Electrochemical deep grinding of cast nickel-base superalloys

Nickel-based superalloys are considered as typical difficult-to-cut materials for traditional machining. Compared with wrought nickel-based alloys, numerous of disordered micro-particles are involved in the matrix of cast nickel-based superalloys, further worsen their machinability. In this paper, a hybrid process of electrochemical deep grinding (ECDG) combined by electrochemical machining (ECM) and deep grinding was employed to process cast nickel-base superalloy. By means of high-speed dissolution of anode materials by ECM and timely scraping of electrolytic products and micro-particles by mechanical grinding to realize the expectation of high-performance machining of cast nickel-based superalloy materials. Machining parameters, such as abrasive particle size, cathode rotational speed, etc., were studied in detail through experiments. The results show that better machining performance can be obtained when the cathode rotational speed is 1000 rpm and the abrasive particle size is 325 #. Furthermore, specimens of cast nickel-base superalloys were machined, and the machining performances of ECDG was compared with that of ECG and ECM. The results show that there are significant differences between ECDG and ECG, and the proportion of material removed by mechanical grinding in ECDG process is significantly reduced. Besides, the better machining efficiency and surface quality of cast nickel-based superalloys machined by ECDG is better than that by ECM.