| 摘要 |
PROBLEM TO BE SOLVED: To provide a dice for cold drawing of a pipe, which enables the drawing to be performed without causing cracks.SOLUTION: In a dice 1 for cold drawing, a bearing diameter and a tip diameter of the dice satisfy the following expression (1), and an external radius working ratio &Dgr;r/L of immediately before the bearing satisfies the following expression (2), where &Dgr;r is an external radius working amount defined by (internal diameter of the dice in 5 mm position immediately before the bearing - a bearing diameter)/2 (mm), and L is a distance between the bearing and an external radius working amount set portion (for example, 5 mm). The expressions are: 0.80<bearing diameter/tip diameter<0.93...(1); and 0.03≤&Dgr;r/L≤0.26...(2). Particularly, the dice exhibits an effect for drawing of hard-to-work materials such as two-phase stainless steel or high alloy. |
