| 摘要 |
An ironing mold according to the present invention is provided with a punch, and a die which forms a pushing hole with respect to the punch. When the skewness Rsk of a surface treated metal plate is less than -0.6 and no less than -1.3, then the curvature radius of a shoulder portion of the die and a clearance between a radius end and the punch are determined such that Y, which is expressed by {(t re - C re )/t re } × 100, and X, which is expressed by r/t re , satisfy 0 < Y ‰¤ 18.7X - 6.1, X satisfies X ‰¥ 0.6 and r satisfies r ‰¤ 0.5h. |
