| 摘要 |
PURPOSE: Provided is a method for coating porous refractory, conventional alumina refractory, with graphite to prevent infiltration of molten steel and attachment of nonmetallic materials, and improve Ar-gas bubbling. CONSTITUTION: The coating is performed by spreading a coating solution on the surface of porous alumina refractory such as tundish upper nozzle, in a thickness of 0.01-1.0mm, The coating solution comprises 50-70wt.% of graphite, 10-30wt.% of sodium silicate, and water. The porous alumina refractory with 23-28% of porosity comprises 86-88wt.% of spherical Al, 3-5wt.% of Zr, 1-5wt.% of Cr2O3 and inevitable impurities. Afterwards, the coated refractory is dried at room temperature over 24hrs. or at 100-500deg.C over 6hrs.
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