连铸保护渣结晶行为及其控制机理

The maximum changed value of viscous activation energy, and critical temperature as well as the crystal ratio in solidified slag, have been found and employed to quantitatively assess the crystal precipitation and glassy performances of continuous casting mould fluxes in this research. For the mould fluxes system of CaO, SiO2, Al2O3, MgO, SrO, MnO, Li2O, CaF2, Na2O, B2O3, ZnO etc., the quantitative statistic models of melting temperature and viscosity dependent on component contents were established. By employing the hot simulation on heat transfer, differential thermal analysis (DTA), mineral graphic test as well as X-ray diffraction, the crystal precipitation behavior and related influencing factors of mould fluxes have been probed in detail. The revealed mechanism and obtained methodology to control the crystal precipitation behavior of fluxes suggest that some of the special components as MnO and Li2O possess comprehensive effects on the crystallization and heat transfer properties. The main compositional ranges, which can harmonize the lubrication and heat transfer functions of mould fluxes, are that CaO/SiO2＝0.9～1.05，CaF2＝13%～15%, MnO＝2%～6%，Li2O＝0～4%，MgO＝2%～5%, Na2O＝8％～12% and the kept critical temperature Tc≤1200℃ as well as crystal ratio Rp＝20%～90%. According to the disclosed theory of this research, developed mould fluxes have found satisfactory results in plant trail.

裂纹敏感的中碳钢连铸生产中铸坯润滑与传热的矛盾未得到有效解决，它已成为阻碍高效连铸技术发展的瓶颈问题之一。项目通过热态模拟、数值仿真、高温热物理特性及物相的检测等方法，研究保护渣结晶行为及其控制机理，充分考虑保护渣光学特性和热辐射特性在控制传热中的作用，协调保护渣结晶性能和玻璃性能，实现连铸高拉速与高质量相统一的目的。