To control the chemically active boron (B) in 9CrMoCoB within a narrow target range, thermodynamic calculations using FactSage 7.2 and equilibrium reaction experiments were conducted between slag and steel. First, equilibrium reaction experiments between 9CrMoCoB and slag of 55%CaF₂–20%CaO–3%MgO–22%Al₂O₃–x%B₂O₃ (x ≤ 3) were conducted to supplement and optimize the Henrian activity coefficient γ (lgγ = A/T + C, where A and C are constants) of B₂O₃ in the solution phase of FToxid-OXYL in FactSage 7.2. Second, the equilibrium reactions between 9CrMoCoB steel and slag of 55%CaF₂–20%CaO–3%MgO–22%Al₂O₃–x%SiO₂–y%B₂O₃ (x ≤ 3, y ≤ 3) were calculated by using FactSage 7.2 to study the effects of B₂O₃, SiO₂, and O₂ in the atmosphere on the contents of B, Si, and O in steel. Then, equilibrium reaction experiments were conducted to validate the calculated results. Finally, suitable slag was designed, and electroslag remelting (ESR) experiments were conducted for verification. Results showed that A = −6582 and C = 0 in the Henrian activity coefficient equation were suitable to the slag of 55%CaF₂–20%CaO–3%MgO–22%Al₂O₃–x%SiO₂–y%B₂O₃ (x ≤ 3, y ≤ 3), and the appropriate slag for ESR remelting the 9CrMoCoB steel was 55%CaF₂–20%CaO–3%MgO–22%Al₂O₃–1%SiO₂–1%B₂O₃. The volume percent of O₂ had a stronger influence on the Si content, compared with B content. The volume percent of O₂ should be less than 0.05% to produce the qualified 9CrMoCoB ingot when using the designed proper slag.

为了将9CrMoCoB中的化学活性硼（B）控制在狭窄的目标范围内，使用FactSage 7.2进行了热力学计算，并在炉渣和钢之间进行了平衡反应实验。首先，9CrMoCoB和氟化钙的55％的炉渣之间平衡反应实验₂ -20％的CaO-3％的MgO-22％的Al ₂ ö ₃ - X％B ₂ ø ₃（X  ≤3）进行了补充和优化Henrian活动系数γ（LG γ  B的= A / T + C，其中A和C是常数）₂ ö ₃在FactSage 7.2中的FToxid-OXYL溶液相中。第二，钢9CrMoCoB和氟化钙的55％的炉渣之间的平衡反应₂ -20％的CaO-3％的MgO-22％的Al ₂ ö ₃ - X％的SiO ₂ - ý％B ₂ ø ₃（X  ≤3，ÿ  ≤3通过使用FactSage 7.2计算B ₂ O ₃，SiO ₂和O _{2的影响来计算}大气中钢中B，Si和O的含量 然后，进行平衡反应实验以验证计算结果。最后，设计了合适的炉渣，并进行了电渣重熔（ESR）实验以进行验证。结果表明，Henrian活度系数方程中的A = −6582和C = 0适用于55％CaF ₂ –20％CaO–3％MgO–22％Al ₂ O ₃ – x％SiO ₂ – y％的炉渣乙₂ ø ₃（X  ≤3，ÿ  ≤3），和用于ESR的重熔钢9CrMoCoB适当炉渣为55％的CaF ₂ -20％的CaO-3％的MgO-22％的Al ₂ ö₃ –1％​​SiO ₂ –1％​​B ₂ O ₃。与B含量相比，O ₂的体积百分比对Si含量的影响更大。使用设计适当的炉渣时，O ₂的体积百分比应小于0.05％，以生产合格的9CrMoCoB铸锭。