抄録
This paper discusses the feasibility of characterization of graphite morphology and size in flake graphite cast irons based on electromagnetic nondestructive methods. Several flake graphite cast iron specimens whose graphite form and size are different variously were prepared, and their electromagnetic properties such as conductivity and relative permeability were evaluated systematically. The results showed that both conductivity and relative permeability depend mainly on the form and size of graphite. Especially, the conductivity has a good correlation with form and size of graphite independently from the pearlite ratio of matrix. The conductivity was found to be correlated highly with ultrasonic velocity, and the ultrasonic velocity was found to be highly correlated with amount and size of graphite. Therefore, measurement of conductivity and permeability can be considered to be well applicable to evaluate form and size of graphite in flake graphite cast irons. Focusing on the fact, DC potential drop method was applied to evaluation of graphite form and its capability was evaluated.
