| 摘要 |
A forging stock 10 which is formed by extrusion in such a way that its cross section perpendicular to the direction of extrusion varies along the direction of extrusion. It is cut into portions in the direction of extrusion to be forged individually, each cut portion having cross sections varying along the direction of extrusion. Each cut portion has a pair of first parallel parts 13 and 13 at both ends thereof in the direction of extrusion, a second parallel part 15 which is between said first parallel parts 13 and 13 and which differs in thickness from said first parallel parts 13 and 13, and oblique parts 17 and 17 each of which is between said first parallel parts 13 and 13 and said second parallel part 15. |
