Estimating Volume Fractions of Microstructural Constituents in Austempered High Silicon Alloyed GJS 600-10 Ductile Iron through Magnetic Measurements (VSM)

Abstract

In this paper, austempering heat treatment was applied to a new generation high silicon GJS 600-10 grade ductile iron with an initial ferritic matrix. Different austempering temperatures of 270, 330 and 390°C were applied after austenitizing at 975°C for 120 min. Depending on the austempering temperatures, lower and upper ausferritic microstructures were obtained. Results showed that volume fraction of the retained austenite in the ausferritic microstructures, which was estimated by VSM technique is well correlated with those estimated by XRD technique.