Gao Jin-xing, Wen Guang-hua, Huang Ting, Sun Qi-hao, Tang Ping, Liu Qiang
Guang Pu Xue Yu Guang Pu Fen Xi. 2016 Oct;36(10):3190-6.
Due to the [Al] reaction with the CaO-SiO2-based mold flux used in the high-Al steels continuous casting processes, decreasing the SiO2 content is decreased and the Al2O3 content in mold flux is increased, thus converting the original CaO-SiO2-based mold flux into a CaO-SiO2-Al2O3-based mold flux. This conversion of the mold fluxes can cause the problem of high-Al steels continuous casting. Hence, study on the structural characteristics of the CaO-SiO2-Al2O3- based mold flux can provide fundamental data to design optimum fluxes for high Al-containing steels. In this paper, the structural characteristics of the CaO-SiO2-based and CaO-SiO2-Al2O3-based flux were studied by Raman spectroscopy. The results have shown that, the CaO-SiO2-based flux was the silicate structure whose main micro-structure units were Q0, Q1, Q2 and Q3. The network breakers prefer to depolymerize the silicate network in CaO-SiO2-Al2O3-based flux. While the CaO-SiO2-Al2O3-based flux with low SiO2 content, the [AlO4] tetrahedron was entered the silicate network and the melt converted into the aluminosilicates structure, the formation of Al-O-Al linkages and Si-O-Al linkages increased the degree of disorder of network. The results of Li2O replace Na2O and CaO replace MgO have shown that the ions will influence the formation of [AlO4] tetrahedron linkages. CaF2 replace CaO shown that the polymerization degree of mold slag decreased first, and then increased with the content of CaF2 more than 13 mol%. So, the influences of the ions type and the ions content on the structure were both need considered while designing the CaO-SiO2-Al2O3-based flux.
由于在高铝钢连铸过程中铝与CaO-SiO₂基保护渣发生反应，导致保护渣中SiO₂含量降低，Al₂O₃含量增加，从而使原来的CaO-SiO₂基保护渣转变为CaO-SiO₂-Al₂O₃基保护渣。这种保护渣的转变会引发高铝钢连铸问题。因此，研究CaO-SiO₂-Al₂O₃基保护渣的结构特性可为设计含高铝钢的最佳保护渣提供基础数据。本文采用拉曼光谱研究了CaO-SiO₂基和CaO-SiO₂-Al₂O₃基保护渣的结构特性。结果表明，CaO-SiO₂基保护渣为硅酸盐结构，其主要微观结构单元为Q0、Q1、Q2和Q3。网络外体倾向于解聚CaO-SiO₂-Al₂O₃基保护渣中的硅酸盐网络。当SiO₂含量较低的CaO-SiO₂-Al₂O₃基保护渣时，[AlO₄]四面体进入硅酸盐网络，熔体转变为铝硅酸盐结构，Al-O-Al键和Si-O-Al键的形成增加了网络的无序度。Li₂O替代Na₂O和CaO替代MgO的结果表明，这些离子会影响[AlO₄]四面体键的形成。CaF₂替代CaO表明，保护渣的聚合度先降低，然后随着CaF₂含量超过13 mol%而增加。所以，在设计CaO-SiO₂-Al₂O₃基保护渣时，需要同时考虑离子类型和离子含量对结构的影响。
