METHOD OF PRODUCTION OF 325×31-60 mm SEAMLESS PIPES FOR STEAM BOILERS, STEAM PIPELINES AND MANIFOLDS OF PLANTS WITH CRITICAL AND SUPERCRITICAL STEAM PARAMETERS OF STEEL GRADE "10Х9МФБ-Ш" Russian patent published in 2015 - IPC B21B19/04 

FIELD: metallurgy.

SUBSTANCE: method of production of seamless commercial pipes 325×31-60 mm for steam boilers, steam pipelines and headers of units with high and ultra critical steam parameters out of ingots of electroslag remelting of steel grade "10Х9МФБ-Ш" includes melting by the electroslag remelting of the ingots, their turning to cakes 490×100×1750±50 mm, the cakes heating to plasticity temperature, pierced by a rotary piercer to shells from 500xint.290×2330-2450 to 500xint.240×2000-2100 mm using the mandrels with diameter from 275 to 225 mm with drawing-down from µ = 1.36 to µ = 1.17 and rise as to diameter 1.9-2.1%, shells rotting at tube-forming installation 8-16" with Pilger mills to commercial pipes 325×31×7100-7600-325×60×4000-4300 mm with drawing-down from µ = 4.54 to µ = 2.51 and swaging as to diameter 35.0%, cutting, heat treatment, etching, straightening, ultrasound testing and acceptance with diameter tolerance +1.25/-1.0% and wall thickness tolerance +15/-5%.

EFFECT: production of seamless commercial pipes with improved mechanical properties.

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