低合金高强钢中非金属夹杂物的改性

Modification of non-metallic inclusions in high-strength low-alloy steel

摘要: 借助热力学软件Thermo-Calc和ASPEX自动扫描电镜等分析手段,研究了低合金高强钢精炼过程渣-钢反应和钙处理对夹杂物改性行为的影响.通过提高炉渣碱度和w(CaO)/w(Al₂O₃)值以及降低炉渣氧化性等措施,钙处理前钢中Al₂O₃夹杂物转变为靠近1600℃液相区的CaO-MgO-Al₂O₃复合夹杂物和少量的MgO·Al₂O₃尖晶石.在渣-钢反应对Al₂O₃部分变性的基础上,钙线喂入量每炉由优化前的800 m减少到300 m仍能达到夹杂物改性的目的.

Abstract: The influences of slag-metal reaction and calcium treatment on inclusion modification in high-strength low-alloy steel were studied by means of Thermo-Calc thermodynamic software and ASPEX automated scanning electron microscope. The results of industrial trials show that by increasing the basicity, reducibility and w(CaO)/w(Al₂O₃) of slag, Al₂O₃ inclusions are partially modified to CaO-MgO-Al₂O₃ complex inclusions nearby the liquid phase zone at 1 600℃, as well as a few MgO·Al₂O₃ spinel. On the basis of this change, the purpose of inclusion modification is still achieved with the addition of CaSi-wire decreasing from 800 m to 300 m for a heat.