Current Situation of Research and Development of Nickel-based Alloy Forgings for Steam Turbine Rotors at Home and Abroad
For the 650℃grade ultra supercritical steam turbine rotor,the heat-resistant steel can not be used because it can not meet the anti-oxidation and high-temperature property requirements,and nickel-based alloys shall be used.However,nickel-based alloys have complex compositions,making it difficult to manufacture the ingot larger than ∅1 000 mm.At the same time,the forging deformation temperature range is narrow and the deformation stress resistance is high,making it difficult to manufacture large rotor forgings over ∅1 000 mm and weighing over 10 t.In this paper,the composition characteristics,smelting process,forging size,performance level of large nickel-based alloys used for high-temperature rotors of ultra supercritical steam turbines at home and abroad are introduced.It focuses on the research status of smelting process,forging,heat treatment and other manufacturing processes of large nickel-based alloys in China,and points out the focus of large nickel-based alloy forgings of next stage in China.
stream turbine rotorsmelting processnickel base alloyvacuum arc remeltingelectric slag remelting