Study on effect of graphite electrode on accuracy of hole using electrochemical machining

Abstract

 Graphite electrodes are widely employed in electrochemical processes due to their conductivity, chemical stability, and resilience to high temperatures. However, graphite electrode corrosion or pitting can occur under certain conditions, reducing the electrode's efficiency and longevity. In this research, 316L stainless steel is machined through electrochemical machining (ECM) process using 0.7 graphite electrode. The voltage, electrolyte concentration and duty cycle are varied to understand the effect of graphite electrode on overcut and surface area of micro-spalling affected zone (MSAZ). The MSAZ reduces with voltage. The micro-spalling in graphite electrode occurs due to chemical reactions. At lower voltage levels, the MSAZ decreases, and a linear reduction in MSAZ is noticed in the voltage range of 8 to 9 V. The micro-spalling develops micro wavy circumference affecting the hole circularity. Moreover, the salt deposition on the electrode develops undercut region in the hole.

KEY WORDS: Micro-spalling, Stainless steel, Overcut, Voltage, Electrolyte concentration, Duty cycle.

Bull. Chem. Soc. Ethiop. 2025, 39(5), 1019-1028.                                                    

DOI: https://dx.doi.org/10.4314/bcse.v39i5.15