As inclusion defects in iron casting with green sand, green sand and slag are often detected together. Suspecting that slagging tends to occur easily when green sand mixes into molten metal, slagging of green sand was investigated by SEM-EDS analysis using green sand slagged by molten metal at 1673K.
First, green sand and silica sand used as reference were compared, and it was found that green sand is easier to slag than silica sand. This may be because the refractoriness of the bentonite or oolitics of green sand is lower than that of quartz or feldspar. Secondly, the effects of the different types of components of green sand were investigated, and it was found that the higher the sea coal content of green sand, the longer is the slagging time. This may be due to the delay in the generation of MnO, which is a slag component, resulting from the delay in the generation of oxides because of the reductive atmosphere of the sea coal. Thirdly, it was also found that slagging occurs easily at low concentrations of SiO2 in the silica sand or green sand.
Finally, sand inclusion defects that occur in iron casting factories using green sand and the findings obtained in this study were compared, and it was found that sand inclusion defects decrease when sea coal and quartz contents are increased, and increase when oolitics content is increased, showing that the obtained findings match the phenomena occurring at the factories.
