SKELP STEEL AND ITEM MADE OUT OF IT Russian patent published in 2011 - IPC C22C38/58 C22C38/54 C22C38/50 C22C38/48 C22C38/46 C22C38/44 

FIELD: metallurgy.

SUBSTANCE: steel contains carbon, silicon, manganese, nickel, chromium, copper, sulphur, phosphorus, aluminium, nitrogen and one or more elements from group: titanium, molybdenum, niobium, vanadium, boron, calcium and unavoidable impurities at following ratio, wt %: carbon 0.02 - 0.12, silicon 0.05 - 0.60, manganese 1.1 - 2.2, nickel 0.05 - 1.2, chromium 0.005 - 0.50, copper 0.005 - 0.50, sulphur as high, as 0.012, phosphorus as high, as 0.018, aluminium 0.01 - 0.08, nitrogen as high, as 0.010, one or more elements of group: titanium 0.001 - 0.04, molybdenum 0.001 - 0.6, niobium 0.001 - 0.12, vanadium 0.001 - 0.12, boron 0.0001 -0.004, calcium 0.0001 - 0.006, iron and unavoidable impurities the rest. Additionally, steel can contain 0.0001 - 0.005 wt % of REE (rare earth elements). At 480≤σ_Y≤635 summary contents of manganese and nickel is [Mn]+[Ni]≥0.0025*σ_T+0.1622 and steel has C_e≤0.43, P_fs≤0.23, δ₅≥19. At 635≤σ_t<705 summary contents of manganese and nickel is [Mn]+[Ni]≥0.0019σ_T+0.5417 and steel has C_e≤0.46, P_fs≤0.25, δ₅≥17. At 705≤σ_t<775 summary contents of manganese and nickel is [Mn]+[Ni]≥0.0014*σ_T+0.8929 and steel has C_e≤0.57, P_fs≤0.26, δ₅≥14. At σ_T≥775 summary contents of manganese and nickel is [Mn]+[Ni]≥0.0034*σ_T -0.6531 and steel has C_e≤0.60, P_fs≤0.27, δ₅>12, where [Mn], [Ni] are contents of manganese and nickel in steel, %, 0.0025, 0.0019, 0.0014, 0.0034 are empiric coefficients, %/MPa, 0.1622, 0.5417, 0.8929, 0.6531 - are non-dimensional empiric coefficients, Ce is carbon equivalent, %, P_fs is coefficient of fracture strength, %, δ₅ is percent elongation, %, σ_t is yield point of steel, MPa.

EFFECT: extended consumer properties and processability of utilisation of skelp steel and items made out of it possessing sufficient strength, plasticity, weldability, corrosion resistance and cold resistance.

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