Research On The Performance Of Cr Steel For Ultra-supercritical Rotor

In order to improve the efficiency of the steam turbine generator of power station, and to reduce carbon dioxide emissions, many countries are building ultra supercritical steam turbine units actively. And the operation condition of the ultra supercritical steam turbine rotor is very harsh, which challenging the material of rotor and its manufacturing process. 12%Cr steel is a kind of heat resistant steel which is often used in producing the high pressure rotor in recent years. However, the high component of the alloys, and the size of high pressure rotor is very big, which resulting in the abnormal structure in the process of heat treatment, the mechanical properties are poor and the quality of parts is difficult to control. In this paper, the forging, heat treatment process and microstructure and properties of the rotor material for ultra high pressure and high pressure are studied. The main research contents and conclusions are as follows:At first, the phase diagram analysis of the test steel was carried out by using the Thermo-Calc software of Royal Institutet of Technology. In order to study the phase composition of the test steel, and test the accuracy of the calculated phase diagram, this paper observed the microstructure of the original sample by optical microscope and study the compositon of phase by XRD.Secondly, the paper studied the CCT curve of the continuous cooling transformation on the GLEEBLE-3500, tested the high temperature mecha- nical properties, and measured the elongation(?) and the cross section shrinkage rate(?). According to test data, then the high temperature plastic figure of the material was drawn, which laid the foundation for the forging and heat treatment of the rotor.Then, on the basis of the experimental results of the rotor material, this paper produced the real rotor by K11E89 A, similaring to the experial rotor's material. And the forging and heat treatment was processed to the real rotor.Finally, the structure and performance of the real machine rotor materi al are studied. After testing, the mechanical properties(such as fracture strength, elongation, shrinkage, impact energy, FATT50, etc.) of the domestic rotor are in line with the requirements of the technical standards.