Abstract
Ingot weight of steel has increased as a result of recent mass-production and modernization of the steel plant, with such progress, that the reducing of sulphur segregation in the ingot of rimmed steel became an important problem for maintenance of the quality of steel product.
We considered that the segregation of sulphur in the ingot was influenced remarkably by the shape of the ingot, and studied many rimmed steel ingots with different shapes, with the following results:
1) Degree of maximum segregation of sulphur increases with an increasing of the ingot weight, therefore it is necessary to consider the shape of the ingot and pouring pit practices for a large ingot.
2) Increasing of ingot thickness widens the heavy segregation range of sulphur more than the proportional ratio of ingot shape.
3) Maximum segregation of sulphur is shifted to ingot top direction by the decreasing of ingot thickness or increasing of the ratio of width to thickness.
4) It is considered that the heavy segregation of sulphur in rimmed steel ingot results from the rising and coagulation of sulphide during the solidification of molten steel, and that the position and shape of the heavy segregation zone are mainly influenced by the solidifying speed of ingot from top and side to center.
