METHOD forward or backward EXTRUSION metal tubes, cores for EXTRUSION metal pipe PRESS EXTRUSION metal pipes and extruded metal pipe

摘要

1. A method for the direct or reverse pressing of metal pipes, in which a heated metal bar (5) to produce the metal tube (9) is extruded through a press matrix (2) using a mandrel (6), said mandrel (6) comprises two surfaces pressing (63, 64) which are offset relative to each other in the axial direction and have different radial characteristics and is capable of finding in an axial direction relative to said press matrix (2) in two positions of the pressing, while in the first upomyan ies two pressing positions on the workpiece, compressible from said metal billet (5) into said metal tube (9), ensuring its molding, act first of said two press surfaces (63, 64), and the second of said two pressing positions on it affect the second of said two press surfaces (63, 64), characterized in that during the movement of the mandrel (6) relative to the press matrix (2) from its first pressing position to its second position for pressing said workpiece provide support from the mandrel at the height of the axis of the press matrix (2) .2. Method of pressing metal tubes according to claim. 1, characterized in that the support for the workpiece provided only after a preform forms a free surface relative to a mandrel (6) .3. Method of pressing metal tubes according to claim. 2, characterized in that the support for the workpiece provided only when said free surface is displaced in the direction of the mandrel (6) .4. Dorn (6) for pressing the metal tube (9) comprising two pressing surfaces (63, 64) which are offset relative to each other in axial