The evaluation of machining performances and recast layer properties of AISI H13 steel processed by tungsten carbide powder mixed EDM process in the semi-finishing process

Abstract

In the literature, investigations on the electrical discharge machining (EDM) process with Tungsten carbide powder mixed into dielectric fluid, also called PMEDM, are still limited. In this study, machining performances of PMEDM, including material removal rate (MRR) of AISI H13 steel and tool wear rate (TWR), were investigated in the semi-finishing process. Thereafter, recast layer properties of AISI H13 steel, including composition and content of chemical elements, recast layer thickness (RLT), and acreage percentage of micro-cracks on surfaces (APCS), were evaluated and discussed. Quantitative methods of MRR, TWR, RLT, APCS, and the composition and content of chemical elements on machined surfaces have been proposed. The results revealed that machining performances and recast layer properties were influenced by peak current (Ip), pulse on time (Ton), and powder concentration (Cp). MRR and TWR have been changed in an uptrend when Ip, Ton, and Cp increased. The chemical composition of machined surfaces was modified. APCS and RLT formed by PMEDM are notably decreased as compared with EDM, with a reduction of 41.093% and 48.982%, respectively. In addition, the changing trend of machining performances and recast layer properties were also explored.