PRODUCTION OF SEAMLESS HOT-STRAINED MACHINED 610(36,53(3000-3400MM-PIPES FROM "08-18=10T-+"-GRADE STEEL FOR NUCLEAR POWER PRODUCTION Russian patent published in 2015 - IPC B21B21/00 

FIELD: process engineering.

SUBSTANCE: invention relates to pipe rolling. ESR blanks are heated to ductility temperature and pierced at screw rolling stand to sleeves-blanks. Rate of forming of the ends of sleeves-blanks at exit of rolls for the length of 0.50-0.75 of strain source length is decreased by 25-40%. Sleeves-blanks are heated from cold charge to ductility temperature and bored-rolled at screw rolling stand to rerolled sleeves-blanks. Rolling rate V_out of lengthwise sleeves-blanks rear ends at roll outlet by length equal to 0.75-1.0 of deformation source is decreased and its magnitude is defined by expression: $$V_{out.}=\frac{{\mu }_p}{{\mu }_r}{V}_{r.spec.}$$ , where µ_p is drawing at piercing to sleeve-blanks, µ_r is drawing at rolling of sleeves-blanks to rerolled stock, V_r.spec. is roll rpm at rolling. Rerolled sleeves-blanks are heat treated, bored and turned to commercial pipes.

EFFECT: higher mechanical properties and precision of pipe sizes.

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