Hitachi, Ltd.

Tetsuya Matsunaga

Masakuni Ezumi

Kazushige Fukuyori

Kazusige Fukuyori

Yoshihiko Ina

Masaaki Shigeyama

The purpose of the present invention is to provide a method that can be easily applied to friction stir welding where the thickness of face plates at one welding portion is different from the thickness of face plates at another welding portion. Three shape membershaving two butt joint portions are mounted on a jigThe face plateof shape memberis thick and the face plateof shape memberis thin. The protruded height of projectionis greater at portion B where surface platesbeing welded are thin than the protruded height of projection A where surface platesare thick. The depths for inserting rotary tools to shape membersfor friction stir welding are the same. Friction stir welding is facilitated since the size and insertion depth of all the rotary tools being applied can be the same.

Friction stir welding method and group of shape members for friction stir welding

The purpose of the present invention is to provide a method that can be easily applied to friction stir welding where the thickness of face plates at one welding portion is different from the thickness of face plates at another welding portion. Three shape membershaving two butt joint portions are mounted on a jig. The face plateof shape memberis thick and the face plateof shape memberis thin. The protruded height of projectionis greater at portion B where surface platesbeing welded are thin than the protruded height of projection A where surface platesare thick. The depths for inserting rotary tools to shape membersfor friction stir welding are the same. Friction stir welding is facilitated since the size and insertion depth of all the rotary tools being applied can be the same.

Abutted portions of face plates and of frame members and are friction stir welded. With the abutting, a projecting portion of an end portion of the face plate of the frame member is inserted into a recessed portion of an end portion of the face plate of the frame member . By this engagement, the outer face on one face side of the face plates and form a smooth surface, so that there is no step at the joined edges. Next, a rotary tool is inserted into the gap between the abutted plates, from the side of the raised portions and of the face plates and , while the other faces and of the face plates and are supported flatly on a bed during the friction stir welding. Accordingly, the welding of the engaged plates can be carried out without any step-wise difference.

Frame member for friction stir welding

A rim member forming an entrance and a plate ( ) are friction stir welded by moving a rotary tool along the rim member . The rotary tool is tilted along the direction of movement. Welding is started at right block R, and when the tool reaches corner portion P between the right block R and a center block C, the tool is pulled out of the rim member and plate ( ). Next, the tool is tilted toward the direction of movement along center block C. Thereafter, the tool is lowered and inserted to position, and friction stir welding is restarted. According to the invention, the direction of the rotary tool is not changed while the tool is inserted to the rim member . This prevents generation of excessive friction heat, and thereby realizes a good weld.

Friction stir welding method

The abutted face plates of frame members are joined using friction stir welding. Next, a connection member is mounted on seats formed in the frame members, while a projection of one end of the connection member is inserted into a groove of an end portion of a face plate of the frame member. Next, the other end of the connection member is temporarily welded to the face plate of the hollow frame member. With this condition, an abutted portion of the face plate and the connection member are joined using friction stir welding. Then, the overlapped portion between the other end of the connection member and the frame member is joined by friction stir welding. When the hollow frame members are welded from one side, a temporary welding of the connection member can be reduced.

Friction stir welded body and frame member therefor

End portions of members are abutted against each other. A trapezoidal convex portion of the member is inserted into a trapezoidal concave portion of the member . A friction stir welding is performed by inserting a rotary tool from the side of raised portions . A small-diameter portion of the rotary tool is tapered and is provided with a screw thread . A large-diameter portion is of a member different from an axis portion of the rotary tool and is connected thereto by a pin . The screw thread of the screw thread portion could be formed in the vicinity of a concave surface of an end surface of the large-diameter portion , so that stirring near the end surface can be performed sufficiently. Therefore, good friction stir welding can be achieved.

Friction stir bonding method

Abutted portion of face plates and of frame members and are friction stir welded. With the abutting, a projecting portion of an end portion of the face plate of the frame member is inserted into a recessed portion of an end portion of the face plate of the frame member . By this engagement, the outer faces on one face side of the face plates and form a smooth surface, so that at the joined edges there is no step. Next, a rotary tool is inserted into the gas between the abutted plates from the side of the raised portions and side of the face plates and , while the other faces and of the face plates and , are supported flatly on a bed during the friction stir welding. Accordingly, the welding of the engaged plates can be carried out without any step-wise difference.

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Kudamatsu, Japan

Tetsuya Matsunaga