Study On Surface Quality And Processing Technique For Machining The V-Groove Of Low-Pressure Rotor In The 1000MW Steam Turbine

The 1000MW steam turbine with Low-Pressure rotor, which is domestically produced, is an important project of Shanghai Turbine Company Limited. In this paper, the processing technique was deeply investigated in details for machining the ultra-large palm-type groove of low-pressure rotor in 1000MW supercritical steam turbine. Through the studies on the processing of production line, cutting experiments and simulation, the tool drafts were determined and the residual stresses on the surface of grooves were also analyzed. Furthermore, the influences of tool, cutting force, cutting heat and cutting parameters on the residual stress were discussed, and the modeling and simulation on the residual stress on the surface of surface of grooves was studied. Therefore, this work has an important significance in theory and application for investigating the formation of residual stress on the complex surface of steam turbine rotor and the design of the succeeding rolling process. However, these researches in this paper are developed as following.(1) Study on the machinability of 26NiCrMoV145 rotor steel of steam turbineThe machinability and surface quality of 26NiCrMoV145 rotor steel was developed based on its microstructure, composition and mechanical properties. And the cutting heat and cutting force of palm-type groove was investigated according to the equivalent concept.(2)Study on the intergrated power metallurgical high-speed steel toolThe vabrivating signals of the intergrated power metallurgical high-speed steel tool during cutting were collectted, and the residual stress on the finished surface and cutting-tool wear were also analyzed. The performance of intergrated power metallurgical high-speed steel tool was investigated and the different cutting schemes were evaluated.(3) Study on the imbedded cemented carbide toolThe vabrivating signals of the imbedded cemented carbide tool during cutting were collected. The residual stress on the finished surface and cutting-tool wear were also analyzed. Therefore, the performance of intergrated power metallurgical high-speed steel tool was investigated and the different cutting schemes were evaluated. The comparison between the the intergrated power metallurgical high-speed steel tool and the imbedded cemented carbide tool were given.(4) Simulaiton on the residual stress of grooveThe simulation and prediction of the residual stress on the key regions of groove were completed through the modeling and verification.