METHOD OF PRODUCTION OF 325×16-30 mm SEAMLESS PIPES FOR STEAM BOILERS, STEAM PIPELINES AND MANIFOLDS OF PLANTS WITH CRITICAL AND SUPERCRITICAL STEAM PARAMETERS OF STEEL GRADE '10-9¦L+-+'

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to the method of production of seamless commercial pipes 325×16-30 mm for steam boilers, steam pipelines and headers of units with high and ultra critical steam parameters out of steel grade "10Х9МФБ-Ш". The method 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 500×int.315×2550-2700 to 500×int.290×2330-2450 mm using the mandrels with diameter from 300 to 275 mm with drawing-down from µ=1.50 to µ=1.37 and rise as to diameter 1.9-2.1%, shells rotting at tube-forming installation 8-16" with Pilger mills to commercial pipes 325×16×15900-17000 - 325×30×9300-9900 mm with drawing-down from µ=7.62 to µ=4.69 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 +20/-5%.;EFFECT: production of seamless hot-rolled pipes with improved mechanical properties.;2 tbl