STEEL, ARTICLE FROM STEEL AND METHOD OF ITS PRODUCTION Russian patent published in 2019 - IPC C22C38/58 C22C38/54 C21D8/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of martensite-austenitic grade stainless steel intended for production of high-loaded parts working for torsion and bending under dynamic load in aggressive acidic media with high content of alkali and alkali-earth metal salts, salts of nitric and sulfuric acids, chlorine ions, hydrogen sulphide. Steel contains components, wt%: carbon 0.005÷0.07; silicon not more than 1.0; manganese not more than 1.8; chromium 12.5÷17.0; nickel 2.0÷8.0; molybdenum + 3 × tungsten 0.05÷4.5; nitrogen 0.005÷0.15; boron 0.0001÷0.01; at least one of components: aluminum, titanium, niobium – 0.01÷5.0; iron and impurities – balance. At that (Mo+3·W)≤(k₁-Cr·a₁), where k₁=15.9, a₁=0.87, as well as Ni=k₂-a₂·(Cr+Mo+W), where k₂=16.25±1.5, a₂=0.7±0.1. Method of article manufacturing includes casting into ingots or continuously-cast billets, rolling and thermal treatment.

EFFECT: high ductility, corrosion resistance in hydrogen sulphide media with simultaneous improvement of stability of mechanical properties of steel.

25 cl, 2 tbl