HEAT-RESISTANT ALLOY Russian patent published in 2009 - IPC C22C19/05 C22C38/54 C22C38/58 C22C30/00 

FIELD: metallurgy.

SUBSTANCE: invention concerns metallurgy of heat-resistant alloys with cast structure on the basis of iron-chrome-nickel with carbide strengthening and can be used while creating of units for high-temperature pyrolysis for petrochemical industries. Alloy contains carbon, nitrogen, chrome, nickel, niobium, tungsten, molybdenum, titanium, silicium, manganese, aluminium, copper, magnesium, zirconium, yttrium, boron, cerium, lanthanum, neodymium, praseodymium and iron, at following ratio of components, wt %: carbon 0.35 - 0.55, nitrogen 0.02 - 0.05, chrome 22 - 27, nickel from 25 till less than 40, niobium 1 - 2, tungsten 0.5 - 5, molybdenum 0.2 - 0.6, titanium 0.05 - 0.6, silicon 0.8 - 2.0, manganese 0.8 - 1.5, aluminium 0.1 - 1.0, copper 0.1 - 1.0, magnesium 0.01 - 0.1, zirconium 0.005 - 0.15, yttrium 0.008 - 0.1, boron 0.007 - 0.01, cerium 0.022 - 0.063, lanthanum 0.006 - 0.027, neodymium 0.002 - 0.005, praseodymium 0.005 - 0.008, iron - the rest. At that there are kept correlations %C+%N-((%Nb+2×%Ti)/10)=0.24÷0.28 and (%La+%Ce+%Nd+%Pr)/%B=5÷10.

EFFECT: durability increasing in air medium against stress corrosion fracture in conditions of continuous static loading at temperatures of degree 1100°C, and also increasing of plasticity without impairment of long-term strength at specified temperatures.

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