METHOD FOR PRODUCING IN TUBE ROLLING PLANTS WITH PILGER MILLS SEAMLESS HOT DEFORMED LARGE- AND MEAN-DIAMETER TUBES FOR STEAM BOILERS, STEAM PIPES AND COLLECTORS OF PLANTS WITH HIGH AND SUPERCRITICAL PARAMETERS OF STEAM

摘要

FIELD: rolled tube production, namely production of seamless hot deformed tubes from solid and hollow ingots of electroslag refining, possibly in tube rolling plants with pilger mills having also helical rolling mills. ^ SUBSTANCE: method comprises steps of melting ingots in electric and Martin furnaces on base of direct reduction at using processes for treating with liquid slag in ladle, electroslag refining and direct reduction of steels of given (in specification) kinds; forging ingots to forged pieces with forging ration 2 - 3 depending upon steel kind; continuously casting steel of given (in specification) kinds treated with synthetic slag; continuously casting steels of given kinds from evacuated or non-evacuated metal treated with synthetic slag for further forging them to blanks with forging ration no less than 1.5; cutting off ends of forged pieces at removing bottom and shrinkage portions; melting ingots of given kinds of steel by means of electroslag refining; mechanically working forged pieces and ingots of electroslag refining to predetermined-diameter blanks with allowance +10/-5 mm; heating ingots and blanks till plastic temperature depending upon kinds of steel; piercing them in skew rolling mills on mandrels whose diameter depend upon geometry size of sleeves; rolling tubes in pilger mills at elongation values depending upon diameter and wall thickness; calibrating and straightening tubes. Ingots of electroslag refining of given kinds of steels are heated till plastic temperature without drilling central opening in them; before piercing centering them from bottom end along axis; piercing in skew rolling mills to sleeves and rolling them in pilger mills to tubes of predetermined size. Hollow ingots of electroslag refining are used as conversion tube blanks of steel of given kinds. Hollow ingots of electroslag refining of given kinds of steel are heated till plastic temperature and rolled in pilger mills to tubes. Hollow ingots of electroslag refining of given kinds of steel are heated till plastic temperature and rolled in pilger rolling mills to tubes depending upon diameter and wall thickness. ^ EFFECT: improved manufacturing process due to lowered metal consumption for conversion of solid or hollow ingot of electroslag refining to boiler tube, reduced cost of boiler tubes. ^ 3 cl, 1 tbl