| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a bar shape member having an opened hole on its one end and a flange provided on the other end, which method can provide almost uniform hardness the bar shape member without carrying out the quenching work. SOLUTION: In the method for manufacturing the bar shape member 1 (Fig. (d)) having the opened hole 2 on its one end and the flange 3 provided on the other end, a raw material 11 (Fig. (a)) having a diameter which is larger than that of the stem portion 1a of the bar shape member 1 and is capable of forming the flange 3 by one cold forging process is subjected to an annealing treatment. After that, the raw material 11 is subjected to a cold forging process to obtain an intermediate material 15 (Fig. (b)) which has a large diameter portion 12 nearly equal to that of the diameter of the raw material 11 and a small diameter portion 13 nearly equal to that of the stem portion 1a. And then, the flange 3 is formed on the large diameter portion 12 side of the intermediate material 15 by a cold forging process (Fig. (c)), and then, the hole 2 is formed on the small diameter portion 13 side by a cold forging process (Fig. (d)). COPYRIGHT: (C)2006,JPO&NCIPI
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