Machining of 7Cr13Mo steel by US-PMEDM process
Weishen Zhang, L. Li, N. Wang, Yue Teng
Abstract
7Cr13Mo steel is widely used in many industries given its good properties. However, it has poor wear resistance and difficult-to-cut characteristics. In this study, ultrasonic-assisted and powder-mixed electrical discharge machining (US-PMEDM) was applied to investigate the machining characteristics of 7Cr13Mo steel. The parameters including peak current and pulse duration were varied to explore their influence on surface morphology, material removal rate (MRR), surface roughness (SR) and micro hardness. The experimental results indicated that the US-PMEDM process has a better performance on 7Cr13Mo steel surface. The US-PMEDMed surface has less micro cracks and lower surface roughness compared with that by EDM. XRD analysis showed Ti, Fe0.975-Ti0.025 and Fe-Cr formed in 7Cr13Mo steel machined surfaces and thus the micro hardness was increased by a maximum of about 78% as compared to that of EDM process. The MRR was improved by almost 57% than that of EDM process.