摘要
在高铝钢的连铸过程中,CaO-SiO_2系保护渣在与钢中的[Al]反应过后转变为CaO-SiO_2-Al_2O_3系保护渣,同时液渣结晶能力增强,润滑效果变差。为了控制钢渣反应后形成的CaO-SiO_2-Al_2O_3系保护渣的结晶行为,利用差热分析研究了保护渣的非等温结晶动力学,基于Avrami方程及Friedman法分析了Li_2O及Na_2O的加入对保护渣的结晶速率、晶体生长方式,及有效结晶活化能的影响。结果表明,Li_2O的加入在降低保护渣结晶温度的同时使结晶速率变慢。此外,Li_2O的加入可以降低保护渣的有效结晶活化能,这表明Li_2O的加入可以使保护渣的结晶变得更容易。当渣中含有8%Na_2O时,Li_2O的加入促进了渣膜中12CaO·Al_2O_3的生成,导致固态渣膜的结晶比升高,这有可能对保护渣的润滑效果带来不利影响。
During continuous casting of high AI steel, the mold flux based CaO-SiO2 will react with the molten steel. The reduction of the Si02 will improve the crystallization of the spent flux based CaO-SiO2-Al2O3, which may affect the lubrication effect of mold flux. In order to optimize the crystallization behavior of mold flux based CaO-SiO2-Al2O3, the Differential Scanning Calorimetry is used to investigate the nonisothermal crystallization kinetics of mold flux based CaO-SiO2-Al2O3. The Avrami equation and the Friedman method are used to study the effects of Na2O and Li2O on the crystallization kinetic parameters, including crystallization rate, Avrami exponent and the effective activation energy. The results indicate that, the increase of Li2O content may decrease the crystallization temperature and the crystallization rate of mold flux. Furthermore, the addition of Li2O will decrease the effective activation energy of mold flux. However, when mold flux contains 8 % Na2O, the addition of Li2O may promote the precipitation of 12CaO-Al2O3 ,which may be harmful for the lubrication effect of mold flux.
出处
《炼钢》
CAS
北大核心
2017年第3期31-37,共7页
Steelmaking
关键词
连铸
高铝钢
结晶器保护渣
结晶动力学
continuous casting
high aluminum steel
mold flux
crystallization kinetics
