| 摘要 |
The invention relates to a method for producing cylindrical tubes by plastically deforming a hollow-cylindrical slug (3) by extrusion to a cylindrical tube. According to the inventive method, the slug is introduced into a substantially cylindrical drawing die (2) up to a stop (4). A drawing mandrel (6) that has an outer diameter that is larger than the inner diameter of the slug is moved in the drawing die through the hollow space of the slug. Due to the flowing of the slug material pressed by the drawing mandrel, the length of the slug increases while the cross-section of the wall of the slug is reduced. The inner diameter of the drawing die and the outer diameter of the slug are chosen such that there is a radial play between the drawing die and the slug. When the drawing mandrel is drawn through the drawing die, the wall of the slug is radially pressed against the die, thereby expanding the outer diameter of the slug. |
