The development of steel grade 92 for large thick section components for advance coal fired power plant

Energy utilisation throughout the world has seen a significant transformation over the past 30 years. Factors such as economic considerations and environmental impact have become key drivers in the trend towards power generation plant which is both efficient and clean. Consequently, energy derived from renewable sources such as hydro, wind and solar, has seen a rapid rise in utilisation by some 145% and today accounts for 15% of the total world energy demand. Conventional fuels, however, such as coal still account for 40% of world electrical power generation and are predicted to continue to be a major energy source. However, they have also been influenced by environmental pressures which has seen the development of advanced clean coal technologies incorporating advanced steam cycles to increase efficiency and reduce emissions. Essential to clean coal technology is the development and availability of cost effective steels which can be used for thick section components and which are capable of operating at elevated temperatures in corrosive atmospheres. Much of the work in materials development for these applications has centred around the 9-12% Cr family of steels. This payer describes the development, manufacture and properties of an advanced 9% Cr steel containing tungsten (Grade 92) for thick section forged components up to 425 mm for use in advanced high temperature power plant applications.