MANUFACTURE OF FORGED WORKPIECE WITH FLANGE AND BENDING DEVICE FOR THE FLANGE

PROBLEM TO BE SOLVED: To form a flange section perpendicular to the axis along a direction perpendicular to the axis and to contribute to reduction in an imbalance of rotation without adopting an upsetter. SOLUTION: A forged part 1 having a large diameter cylindrical section 2, a contracted section 3, and plural flange sections 4 which are in parallel with an axis, is formed in a forging process. In a first bending process, a flange section 4 parallel with the axis of a forged part 1 is slanted wit respect to a center axis P1, in such a way that the flange section parallel with the axis gradually widens toward its tip, forming a slanting opening flange section 5. In a second bending process, the slanting opening flange section 5 is further slanted outward, so that it becomes a flange section perpendicular to the axis which extends along the direction perpendicular to the center axis P1 of the large-diameter cylindrical section 2.