Production method of tundish cover castable

The tundish cover mainly provides an environment for the tundish to keep warm and prevent molten steel from splashing. Its production history includes all-cast steel and all-cast iron, and then gradually developed into the current general metal frame + refractory castable composite structure. The cover of the all-cast steel structure is heated extremely unevenly when working in the state of high temperature heat radiation, which is prone to large thermal stress and thermal stress difference. , which will eventually lead to deformation and warping; and the cover of all-iron castings is brittle, and after only one use, the cover will crack and then break, so this material structure is not suitable for cover materials; metal frame + refractory The material composite structure is now a relatively mature technology for cover applications. This mode is to cast the refractory material as a whole in a mold made of a metal frame. Moisture control within the ideal range and put into use. The refractory material can resist the extremely cold and extremely hot working environment, and has good slag resistance, which greatly increases the life of the cover. At the same time, the metal frame can firmly fasten the refractory material, enhance the flexural strength, and resist the splash of molten steel. At present, the more common refractory materials are clay and high alumina materials. Although the composite structure has improved the life of the tundish cover, there is still a phenomenon of unbalanced thermal stress between the castable and the metal frame during use. Causes partial cracks, low thermal strength, and partial structural spalling. The tundish covers the castable, and the raw material is composed of the following components by weight: 8 < particle size≤12mm brown corundum 19-20%, 3≤ particle size≤8mm brown corundum 16-17%, 1 < particle size ≤3mm coke gemstone 6~8%, 0.149≤particle size≤1mm coke gemstone 7~8%, particle size <0.044mm fused magnesium powder 6~8%, 1≤particle size≤3mm zircon 5~7%, 0.149≤particle size≤1mm Sintered mullite 10～12%, particle size＜0.044mm alumina powder 9～10%, particle size＜0.005mm alumina powder 6～7%, particle size＜0.074mm silica dust Powder 1-2%, particle size <0.074mm cement 5-6%; plus 0.1-0.2% water reducing agent, 0.05-0.08% explosion-proof fiber, 0.5-1% stainless steel fiber by the total weight of the above materials. Further, the chemical composition of the tundish covering castable is calculated by weight percentage: al2o3≥65%, mgo≥5%, sio2≥5%, zro2≥3%. Further, the above-mentioned tundish covers the castable, and the water content is less than or equal to 1wt%. Specifically, in the above-mentioned tundish-covered castable, the brown corundum contains al2o3≥95wt%.

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