NITROGEN-BEARING CORROSION RESISTANT STEEL FOR MANUFACTURE OF OIL-GAS PIPES Russian patent published in 2012 - IPC C22C38/26 

FIELD: metallurgy.

SUBSTANCE: steel contains the following ingredients, wt %: carbon of not more than 0.05, manganese of not more than 0.60, silica of not more than 0.60, chrome 1.50 - 3.00, vanadium 0.06 - 0.12, niobium 0.06 - 0.12, molybdenum 0.20-0.40, aluminium 0.025-0.40, rare-earth elements of not more than 0.05, nitrogen 0.10-0.30, iron and inevitable impurities are the rest.

EFFECT: obtaining the required strength and viscoplastic characteristics at high resistance to sulphide, carbon-dioxide and bacterial corrosion.

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