PRODUCTION OF SEAMLESS HOT-WORKED MACHINED 610×36,53×3000-3450 mm FROM 15X5M-GRADE STEEL FOR REFINERY COMMUNICATIONS WITH STRINGENT REQUIREMENTS TO GEOMETRICAL SIZES

摘要

FIELD: process engineering.;SUBSTANCE: invention relates to metallurgy. Forged pieces sized to 650×1630±50 mm are turned to billets to bore central holes therein. 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 30-40%. Blanks are heated to ductility temperature and pierced at screw rolling stand to sleeves-blanks. Rolling rate V_roll.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: $V_{roll.out.}=\frac{{\mu }_p}{{\mu }_r}{V}_{roll.est.},\mathop{\mathrm{image}}$ where µ_p is drawing at piercing to sleeve-blanks, µ_r is drawing at rolling of sleeves-blanks to rerolled stock, V_roll.est. is roll rpm at established rolling. Rerolled sleeves-blanks are heat treated, bored and turned to commercial pipes.;EFFECT: higher mechanical properties and precision of pipe sizes.;1 tbl