FIELD: metallurgy.
SUBSTANCE: invention relates to production of 260-450×40-70 mm-hot-rolled conversion pipes for subsequent tooling into high-quality pipes sized to 245×19, 351×36, 415×50, 426×40, 426×50 and 436×45 mm from antirust steel or for rolling at step-rolled mill of conversion 250-440×30-60 mm-pipes with subsequent tooling for re-rolling at mills "ХПТ" into pipes of aforesaid sizes. Proposed method comprises producing flat ingots by electroslag remelting, producing 100±5.0 mm-diametre central bores in said ingots, heating them to plasticity temperature, piercing ingots at skew rolling mill into barrels, rolling of conversion pipes at step-rolled mill, cutting off step-rolled billets and seed ends by hot-cutting saw, pipe straightening, austenitisation, turning and boring to preset size with inner and outer surface roughness not exceeding Ra 10.0 mcm. Note here that conversion pipe rolling at step-rolled mill is performed for rerolling at "ХПТ" mills. Conversion hot-rolled pipes are bored and turned at servo-drive machine tools into conversion pipes with metal removal defined by expressions ΔS"В.П."=KΔS"В.С.", ΔS"Н.П."=K1ΔS"Н.С.", where ΔS"В.П." is metal removal amount in boring for rerolling, mm; ΔS"В.С." is removed metal layer thickness in boring for finished size, mm; K=(0.5 - 0.6) is coefficient of metal layer thickness reduction with its larger magnitudes relate to large diametre pipes; ΔS"Н.П." is metal layer thickness in boring for temporary rerolling, mm; ΔS"Н.С." is removed metal layer thickness in boring for finished size, mm; K1=(0.4 - 0.5) is coefficient of metal layer thickness reduction with its larger magnitudes relate to large diametre pipes.
EFFECT: higher quality, reduced costs.
4 cl, 1 tbl
