MARTENSITIC-FERRITIC STAINLESS STEEL, MANUFACTURED PRODUCT AND METHODS OF THEIR APPLICATION Russian patent published in 2019 - IPC C22C38/44 C22C38/46 C22C38/48 C22C38/50 C21D8/02 C21D8/10 

FIELD: chemistry.

SUBSTANCE: invention relates to martensite-ferritic stainless steel with high corrosion resistance, finished product and methods of making stamped or rolled products or rolled products and seamless pipes of martensite-ferritic stainless steel. Steel has martensite-ferritic structure and chemical composition, wt. %: C from 0.005 to 0.030, Si from 0.10 to 0.40, Mn from 0.20 to 0.80, P maximum 0.020, S maximum 0.005, Cr from 13 to 15, Ni from 4.0 to 6.0, Mo from 2.0 to 4.5, V from 0.01 to 0.10, Nb from 0.01 to 0.50, N from 0.001 to 0.070, Al from 0.001 to 0.060, Ti from 0.001 to 0.050, Cu from 0.01 to 1.50, B below 0.01, O maximum to 0.005, rest - Fe and unavoidable impurities caused by industrial treatment. Steel has local corrosion parameter (LCP) from 3.2 to 6.2, determined by the equation: LCP = 0.500 × % Cr + 1.287 × % Mo + 1.308 × % N - 5.984. In methods of producing ready products, heating temperature at a given stage satisfies the equation: T - 16.9 × % Cr - 49.9 × % Mo > 535.

EFFECT: technical result consists in improvement of corrosion resistance of steel containing fewer phases having harmful effect.

23 cl, 2 tbl, 7 dwg