an active controller to provide constant power to a friction stir zone during a friction stir operation. Providing constant power facilitates temperature control within the friction stir zone and thereby improves the result of the operation

A different materials joint structure includes: an iron member; an aluminum member disposed on the iron member and integrally joined with the iron member; and a sealant disposed between the iron member and the aluminum member. The aluminum member includes a lateral edge section projecting outwardly from the iron member and extending downwardly, the lateral edge section and a surface of a lateral end of the iron member define a concave section therebetween, and the sealant protruding outwardly from a position between lateral sections of the iron member and the aluminum member is held in the concave section.