METHOD OF MANUFACTURE OF SEAMLESS PIPE AND CONTINUOUS MANDREL FOR ITS REALISATION Russian patent published in 2011 - IPC B21B17/00 

FIELD: technological processes.

SUBSTANCE: invention relates to the method and a continuous mandrel for manufacturing of a seamless pipe. The method includes billet clamping and preliminary formation of a pipe wall on a mandrel by alternate deformation at two sides with rotation of clamped areas at the angle of 90° to each other, formation of a round profile of the pipe with simultaneous break of the pipe wall from the surface of the mandrel by deformation of the pipe profile at four sides in the same directions as in the previous clamping of pipe walls, pipe calibration at the mandrel by alternate deformation at two sides with rotation of clamped areas at the angle of 90° relative to each other and at the angle 45° relative to previous directions of the clamping zones. After calibration the final formation of the round pipe profile is done with simultaneous break of the pipe wall from the surface of the mandrel by deformation of the pipe profile at four sides at the same directions as during calibration. A continuous mandrel comprises a clamping section, which includes two-high stands, rollers of which are arranged at 90° to each other, and a calibrating section, including two four-high stands. Rollers of the first four-high stand are arranged in the same directions as the rollers of the clamping section. The rollers of the second four-high stand are turned at the angle of 45° relative to the rollers of the four-high stand. Between four-high stands there are two two-high stands, rollers of which are turned at 90° to each other and at 45° relative to rollers of the clamping section.

EFFECT: increased quality of produced pipes by reduced difference in wall thickness and elimination of damage of pipe inner surface as a mandrel is withdrawn from it.

2 cl, 2 dwg