Abstract: By vacuum induction melting 08Cr9CoMo steel using MgO crucible, the pure iron is derusted and baked with other alloys, the charging ingredients are 0. 06% C, 1. 3% Co, 9. 0% Cr, 1. 5% Mo, 0. 02% La-Ce, the balance is iron,turn on the power with vacuum ≤10 Pa, controlling the vacuum 25 ~30 Pa during the melting period, controlling the liquid temperature 1 600 °C and the vacuum 10 Pa during the refining period, and refining for 20 min, adding 0. 02% La-Ce before casting, the final analysis result is 0. 022% C and 0.002 8% 0. The carbon deoxidation capacity under vacuum is calculated by thermodynamics, and it is significantly enhanced as vacuum reduces, the relationship between oxygen supply of the MgO crucible and vacuum is analyzed by thermodynamic calculation, when the vacuum is lower than 25 Pa, the crucible decomposes and supplies oxygen more significantly, when the decomposition rate of the MgO crucible is equal to the carbon deoxidation rate, the molten steel reaches the minimum oxygen content.

摘要： 采用MgO坩埚真空感应熔炼08Cr9CoMo钢，纯铁经除锈与其他合金烘烤后按照0.06%C、1.3%Co、9.0%Cr、1.5%Mo、0.02%La-Ce，余量为铁配料，真空度≤10 Pa通电，熔化期控制真空度25~30 Pa，精炼期控制温度1600 ℃和真空度10 Pa，精炼20 min，出钢前添加0.02%稀土，最终分析结果为0.022%C，0.002 8%O。通过热力学计算了真空下碳脱氧能力，随着真空度的降低碳脱氧能力显著增强，热力学计算分析了MgO坩埚供氧与真空度的关系，真空度低于25 Pa后坩埚分解供氧更显著，当MgO坩埚分解供氧速率等于碳脱氧速率时钢液达到最低氧含量。