| 摘要 |
PURPOSE:To prevent the deposition of Al2O3, etc., on a refractory and to effectively and stably obviate the clogging of a nozzle by coating the surface of a CaZrO3 refractory with an SiO2-base coating material and heat-treating the refractory with the temp. and time controlled. CONSTITUTION:A refractory (e.g. a submerged nozzle) contg. 50-80wt.% of the grain consisting of 5-35wt.% Ca0 and 95-65wt.% ZrO3, 10-30wt.% C and 5-25wt.% of a siliceous material is prepared. The refractory surface is coated with a coating material consisting of SiO2 or a coating material contg. >=1 kind among SiO2, Na2O, Al2O3, B2O3, ZrO2, K2O, Li2O, BaO, SrO, CaO, MgO, ZnO, CdO, PbO and Bi2O3. The refractory is then heat-treated at >=1200 deg.C for >=60min. Consequently, the CaZrO3 in the refractory reacts with the SiO2 in the coating material to form a low-m.p. material on the refractory surface, and the Al2O3 originated from molten steel is dissolved in the low-m.p. material and melted away. |
