Thermodynamic Analysis of Components Variation on the Inclusions Precipitation in GCr15 Bearing Steel during Solidification

The evolution of non-metallic inclusions in the GCr15 bearing steel during solidification with different content of[Ca],[Al],[O]and[Mg]was investigated by Fact Sage software which is based on minimum Gibbs free energy principle.The results showed that the inclusion types changed from CaO·2MgO·8Al₂O₃,CaO·2Al₂O₃ to 2CaO·SiO₂,Ca S,meanwhile,the total mass fraction of inclusions increased from 0.004 5% to 0.009 4% with the Ca content increased from 0.000 5% to 0.004 5%.With the Mg content increased from0.000 1% to 0.000 9%,inclusion types changed from CaO·Al₂O₃,2CaO·SiO₂ to MgO·Al₂O₃,Ca S and the total mass fraction of inclusions increased from 0.003 2% to 0.004 1%.With the Al content increasing from 0.005% to 0.05%,the inclusions of 2CaO·SiO₂ changed into CaO·Al₂O₃,CaO·2Al₂O₃,while total mass fraction of inclusions unobviously increased from 0.002 8% to about 0.003 3%.In addition,with the O content increasing from 0.000 3% to 0.002 1%,inclusion types changed from Ca S to CaO·Al₂O₃,CaO·2Al₂O₃,and the total mass fraction increased from 0.002 4% to 0.005 1%.