Continuous casting tundish
A tundish assembly, including an element, for preventing or limiting steel reoxidization in the continuous casting of molten steel, is used in combination with a refractory nozzle. The element has an orifice engaging the outer surface of the nozzle, a main surface surrounding the main orifice and having a lowest level lower than the top outer edge of the nozzle inlet portion, and a periphery having an upper face surrounding the man surface of the element. The upper face of the periphery of the element is higher than the main surface of the element and is higher than the surface of the bottom well of the tundish. The main surface of the element is arranged so as to contact molten steel when the tundish is in use.
1. Assembly of (a) a tundish for the continuous casting of molten steel and of (b) a refractory nozzle forming a passage for transferring a molten metal through the bottom wall of the tundish, the tundish having a bottom wall having an upper surface, the tundish comprising an element surrounding an inlet portion of the nozzle, the element being made from a refractory material and comprising a main orifice adapted for matching engagement with at least a portion of the outer surface of the nozzle, an exposed main surface of the element surrounding the main orifice and having a lowest level, the lowest level of the main surface of the element being lower than the top outer edge of the nozzle inlet portion, a periphery of the element having an upper face surrounding the main surface of the element, the upper face of the periphery being higher than the main surface of the element, wherein the upper face of the periphery of the element is higher than the upper surface of the bottom wall of the tundish.
2. Assembly according to claim 1 , wherein the element is made from a material having an open porosity lower than 20%.
3. Assembly according to claim 1 , wherein the nozzle is constituted of a material that loses less than 2% by weight between 1000 and 1500° C. when subjected to a test wherein a 100 g sample of the material is placed in a furnace under argon atmosphere, the temperature is raised to 1000° C., then raised to 1500° C. in 1 hour and left at 1500° C. for 2 hours.
4. Assembly according to claim 1 , wherein a mortar joint is present between the nozzle and the element and the mortar forming the mortar joint has an open porosity lower than 20%.