| 摘要 |
PROBLEM TO BE SOLVED: To provide an ironing method for a cup-shaped member capable of suppressing a crack during the working even though heat treatment for softening a preliminary molded article to enhance deformability thereof is omitted or simplified. SOLUTION: In the ironing method, the preliminary molded article 10 is axially passed through a die 14 together with a punch 12 in a state that the punch 12 is inserted into a center hole of a preliminary molded article 10 formed by preliminarily molding a steel into a cup shape in advance. The outer peripheral part of the molded article 10 is subjected to ironing to be thickened to the punch 12 side. The finishing work of outer and inner peripheral shapes is carried out, wherein the die angleαof the die 14 is set to 12.5°or less, or the reduction of area is set to 5.5% or less. COPYRIGHT: (C)2007,JPO&INPIT
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