Experimental investigation of the electrolyte type effect on the specifications of electrochemical machining (ECM) of the 304 stainless steel

Electrolyte type, due to the nature of its constituent ions, affects the reaction rate, the uniformity of the electric field and formation of the external layer on the workpiece surface in the machining area during the electrochemical machining process, as well as it causes to create different dissolution behaviors of the workpiece. Therefore in this study the effect of sodium chloride, sodium nitrate, potassium chloride and hydrochloric acid electrolytes with different currents on the electrochemical machining characteristics of stainless steel 304, including material removal rate, side gap and surface roughness, has been investigated. The results showed that the formation of passive layer during the machining with sodium nitrate electrolyte reduces the material removal rate and side gap compared with sodium chloride and potassium chloride electrolytes. According to the experimental results the surface roughness in the sodium chloride and potassium chloride electrolytes is decreased by increasing the machining current, but increases in the sodium nitrate electrolyte. Also the material removal rate slight increase and side gap increase at sodium chloride, sodium nitrate and potassium chloride when combined with hydrochloric acid. On the other hand, the surface roughness reduces in the combined sodium chloride and potassium chloride electrolytes, but increases in the combined sodium nitrate electrolyte.