PIPE EXPANSION METHOD Russian patent published in 2021 - IPC B21D31/04 B21C37/30 

FIELD: metal processing.

SUBSTANCE: invention relates to the field of metal processing by pressure; it can be used for calibration of welded pipes of large diameter. A pipe is positioned relatively to an expander and its step distribution is performed along its entire length. An expander having a head with segments, a device for measuring a deviation in the shape of the pipe before its distribution, during distribution and after distribution, and a device for measuring the load on each segment of the head during distribution are used. Distribution at each step is carried out by plastic deformation of a pipe section with its rotation at an angle that provides overlap of non-contact zones between segments of the expander head. At each step of distribution, the shape of the pipe is determined before distribution, and a distribution mode is corrected, if actual pipe parameters deviate from the specified ones. In this case, sections of the pipe are obtained that have an equal diameter and an equal perimeter in length after unloading the pipe.

EFFECT: quality of obtained pipes is improved, equipment setup time is reduced and load on the expander is reduced.

4 cl, 4 dwg