GCr15轴承钢精炼渣结壳机理

 针对GCr15轴承钢生产过程中精炼渣结壳严重，导致钢液大量吸气、钢中夹杂物增多的问题，通过对结壳程度不同的精炼渣进行工业取样，采用化学分析、物理测试、微观测定的方法，研究其化学成分、熔化状况和微观结构对结壳的影响。研究发现，结壳物主要物相为钙铝酸盐、氧化钙、尖晶石和硅酸二钙，且高熔点的氧化钙、尖晶石、硅酸二钙先于低熔点的钙铝酸盐析出，并存在于钙铝酸盐之中，增加了钙铝酸盐晶体之间的结合强度，造成精炼渣结壳；应优化精炼渣成分，使其处于CaO-SiO2-Al2O3-MgO相图中钙铝酸盐物相区，减少冷却过程高熔点物相析出，防止凝固结壳的发生。

Solidified crust mechanism of refining slag for GCr15 bearing steel

The problem of increasing of gas and inclusions in molten steel was caused by the solidified crust of refining slag during the production of the GCr15 bearing steel. The effect of the chemical composition，melting conditions and microstructure on solidified crust was studied by chemical analysis，melting test，SEM and XRD of the industrial refining slag. The results showed that the crust composed primarily of calcium aluminates，calcium oxide，magnesium-aluminium spinel，and dicalcium silicate. The bond of calcium aluminates crystals was strengthened，which made the refining slag crusted caused by numerous high melting point precipitates of calcium oxide，magnesium-aluminium spinel and dicalcium silicate precipitate ahead of the low melting point calcium aluminates，and enriched the low melting precipitates. Solidified crusts can be prevented by reducing the precipitation of high melting point phase during cooling process when the refining slag composition is optimized in the range of low melting point area in CaO-SiO2-Al2O3-MgO phase diagram.