Large-Scale Manufacture of Nickel Alloy Turbine Rotor Forgings for A-USC Power Plants

Coal-fired power plants will remain an essential major part of energy supply in the world for the next decades. However, the need to reduce carbon dioxide emissions of new fossil plants by improved net efficiency by increased steam temperature is one of the biggest challenges of mankind in the near future. The goal to realize a steam power plant with a net efficiency of 50% and more can only be achieved by the use of Nickel-base Alloys, because of the needed steam temperatures of 700 °C. One of the most promising candidate alloys for rotor forgings subjected to 700 °C is Alloy 617, which was already intensively investigated and producibility for large parts was proven (in Blaes, Proceedings 6th international conference on advances in materials technology for fossil power plants, 2010, pp 436–449). In 1998, in Europe, the development of a 700 °C Power Plant started with the project AD700. Saarschmiede was always involved in most of the important 700 °C technology RD Proceedings 19th international forgemaster meeting, 2017, pp 335–344). The development, manufacturing process and test results of production for very large prototype nickel-base alloy rotor forgings for A-USC power plants are reported.