Research On Group Holes Machining On MA956 Superalloy Sheet By Electrochemical Machining Method

MA956 superalloy is one of Oxide Dispersion Strengthened?ODS?superalloy,which has wide application prospect in high temperature anti-oxidation components of advanced aero engine and gas turbine because of its excellent corrosion resistance,high temperature oxidation resistance and good creep resistance.At the same time,more and more components with holes structure are widely used in Aeronautics and Astronautics.Therefore,it is necessary to study the machining characteristics of MA956 superalloy.Compared with the traditional machining,electrochemical machining?ECM?has obvious advantages in small holes machining and difficult-to-machine material machining.Electrochemical machining with movable cathode mask is based on ECM,and many literatures show its advantages.In this paper,optimal design of the fixture and processing is discussed.By using electrochemical machining with double-cathode movable mask in 10% w.t.NaNO₃ electrolyte,the processing of machining group holes on the thin plate of MA956 superalloy is tested.The main research work of this paper includes:1.The electrochemical properties of MA956 superalloy were obtained by experiments including anodic polarization curve and ??-i curve.The cut-off current density in ??-i curve was found.2.Fixture of the support cylinder and the double-cathode movable mask were designed.Simulation of flow channel and process of small holes forming was completed.3.The effects of the parameters on holes machining were discussed,including electrolyte temperature,electrolyte pressure,machining voltage,duty cycle and pulse frequency of the power source.And optimized parameters were applied to machine multiple micro holes on MA956 superalloy sheet.The study shows that the machined multiple micro holes with good surface quality,uniform size and low taper can be obtained on the MA956 sheet in the electrolyte of 10% w.t.NaNO₃,when the electrolyte temperature is 30?,the electrolyte pressure is 0.6MPa,the machining voltage is 40 V,the power duty cycle is 30%,the power pulse frequency is 400 Hz.