Inconel 740H is a nickel-based precipitation-hardening superalloy that delivers an exceptional combination of high strength and creep resistance at elevated temperatures, along with coal ash corrosion resistance. Originally designed for A-USC boiler tubes in overheated sections of power plants, this alloy has since been adapted for use in steam header connections. A-USC boiler tubes typically feature conventional dimensions [generally 1.5 to 3 inches (38-76 mm) in outer diameter]. In contrast, main steam header pipes require significantly larger diameters, exceeding 12 inches (305 mm) in outer diameter with wall thickness potentially surpassing 1.5 inches (38 mm). Seamless steam reheating pipes, which can reach up to 30 inches (760 mm) in outer diameter, also represent a viable product line utilizing Inconel 740H.
Inconel740H (UNSN07740) is a nickel-chromium-titanium alloy developed from 263. With its high chromium content (24.5%), Inconel740H provides a significantly enhanced resistance to high-temperature corrosion. The material undergoes aging hardening due to precipitation of Y’ phase. By balancing the content of hardening agents (niobium, aluminum, and titanium), Inconel740H not only exhibits high strength but also demonstrates excellent thermal stability.
The density of the alloy is ρ=8.05g/cm³.
