PRODUCTION OF SEAMLESS HOT-STRAINED MACHINED 610×36,53×3200-3550 mm PIPES FROM "08Х18Н10Т-Ш" GRADE STEEL FOR NUCLEAR POWER PRODUCTION Russian patent published in 2014 - IPC B21B21/00 

FIELD: process engineering.

SUBSTANCE: invention relates to production of pipes for nuclear power engineering. ESR ingots are turned to blanks to bore through holes therein. Blank bottom and shrink ends are shaped to spherical outer surface. 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 0.25-0.50 of strain source length is decreased by 20-25%. Sleeves-blanks are heated from cold charge to ductility temperature and bored-rolled at screw rolling stand to rerolled sleeves-blanks. Straining rate V_ex. at exit of rerolled sleeve rear ends from tolls equal to strain source length is decreased to magnitude defined by equation $$V_{ex.}=\frac{{\mu }_c}{{\mu }_r}{V}_{r.stead.},$$ where µ_c us drawing at conversion of blanks to sleeves-blanks, µ_r is drawing at rolling-off of sleeves-blanks to rerolled sleeves-blanks, V_r.stead is roll rpm at steady rolling-off process. Rerolled sleeves-blanks are heat treated, bored and turned to commercial pipes.

EFFECT: higher mechanical properties, precision and surface quality.

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