Abstract: Tested steel 31CrMoV9 (/% : 0.28 ~0.33C, 0.30 ~0.35Si, 0.49 ~0.60Mn, 0. 011 ~0.016P, 0.027 ~ 0.031S, 2.47 ~2.60Cr, 0. 16 ~0.23Mo, 0. 12 ~0. 19V) is melted by a 25 kg induction furnace, and the effect of binary basicity 2.5 ~ 3.5 of different ingredient refining slag (/% : 46.43 - 59. 89CaO, 15.16 - 23.50Si0₂, 10 〜20Al₂O₃, 6 〜 10MgO, 2 ~5CaF₂) on number, size and composition of inclusions in steel 31CrMoV9 has been studied by orthogonal experiment method. Results show that the effect of binary basicity and alumina content in refining slag on inclusion content in this steel is obvious ； as the binary basicity of slag increases from 2.5 to 3.5, for per 0.3 mm² steel the average area of inclusions increases from 22.07 μm² to 25.67 μm²  i. e. that increases by 16.31% and the number of inclusions decreases from 316.67/0.3 mm² to 255.00/0. 3 mm², i. e. that decreases by 19. 47% , it is available to form composite inclusions； as alumina content in slag increases from 10% to 20% , for per 0. 3 mm² steel the area of inclusions increases from 22. 57 μm² to 24. 28 μm², i. e. that increases by 7. 55% and the number of inclusions decreases from 292. 67/0.3mm² to 272.00/0.3 mm², i. e. that decreases by 7. 06% , it is available to form aluminium-magnesium spinal inclusions. With comprehensive analysis the refining slag contained 10% Al₂O₃ , 10% MgO and 5% CaF₂ with binary basicity 3.5 has better refining effect.

摘要： 试验用31CrMoV9钢（/%:0.28~0.33C,0.30~0.35Si,0.49~0.60Mn,0.011~0.016P,0.027~0.031S,2.47~2.60Cr,0.16~0.23Mo,0.12~0.19V）由25kg感应炉熔炼,采用正交试验研究了二元碱度2.53.5不同成分精炼渣（/%:46.43~59.89CaO,15.16~23.50SiO₂,10~20Al₂O₃,6~10MgO,2~5CaF₂）对31CrMoV9钢夹杂物数量、尺寸和成分的影响。结果表明,精炼渣二元碱度和氧化铝含量对该钢夹杂物含量的影响显著;当二元碱度从2.5增加到3.5时,每0.3 mm²钢中夹杂物的平均面积从22.07μm²增至25.67μm²,增幅为16.31%;夹杂物的数量从316.67个/0.3 mm²降至255.00个/0.3 mm²,降幅为19.47%,且有利于形成复合型夹杂物。当氧化铝含量从10%增加到20%,每0.3 mm2钢中夹杂物的面积由22.57μm²增至24.28μm²,增幅为7.55%,夹杂物的数量由292.67个/0.3 mm²降至272.00个/0.3 mm²,降幅为7.06%,并易形成镁铝尖晶石类夹杂物。综合分析,当精炼渣成分为10%Al₂O₃、10%MgO、5%CaF₂、二元碱度为3.5时精炼效果最佳。

关键词: 31CrMoV9钢, CaO-SiO₂-Al₂O₃-MgO-CaF₂系精炼渣, 碱度, Al₂O_3, , 夹杂物