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 B2O3-containing mould fluxes were studied. The co...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 B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows： the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.展开更多
In order to research the influence of La2O3 on crystallization behavior of free-fluoride mould flux and the heat transfer of slag film,free-fluoride mould flux with various La2O3 content were investigated by using sel...In order to research the influence of La2O3 on crystallization behavior of free-fluoride mould flux and the heat transfer of slag film,free-fluoride mould flux with various La2O3 content were investigated by using self-made mould simulator,comprehensive thermal analyzer and SEM-EDS.With the increase of La2O3 content from 0% to 20%,the crystallization ratios of mould flux films were improved from 2% to 90% and the thicknesses of films were also enhanced over two times.Moreover,crystallization temperature was greatly raised and its increasing extent reached 100 oC.It could also decrease the melting temperature of casting powder about 50 oC.However,the undissolved La2O3 particles appeared in slag film if the ratio of La2O3 in free-fluoride mould flux was much too high.展开更多
Due to the high content of the Al-TRIP steel, Al reacts with SiO2 in the mold slag during the casting process, which results in the increase of ωAl2O3 /ωSiO2 ratio and the Al2O3 content, respectively; the characteri...Due to the high content of the Al-TRIP steel, Al reacts with SiO2 in the mold slag during the casting process, which results in the increase of ωAl2O3 /ωSiO2 ratio and the Al2O3 content, respectively; the characteristic of heat transfer through the slag film is then changed, which influences the smooth operation of the continuous casting process. The heat flux simulator of mold slag film was used to study the change tendency of the heat flux density through slag film and the results were discussed; at the same time, the characteristics of the crystals in the No. 15 mold slag were determined by BSE and XRD. The results obtained show that heat flux density decreases with the increase of ωAl2O3 /ωSiO2 ratio. Heat flux density increases with the increase of Li2O and/or B2O3 content in the mold slag which contains 30 % of Al2 O3. Compared with the heat flux density of common slag of peritectic steel, a suitable mold slag containing 4% of B2O3 and 4% of Li2O is designed. The heat flux density is 0. 645 MW/m^2 when ωAl2O3 /ωSiO2 = 1. 46. Under this experimental condition, the CaF2 crystals precipitate in the mold slag used for Al-TRIP steel.展开更多
基金Item Sponsored by National Natural Science Foundation of China (50474037) Jiangsu Province Natural Science Foundation forUniversity of China (04BJK430022)
文摘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 B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows： the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
基金Project supported by the Inner Mongolia Science Foundation of China (20080404MS)
文摘In order to research the influence of La2O3 on crystallization behavior of free-fluoride mould flux and the heat transfer of slag film,free-fluoride mould flux with various La2O3 content were investigated by using self-made mould simulator,comprehensive thermal analyzer and SEM-EDS.With the increase of La2O3 content from 0% to 20%,the crystallization ratios of mould flux films were improved from 2% to 90% and the thicknesses of films were also enhanced over two times.Moreover,crystallization temperature was greatly raised and its increasing extent reached 100 oC.It could also decrease the melting temperature of casting powder about 50 oC.However,the undissolved La2O3 particles appeared in slag film if the ratio of La2O3 in free-fluoride mould flux was much too high.
基金Item Sponsored by National Natural Science Foundation of China (50874125)
文摘Due to the high content of the Al-TRIP steel, Al reacts with SiO2 in the mold slag during the casting process, which results in the increase of ωAl2O3 /ωSiO2 ratio and the Al2O3 content, respectively; the characteristic of heat transfer through the slag film is then changed, which influences the smooth operation of the continuous casting process. The heat flux simulator of mold slag film was used to study the change tendency of the heat flux density through slag film and the results were discussed; at the same time, the characteristics of the crystals in the No. 15 mold slag were determined by BSE and XRD. The results obtained show that heat flux density decreases with the increase of ωAl2O3 /ωSiO2 ratio. Heat flux density increases with the increase of Li2O and/or B2O3 content in the mold slag which contains 30 % of Al2 O3. Compared with the heat flux density of common slag of peritectic steel, a suitable mold slag containing 4% of B2O3 and 4% of Li2O is designed. The heat flux density is 0. 645 MW/m^2 when ωAl2O3 /ωSiO2 = 1. 46. Under this experimental condition, the CaF2 crystals precipitate in the mold slag used for Al-TRIP steel.
