Experimental Investigation on Electrochemical Grinding of Inconel 718

Abstract

Electrochemical grinding (ECG) is a variation of electrochemical machining (ECM), in which material is removed from the workpiece by simultaneous electrochemical reaction and mechanically abrasive action. It offers a number of advantages over conventional grinding, such as low induced stress, large depths of cut, and increased wheel life. It has been reported that ECG was employed in machining stainless steel 304, metal-ceramic hard alloy of WC-Co groups, and Tungsten carbide. Inconel 718 is used extensively in aerospace because of their excellent combination of high specific strength (strength-to-weight ratio) which is maintained their fracture resistant characteristics, and their exceptional resistance to corrosion at elevated temperature. The machinability of Inconel 718 is generally considered to be poor owing to several inherent properties of the materials. Poor thermal conductivity, chemically reactivity and low elastic modulus are the common problems.In this paper, ECG is employed to process Inconel 718. To prolong the wheel life, the brazed diamond wheel is introduced to be a tool instead of the electrodeposited diamond wheel. Experiments illustrated that the tool durability has been improved from 15hours to 50hours when a brazed diamond wheel was employed to replace an electrodeposited diamond wheel. In addition, a proper high applied voltage and electrolyte temperature was verified to be conductive to improve the maximum electrode feed rate and material removal rate. A electrode feed rate of 6.6mm min-1 was obtained at 30V and 36°C, respectively.