Abstract: Disclosed is a friction stir welding technique which avoids occurrence of a dent, in adjoining region, extending to a level beneath the joined surfaces, structural body formed. At end portions of the frame members to be joined, at the joining region, thickened parts which project toward the rotary body joining tool are provided. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion. The rotary body joining tool is inserted in the thickened parts. In a state where the rotary body joining tool has been inserted small-diameter tip end first, to a level where the larger diameter portion of the rotary body joining tool overlaps the thickened part but does not extend below the upper surface of the non-thickened surfaces of the members joined, the rotary body is rotated and moved along the joining region.

Abstract: Disclosed is a friction stir welding technique which avoids occurrence of a dent, in adjoining region, extending to a level beneath the joined surfaces, structural body formed. At end portions of the frame members to be joined, at the joining region, thickened parts which project toward the rotary body joining tool are provided. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion. The rotary body joining tool is inserted in the thickened parts. In a state where the rotary body joining tool has been inserted small-diameter tip end first, to a level where the larger diameter portion of the rotary body joining tool overlaps the thickened part but does not extend below the upper surface of the non-thickened surfaces of the members joined, the rotary body is rotated and moved along the joining region.

Abstract: Disclosed is a friction stir welding technique which avoids occurrence of a dent, in adjoining region, extending to a level beneath the joined surfaces. At end portions of the frame members to be joined, at the joining region, thickened parts which project toward the rotary body joining tool are provided. Two adjoining thickened parts, of adjacent members to be joined, can form a trapezoid shape. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion. The rotary body joining tool is inserted in the thickened parts. In a state where the rotary body joining tool has been inserted small-diameter tip and first, to a level where the larger diameter portion of the rotary body joining tool overlaps the thickened part but does not extend below the upper surface of the non-thickened surfaces of the members joined, the rotary body is rotated and moved along the joining region. Even when a gap exists between two thickened parts, a desirable joining can be carried out.

Abstract: The invention intends to reduce a frequency at which defects occur in a welding region during friction stir welding, and to improve the reliability of the welding region. The invention resides in a friction stir welding apparatus wherein a distance to the surfaces of the workpieces is detected by a detector, a change of the detected distance is found by a signal processing device, and a tool is rotated by a rotation driving device in a state where a vertical driving device is controlled by a control device so as to suppress the found change, whereby a plastic fluidity of the workpieces is caused to accomplish joining of the workpieces.

Abstract: A liquid-cooled circuit device including: a module having a circuit element and a module base plate on surface of which the circuit element is mounted; a circuit case for accommodating the module; and a cooling liquid chamber for flowing a cooling liquid in contact with a back face of the module base plate of said module. The module base plate of the module is fitted into an opening provided in a member forming the cooling liquid chamber and welded without a gap.

Abstract: A liquid-cooled circuit device including: a module having a circuit element and a module base plate on surface of which the circuit element is mounted; a circuit case for accommodating the module; and a cooling liquid chamber for flowing a cooling liquid in contact with a back face of the module base plate of said module. The module base plate of the module is fitted into an opening provided in a member forming the cooling liquid chamber and welded without a gap.

Abstract: Structural components obtained by a process for welding iron-base materials, where the iron-base material is iron-base fine grained materials free from any amorphous phase, which comprises welding two kinds of fine grained materials of chemical and crystallographically same or different kinds from one another, whose average grain sizes d are in a range of 10 nm<d≦5×103 nm, etc., by friction stir welding can maintain distinguished properties of fine grained materials, such as strength and corrosion resistance.

Abstract: Disclosed is a friction stir welding technique which avoids occurrence of a dent, in adjoining region, extending to a level beneath the joined surfaces. At end portions of the frame members to be joined, at the joining region, thickened parts which project toward the rotary body joining tool are provided. Two adjoining thickened parts, of adjacent members to be joined, can form a trapezoid shape. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion. The rotary body joining tool is inserted in the thickened parts. In a state where the rotary body joining tool has been inserted small-diameter tip and first, to a level where the larger diameter portion of the rotary body joining tool overlaps the thickened part but does not extend below the upper surface of the non-thickened surfaces of the members joined, the rotary body is rotated and moved along the joining region. Even when a gap exists between two thickened parts, a desirable joining can be carried out.

Abstract: Disclosed is a friction stir welding method for welding two members to be welded which differ in physical properties and/or mechanical properties by abutting the two members to each other, inserting a pin portion of a rotary tool having the pin portion and a shoulder portion to the abutment surfaces of the two members, and moving the rotary tool along the abutment surfaces. The pin portion is inserted to only one of the members, the pin portion is not inserted to the other of the members but only the shoulder portion is set in contact with the other of the members, and, while this condition is maintained, the rotary tool is moved. With this method, only the member on the side where the pin is inserted can be made to undergo plastic flow attendant on a friction stir action. The metal in plastic flow is pressed against the opposite member at an elevated temperature and high pressure, whereby diffusion of atoms is caused in the vicinity of the abutment surfaces, and the members are welded.

Abstract: It is an object of the present invention to provide a friction stir welding method and apparatus capable of maintaining a rotating tool and workpieces at a substantially constant geometrical relation for arbitrary curved surfaces having a three-dimensional shape, as well as a welded structure obtained thereby.

Abstract: Provided are an underwater processing apparatus which can effectively prevent water from entering a shield for a workpiece having a surface ruggedness, and in which variation in a gas flow for a processing part is reduced, a processing method and an application thereof to a nuclear reactor, and the under water processing device is composed of a shield means which locally cover the processing part with the gas in order to prevent water from entering the shield member, the shield means having a solid wall formed of a member which is slidable in a part where it make contact with the workpiece, and adapted to make contact with the workpiece and to be moved up and down by a pressing force, and a water jetting means for forming a water curtain around the outer periphery of the solid wall.

