Now rare earth has been widely introduced in heat-resistant steel. For example, in 253 MA steel, cerium combined with silicon improves the oxidation resistance and erosion corrosion resistance. The desired content of ...
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Now rare earth has been widely introduced in heat-resistant steel. For example, in 253 MA steel, cerium combined with silicon improves the oxidation resistance and erosion corrosion resistance. The desired content of cerium is about 0.03 wt.%–0.08 wt.%. However, excessive rare earth should be added due to the low yield rate, and the molten steel in the mold was of strong reducibility. Sever slag metal interface reaction occurred when conventional mold fluxes were used. In order to restrain the interface reaction during heat resistant steel containing rare earth continuous casting, a new method of designing mold flux was proposed, and different flux systems containing rare earth were devised based on theoretical calculation and phase *** properties such as melting temperature, viscosity, and crystalline phase of the different mold fluxes were systemically investigated. Comparisons of properties between the new fluxes and the conventional mold fluxes without rare earth were conducted. The results show that properties similar to those of the conventional mold flux could be obtained with adopting Li2 O and BO as fluxing agent in the new designed system. However, the melting temperature of the new flux containing rare earth with higher content of Si O and Ca O was too low, and the full crystallization could not be obtained in the continuous cooling process. The flux with higher content of Si O and AlO had a relatively proper melting temperature and crystallization ability,but the viscosity was too high to apply to the continuous casting process. With adopting Li O and BO as fluxing agent, the new mold flux with high content of Ca O and AlO had approximate properties with the conventional mold flux. Cerium oxide could not separate out in continuous cooling process. The main crystalline phase was Li Al O in new mold fluxes, which is different from the cuspidine（3Ca O·2Si O·Ca F） in the conventional mold flux. Li Al O can be a good substitution for cuspidine. It was
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