耐火材料对95Cr切割丝用钢中夹杂物的影响

 为了开发更优质的耐火材料以提高切割丝用钢的洁净度,试验采用MoSi₂炉研究了MgO、MgO-CaO两种耐火材料对95Cr切割丝用钢中夹杂物的影响。结果表明,MgO、MgO-CaO两种坩埚冶炼均能使钢成分控制在目标范围内,夹杂物成分落点控制在目标低熔点区内。但与MgO坩埚相比,MgO-CaO坩埚净化钢液的效果更好,主要表现为两个方面。一方面,钢中P、S、Al_s、TO]含量均更低。特别是w(S])可降低至0.000 6%,w(Al]_s)降低到0.000 3%,w(TO]) 降低到0.000 5%。另一方面,钢中夹杂物数量更少、尺寸更小、复合夹杂物中Al₂O₃的含量更低。具体表现为,经MgO-CaO坩埚冶炼后,钢中等效直径小于2 μm的夹杂物所占比例为91%,而经MgO坩埚冶炼的钢,此项值仅为78%;经MgO-CaO坩埚冶炼后,钢中复合夹杂物中w(Al₂O₃])几乎都低于10.0%。这主要是因为MgO-CaO耐火材料中的MgO、CaO均能脱磷,同时CaO还有间接脱硫、去除钢中Al₂O₃夹杂物的作用。

Effect of refractories on inclusions in 95Cr saw wire steel

In order to develop better refractories to improve the purity of saw wire steel, the effects of MgO and MgO-CaO refractories on inclusions in the 95Cr saw wire steel were studied using MoSi₂ furnace in the present experiment. The results indicated that both MgO and MgO-CaO crucibles can control the composition of all of the elements in the steel within the target range and the drop point of inclusion composition within the target low melting point zone. However, compared with the MgO crucible, the MgO-CaO crucible has a better effect in purifying the molten steel, mainly in two aspects. On the one hand, the contents of P, S, Al]_s and TO] in steel are lower. Especially, the w(S]) can be reduced to 0.000 6%, the w(Al]_s) to 0.000 3% and the w(TO]) to 0.000 5%. On the other hand, the number of inclusions in steel is less, the size is smaller, and the content of Al₂O₃ in composite inclusions is lower. Specifically, the proportion of inclusions with an effective diameter of less than 2 μm in steel is 91% after smelting with MgO-CaO crucible, while that of the steel smelted with MgO crucible is only 78%. Moreover, after the MgO-CaO crucible smelting, the mass percent of Al₂O₃ in complex inclusions in steel is almost less than 10.0%. This is mainly because both MgO and CaO in MgO-CaO refractories can remove P, and CaO also removes S and Al₂O₃ inclusions in the steel.