FORMING ROLL AND FORMING METHOD

PROBLEM TO BE SOLVED: To provide a forming roll for manufacturing formed goods having an adequately low yield rate (YR) even in any part excepting the weld zone after forming in roll forming by which forming is performed by pressing a roll having the surface of a circular-arcuate shape against the upper and lower surfaces of a plate including an electric resistance welded tube. SOLUTION: Because a condition that the plate is pressed with upper and lower rolls in the center part 10 of pressing is released, the local reduction in the center part 10 of the pressing is prevented and the rising of the YR in that part is prevented by reducing the swelling in the middle part of the width of the upper roll 1 of the forming rolls or making the part into a recessed shape, the manufacture of formed goods having the low YR is enabled. As for the shape of the upper roll 1, the roll shape on the both sides of the center part of pressing has a radius R1of curvature and, when drawing a virtual circle 11 of the radius R1in contact with the roll shape on the both sides of the center part, the position C of the roll surface in the center part of width is situated on the side of the roll center of the position of the virtual circle 11. COPYRIGHT: (C)2003,JPO