ROD FROM HIGH-STRENGTH LOW-ALLOY MARTENSITIC NITROGEN-CONTAINING STEEL Russian patent published in 2025 - IPC C22C38/58 C22C38/46 C22C38/44 C21D8/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to rods from high-strength martensitic steel used for production of high-loaded parts and structures. Bar is made of steel containing components at the following ratio of components, wt.%: carbon – 0.27-0.45, nitrogen – 0.13-0.30, chrome – 2.0-5.00, nickel – 1.0-3.00, manganese – 1.0-3.00, vanadium – 0.05-0.50, molybdenum – 0.5-2.00, silicon – 0.10-0.40, calcium – 0.005-0.010, barium – 0.005-0.020, cerium – 0.005-0.020, lanthanum – 0.005-0.020, sulphur – 0.003-0.006, phosphorus – 0.010-0.020, iron – balance. After quenching from 950 °C with cooling in oil and tempering at 190 °C for 3 hours, it has a fine-grained rack martensite structure with a grain size of 10-20 mcm in amount of 85-90%, containing residual austenite in amount of 10-15%, in the absence of δ-ferrite, σ-phase and coarse grain-boundary carbides of type Me₂₃C₆.

EFFECT: steel has high strength (σ_c>2,000 MPa) while maintaining the required plasticity.

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