JPS5656750A - Forging method - Google Patents

Abstract

PURPOSE: To prevent the occurrence of internal void defects by specifying anvil ratio, anvil tap shape, draft, etc. in a restrained forging method.

CONSTITUTION: At the time of forging the work M of a diameter D by upper, lower anvils 1, 2 of a width B, an anvil ratio (D/B) is made 1.5W2.0. Below and above these, the width B becomes wider respectively, and this causes lack of pressing capacity and the lack of central part forging. The sizes (a), (b) of the two-step cuts of anvil tap corners are made 30mm≤a≤60mm, 130mm≤b≤200mm. The sizes (a), (b) below or above these have the drawbacks that flaws are tend to be produced and the width B becomes wide. In addition, the 1st, 2nd angles α, β of inclination are made 10°≤α≤20°, β=45°. The angle α below or above these has the drawbacks that the width B becomes wide and flaws are tend to be produced. On the other hand, a draft is made 15W20%, and forging is performed by 1 heat 2-time feeding. The draft above these associates problems such as flaws and lack of pressing capacity.

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