Electrochemical micromachining behavior on 17-4 PH stainless steel using different electrolytes

Abstract

Abstract The microtextured surfaces are used to improve the efficiency of engineering components like aerospace, biomedical, tribology, defense, etc. Electrochemical micromachining (ECMM) is a more promising technique for fabrication of microtextured surfaces because of its advantages like high material removal rate, less energy require, less space and tool-material wastage over other methods. 17-4 PH SS alloy is a precipitation hardened (PH) martensitic grade of stainless steel (SS) used in the field of aerospace for making turbine blades, power plant, marine and chemical industry. Properties such as high tensile and fatigue strength, good toughness, high hardness and formability make its machinability inferior. ECMM behavior of 17-4 PH SS alloy is completely unfamiliar. Since, there is no information available on the suitability of electrolyte dissolution with 17-4 PH SS while using ECMM, the present study aims to provide a suitable electrolyte for microfabrication on 17-4 PH SS alloy using ECMM with tungsten carbide for achieving better surface integrity. Electrolytes used for ECMM are aqueous solution of NaBr and combined aqueous solution of NaCl+NaNO 3 . The performance characteristics such as radial overcut, material removal rate (MRR), dimple depth and some aspects of surface integrity have been investigated. Owing to non-passivating behaviour of NaBr electrolyte, it actively participate with 17-4 PH SS alloy and results in overcuts and pits on the surface. The better dimensional accuracy and surface integrity have been achieved with NaCl+NaNO 3 electrolyte.