Ultrasonic vibration-aided electrochemical drill-grinding of SLM-printed Hastelloy X based on analysis of its electrochemical behavior

Abstract

Selective laser melting (SLM) technology is one of the research hotspots of additive manufacturing technology, and Hastelloy X is a material which is widely used in the aerospace field. However, the forming accuracy and surface quality of Hastelloy X holes printed by SLM often do not meet engineering requirements and need further processing. Therefore, ultrasonic vibration-aided electrochemical drill-grinding technology (UAECDG) was proposed as a method for machining small holes with high quality on SLM-printed Hastelloy X workpieces. Firstly, the electrochemical behavior of SLM-printed Hastelloy X was investigated, and its microstructure and corrosion resistance were studied using electron backscattered diffraction (EBSD). Secondly, numerical simulation of the electrochemical drill-grinding process was performed. Thirdly, a series of experiments was carried out to explore the influence of electrode shape, electrical parameters and ultrasonic vibrations on the quality of the small holes. Finally, the UAECDG method with a hemispherical electrode was successfully used to machine with high precision small holes with a diameter of 1215.0 ± 5 μm, surface roughness of 0.446 μm and a taper of less than 1.5 degrees on a 1.2 mm thick SLM-printed Hastelloy X workpiece. This demonstrated the usefulness of UAECDG technology for machining small holes in a SLM-printed superalloy.