CORROSION RESISTANT STEEL FOR FLOW AND CASING STRINGS Russian patent published in 2011 - IPC C22C38/28 

FIELD: metallurgy.

SUBSTANCE: steel contains carbon, silicon, manganese, chromium, molybdenum, vanadium, niobium, aluminium, zirconium, iron and unavoidable impurities at following ratio of components, wt %: carbon 0.03 - 0.12, silicon 0.17 - 0.40, manganese 0.40 - 0.70, chromium 1.20 - 2.00, molybdenum 0.15 - 0.30, vanadium from 0.04 to less, than 0.05, niobium 0.03 - 0.06, aluminium from over 0.05 to not over 0.06, zirconium 0.01 - 0.07, iron and unavoidable impurities - the rest.

EFFECT: best relationship between strength characteristics and corrosion resistance facilitating usage of steel at fabrication of flow and casing strings operating under corrosive mediums containing H₂S and CO₂.

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