METHOD OF PRODUCING LARGE SIZE SEAMLESS TUBES Russian patent published in 2012 - IPC B21J5/10 B21K21/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metal deformation processes and can be used for production of large seamless pipes on hydraulic presses. The ingot is calibrated by pushing it through a ring matrix. The matrix is made by the conical piercing container lower base diameter. At the same time the bar bottom part is deformed to form a mark in the centre. Then the bar is pressed in a conical piercing container on the side of the bar mark when it is centred along the container axis. At the same time in the centre of the pressed bar a mark is made for a piercing punch. Then at least one piercing is made on the side of the pressed bar bottom part. The resultant pierced bar is subjected to pulling.

EFFECT: reduced variation in wall thickness in the received tubes, reduced metal consumption, and complexity of manufacturing and expansion of assortment of tube lengths.

4 dwg, 2 ex