渣系中 MgO 含量对镁铝铁合金脱氧 H13钢中夹杂物的影响

摘要

采用 CaO-MgO-Al2 O 3-SiO 2-CaF2渣系的精炼渣,研究了渣系中 MgO 含量对镁铝铁合金脱氧 H13钢中夹杂物密度、尺寸和成分的影响.结果表明：采用质量分数5％MgO 精炼渣精炼后,钢中的夹杂物最少,密度为55．62个.mm-2,夹杂物尺寸均小于8μm；当 MgO 的质量分数低于或高于5％时,夹杂物数量都较多,都含有尺寸为8~10μm 的大型夹杂物；当精炼渣中 MgO 的质量分数为0时,钢中夹杂物主要为 MgO.Al2 O 3和 Al2 O 3-SiO 2,当精炼渣中 MgO 的质量分数为5％,8％和12％时,钢中的夹杂物分别主要为 MgO.Al2 O 3和 Al2 O 3-SiO 2、MgO.Al2 O 3和 Al2 O 3-SiO 2-CaO、MgO.Al2 O 3和 Al2 O 3-SiO 2-CaO-MgO；通过热力学数据计算得到的与钢中镁、铝相对应的氧化物稳定区图与试验得到的 A 类夹杂物的成分一致.%The effects of MgO contents in slag system CaO-SiO 2-Al2 O 3-MgO-CaF2 on the number,size and composition of inclusions in H13 steel deoxidized with Mg-Al-Fe alloy were studied.Results show that when the content of MgO in the slag was 5wt%,the minimum number of inclusions was 55.62 per square millimeter,and the size of all inclusions was less than 8 μm.When the content of MgO in the slag was less than or more than 5wt%, there was more number of inclusions in the steel,and the size of some inclusions was 8-10 μm.When the content of MgO in the slag was 5wt%,8wt%,12wt%,respectively,the inclusions were MgO.Al2 O 3 and Al2 O 3-SiO 2 , MgO.Al2 O 3 and Al2 O 3-SiO 2-CaO,MgO.Al2 O 3 and Al2 O 3-SiO 2-CaO-MgO,respectively.A stability diagram of inclusions corresponding to magnesium and alumina contents in the steel was calculated employing available thermodynamic data,and the A-type inclusion composition experimentally obtained well agreed with the diagram.