Effect of Alkali Oxide on Cuspidine Crystallization for CaO-SiO2- CaF2-R2O (R=Li,Na,K) Slag
The hot thermocouple technique is suitable for characterizing the crystallization properties of mold flux for continuous casting of steel,since the slag sample can be heated or cooled rapidly.In case of slags containing fluorine and silica,it is inevitable that composition change occurs by vaporization of SiF4 gas,even if any water vapor is eliminated completely in the experimental system.In the present study,the SiF4 vaporization from the sample was prevented by preliminary saturating SiF4 vapor pressure from first heating a dummy sample.In this research,the effect of alkali oxide addition on the crystallization of CaO-SiO2-CaF2-R2O(R=Li,Na,K)slags were investigated by making time-temperature-transformation(TTT)diagrams.Comparing the obtained TTT diagrams among the equimolar modified slags,each sample shows two curves.Upper and lower curves correspond to the crystallization start of “wollastonite and cuspidine,and “cuspidine,respectively.The order of nose temperatures of the curve for wollastonite and cuspidine crystallization start is K2O,Na2O and Li2O.The order of the time required for complete coverage of crystalline phases is K2O,Na2O and Li2O.These tendencies are consistent with those observed during previous quenched glass annealing research.These differences are attributed to the power of influence of alkali oxides on slag properties; liquidus temperature,viscosity and so on.Saturated cuspidine crystallinity is also influenced by the affinity between the respective alkali oxides and silicate.
mold flux crystallization hot thermocouple alkali oxide
Takashi WATANABE Motoki KAKIZAKI Miyuki HAYASHI
Graduate School of Science and Engineering,Tokyo Institute of Technology,2-12-1,Ookayama,Meguro-ku,Tokyo,Japan
国际会议
the 6th International Congress on the Science and Technology of Steelmaking,ICS2015(第六届国际炼钢科技大会)
北京
英文
596-600
2015-05-12（万方平台首次上网日期，不代表论文的发表时间）