The Practical Application and Long-Term Experience of New Heat Resistant Steels to Large Scale USC Boilers

This paper focuses on the key properties of newly developed high-strength, heat-resistant steels for application in ultra-supercritical (USC) boilers. For some ferritic steels, improvements made to enhance their resistance to steam oxidation are highlighted. The latest welding techniques employed for these steels are introduced. Additionally, the high-temperature strength and weldability of Alloy 617 (52Ni-22Cr-13Co-9Mo-Ti-Al), a potential candidate material for the next generation of 700°C USC boilers, are described. The paper provides insights into the materials and welding technologies crucial for the development of advanced USC boilers operating at higher temperatures.