METHOD OF COMBINED PIPE END UPSETTING Russian patent published in 2016 - IPC B21J5/08 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to metallurgy and can be used in production of oil and gas pipes with upset ends. Heated pipe end is deformed at press in working cavity of die by male die in several operations. At that, outer transition zone and elongated inner transition zone are produced on pipe. Inner transition zone is formed in series along circular sections with reduction from first operation to each subsequent operation of puncheon stroke and heated pipe section length. Besides, on every next operation matrix is used with increased inner diameter of working cavity and punch with decreased outer diameter of working surface.

EFFECT: ruled out occurrence of critical deformations and loss of upset pipe end stability.

1 cl, 1 dwg