Cutting Experiments And Finite Element Analysis Of Key Parts Of 1000MW Ultra-Supercritical Steam Turbine

1000MW Ultra-supercritical steam turbine is an important part of the National Project 863 relying project—Huaneng Yuhuan Power Plant 4×1000MW Ultra-supercritical machines, which is the key of the Ultra-supercritical steam turbine localization process and has a significant influence on our economic growth and daily life. However, due to the severe working environment, higher standard of the performance and quality of different parts is needed, so is the machining quality. Sealing ring and the final groove of low pressure rotor are two key parts in 1000MW Ultra-supercritical steam turbine which are hard to machine, the difficulties are that the former has a high requirement on the dimension accuracy and stability, so the residual stress of machined workpiece should be controlled to the least point, but for the latter, a high compressive residual stress 300MPa in 0.5 mm depth is needed.In this paper, the seal ring and the final groove of low pressure rotor of 1000MW steam turbine are studied in two means: cutting experiments and finite element method. For the seal ring, mechanical properties and structure of GH80A are introduced, together with the finite element analysis, the formation mechanism of machined surface, work-hardening and residual stress for dry turning of GH80A are studied, especially the influence of cutting parameters on the residual stress, and FEM is used to simulate the on-site wet machine, the results show that the depth of residual stress is 0.3mm and then the following machining parameter is simulated which shows that the depth of residual stress is very small and the cutting force is also controlled. For the groove, the study was divided into two parts, the first part is the groove milling process, by comparing the advantages and disadvantages of V type and T type machine, we chosed V type machine. With the measurementand FEM, the comprehensive residual stress can only be found in 0.3mm depth which is far from the set value. The second part is the rolling process of the groove, the principle and key parameters are introduced, and the rolling process is simulated in the finite element software, which shows that when the rolling pressure is 50bar, only 100Mpa comprehensive residual stress is found in 0.3mm depth, but it also shows that if the rolling pressure can be increased to a certain point that the set residual stress value can be reached.