PRODUCTION OF SEAMLESS HOT-ROLLED, SMOOTH, THREADED, BOILER-ROOM, THICK-WALL AND SPECIAL-PURPOSE PIPES 273-630 MM IN DIAMETER AT PRU WITH PILGER MILLS

摘要

FIELD: process engineering.SUBSTANCE: invention relates to pipe rolling. Continuously-cast, forged billets, solid and hollow ESR 400-650 mm-sized ingots-billets are heated to ductility temperature. Threes are broached at helical rolling mills at short mandrel to sleeves or sleeve-blanks at one stand. Sleeves-billets are broached-rolled at short mandrel at second helical rolling mill without heating or after reheating. Sleeves are blown and transferred to Pilger mills. Sleeves are rolled in rolls with body diameter varying from 975 to 1250 mm with multiple 25 mm increase per every next diameter of the size spectrum pipes with gages of 280-562 mm at mandrels with taper of 1.0-6.0 mm subjected to the steel linear expansion factor. Pilger heads and seed ends, process wastes, are removed. Pipes are cut to multiple lengths by hot cutting saws and heated in continuous sectional furnaces or furnaces with walking beams. Pipes are gaged and carried on conveyors with rotation. Pipes are straightened in six-roll straightening machines, inspected and subjected to further machining.EFFECT: lower metal input.8 cl