HEAT RESISTANT ALLOY Russian patent published in 2022 - IPC C22C19/05 C22C30/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to heat-resistant chromium-nickel alloys of the austenitic class with intermetallic hardening, and can be used in the production of reaction tubes for ammonia and methanol units with operating temperatures of 800-950°C and a pressure of 2.5-5 MPa and oil and gas processing plants with operating modes from 950 to 1160°С and pressure up to 0.7 MPa. The high-temperature alloy contains, wt.%: carbon 0.35÷0.45; silicon 1.0÷1.80; manganese 0.9÷1.60; chromium 28.0÷31.0; nickel 37.0÷40.0; niobium 0.9÷1.70; titanium 0.26÷0.50; cerium> 0÷010; lanthanum> 0÷0.10; zirconium> 0÷0.10; tungsten 0.05÷0.25; aluminum> 0÷0.12; vanadium> 0÷0.10; cobalt> 0÷0.10; molybdenum> 0÷0.10; sulfur ≤0.02; phosphorus 0.02; lead ≤0.007; tin ≤ 0.006; arsenic ≤ 0.006; zinc ≤ 0.006; antimony ≤0.007; nitrogen ≤ 0.01; copper ≤0.1; iron is the rest. The alloy has a structure consisting of an austenite matrix and intermetallic compounds Cr_(24÷58)Fe_(3÷6)Ni and Nb_(26÷34)Cr_(2,6÷3,4)(FeNiTi)_(0,9÷1,1), with the mass ratio of the austenite matrix and intermetallic compounds (89÷95):(4÷10):(1÷3).

EFFECT: structure of the alloy is improved and the homogeneity of secondary carbides increases, high values ​​of strength, heat resistance are provided, as well as the absence of cracks during pipe welding and during long-term operation.

1 cl, 2 ex