PURPOSE: To provide the bending method by which a cracking is not caused in the joint of the split bodies, in the case of bending at least one of the bifurcate split bodies which confront each other at an interval of a narrow clearance, in the mutual separating direction.
CONSTITUTION: First, a mutual narrow clearance 2 of the split bodies is widened to a V-shaped. Subsequently, in the tip position of the joint 1a of the split bodies 1, 1 a rotary bending die 4 is arranged, and the tip part of the rotary bending die is pressed in the bending direction by a clamping die 5, and while pressing the split body 1 against the rotary bending die 4, bending is executed. Accordingly, force in the expanding direction in the vicinity of the joint 1a of the split bodies 1, 1 is suppressed, and a cracking caused by stress concentration is suppressed.
Oku Yasunori
Tashiro Yasushi
Yokoyama Masao
Showa Aluminum Co., Ltd.