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某钢厂为节约炼钢成本,试图采用CAS工艺替代传统LF工艺精炼SPA-H钢,但是否会影响钢材洁净度仍存争议。采用总氧分析与ASPEX扫描电镜的自动特征分析功能研究了SPA-H钢卷的洁净度,并对比了CAS与LF工艺的夹杂物特征。结果表明:两种精炼工艺生产的钢卷w(T.O)=(18~19)×10~(-6),相差不大。钢卷中显微夹杂物主要有CaS-Al2O3,Al2O3,(Ca,Mn)S和TiN夹杂物,大型夹杂物全部为纯MnS夹杂物。典型CAS工艺炉次轧板的显微夹杂物主要是(Ca,Mn)S和Al2O3,而典型LF精炼工艺炉次轧板的显微夹杂主要为CaS-Al2O3夹杂物(比例达81.3%)。CAS工艺的大型MnS夹杂物数量明显高于LF工艺,与Factsage热力学计算吻合较好。夹杂物特征差异的原因是试验CAS工艺炉次的精炼渣平均w(TFe)=2.1%高于LF工艺(0.6%),CAS工艺在硫含量和喂钙吸收率控制上不如LF工艺,导致钢中w(Ca)/w(S)小于LF工艺,因此,为减少大型夹杂物数量,采用低成本CAS工艺精炼SPA-H应加强钙处理效果和顶渣改质。
A steel mill to save the cost of steel, trying to use the CAS process to replace the traditional LF refining SPA-H steel, but it will affect the steel cleanliness is still controversial. The cleanliness of SPA-H coil was studied by the total oxygen analysis and the automatic feature analysis of ASPEX SEM. The inclusion features of CAS and LF were compared. The results show that the steel coils w (T.O) = (18 ~ 19) × 10 ~ (-6) produced by the two refining processes have little difference. The microscopic inclusions in the coil mainly include CaS-Al2O3, Al2O3, (Ca, Mn) S and TiN inclusions, and all the large inclusions are pure MnS inclusions. The microscopic inclusions of typical CAS process plates are mainly (Ca, Mn) S and Al2O3. The typical micro-inclusions in the typical LF refining process are CaS-Al2O3 inclusions (81.3%). CAS process of large number of MnS inclusions significantly higher than the LF process, Factsage thermodynamic calculation is in good agreement. The reason for the difference in inclusions was that the average refining slag w (TFe) = 2.1% of the trial CAS process was higher than that of the LF process (0.6%), and the CAS process was inferior to the LF process in controlling the sulfur content and the calcium absorption rate, Therefore, in order to reduce the number of large inclusions, refining the SPA-H with a low-cost CAS process should enhance the calcium treatment effect and the top slag modification.