METHOD OF FABRICATION OF SEAMLESS PIPES WITH SIZES 325×26-45 mm FOR BOILERS, STEAM LINES AND MANIFOLDS OF UNITS WITH HIGH AND SUPERCRITICAL STEAM PARAMETERS FROM "10Х9МФБ-Ш" BRAND STEEL Russian patent published in 2015 - IPC B21B19/00 B21B19/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to pipe rolling, and namely to the method of producing seamless pipes with sizes 325x26-45 mm for boilers, steam lines and manifolds of units with high and supercritical steam parameters from "10Х9МФБ-Ш" brand steel.. The method includes the smelting of hollow ingots by electroslag remelting, the drilling and machining of hollow ingots into hollow work piece ingots with the size 500xouter.160×2100±50, heating of work piece ingots in the continuous furnace up to the temperature 1160-1180°C, an piercing-expansion in the slant rolling mill into bushes with the size 500×out.290×2700-2860 mm or 500×out.275×2580-2710 mm on mandrels with the diameter 275 and 260 mm with draw formings with the sizes µ = 1.33 and µ = 1.26 same with the outer diameter, rolling of bushes on TPU 8-16" by Pilger mills into commodity pipes with the sizes 325×26×11000-11800 - 325×35×8800-9400 mm and 325×36×8500-9100 - 325×45×7900-8300 mm with draw formings, respectively, from µ = 4.89 up to µ = 3.81 and from µ = 3.91 up to µ = 3.06, crimping along the diameter Δ = 34.0% and with supply of sleeves to the deformation centre, respectively, m = 20-24 and m = 22-26 mm, cutting of process waste in the form of the seed ends and the Pilger heads by a hot cutting saw, levelling, heat treatment, if necessary repair, ultrasonic inspection and acceptance of pipes with the diameter tolerance +1.25/-1.0% and wall thickness +20.0/-5.0%.

EFFECT: decrease of metal consumption coefficient and increase of productivity with pilger mills.

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