PRODUCTION OF SEAMLESS HOT-ROLLED PIPES AT PRU WITH PILGER MILLS Russian patent published in 2014 - IPC B21B19/04 

FIELD: metallurgy.

SUBSTANCE: process comprises heating of ingots-billets to ductility temperature and their piercing at helical rolling mill to taper sleeves with different rolling-outs with subsequent rolling at Pilger mill to pipes at constant feed to straining zone and constant rolling-out. Pilger heads are withdrawn from sleeves to cut pipe units to pipe lengths. Process wastes, that is Pilger heads and seed ends, are cut off by hot cutting saws. Fixed feed and ruled out collapse of sleeve rear ends at Pilger rolling are ensured by billets are pierced to sleeves shaped to hollow truncated cone with larger base at sleeve front end and smaller base at rear end. This is done ay increase in rolling-out by smooth convergence of working rolls relative to rolling axis from piercing start to end by regulated magnitude L. Rolling at Pilger mills to pipes is done by feeding the sleeve front ends at constant feed and variable rolling-out so that Pilger heads are formed from sleeve rear ends.

EFFECT: lower metal input, higher efficiency of Pilger mills.

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