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在芬兰奥托昆普不锈钢厂的2号连铸机上对固态结晶器保护渣渣层的演变作了研究。为研究固态保护渣渣层的形成,在不锈钢连铸的初期阶段,在保护渣中添加了氧化钡示踪剂。实验钢种牌号为美国钢铁学会标准304钢种。实验中,浇铸一炉钢水,尾坯输出时,在结晶器顶部提取固态渣层渣样。采用的取样方式可在钢液弯月面下方取得几乎和结晶器同样宽度,长度大约为25cm的一些大尺寸渣样。从这些渣样上提取3个与钢液弯月面距离各不相同的小渣样,然后对这3个小渣样进行X射线荧光光谱分析,检测氧化钡。有些情况下在大渣样的底部边缘处检测到了最高浓度的氧化钡。大渣样底部的氧化钡浓度较高意味着在浇铸初期,钢液弯月面附近已固化的保护渣渣层已向下移动。而在钢液弯月面附近的固态渣层中的氧化钡浓度更低,意味着由于结晶器顶部液态渣层中氧化钡的浓度已下降,渣层在浇铸期间形成的时间较晚。结晶器中固态渣层的形成及渣层在弯月面下方的破裂和再固化与氧化钡的浓度密切相关。
The evolution of solidified mold slag layer was investigated at No.2 caster at Outokumpu’s stainless steel plant in Finland. In order to study the formation of the solid slag layer, a barium oxide tracer was added to the mold powder in the initial stage of continuous casting of stainless steel. Experimental steel grades for the American Iron and Steel Institute standard 304 steel. In the experiment, a molten steel was cast, and when the tail blank was exported, a solid slag layer was sampled at the top of the crystallizer. Sampling method used in the molten steel can be obtained below the meniscus and almost the same width of the mold, the length of about 25cm of some large-size slag samples. Three slag samples with different distances from the meniscus of the molten steel were extracted from these slag samples, and the three small slag samples were analyzed by X-ray fluorescence to detect barium oxide. In some cases, the highest concentration of barium oxide was detected at the bottom edge of the large slag sample. The higher concentration of barium oxide at the bottom of the large slag means that the solidified slag layer near the meniscus of molten steel has moved downward during the initial casting. The lower concentration of barium oxide in the solid slag layer near the meniscus of the molten steel means that the slag layer is formed later during casting due to the reduced concentration of barium oxide in the liquid slag layer at the top of the mold. The formation of solid slag layer in the mold and the rupture and re-solidification of slag layer below the meniscus are closely related to the concentration of barium oxide.