著者

堀川 紀孝 王 麟

出版者

公益社団法人 日本鋳造工学会

雑誌

鋳造工学 (ISSN:13420429)

巻号頁・発行日

vol.91, no.12, pp.850-855, 2019-12-25 (Released:2020-01-01)

参考文献数

13

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The microstructure and mechanical properties of ductile cast iron are affected by the chemical compositions and thickness of casting products. Thus, a nondestructive estimation method for casting is required. This research investigated effects of casting surface on the eddy current evaluation of ductile cast iron matrix. Ductile cast iron specimens having various microstructures were prepared by adding alloy elements and varying the thickness. One of the surfaces of the specimen was machined by face milling, and annealed after machining. Eddy current testing and microstructure observation were performed on both the machined surface and casting surface. Pearlite ratio showed good correlation with the eddy current signals measured on the machined surface. Similar correlation was obtained by measurement on the casting surface. However, the eddy current signal was affected by the casting surface. The influence of surface roughness and pearlite ratio on the eddy current signal differed according to the signal component. Selecting the signal components enables the effects of the surface roughness to be reduced. The effects of the testing frequency were also examined, and the results showed that the variation in the correlation between the eddy current and the pearlite ratio increased at lower and higher testing frequencies than 1 to 5kHz. Comparison of the correlations between the pearlite ratio and eddy current signals obtained by measurements on the machined surface and the casting surface showed that of the casting surface tends to have low pearlite ratio, due to the effects of the microstructure transient layer beneath the casting surface. Thus, it can be suggested that choosing a suitable testing frequency and an eddy current signal component enables the estimation of the matrix of ductile cast iron by eddy current testing regardless of the surface conditions.

著者

谷 和麻 堀川 紀孝 王 麟

出版者

公益社団法人 日本鋳造工学会

雑誌

鋳造工学 全国講演大会講演概要集 第170回全国講演大会講演概要集 (ISSN:18805388)

巻号頁・発行日

pp.85, 2017 (Released:2017-11-01)