METHOD OF MANUFACTURING SEAMLESS COLD PIPES OF SIZE 168,3X10,6X8,900-9,100 MM OF CORROSION-RESISTANT ALLOY OF "ХН30МДБ" GRADE Russian patent published in 2017 - IPC B21B21/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the manufacturing method of seamless cold-deformed pipes of size 168.3×10.6×8,900-9,100 mm from corrosion-resistant alloy of "ХН30МДБ" grade. The method includes casting of hollow centrifugaly cast billets with a size of 470×115×2,500±50 mm, boring and turning them into mechanically machined billets of size 460×100×2,500±50 mm, heating to the plasticity temperature, rolling on a pilgrim mill on conical mandrels with a diameter of 235/241 mm in the caliber 332 mm with a drawing factor μ=2.80 into rerolled hot-rolled pipes of 325×45×5,700-5,900 mm, boring and turning of rerolled hot-rolled pipes into pipe billets with dimensions of 310×30×5,700-5,900 mm, rolling on the HPT mill along routes 310×30×5,700-5,900 - 273×23×8,100-8,300 - 219×16×14,100-14,400 mm, cutting of rerolled pipes with size 219×16×14,100-14,400 mm into three pipes of equal length and rolling them on a HPT mill into commodity pipes with size 168.3×10.6×8,900-9,100 mm with relative wall compressions, correspondingly, δ_1m=23.3%, δ_2m=30.4%, δ_3m=33.8% and drawing factor μ, correspondingly, 1.46, 1.77, 1.94.

EFFECT: reduced metal consumption.

1 tbl