スラグ鋳造時の熱応力亀裂防止のための冷却条件

抄録

Ferrous Slag Hydrated Matrix has been developed by mixing steel slag as aggregate. The direct casting process from molten slag was investigated instead of the complicated and expensive Matrix manufacturing process. However, cracks during casting can reduce strength. To prevent crack formation, the mechanism of thermal stress crack initiation and the appropriate conditions for casting molten slag in rock form were investigated by casting experiments, sound measurements, and thermal stress analysis. Compared with the slag cooled in the mold, the slag under the optimum cooling condition suppressed the cracks and did not cause cracks inside the slag. The crack sound was measured by sound measurements. To suppress the cracks, it was suggested that the temperature in the slag should be uniform quickly within 10 min after the slag injection. The required solidification shell thickness could be estimated based on the tensile stress generated on the slag surface. Through casting experiments and thermal stress analysis, cooling conditions to suppress thermal stress cracks in slag casting were revealed. In other words, it was found that when the molten slag is poured into the mold and then is demolded at the stage where the solidification shell thickness sufficiently exceeds the strength of the slag surface against the tensile stress applied to the solidification shell. The solidified slag is thermally insulated, and the temperature inside the slag is uniform. It cools while remaining uniform.