Effect of titanium inclusions on performance of mold flux during continuous casting of Ti-bearing steel
CHEN Zhuo1,2, ZHENG Rui-qi1, WANG Qian3
1. College of Metallurgy and Material Engineering, Jiangsu University of Science and Technology, Zhangjiagang 215600, Jiangsu, China; 2. Suzhou Institute of Technology, Jiangsu University of Science and Technology, Zhangjiagang 215600, Jiangsu, China; 3. Materials Science and Engineering, Chongqing University, Chongqing 400044, China
Abstract:During the continuous casting process, titanium nitride inclusions are precipitated in the Ti-bearing steel and participate in the steel-slag interface reaction, which seriously deteriorates the physical and chemical properties of the traditional mold flux for Ti-bearing steel. This study measured the influence of different contents of TiN and TiO2 on the melting temperature, viscosity, crystallization ratio and solidification temperature of mold fluxes with different basicity. The results show that TiN has the greatest impact on the performance of CaO-SiO2 based mold fluxes. With the increase of TiN content, the viscosity, crystallization ratio and solidification temperature of mold fluxes extremely increase. When the mass fraction of TiN is greater than 5%, the melting point increase sharply. The properties of CaO-Al2O3 are sensitive to the TiO2 content. When TiO2 is less than 4%, the viscosity and solidification temperature of the mold flux can be reduced slightly. When the TiO2 is larger than 10%, the perovskite is the main precipitated phase in the mold flux and the performance of mold flux is seriously deteriorated, which is not conducive to the lubrication effect on the billet shell. By comparing three basic mold fluxes with different basicity, it is found that CaO-SiO2-Al2O3-based mold can absorb titanium inclusions preferably.
Z·uk M, Czupryński A, Czarnecki D, et al. The effect of niobium and titanium in base metal and filler metal on intergranular corrosion of stainless steels[J]. Welding Technology Review,2019,91(6):30.
Nunnington R C, Sutcliffe N. The steelmaking and casting of Ti stabilized stainless steels[C]//59th Electric Furnace Conference and 19th Process Technology Conference.Phoenix,AZ,USA,2001:361.
Scheller P R. Interfacial phenomena between fluxes for continuous casting and liquid stainless steel [J]. Ironmaking and Steelmaking, 2013, 29(2): 154.
[15]
WANG Z, SHU Q, HOU X, et al. Effect of substituting SiO2 with TiO2 on viscosity and crystallisation of mould flux for casting titanium stabilised stainless steel[J]. Ironmaking and Steelmaking,2012,39(3):210.