JPS54159366A - Forging method with multistage anvil - Google Patents

Abstract

PURPOSE: To prevent the jutting of the inner metal outside, to maintain the constant thickness of the fine structure in the surface layer, and to improve the forging effect for the inner metal, by employing the multistage anvil provided with steps, for executing the hot forging work.

CONSTITUTION: If the anvil's effective breadth 3 is made large so as to make the ratio of this effective breadth 3 to the blank's thickness 4 to be above 0.6, the forging effect on the inner metal of the blank is assured, however, the local strain in the surface layer at the point of the border 6 between the blank and the tool becomes large, so that the inner coarse structure juts out into the surface layer. On the contrary, if above ratio is reduced to under 0.3 by reducing the breadth 3, the local strain in the surface layer is restrained, however, the inner forging becomes unsatisfactory. Moreover, if the draft percentage is increased, the surface strain increases. On purpose to dissolve these negative effects, the multistage anvils 7, 9, are employed; in which, the anvil's effective breadth is maintained small respectively. the draft of all stages is simultaneously executed, and the effectcan be obtained similarly to the case that the range of draft is made large as a whole. According to this method, the number of times of the draft is reduced, and the good working efficiency can be obtained.

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