HIGH-STRENGTH LOW-ALLOY NITROGEN-CONTAINING MARTENSITIC STEEL Russian patent published in 2017 - IPC C22C38/18 

FIELD: metallurgy.

SUBSTANCE: steel contains, wt %: carbon 0.05-0.10, silicon 0.2-0.4, manganese 0.5-1.0, chromium from 2.5 to less than 3.0, nitrogen from 0.15 to less than 0.2, the rest is iron and impurities.

EFFECT: increased strength indicators due to presence of nitrogen in αsolid solution and further hardening by particles of chromium carbonitrides released during tempering, and satisfying the ductility and toughness characteristics due to the presence of small amount of retained austenite in the structure located between the martensite crystals.

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