The effect of heterogeneous second phase on the machinability evaluation of spheroidal graphite cast irons in the WEDM process

This paper presents an investigation about the relationships between the heterogeneous second phase and the machinability evaluation of the ferritic SG cast irons in the wire electric discharge machining (WEDM) process. The factors of second phase considered are the quantity, diameter and area fraction of spheroidal graphite particles. The experimental specimens adopted a range of 2.1–4.1 mass% to change the carbon content for clarifying the effect of graphite particles on the machinability evaluation of the ferritic SG cast irons. The machining performance evaluations performed by the experiment are the ridge density, discharge density, material removal rate (MRR) and surface roughness (SR). The conclusions reveal that the more ridge density promotes the amount of discharge density and promote the machining efficiency in the WEDM process. The formation of the ridges is closely related to the quantity and shape of graphite particles. The status of graphite particles are found to be an important factor in determining the material removal rate (MRR) and surface roughness (SR).