精炼渣对轴承钢中氧含量和夹杂物的影响

采用MoSi₂电阻炉在MgO质坩埚内进行了精炼渣成分(%:47～64CaO、13～23SiO₂、15～25Al₂O₃、5～10MgO、0～8CaF₂；CaO/SiO₂=2.0～4.5)对0.95%C-1.50%Cr GCr15轴承钢中氧含量和夹杂物的影响的实验研究。实验中发现,随精炼渣碱度CaO/SiO₂由2增加至4.5,钢液中的终点全氧含量由20×10^-6降至11×10^-6,夹杂物的总数量、总面积和平均半径减小。适当提高Al₂O₃含量或添加CaF₂,减少MgO含量,可以显著提高炉渣吸附夹杂物的速度和能力。低碱度渣精炼的钢液中夹杂物成分含有≥20%SiO₂,塑性较好,夹杂物的尺寸为15～20μm。高碱度渣精炼的钢液中典型的夹杂物是氧化铝和铝镁尖晶石等脆性夹杂物,尺寸≤5μm。

Influence of Refining Slag on Oxygen Content and Inclusions in Bearing Steel

The infuence of ingredient of refining slag(47～64CaO,13～23SiO₂,15～25Al₂O₃,5～10MgO,0~ 8CaF₂;CaO/SiO₂=2.0~4.5) on oxygen content and inclusions in 0.95C-1.50Cr CCr15 bearing steel has been tested and studied by MoSi₂ electrical resistance furnace with MgO crucible. It was found in test that with increased refining slag basicity CaO/SiO₂ from 2 to 4.5,the end total oxygen content in liquid steel decreased from 20×10^-6 to 11×10^-6,and the total amount,total area and average size of inclusions in steel decreased; the speed and capability of refining slag to absorb inclusions could remarkably increase with increasing Al2O3 content or adding CaF₂,decreasing MgO content in slag; with low basicity refining slag,the size of inclusions in liquid steel,which contained ≥20% SiO₂,was 15～20 μm with quite good plasticity; and with high basicity slag the typical inclusions in liquid steel were brittle inclusions such as alumina and MgO-Al₂O₃ spinel,of which the size was ≤5 μm.