| 摘要 |
When forming a cross-sectional hat-shaped member which has, on the cross section perpendicular to the longitudinal direction, vertical wall sections (1b, 1b) on both sides, flange sections (1a, 1a) on both sides which are connected to each of the vertical wall sections (1b), and a top plate section (1c) which is connected to the vertical wall sections (1b, 1b) on both sides, and which has a bent section (2) which is bent in the longitudinal direction with the flange sections (1a, 1a) made on the outside using a punch (5) and a die (4), the forming is performed, with the die shoulder radius of the die (4) for obtaining the final shape of the cross-sectional hat-shaped member as R0, in a die (4) which has die shoulder radius (R1) larger than the die shoulder radius (R0), and then the forming is performed in the die (4) of the die shoulder radius (R0). In this way, by dividing the forming into two stages, the stress balance of tensile-compression can be minimized in the final shape resulting from the action of the stress which is relieved in the compression direction in the flange sections (1a, 1a). |
