The relationship between the binary basicity （CaO/SiO2）,TiO2,Na2O,Li2O,MgO,MnO,B2O3 and viscosity for fluoride-free and titanium-bearing mold fluxes were systematically researched. The rotating cylinder method was e...The relationship between the binary basicity （CaO/SiO2）,TiO2,Na2O,Li2O,MgO,MnO,B2O3 and viscosity for fluoride-free and titanium-bearing mold fluxes were systematically researched. The rotating cylinder method was employed in the experiment to measure the viscosity of the slag. The results indicate that Li2O, B2O3 and Na2O play major roles in decreasing viscosity, especially Li2O, which is the most effective flux, while MgO and MnO exert little influence on viscosity. Meanwhile, it can be concluded that with increasing TiO2 content, the viscosity of fluoride-free and titanium-bearing mold fluxes increases at first but then falls when the amount of TiO2 is greater than 6.0%. Based on large amounts of experimental statistics of the viscosity of fluoride-free and titanium-bearing mold fluxes, an available model in literature for predicting the mold-slag viscosity was modified. This modified model can be used to predict the viscosity of fluoride-free and titanium-bearing mold fluxes. In fact, the predicted values approximate the observed values with a ±10.6% average deviation. Compared with the classical models,the average deviation is higher and it was found that the modified model can be used to estimate the viscosity of fluoride-free and titanium-bearing mold fluxes.展开更多
The time-temperature-transformation （TTT） diagrams of fluoride-free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope （CSLM） technique. It was found that the crystall...The time-temperature-transformation （TTT） diagrams of fluoride-free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope （CSLM） technique. It was found that the crystallization temperature of F-free mold fluxes containing TiO2 or ZrO2 increases,while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt,as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed,corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity,and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature,suggesting that the crystal/melt interface reaction is the controlling step in the present experiment.展开更多
基金Item Sponsored by National Natural Science Foundation of China and Shanghai Baosteel Group (50374086)
文摘The relationship between the binary basicity （CaO/SiO2）,TiO2,Na2O,Li2O,MgO,MnO,B2O3 and viscosity for fluoride-free and titanium-bearing mold fluxes were systematically researched. The rotating cylinder method was employed in the experiment to measure the viscosity of the slag. The results indicate that Li2O, B2O3 and Na2O play major roles in decreasing viscosity, especially Li2O, which is the most effective flux, while MgO and MnO exert little influence on viscosity. Meanwhile, it can be concluded that with increasing TiO2 content, the viscosity of fluoride-free and titanium-bearing mold fluxes increases at first but then falls when the amount of TiO2 is greater than 6.0%. Based on large amounts of experimental statistics of the viscosity of fluoride-free and titanium-bearing mold fluxes, an available model in literature for predicting the mold-slag viscosity was modified. This modified model can be used to predict the viscosity of fluoride-free and titanium-bearing mold fluxes. In fact, the predicted values approximate the observed values with a ±10.6% average deviation. Compared with the classical models,the average deviation is higher and it was found that the modified model can be used to estimate the viscosity of fluoride-free and titanium-bearing mold fluxes.
基金Item Sponsored by National Natural Science Foundation of China (50902003)National Key Technology Research and Development Programin 11th Five-Year Plan of China (2009BAC64B05)
文摘The time-temperature-transformation （TTT） diagrams of fluoride-free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope （CSLM） technique. It was found that the crystallization temperature of F-free mold fluxes containing TiO2 or ZrO2 increases,while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt,as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed,corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity,and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature,suggesting that the crystal/melt interface reaction is the controlling step in the present experiment.
