TiN inclusions are known to exacerbate slag rimming and nozzle clogging during continuous casting of Ti-bearing steels. Herein, the effect of TiO2 and TiN on the viscosity and fluidity of a fluorine-free (F-free) mold flux, as well as the corresponding precipitated crystalline phase is studied. Higher TiO2 is found to lower the viscosity and increase the strip length of the molten slag at TiO2 contents less than 10 wt%, whereas the viscosity increases suddenly and the strip length decreases rapidly at TiO2 contents above 10 wt%, due to the precipitation of CaTiO3 crystals, resulting in a solid–liquid coexisting melt. TiN has a low solubility in F-free mold fluxes without MnO additions, and TiN is distributed in the molten slag as solid particles. TiN addition significantly increases the viscosity and shortens the strip length of the molten slag. On the other hand, F-free mold fluxes containing MnO dissolves TiN into the molten slag through the oxidization of TiN to TiO2. However, beyond the solubility limit of TiN in fluorine-free mold fluxes containing 5 wt% MnO, excess TiN is not completely dissolved. Then, the precipitation of Ca2Ti2O6 crystals is promoted.
Bibliographical noteFunding Information:
Financial support from National Natural Science Foundation of China (U1760202), Guangxi Scientific technology project (AD 18281073), Hunan Scientific Technology projects (2018RS3022 and 2018WK2051), and support from Hunan Provincial Innovation Foundation for Postgraduate (CX20190060) is gratefully acknowledged.
© 2020 Wiley-VCH GmbH
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Metals and Alloys
- Materials Chemistry