Electrochemical machining of 20MnCr5 alloy steel with ferric nitrate mixed aqueous NaCl electrolyte

Abstract

Electrochemical machining (ECM) is a fast growing and widely used advanced machining process. Improving a material removal rate (MRR) of ECM is still a topic of concern in order to utilise its full potential. In this paper, ferric nitrate (FeNO3) was included in small proportions in the aqueous NaCl electrolyte solution in the direction of improving ECM performance. The performance parameters i.e. MRR and surface roughness (Ra) have been greatly improved by enhancing the ionisation of the electrolyte by this new mixture of electrolyte. It was found that FeNO3 has suitable characteristics to mix with NaCl to enhance the ionisation reaction. In this work, experimental investigation was conducted to study the electrochemical machining characteristics of 20MnCr5 alloy steel for both aqueous NaCl and FeNO3 mixed aqueous NaCl electrolytes. The significance of ECM process parameters such as flow rate of electrolyte, tool feed rate, voltage and current on MRR and Ra was analysed. Microstructure of surface of the specimen machined with FeNO3 mixed aqueous NaCl electrolyte shows the improvement in surface finish.