Abstract: A friction stir welding system capable of maintaining a rotating tool and workpieces at a substantially constant geometrical relation for arbitrary curved surfaces having a three-dimensional shape, as well as a welded structure obtained thereby. A method comprises joining workpieces while setting rotational angles of two rotational axes of a rotating tool which the two rotational axes are rotatable in intersecting directions or perpendicularly intersecting directions independently of rotation of the rotating tool, detecting a normal line direction with respect to joint surfaces of the workpieces and a tangential direction of a joint line, and joining the workpieces in three-dimensional directions while setting, on the basis of the detected normal line direction and tangential direction, an angle relative to a normal line direction, as well as a tangential direction, at a tip end of the rotating tool, and also resides in a friction stir welding apparatus using the method.

Abstract: A liquid-cooled circuit device including: a module having a circuit element and a module base plate on surface of which the circuit element is mounted; a circuit case for accommodating the module; and a cooling liquid chamber for flowing a cooling liquid in contact with a back face of the module base plate of said module. The module base plate of the module is fitted into an opening provided in a member forming the cooling liquid chamber and welded without a gap.

Abstract: A liquid-cooled circuit device including: a module having a circuit element and a module base plate on surface of which the circuit element is mounted; a circuit case for accommodating the module; and a cooling liquid chamber for flowing a cooling liquid in contact with a back face of the module base plate of said module. The module base plate of the module is fitted into an opening provided in a member forming the cooling liquid chamber and welded without a gap.

Abstract: The invention provides a friction stir welding apparatus and method and a processing apparatus and method, which are not easily affected by deformations of a work being processed. The friction stir welding apparatus inserts a rotating tool into the work and moves the rotating tool relative to the work to join members of the work. The friction stir welding apparatus and method and the processing apparatus and method of the invention, the latter cutting or grinding the work with a rotating cutter or grindstone, comprises controlling a relative distance between the tool, cutter or grindstone and the work under the joining or processing operation or an insertion depth so that the load factor or electric current of a spindle motor for rotating the tool, cutter or grindstone is within a predetermined range, and a controller therefor.

Abstract: Structural components obtained by a process welding iron-base materials, where the iron-base material is iron-base fine grained materials free from any amorphous phase, which comprises welding two kinds of fine grained materials of chemical and crystallographically same or different kinds from one another, whose average grain sizes d are in a range of 10 nm<d≦5×103 nm, etc., by friction stir welding can maintain distinguished properties of fine grained materials, such as strength and corrosion resistance.

Abstract: The invention provides a friction stir welding apparatus and method and a processing apparatus and method, which are not easily affected by deformations of a work being processed. The friction stir welding apparatus inserts a rotating tool into the work and moves the rotating tool relative to the work to join members of the work. The friction stir welding apparatus and method and the processing apparatus and method of the invention, the latter cutting or grinding the work with a rotating cutter or grindstone, comprises controlling a relative distance between the tool, cutter or grindstone and the work under the joining or processing operation or an insertion depth so that the load factor or electric current of a spindle motor for rotating the tool, cutter or grindstone is within a predetermined range, and a controller therefor.

Abstract: Face plates 11b and 12b of a hollow shape member 10 are abutted against face plates 21b and 22b of a hollow shape member 20. Projections 15, 16, 25 and 26 are formed to both sides of the face plates at the abutted areas. The rotary tool 50 comprises two large-diameter portions 53 and 54, and a small-diameter portion 51 disposed therebetween. The projections 15, 16, 25 and 26 of the portions 11b and 21b (12b and 22b) to be welded are sandwiched between the two large-diameter portions 53 and 54 upon performing the friction stir welding. According thereto, even if the heights of the abutted areas of the plates against the two large-diameter portions 53 and 54 differ, the face plates 11b and 21b (12b and 22b) will not be damaged (cut) by the tool since only the depth of the large-diameter portion being inserted to the projections varies. Therefore, the welding process will not reduce the thickness of the face plates, leading to design-related and function-related problems.

Abstract: Disclosed is a friction stir welding method for welding two members to be welded which differ in physical properties and/or mechanical properties by abutting the two members to each other, inserting a pin portion of a rotary tool having the pin portion and a shoulder portion to the abutment surfaces of the two members, and moving the rotary tool along the abutment surfaces. The pin portion is inserted to only one of the members, the pin portion is not inserted to the other of the members but only the shoulder portion is set in contact with the other of the members, and, while this condition is maintained, the rotary tool is moved. With this method, only the member on the side where the pin is inserted can be made to undergo plastic flow attendant on a friction stir action. The metal in plastic flow is pressed against the opposite member at an elevated temperature and high pressure, whereby diffusion of atoms is caused in the vicinity of the abutment surfaces, and the members are welded.

Abstract: A rotary tool 200 having on the end surface of a large-diameter portion 210 facing a small-diameter portion 220 grooves 213 formed in arc-like shapes, and performing friction stir weld by inserting the end surface of the large-diameter portion 210 and the small-diameter portion to members and rotating the tool 200. By the rotation, the metal of the members moves along the grooves 213 to the center axis direction of the rotary tool 200. The arc-shaped grooves 213 are formed to curve toward the direction of rotation. Since the metal material of the members is moved toward the center, a good weld is realized even when only one of the members to be welded has a projection, or when a large gap is formed therebetween.