抄録
The effects of anions on the electrochemical machining of mild steel were investigated. The cell used for the electrochemical machining tests was of a fixed electrode type, consisting of a copper tube cathode (4mm in outside and 3mm in inside diameter) and a plane steel anode. The electrolytes used were 2mol solutions of NaCl, NaNO3, NaClO3 and NaH2PO4. The current efficiency for dissolution of the steel in NaCl solution was approximately 100%. The efficiencies in NaNO3 and NaClO3 solutions were less than 100%, but increased with the increase of the current densities. The efficiency in NaH2PO4 solution was about 3%. The cell voltages in NaCl, NaNO3 and NaClO3 solutions gradually increased with the machining time under the effect of electric resistance between the electrodes. The cell voltage in NaH2PO4 solution showed the maximum value immediately after the start of electrolysis, when sparks were emitted between the electrodes; but, afterwards, it kept a higher constant value. The profiles of the machined surfaces were measured with a specially designed device, and a method for estimating the degree of stray cutting was proposed. The un-machined surface was not corroded during the machining process in NaClO3 solution. It was also shown that good dimensional control resulted from a small current in NaClO3 solution.
