Effect of Na2O on Crystallization of Mould Fluxes for Continuous Casting of Steel
Effect of Na2O on Crystallization of Mould Fluxes for Continuous Casting of Steel
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DOI：
10.2355/isijinternational.46.1805
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发表时间：
2006-12
影响因子：
1.8
通讯作者：
M. Hayashi;Takashi Watanabe;H. Nakada;K. Nagata
中科院分区：
文献类型：
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作者：
M. Hayashi;Takashi Watanabe;H. Nakada;K. Nagata
采用固体19r核磁共振波谱、差热分析和x射线衍射分析研究了Na 2o对cao - sio2 - caf2 -Na 2o季渣析出cuspidine行为和机理的影响。发现在工业助熔剂的组成范围内，F主要与ca2 +而不是Na'结合。这一结果表明，na2o的存在可能不会阻止渣中cuspidine的析出。随着na2o含量的增加，cuspidine的玻璃化转变温度和结晶温度降低。在973 K温度下，样品中cuspidine的质量分数随热处理时间的变化而变化。结果表明：cuspidine的质量分数在热处理初期显著增加，但在热处理后期趋于平稳。当na2o含量为4质量%时，匀平处cuspidine的质量分数最大，当na2o含量小于或大于4质量%时，cuspidine的质量分数较小。还发现结晶开始前观察到潜伏期，样品中Na 2o含量越大，潜伏期越短。
The effect of Na 2 O on the behavior and mechanism of the precipitation of cuspidine from the CaO-SiO 2 -CaF 2 -Na 2 O quaternary slags has been investigated by solid-state 19 R nuclear magnetic resonance spectroscopy, differential thermal analysis and X-ray diffraction analysis. It is found that F predominantly bonds with Ca 2+ rather than Na' in the composition range of the commercial mould fluxes. This result indicates that the presence of Na 2 O may not prevent the precipitation of cuspidine from the slags. The glass transformation temperature and the crystallization temperature of cuspidine decrease with increasing Na 2 O content. The mass fraction of cuspidine in the samples heated at 973 K was obtained as a function of heat treatment time. It is'found that the mass fraction of cuspidine significantly increases at the early stage of the heat treatment, but levels off later on. The mass fraction of cuspidine at the leveling-off is the largest for the sample with 4mass% Na 2 O, and is smaller as the Na 2 O content is either smaller or larger than 4 mass%. It is also found that the incubation period is observed before the crystallization starts, and that the incubation period is shorter as the Na 2 O content in the sample is larger.