Abstract
The article is devoted to the issues of improving heat-resistant austenitic alloys intended for the manufacture of reaction pipes for reforming furnaces of high-temperature aggregates used in the petrochemical and gas chemical industries. The research is aimed at improving the structural stability and reliability of materials of reaction pipes operating for a long time under conditions of simultaneous exposure to high temperatures, internal pressure and an aggressive gas environment. The main attention is paid to improving the long-term strength, thermal resistance and creep resistance of austenitic alloys through the combined action of carbide and intermetallic hardening mechanisms. The chemical composition of the KHN33BS alloy based on the iron–chromium–nickel system, the features of centrifugal casting technology, as well as the microstructural and phase state of the resulting metal are comprehensively studied. According to the results of electron microscopy and microrentgenospectral analysis, the formation of intermetallic phases enriched in chromium and niobium, as well as secondary carbides, in the austenitic matrix has been established. These structural formations prevent metal deformation at high temperatures and ensure the preservation of its strength characteristics.