METHOD FOR STRAIGHTENING ENDS OF SEAMLESS PIPES Russian patent published in 2021 - IPC B21C37/30 

FIELD: metal processing.

SUBSTANCE: invention relates to the field of metal processing by pressure, in particular pipe production. A method for straightening ends of seamless pipes with a diameter of 114-508 mm on a press includes feeding a pipe to its initial position, rigid fixation of the pipe in clamps, pressing a calibration tool into an inner cavity of the pipe with subsequent removal of the tool. The straightening is carried out in two stages using a non-circular tool, which, depending on the diameter of the pipe, is 3-8 axisymmetric sectors adjustable in a radial position with a radius of curvature of 0.7-0.95 of the nominal inner radius of the pipe. Each sector has cylindrical working and conical input and output parts with angles of 4-15°. The second stage is performed by the mentioned tool, turned relatively to the longitudinal axis of the tool by an angle Δα, defined in degrees as: , where n is the accepted number of sectors of the tool.

EFFECT: straightening of ends of pipes of a wide range of initial ovality is provided.

1 cl, 3 dwg, 1 tbl