PRODUCTION SEAMLESS HOT-ROLLED 550×46-60 mm SIZE PIPES FOR BOILERS, STEAM LINES AND MANIFOLDS OF PLANTS WITH HIGH AND SUPERCRITICAL STEAM PARAMETERS MADE OF 10?9???-?-GRADE STEEL

摘要

FIELD: process engineering.SUBSTANCE: invention relates to metal forming, particularly to production of seamless hot-rolled 550x46-60 mm size pipes for boilers, steam lines and manifolds of plants with high and supercritical steam parameters made of "10?9???-?"-grade steel. The pipes are produced by ESR process to get the hollow ingots to be turned and bored to the hollow ingots-blanks of 660×out.340×2300±50 mm size. These are heated to 1170-1190°C, broached-rolled at the helical rolling mills on 475 mm and 450 mm diameter sleeves sized to 680×out.490×3170-3310-680×out.465×2860-2980 mm. Sleeves are rolled at PRU 8-16" with Pilger mills to commercial pipes sized to 550×46×5900-6200 - 550×60×5000-5300 mm. Seed ends and Pilger ends are cut by hot sawing. Said ingots-blanks are straightened at six-roll straightener, heat treated and subjected to ultrasound control and acceptance of commercial pipes.EFFECT: decreased metal input, higher efficiency of Pilger plant.1 tbl