铝脱氧轴承钢GCr15精炼渣最优成分的分析与实践

为了研究铝脱氧轴承钢GCr15最适合的精炼渣系,利用FactSage热力学计算软件对MgO对精炼渣熔点的影响、精炼渣对平衡钢液成分的影响及精炼渣的脱硫能力等进行热力学计算,得出最适合的渣系成分,并将优化结果应用于国内某厂"100tEAF→LF→VD→CC"流程生产轴承钢GCr15的工业试验。结果表明,优化后的精炼渣系的主要成分(质量分数)为CaO 50%~55%,Al2O325%~33%,SiO26%~10%,MgO 5%~7%,R=5~7;使用该渣系进行工业试验,VD出站时全氧质量分数可达到0.001 1%~0.001 3%;铸坯中主要夹杂物为Al_2O_3、MgO-Al_2O_3、MnS、TiN、钙铝酸盐和硅酸盐等,其中氧化物类夹杂的个数密度在3个/mm~2以下,平均等效直径在4μm以下。

Technical practice and research on optimal composition of refining slag of aluminium deoxidation bearing steel GCr15

Thermodynamic calculations on the effect of MgO on the melting point of refining slag, and the effect of refining slag on the equilibrium steel compositions and desulfurizing capacity were carried out by using FactSage to optimize the refining slag of aluminium deoxidation bearing steel GCr15. The optimal compositions of slag were obtained through the calculation. Commercial tests of the optimized result were carried out in the "100t EAFLFVDCC" bearing steel GCr15 production in a domestic factory. The results showed that the compositions of the optimal slag were CaO of 50%- 55%, Al2O3 of 25%- 33%, SiO2 of 6%- 10%, MgO of 5%- 7% and R of 5- 7. After the commercial tests, the main inclusion types in billet were Al2O3, MgO- Al2O3, MnS, calcium- aluminate, metasilicate and TiN. The number density of oxide inclusions was below 3/mm2. The average equivalent diameter was below 4 μm.