METHOD OF PRODUCING SEAMLESS COLD-DEFORMED COUPLING PIPES OF 88,9 × 6,45 mm SIZE FROM CORROSION-RESISTANT ALLOY OF "ХН30МДБ-Ш" GRADE Russian patent published in 2017 - IPC B21B19/06 

FIELD: metallurgy.

SUBSTANCE: method of producing seamless cold-shaped pipes of 88.9×6.45 mm from corrosion-resistant alloy "ХН30МДБ-Ш" includes casting of centrifugal steel hollow billet of 440×100×2300 50 mm size, which are bored and faced to hollow machined billets of 430×85×2300±50 mm size, heated to the temperature of 1180-1200°C, rolled on pilgrim mill to hot-rolled pipes of 260×30×9000-9400 mm size which cut into two tubes-billets of equal length, bored and faced to the disposal pipes of 245×16×4500-4700 mm sizes and rolled on cold-pilgering mill on routes: 245×16×4500-4700 - 219×13×5900-6200 - 168×10×9800-10200 - 140×8×14450-15050 mm, pipes of 140×8×14450-15050 mm sizes are cut into three equal parts and rolled on cold-pilgering mill to the salable pipes of 88.9×6.45×9350-9750 mm size with relative reduction of cross-sectional area on wall of δ₁=18.8%, δ₂=23.1%, δ₃=20.0%, δ₄=25.8% and reduction ratios μ₁=1.37, μ₂=1.70, μ₃=1.50, μ₄=1.99.

EFFECT: reduction of metal consumption coefficient.

2 cl, 1 tbl