METHOD OF PRODUCTION OF SEAMLESS HOT-ROLLED LARGE- AND MEDIUM-DIAMETER PIPES FROM STEEL AND ALLOYS AT PIPE ROLLING PLANTS WITH PILGRIM MILLS FROM TUBULAR BLANKS

摘要

FIELD: process engineering.SUBSTANCE: invention relates to metallurgy. Ingots or blanks are heated to ductility temperature, pieced at cross-rolling mill to sleeves with ID larger that mandrel diameter or to tube blanks. First and second bottle conversions are fitted on mandrels and deformed to commercial pipes at preset magnitude of feed. Sleeves are subjected to rejection. After 2-3-fold heating, sleeves not fitted on mandrel or those with flaws are rolled at smaller-diameter to tubes with thicker walls. Sleeves with increased curvature are rolled, reduced to blanks at smaller-diameter mandrel at draw factor of 0.95?µ?0.98.Sleeves are pierced with elevation in diameter equal to amount of rolling for increased curvature tubes, fitted on mandrel and rolled to preset-diameter commercial tubes at design pass.EFFECT: commercial tubes from rejected stock, lower metal input.2 cl, 1 tbl