| 摘要 |
PROBLEM TO BE SOLVED: To prevent a joint bead part and the vicinity from breaking by locally forming the wall thickness of the end parts of a member mainbody with which a joint is joined to be thick. SOLUTION: On the outer circumferential faces of the circumferential wall part of both end parts of an aluminum pipe material, thick wall parts 3a swelling toward the outside are formed extending over the full circumference, and hence the wall thickness of both end parts 3 of a member main body 2 are locally formed to be thick. Consequently, mechanical strength of both end parts 3, 3 of the member main body 2 is high, and thermal distortion generated by joint heat at joining together is small. Accordingly, a joint bead part W and the vicinity are hardly broken down. Consequently, when a tensile load in the axial direction is added to this arm member 1, for example, it is broken on the circumferential wall part of the intermediate part in the lengthwise direction of the pipe material constituting the member main body 2, and hence this member has high reliability in strength. |
