Abstract
The necessity to reduce carbon dioxide emissions of new fossil plant, while increasing net efficiency has lead to the development of not only new steels for potential plant operation of 650°C, but also cast nickel alloys for potential plant operation of up to 700°C and maybe 750°C. This paper discusses the production of prototype MarBN steel castings for potential plant operation up to 650°C, and gamma prime strengthened nickel alloys for advanced super critical plant (A-USC) operation up to 750°C. MarBN steel is a modified 9% Cr steel with chemical concentration of Cobalt and tungsten higher than that of CB2 (GX-13CrMoCoVNbNB9) typically, 2% to 3 Co, 3%W, with controlled B and N additions. The paper will discuss the work undertaken on prototype MarBN steel castings produced in UK funded research projects, and summarise the results achieved. Additionally, within European projects a castable nickel based super alloy has successfully been developed. This innovative alloy is suitable for 700°C+ operation and offers a solution to many of the issues associated with casting precipitation hardened nickel alloys.
