MARTENSITIC STAINLESS STEEL 0Crl3Ni4Mo FOR HYDRAULIC RUNNER

摘要

Three Gorges hydraulic runner is the largest one in the world with the weight of nearly 450 ton and the diameter of 10 meter. It consists of the top crown and the lower band through the blades which are assembled by welding. All of the crown, band and blade are made of 0Crl3Ni4Mo low carbon martensitic stainless steel.The chemical composition optimization, heat treatment specification and microstructure controlling to the martensitic stainless steel 0Crl3Ni4Mo were systematically studied in this paper to meet the properties' requirements for the hydraulic turbine runner. By controlling the Ni/Cr equivalent proportion, the 8-Fe can be avoided in the microstructure and improve the impact performance. Single normalizing with double tempering is recommended for the heat treatment system. The normalizing microstructure consists of 100% lath martensite. The final microstructure in 0Crl3Ni4Mo stainless steel is tempered martensite and a certain amount of inversed austenite which has an excellent mechanical properties and good weldability.The three gorges is the biggest hydropower facility in the world. It is of great importance for China to harness and develop the Yangtze River. By 2020, the gross installed capacity of hydropower will reach 300GW, 225GW of which will be from the large and middle-scale hydropower, while 75GW from small hydropower.