氟离子对保护渣传热和渣膜矿相结构的影响

Influence of F^- on Heat Transfer of Mold Flux and Mineralogical Structure of Flux Film

连铸过程中保护渣的渣膜结构及结晶器传热情况对铸坯质量有重要影响,试验采用高温导热系数测定装置及结晶器渣膜黏度和热流模拟测试仪,研究不同F^-配加量渣膜的高温导热系数和矿相结构。结果表明:随F^-含量(4.22%~13.33%)的增加,渣膜的导热系数逐渐减小,对应的渣膜结晶率逐渐增大,且试验渣膜结晶率均较高,达75%以上。不同F^-含量的保护渣所对应渣膜的结晶矿物种类相同,主要为枪晶石和硅灰石。随F^-含量的增加,枪晶石析出量不断增多,晶形逐渐变大;硅灰石生成量不断减少,晶形逐渐变小。该研究成果对改善低氟保护渣浇铸的铸坯质量具有重要指导意义。

During continuous casting,the mineralogical structure of flux film and heat transfer of mold flux play important roles in strand quality. In this paper,the thermal conductivity and mineralogical structure of flux film with different F--content were analyzed by the high temperature coefficient of thermal conductivity measuring device and heat flux and viscosity testing device. The results show that with F--（ 4. 22% -13. 22%） increasing,the thermal conductivity of flux film decreases,and the crystallization ratio of corresponding flux film increases. The crystallization ratio of flux films are very high,reaching more than 75%overall. The crystalline minerals of flux films remain same kinds,with dominant cuspidine and wollastonite at different F--Contents. Meanwhile,with the increase in F--contents,the cuspidine content continues to increase while wollastonite content decrease significantly. These results have vital guiding significance on improving the strand quality for continuous casting of low fluorine mold flux.