高强冷镦钢LF精炼过程夹杂物的变化行为

Change behavior of inclusions in high strength cold heading steel during LF refining

通过多种分析手段系统研究了40Cr冷镦钢LF精炼过程夹杂物的变化，得到LF精炼过程钢中夹杂物面积比与T．O含量变化规律相一致，从LF进站到LF出站，钢中夹杂物面积比由1．41％减小到0．45％；并且LF精炼能够有效地去除当量直径大于10μm的大颗粒夹杂物，绝大部分夹杂物的当量直径都落在2～5μm。LF采用高碱度、强还原性炉渣精炼，结合钙处理技术，可以有效地使钢中Al2O3夹杂转变为MgO-Al2O3系、CaO-Al2O3系和CaO-MgO-Al2O3系夹杂，改善钢的可浇性和冷镦性能；但需进一步合理的控制钙处理工艺，减少钢液的卷渣和二次氧化，提高钢液的洁净度。

In this paper, the change of inclusions in 40Cr cold heading steel during LF refining was systematically studied by a variety of analysis means. It was found that the area ratio of inclusions and total oxygen in steel changed consistently during LF refining, and inclusion~ s area ratio in steel was reduced from l. 41 % to 0.45 % after LF refining. And LF refining could effectively remove the large inclusions whose equivalent diameter was greater than 10μm, and most of the equivalent diameter of inclusions were fall in the range of 2 - 5μm. Moreover, when high basicity and highly reductive slag was used in LF refining, combining with calcium treatment technology, it could effectively transfer Al2O3 inclusions to MgO-Al2O3 system,CaO-Al2O3 system and CaO-MgO-Al2O3 system inclusions~ therefore, the castability and cold-heading properties of steel were improved. But calcium treatment process was necessary to be controlled more reasonably in order to reduce slag entrapment and secondary oxidation and improve cleanliness of molten steel.