On the Positive Way to Prevent the Occurrence of the Defect of a Billet

Study on continuous casting of steel. -VII

Abstract

In the previous reports (Tetsu-to-Hagané 45 (1959) No. 12, p. 1341 and 46 (1960) No. 7, p. 753) it was revealed that defects which were occurred on the surface and in the core of a billet were prevented by setting the primary and the secondary cooling under the suitable conditions. But the range of the suitable conditions of cooling of the billet was rather narrow and it must be operated restrictedly.
Therefore it was important to find out the positive way to prevent the occurrence of the defect of a billet, besides those suitable conditions.
In this report, the results of the experiments which were held in order to prevent the occurrence of the surface defects of a billet in other words, to intensify the cooling of a billet in the mold, shall be revealed. To intensify the cooling of a billet in the mold, the first experiment was carried out to remove the air gap between a billet and a mold, and the second experiment was carried out on the tubular mold with thinner wall.
It was revealed that the inverse tapered solid mold and thin wall tubular mold showed a greater cooling capacity than with the normal solid mold. But in view of the availability of the mold life, the solid mold with inverse taper is only effective way to intensify the cooling of a billet.