THICK COLD-RESISTANT STEEL Russian patent published in 2018 - IPC C22C38/50 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to cold-resistant steels used in the manufacture of hot-rolled plate for the production of welded products operated at low (to -90 °C) temperatures under dynamic loads. Steel contains the components at the following ratio, mass%: carbon 0.05–0.08, silicon 0.15–0.30, manganese 0.30–0.60, nickel 2.35–3.50, molybdenum 0.25–0.35, copper 0.40–0.70, vanadium 0.05–0.08, niobium 0.02–0.05, aluminium 0.01–0.05, cerium 0.001–0.02, calcium 0.005–0.025, zirconium 0.05–0.08, zirconium carbonitride particles 0.05–0.10, chromium 0.3–0.6, iron and impurities remaining, the total content of aluminum, cerium, calcium, zirconium and zirconium carbonitride particles is <0.25 wt.%. Steel further comprises at least one element selected from the group, by weight: barium 0.005–0.025, titanium 0.03–0.08, nitrogen 0.005–0.012. It contains the following components as impurities: sulfur <0.008 wt.%, phosphorus <0.008 wt.% and oxygen <0.005 wt.%, and as impurities of low-melting metals it contains lead, bismuth, tin, antimony and arsenic, while the total content of impurities of low-melting metals does not exceed 0.05 wt.%. Zirconium carbonitride particles have a size of 30–65 nm.

EFFECT: homogeneity of physical and mechanical characteristics of a sheet of 70 mm thick and higher at high strength and high cold resistance at temperatures up to -90 °C, and also increased strength of the weld when subjected to dynamic loads.

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