PROCESSING LINE FOR MANUFACTURING SEAMLESS STEEL PIPE AND METHOD OF MANUFACTURING SEAMLESS PIPE FROM HIGH-STRENGTH STAINLESS STEEL FOR OIL WELLS IN PROCESSING LINE Russian patent published in 2018 - IPC C21D8/10 B21B19/00 C22C38/00 C21D9/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy. To improve the low-temperature toughness of steel, the processing line comprises a heating device, a piercing device and a rolling mill, as well as a cooling system which is arranged, in one embodiment, between the heating device and the piercing device, and in the other – between the piercing device and the rolling mill. Thermostat is positioned at the exit side of the rolling mill. Method is carried out on a processing line, wherein the heated steel having the chemical composition of high-strength stainless steel or a hollow steel tube formed by piercing the heated steel is cooled to a temperature of 600 °C or higher, with an average cooling rate of 1.0 °C/s or higher, with the provision in the steel and hollow steel pipe of phase distribution in a nonequilibrium state, and then a seamless pipe having a predetermined size is formed from the hollow steel pipe.

EFFECT: processing enables to obtain a fine microstructure of the steel, even with less hot processing, wherein the thick-walled steel pipe has an improved low-temperature impact strength even at the centre of the wall.

12 cl, 3 tbl, 2 dwg