Hitachi, Ltd.

Akihiro Satou

Masakuni Ezumi

Kinya Aota

Yasuo Ishimaru

Hisanori Okamura

Kazusige Fukuyori

Isao Funyuu

Takeshi Kawasaki

Kazushige Fukuyori

The end of a hollow memberis abutted against the end of a hollow member. The end of a face plateis supported on a protrusion. A small-diameter portionof a rotary toolis inserted into the abutted area, and the toolis moved along the abutted region while being rotated in a clockwise direction as observed from the large-diameter potion. Thus, the pressure of mobilized metal is greater on the right side of the axial center of the rotary tool. The thickness of the member from the tip of the inserted small-diameter portionto the hollow areasandis thicker at the right side where the pressure is higher, thus preventing metal from flowing out into the hollow region

Friction stir welding method

Disclosed is a friction stir welding technique which avoids occurrence of a dent, in a joining 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 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. Even when a gap exists between two thickened parts, a desirable joining can be carried out. After the joining, the remaining parts of the thickened parts can be machined so as to form a smooth surface.

Friction stir welding method, frame members used therein, and product formed thereby

The friction stir welding technique disclosed 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, thickened parts, which project toward the rotary body joining tool, are provided. The Two adjoining thickened parts form a trapezoid shape. The rotary body joining tool has a small-diameter tip portion and a larger diameter portion, and is inserted in the thickened parts. When 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, 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. After the joining, the remaining parts of the thickened parts can be machined to form a smooth surface.

Extruded frame member for use in friction stir welding

A raised portion is provided on an upper face of an end portion of a plate which forms one side of a frame member . An end portion of a plate of another frame member is abutted with the plate of the frame member . The frame members and are aluminum alloy extruded frame members and the directions of extrusion of the two frame members are orthogonal. A welding padding is carried on an upper face of the plate of the frame member . Under this condition, a rotary tool is inserted from above and a friction stir welding is carried out. Accordingly, the padding serves the same function on the plate as the raised portion on the plate , so that a good welding can be carried out.

Structural body formed by friction stir welding

Plural extrusion members , each having plural ribs formed on one surface of a face plate , are mounted on a frame with the surface not having the ribs facing downward, and with the end regions of the adjacent members being butted to each other. Then, the end regions of said members are welded using friction stir welding from the upper direction with a rotary body , and then a hairline finish is applied to said surface not having the ribs, which constitutes the exterior surface of the vehicle body. In this way, there is substantially no need to cut off the joint bead, which improves the appearance of the vehicle body and reduces the manufacturing cost.

Method of manufacturing structural body and structural body

Car body formed by friction stir welding

In a railway car, extruded frame members of an aluminum base alloy containing Si of 0.4-0.9 wt % and Mg of 0.4-1.2 wt % are welded according to a friction stir welding method. In a structure, an aluminum base alloy plate containing Si of 0.4-0.9 wt % and Mg of 0.4-1.2 wt % is prepared, to one face of the aluminum base alloy plate a rib is formed, and the aluminum base alloy plate is an extruded frame member. Accordingly, a railway car having a low welding distortion and a structure having a low welding distortion can be obtained.

Structure and railway car

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. After the joining, the remaining parts of the thickened parts can be machined so as to form a smooth surface.

End portions of face plates and of a frame member are connected by a rib A. To protrusion chips and end portions of face plates and of another frame member are overlapped. The corners between the rib A and the rear faces of the face plates and are in the form of a convex circular arc which protrudes into a hollow portion of the frame member . Both end portions of the circular arc are connected to the rib A and the face plates and by two smooth recessed circular arcs and . Accordingly, since a flow-out of metal does not occur from this portion, the cross-section can be small and a light weight structure an be obtained. A structural body formed of hollow frame members which are joined by friction stir welding provides a light weight structure.

Hollow extruded frame member for friction stir welding and structure body formed therefrom

Frame member used in friction stir welding

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.

Friction stir welding method using members which overlap and have protrusion at the weld location prior to the welding

Structural body formed by friction stir welding method

Structural body formed by friction stir welding two members, one of which has a protruding portion

The rotary tools are disposed to weld along two spaced welding lines. The two rotary tools are inserted into respective welding joints and moved at the same time along the respective welding lines. At a position P of a portion of a window one rotary tool is withdrawn from the welding joint to that the friction stir welding on that welding joint is stopped although the welding tool continues to move. At a position P , the rotary tools are gradually withdrawn from their respective welding joints while they continue to move along the welding line. At a position P , the movement of the rotary tools along the respective welding lines is stopped, the rotary tools are completely withdrawn and the welding is stopped. Next, the rotary tools are inserted into the respective welding joints once again and movement thereof is started again. An insertion amount of the rotary tools at this time is larger than the insertion amount thereof prior to the stopping of the movement of these rotary tools.

Method of manufacture of a structural body

The rotary tools are disposed to weld along two spaced welding lines. The two rotary tools are inserted into respective welding joints and moved at the same time along the respective welding lines. At a position P of a portion of a window one rotary tool is withdrawn from the welding joint so that the friction stir welding on that welding joint is stopped although the welding tool continues to move. At a position P the rotary tools are gradually withdrawn from their respective welding joints while they continue to move along the welding line. At a position P the movement of the rotary tools along the respective welding lines is stopped, the rotary tools are completely withdrawn and the welding is stopped. Next, the rotary tools are inserted into the respective welding joints once again and movement thereof is started again. An insertion amount of the rotary tools at this time is larger than the insertion amount thereof prior to the stopping of the movement of these rotary tools.

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Kudamatsu, Japan

Akihiro Satou