METHOD OF PRODUCING STEEL PIPE Russian patent published in 2018 - IPC B21D3/14 B21C37/08 B21D39/20 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to a method for manufacturing a steel pipe. Method includes performing a first expansion operation on steel pipe with an expansion rate ranging from a lower limit, at which a predetermined roundness is reached, to an upper limit at the maximum value of the expansion rate, at which the load on the expansion device is within the permissible range. Method includes a second expansion operation performed after the first expansion operation, with an expansion rate at which the diameter of the steel pipe reaches a predetermined value. Expansion rate for the first expansion operation ranges from 0.3 % to less than 0.6 %.

EFFECT: roundness of the steel pipe is improved without increasing the load on the expansion device.

1 cl, 4 dwg