铝脱氧含硫钢结瘤现象的分析

对某厂铝脱氧含硫QC40钢的结瘤现象进行了分析研究,取样分析了浸入式水口内壁的结瘤物,并对棒材夹杂物进行了分析。经扫描电镜及能谱分析发现结瘤物分为两层结构,靠近水口内壁层的结瘤物主要是MgO·Al2O3、高熔点CaO-Al2O3和低熔点CaO-Al2O3;第二层的结瘤物主要是MgO·Al2O3、高熔点CaO-Al2O3和CaS。棒材中的夹杂物主要为MgO·Al2O3、高熔点CaO-Al2O3和CaS夹杂物。分析认为出现这种结瘤现象的原因是CaS属于高熔点夹杂物,但其和钢水的润湿角为87°(小于90°),属于和钢水润湿性较好的夹杂物,而MgO·Al2O3和高熔点CaO-Al2O3与钢水的接触角均大于90°,属于高熔点且与钢水润湿性差的夹杂物,因此出现了CaS夹杂物仅能在第二层结瘤的现象。利用FactSage软件对铝脱氧含硫钢的钙处理工艺进行了理论优化,认为通过优化钙处理工艺,减少二次氧化等措施,能够减少乃至杜绝浸入式水口的结瘤行为。

Analysis on clogging phenomenon of aluminum deoxidized sulfur-containing steel

Nodulation phenomenon of aluminium deoxidized sulphur-containing QC40 steel in a certain factory was analyzed.By scanning surface electron microscopy and energy spectrum analysis, it was found that the nodules were divided into two layers. The nodules near the inner layer of the nozzle were mainly MgO·Al₂O₃, high melting point CaO-Al₂O₃ and low melting point CaO-Al₂O₃. The nodules in the second layer are mainly MgO·Al₂O₃, CaO-Al₂O₃ with high melting point and CaS.The inclusions in the bar are mainly MgO·Al₂O₃, CaO-Al₂O₃ with high melting point and CaS inclusions.Analysis that appear this kind of phenomenon of nodular CaS belongs to high melting point is the cause of inclusion, but the liquid steel and wetting angle of 87° （less than 90°）, belongs to the wettability of molten steel and inclusion, Al₂O₃ and MgO style and high melting point CaO-Al₂O₃ and contact angle of liquid steel is greater than 90°, belongs to the high melting point and inclusion with poor wettability of molten steel, thus the CaS inclusions can only in the second the phenomena.The FactSage software was used to theoretically optimize the calcium treatment process of aluminum deoxidized sulfur-containing steel, and it was believed that by optimizing the calcium treatment process and reducing the secondary oxidation, the nodulation behavior of the immersed nozzle could be reduced or even eliminated.