LI Guirong
,
WANG Hongming
,
DAI Qixun
,
ZHAO Yutao
,
LI Jingsheng
钢铁研究学报(英文版)
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3containing mould fluxes were studied. The corresponding physical properties of 3791%CaO4309%SiO25%Al2O35%MgO2%Li2O7%B2O3 mould fluxes were as follows: the melting point was 909 ℃, the flowing temperature was 1 160 ℃, the viscosity and surface tension at 1 300 ℃ were 04 Pa·s and 032 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
关键词:
B2O3containing mould flux;fluoridefree flux;harmless flux;physical property
WANG Hongming
,
LI Guirong
,
DING Zhentao
,
DAI Qixun
,
LI Bo
钢铁研究学报(英文版)
To avoid slag sticking on the ladle immersion cover during the LATS refining and alloying process, the effect of Al2O3 on the melting point of the ladle slag was studied and the additives including CaF2, B2O3, Li2O, and CaO were used to decrease the melting point of the ladle slag. The melting point was measured using the hemisphere method. The results show that the addition of Al2O3 to the ladle slag increases the melting point. The fluxing action is not remarkable if only CaF2 or CaO is used as the additive. The fluxing action of the composite additive obtained by the mixing of CaO and CaF2 in the mass proportion of wCaO∶wCaF2=2∶1 is preferred. The fluxing action of B2O3 is also notable. When the B2O3 content in mass percent is in the range from 2% to 10%, the corresponding melting point is 1 380 ℃ to 1 290 ℃. The fluxing action of Li2O is the most remarkable. When the Li2O content is up to 5%, the melting point of the slag is lower than 1 300 ℃.
关键词:
LATS refining;ladle slag;melting point;additive;immersion cover
WANG Hongming
,
LI Guirong
,
LI Bo
,
et al
钢铁研究学报(英文版)
B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags (the mass ratio of CaO/SiO2 is 3~4) and the high basicity slags (the mass ratio of CaO/SiO2 is 5~8.75) were investigated. The slag melting temperature was measured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and Al2O3. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted with B2O3, the melting temperature can be decreased remarkably. Especially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in range of 1.1~4.0 and 5.25~8.0, respectively, the slag melting temperature is lower than 1300℃. Therefore, the B2O3-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultralow melting temperature. As a result, not only the slag forming speed but also the capabilities of desulfurizing, dephosphorizing and absorbing deoxidation products are expected to be improved.
关键词:
Fluoride-free slag;Boron oxide;CaO-based refining slag;Melting temperature;Basicity
