Nickel Base Superalloys for Next Generation Coal Fired AUSC Power Plants

Utilities 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. This paper describes two new nickel-base alloys, INCONEL® alloys 740 and 740H™, aimed at meeting this challenge. The evolution of the early alloy 740 into alloy 740H is discussed. Since alloy 740's mechanical properties, coal-ash and steam corrosion resistance have already been extensively reported [1,2], emphasis will be given to recent data on alloy 740H and particularly its commercial-scale manufacturability to steam pipe and its subsequent weldability and mechanical properties.