不同铝含量的脱氧剂对钢液洁净度的影响

铝具备较强的脱氧能力，被广泛应用于炼钢过程中钢液的脱氧。然而铝脱氧产生的高熔点、大尺寸Al₂O₃夹杂物不仅会严重降低钢液的洁净度、恶化钢材韧性和疲劳寿命，还容易造成水口结瘤，影响连铸工艺的顺行。考虑到局部过饱和度对夹杂物的形核和长大等有着重要的影响，采用纯铝和Fe-30%Al合金(质量分数)对钢液进行脱氧，且实际加入的铝量保持一致，通过对不同脱氧时间(30、60 s)的钢液成分和夹杂物特征进行分析，研究了不同铝含量的合金对钢液洁净度的影响。结果表明，相较于纯铝脱氧，Fe-30%Al合金在相同时间节点下脱氧效果更好，合金中铝元素溶解速度更慢。此外，在目前试验条件下使用纯铝脱氧的钢样中夹杂物尺寸可达到9μm,而使用Fe-30%Al合金脱氧的夹杂物尺寸最大只有4μm。采用纯铝脱氧60 s后钢中夹杂物平均尺寸为Fe-30%Al合金脱氧的1.35倍，且单位面积夹杂物数量多了23%。两种合金在脱氧过程中残留在钢液中的夹杂物均以多面体夹杂为主，并有少量碰撞聚集形成的松散型团簇状夹杂。使用Fe-30%Al合金脱氧比纯铝脱氧更有利于钢液洁净度的提高，这取决于两...

Effect of deoxidizer with different Al content on cleanliness of molten steel

Al possesses strong deoxidation ability, thus is widely used in the deoxidation of molten steel during steelmaking. However, the high melting point and large size Al₂O₃ inclusions produced by Al deoxidation will not only seriously reduce the cleanliness of molten steel, and deteriorate the toughness and fatigue life of steel, but also easily cause nozzle nodules, which will affect the continuous casting process. Considering that local supersaturation has an important effect on the nucleation and growth of inclusions, pure Al and Fe-30%Al alloy (mass percent) were used to deoxidize the molten steel, and the actual amount of Al addition was consistent, and the effect of Al contents on the cleanliness of the molten steel was studied by analyzing the molten steel composition and inclusion characteristics of different deoxidation times (30, 60 s). The results show that compared with pure Al deoxidation, Fe-30%Al alloy has better deoxidation effect, and the dissolution rate of Al element in the alloy is slower. In addition, the maximum size of inclusions in the steel samples deoxidized with pure Al can reach 9 μm, while that in the test of Fe-30%Al alloy is only 4 μm. The average size of inclusions in the steel after pure Al deoxidation for 60 s is 1.35 times that of Fe-30%Al alloy deoxidation, and the number of inclusions per unit area is increased by 23%. The inclusions remained in the molten steel during the deoxidation process of the two deoxidizers are mainly polyhedral inclusions, and there are some loose cluster-like inclusions formed by collision and aggregation. Deoxidation of molten steel with Fe-30% Al alloy is more effective than that with pure Al, which depends on different local supersaturation in the initial deoxidation process.