结晶器保护渣的润滑与传热控制功能剖析

对保护渣渣膜在润滑与控制传热两个方面的功能发挥进行了剖析,如黏-温曲线、转折温度,渣膜结晶状态和析出相进行了研究,并指出渣膜的转折温度、结晶率对润滑功能发挥起主要作用;而渣膜的闭孔率、表面粗糙度、枪晶石比例对控制传热功能具有关键性的影响。同时,对3种典型保护渣的渣膜凝固特性进行了研究,讨论了与钢种特性和连铸工艺相适应的保护渣基本性能参数,如碱度、熔点、黏度、转折温度、烧结性能、渣膜中气体等对发挥润滑与控制传热两个功能的影响。提出了保护渣管理方面需要重点控制的内容,如保护渣全水含量高低,生产过程中更换不同性能保护渣对传热与润滑的持续影响,液渣池深度的合理值等。

Analysis of lubrication and heat transfer function of mold flux

Functions of mold flux film in lubrication and heat transfer control are analyzed. The physical properties of mold flux film, such as viscosity temperature curve, transition temperature, crystalline state and precipitated phase are studied. It is pointed out that the transition temperature and crystalline rate of mold flux film play a major role in lubrication. The closed pore ratio, surface roughness and cuspidate ratio of the slag film have key effects on heat transfer control. At the same time,the solidification characteristics of slag film of three typical mold fluxes were studied. The basic property parameters of the mold fluxes suitable to the characteristics of steel grades and continuous casting process, such as basicity, melting point, viscosity, turning point temperature, sintering performance and gas in slag film and so on lubrication and heat transfer control were discussed. The key control contents of mold flux management are put forward, such as the total water content of mold flux, the continuous influence of replacing different performance mold flux on heat transfer and lubrication, and the reasonable depth of liquid slag pool.