METHOD FOR PRODUCING HOT ROLLED COMMERCIAL AND CONVERSION TUBES OF LARGE AND MEAN DIAMETERS OF HARD-TO-FORM STEELS AND ALLOYS IN TUBE ROLLING PLANTS WITH PILGER MILLS

FIELD: rolled tube production, possibly in tube rolling plants with pilger mills. ^ SUBSTANCE: method comprises steps of casting hollow ingots with height 1750 - 2100 mm in electroslag refining plants; turning and boring ingots for removing scale and micro-cracking till diameter 400 - 620 mm at relation of diameter to wall thickness D/S = 3.0 - 4.0 whose larger values correspond to ingot-sleeves of less diameter; heating ingots till yielding temperature and rolling them in skew rolling mil to sleeves at elongation factors 1.5 - 1.7 whose larger values correspond to large -diameter sleeves. Sleeves rolled at elongation factors 1.5 - 1.6 are rolled in pilger mills to conversion tubes and sleeves rolled at elongation factors 1.6 - 1.7 are rolled to commercial tubes. Invention provides increased by 8.0 -12.0% length of commercial and conversion tubes. ^ EFFECT: lowered metal consumption, elimination of one operation of heating and piercing drilled ingots to sleeves, increased length of conversion and commercial tubes depending upon their assortment. ^ 2 cl, 1 tbl