METHOD OF HIGH-STRENGTH PIPES RECEIVING Russian patent published in 2009 - IPC B21B19/04 

FIELD: metallurgy.

SUBSTANCE: invention concerns manufacturing technique of hot-rolled seamless pipes by means of helical rolling. Particularly it concerns method of high-strength pipes receiving. Method includes feeding of heated blank to working roll, turned through feed angle not less than 12 degrees, toe angle 6-10 degrees, piercing of blank by mandrel, installed in roll opening, formed by rolls with conical entrance angle of rolls 4-8 degrees and guiding tool. After helical piercing of blank into sleeve it is accelerated cooled till the department temperature and accelerated heated in induction furnace. Then it is implemented helical rolling of heated blank in two-high stand in the direction, matching with direction of piercing, with keeping of roll pass design, rolling-off angle and conical entrance, the same as at piercing. Rolls feed angle fixed 0.5-0.7 of rolls feed angle at piercing. Rolling-off is implemented on mandrel of higher diameter than at piercing, with pipe wall degree of strain at the section of rolling-off by roller in the range 25-70%.

EFFECT: it is provided mechanical properties increasing of pipe metal along the tangential lines at the expense of additional helical involution of metal texture, at keeping of high mechanical properties lengthway.

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