Investigation on dual-purpose electrolyte of electrolytic machining of M50 aviation bearing raceway and electrolytic in-process dressing of grinding wheel

Abstract

In order to realize the integration of M50 bearing raceway electrochemical machining and electrolytic in-process dressing (ELID) grinding, it is necessary to explore a dual-purpose electrolyte suitable for M50 electrochemical machining and electrolytic dressing of grinding wheel. Therefore, the paper searched for the electrolyte compositions suitable for M50 electrochemical machining and electrolytic dressing of grinding wheel were determined via electrochemical basic experiments. Then, the uniform design method was used for relevant electrolytic experiments. According to the experimental results, the optimal ratio of electrolyte composition was determined to be 17.935 % NaNO₃+12.528 % NaClO₃ by using multi-objective optimization theory. Through XPS test, it was found that the electrolysis products of M50 under the action of the above electrolyte were mainly metal (Fe, Cr, Mo) oxides and hydroxyl compounds. Meanwhile, the electrolytic products would form a passivation film on the surface of M50. Through the nanoindentation test, it was found that the hardness of the passivation film was 95.150 HV and the elastic modulus was 75.650 GPa, which were 11.487 % and 36.524 % of the M50 matrix, respectively, which effectively reduces the processing difficulty of M50. Finally, the M50 bearing raceway was compositely processed by electrochemical machining and ELID grinding, it was found that the processing efficiency and surface roughness were significantly improved compared with ordinary grinding.