Abstract: A tundish for continuous casting of molten metal having an outer metal casing and, adjacent the casing, a permanent refractory lining is provided with an inner, expendable lining comprising refractory, heat-insulating slabs having an erosion resistant backing layer and an inward facing layer of lower density than that of the backing layer.The density of the facing layer is at least 0.2 g/cm.sup.3 but not more than 85% of the density of the backing layer. The presence of the inward facing layer exerts less chilling effect on the molten metal poured into the tundish than if the slab consisted of the backing layer alone.

Abstract: A refractory, heat-insulating slab for use in an inner, expendable lining of a tundish has a facing comprising magnesium oxide, inorganic binder but substantially no organic matter and a different backing. The facing has a combined water content not exceeding 2% by weight and the backing has a permeability of at least 10 AFS units. The facing and backing are joined together during formation of the facing or the backing. In the continuous casting of steel, the slabs have the advantage that there is little or no tendency for a significant amount of hydrogen to be picked up by the steel.