METHOD OF PRODUCING HIGH-STRENGTH CORROSION-RESISTANT HOT-ROLLED STEEL Russian patent published in 2017 - IPC C21D8/02 

FIELD: metallurgy.

SUBSTANCE: steel billet containing, wt %: carbon 0.03-0.05, silicon 0.5-0.8, manganese 0.4-0.7, sulfur not more than 0.01, phosphorus 0.005-0.015, aluminium 2.1-5.9, chromium 3.0-10.0, nickel 0.01-0.03, molybdenum 1.01-2.0, titanium 0.01-0.03, vanadium 0.05 -0.07, niobium not more than 0.06, nitrogen 0.005-0.05, iron and unavoidable impurities are the rest, with the total content of chromium and aluminium being [Cr+Al] = 5-15 wt %, being heated in the range of 1100°C to 1200°C, and rolling is carried out in several stages with a reduction ratio of 10 to 25% in each step, and rolling is completed at a temperature of 700-800°C and the strip is cooled to ambient temperature, the time between the two subsequent rolling stages not exceeding 9 s.

EFFECT: increasing strength and corrosion resistance.

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