高铝钢用保护渣结晶行为

Crystallization behavior of mold flux for high aluminum steel

结晶特性是保护渣最重要的理化指标之一,直接影响着连铸坯表面质量和连铸顺行。以高铝钢用传统低碱度CaO-SiO_(2)系和新型CaO-Al_(2)O_(3)系保护渣为对象,采用单丝热电偶技术和扫描电镜对保护渣液相结晶/玻璃相结晶的结晶温度、演变过程和微观形貌进行了研究。结果表明,液相结晶过程中CaO-Al_(2)O_(3)系保护渣更容易结晶,而玻璃相结晶过程中CaO-SiO_(2)系保护渣更容易析出晶体。此外,上述两种保护渣均具有较快的液相结晶速度,且液相结晶与玻璃相结晶的生长方式和形貌存在明显差异。

Crystallization characteristic is one of the most important physical and chemical indexes of mold flux,which directly affects the surface quality of continuous casting billet and the running of continuous casting.The traditional low basicity CaO-SiO_(2) system and new CaO-Al_(2)O_(3) system mold fluxes for high aluminum steel were used as research objects.The crystallization temperature,evolution process and micro morphology of liquid phase crystallization/glass phase crystallization of mold fluxes were studied by using SHTT technology and scanning electron microscope.The research results show that CaO-Al_(2)O_(3) system is easier to crystallize during the liquid phase crystallization process,while CaO-SiO_(2) system is easier to crystallize during the glass phase crystallization process.The liquid phase crystallization speed of the two mold fluxes is faster,and there are also obvious differences in the growth mode and morphology of the liquid phase crystal and the glass phase crystal.