A method of friction-stir welding, FSW, ajoint J, for example a T joint and/or a lap joint, between a first workpiece W1 and a second workpiece W2, is described. The method comprises: performing a first pass P1 of FSW of the joint J by moving therealong a first tool (10), comprising a first probe (100) rotating in a first rotational direction RD1, in a first movement direction MD1 defining a first line L1, on a first side S1 of the joint J, comprising: inserting the first probe (100) to a first depth D1, thereby providing a first welded region WR1; withdrawing at least partially the first probe (100), thereby providing a first partially welded and/or unwelded region PWUR1; and fully withdrawing the first probe (100), thereby resulting in a first exit hole EXH1; performing a second pass P2 of FSW of the joint J by moving therealong a second tool (20), comprising a second probe (200) rotating in a second rotational direction RD2, in a second movement direction MD2 defining a second line L2, on the first side S1 of the joint J, comprising: inserting the second probe (200) to a second depth D2, thereby providing a second welded region WR2; optionally withdrawing at least partially the second probe (200); and fully withdrawing the second probe 200, thereby resulting in a second exit hole EXH2; wherein the second welded region WR2 includes the first exit hole EXH1; and wherein the second exit hole EXH2 is included in the first welded region WR1.

A method of friction-stir welding, FSW, a joint J, for example a T joint J, between a first workpiece W1 and a second workpiece W2 is described. The method comprises: arranging the first workpiece W1 and the second workpiece W2; performing a first pass P1 of FSW of the joint J by moving therealong a first tool 10, comprising a first probe 100 rotating in a first rotational direction RD1 and at least partially inserted into the first workpiece W1 and/or into the second workpiece W2 to a first depth D1, in a first movement direction MD1 defining a first line L1, on a first side S1 of the joint J, thereby providing a first welded region WR1; and performing a second pass P2 of FSW of the joint J by moving therealong a second tool 20, comprising a second probe 200 rotating in a second rotational direction RD2 and at least partially inserted into the first workpiece W1 and/or into the second workpiece W2 to a second depth D2, in a second movement direction MD2 defining a second line L2, on a second side S2 of the joint J, thereby providing a second welded region WR2; wherein the first tool 10 and the second tool 20 are mutually opposed; and wherein performing the first pass P1 of FSW and performing the second pass P2 of FSW are at least partially concurrent.

The present invention includes: a primary joining process in which a coarse portion having a predetermined width is formed in the vicinity of a step side face within a plasticized region while the rotary tool is being moved one round along a first butted portion to perform friction stirring in a state that a tip of a tip side pin of a rotary tool being rotated is inserted to the same depth as or slightly deeper than a step bottom face and an outer circumferential face of a base side pin is in contact with a front face of a sealing body and the tip side pin is slightly in contact with at least an upper portion of a jacket body and an inspection process in which a passed position of the tip side pin is specified by performing, a flaw detection to detect the coarse portion.

A liquid cooling jacket is produced by forming a first butted portion where a step side face of a peripheral wall portion and an outer peripheral side face of a sealing body butt each other and a third butted portion where a step side face of a support pillar portion and a hole wall of the hole portion of the sealing body portion butt each other with a gap, and friction-stirring by inserting a tip side pin and a base side pin of a primary joining rotary tool that is rotating into the sealing body and moving the primary joining rotary tool along the third butted portion with an outer circumferential face of the tip side pin being kept off the step side face while having a second aluminum alloy of the sealing body flow into the gap.

The invention has a feature of comprising a butting process of forming a stepped butted portion and a joining process of performing friction-stir-welding on the stepped butted portion, wherein the rotary tool includes a base side pin having a taper angle larger than a taper angle of a tip side pin, and a pin step portion in a staircase shape is formed on an outer circumferential face of the base side pin, and wherein in the joining process, a rotation direction and a translation method of the rotary tool are set such that the second metal member is on an advancing side, a target angle by which a rotation axis of the rotary tool is inclined toward the second metal member is set such that a burr formed on a front face of the second metal member after the joining process has a thickness between 0 and 130 μm.

A bonding device for joining together a first member (3), an intermediate member (4), and a second member (3) which are layered as a laminated assembly includes a probe (12, 41), an anvil (11, 11b, 11c, 11d), a shoulder member (13,13a, 61,64,68), a drive mechanism (14) configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line, and an electric power supply (15) electrically connected to the anvil and the shoulder member to conduct electric current through the laminated assembly via the anvil and the shoulder member.

A bonding device for joining together a first member (3), an intermediate member (4), and a second member (3) which are layered as a laminated assembly includes a probe (12, 41, 52), an anvil (11), a drive mechanism (14) configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line, and an electric power supply (15) electrically connected to the anvil and the probe to conduct electric current through the laminated assembly via the anvil and the probe.

A tool for friction bit joining a workpiece material includes a bit with a tapered pin and a non-cutting tip. The bit has a top surface opposite the pin with at least one feature recessed in, or extending from, the top surface and configured to transmit torque to the bit to rotate the bit around a rotational axis.

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.

Provided are a long-life and inexpensive friction stir welding tool that is not dependent on the mode of friction stir welding or the type of material to be welded, and a friction stir welding method using the friction stir welding tool. The friction stir welding tool comprises a body portion having a shoulder portion, and a probe portion disposed on a bottom surface of the body portion, and is characterized in that the probe portion is spherical-crown shaped. Preferably, the shoulder portion is flat or convex, and preferably the hardness of the shoulder portion is greater than the hardness of the probe portion.