| 摘要 |
PROBLEM TO BE SOLVED: To provide a drawing method which suppresses whirling or bending of a mother tube resulted in a drawing process to prevent increase in unevenness of a wall-thickness and bending of a drawn metal tube. SOLUTION: In the drawing method of the metal tube including: holding the mother tube in a state where an axial center of the mother tube and a drawing axial center are matched over the entire length of the mother tube and carrying out drawing using a die and a plug, the mother tube is attached to a mandrel movably in the drawing direction using two or more inner surface supports. When the length of the mother tube in the drawing direction from the die to the rear end of the mother tube is assumed as L<SB POS="POST">0</SB>, at least one of the inner surface supports is disposed at a distance from the die in a range of 1/2L<SB POS="POST">0</SB>to L<SB POS="POST">0</SB>, and further, when the distance in the drawing direction from the die to the inner support disposed nearest to the die from among the inner surface supports disposed in the range of 1/2L<SB POS="POST">0</SB>to L<SB POS="POST">0</SB>is assumed as L<SB POS="POST">1</SB>, drawing is carried out so that the other inner supports are disposed at a distance from the die in a range from 1/3L<SB POS="POST">1</SB>to 2/3L<SB POS="POST">1</SB>. COPYRIGHT: (C)2013,JPO&INPIT |
