To suppress the generation of bent streaks and wrinkle marks which are generated at the vertical wall portions and flange portions on the outside of a curvature, suffering shrinkage deformation when bending a channel member including the curved channel portion by a method for forming by a two-stage bending.
In the method for forming a curved channel member, when the channel member including the curved channel portion 1c is formed, firstly a temporally formed body is subjected to a first molding and, next, the temporally formed body is subjected to the second molding. In the temporary formed body, one or several beads 21 which are bulged outward from the flat surface of the temporary vertical wall 12oa are formed along the lower part on the side of a temporary flange 13oa from the upper part on the side of a temporary lateral wall portion 11a of the temporary vertical wall portion 12oa, on the temporary vertical wall 12oa on the side suffering shrinkage deformation in the temporary curved channel portion corresponding to the curved channel portion. The beads 21 are formed so that the upper part on the side of the temporary lateral wall 11a is higher than the lower part on the side of the temporary flange 13oa, in the height from the flat portion.
IWATANI JIRO
KIMURA TAKAYUKI
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