Abstract: Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, pressure and coal ash corrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONELR alloy 740, is described aiming at meeting this challenge. Emphasis will be on describing the alloy's mechanical properties, coal-ash and steam corrosion resistance. Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology employed to arrive at the current chemical composition.

Key words: ultrasupercritical, boiler, tubing