Microstructural evolution of Nimonic 263 for use in next generation power plant

Abstract

Environmental and economical demands are driving the need for the UK and the rest of the world to develop higher efficiency, next generation coal-fired plant. Higher efficiency energy recovery will ultimately result in a combination of cheaper energy for the consumer and enabling industry to meet emission targets. The intention is to increase operating parameters from 550°C and 17.5 MPa to 700°C and 30 MPa resulting in more efficient energy generation. This increase in operating parameters will also increase the demand on power plant materials, resulting in the use of some existing materials to be no longer viable. It is for this reason that nickel based alloys have been considered for areas of the plant which will experience high temperatures, pressure and will also require enhanced creep resistance. Nickel based alloys will be used in high temperature, high pressure components such as steam headers. This research focuses on one of the candidate materials for this area of plant, the alloy Nimonic 263. The ultimate aim of the research is to study the microstructural evolution with respect to time at a range of high temperatures to help assess the suitability of the alloy. To fully assess the alloy’s candidacy it must be studied in each product form in which it is likely to be used, and for this reason this research has considered Nimonic 263 as a forged, welded and cast alloy. [Continues.]