Secondary steelmaking process stream optimization - inclusions, clogging, and segregation

钢中的微粒，也称为夹杂物，是非常不受欢迎的。尽管现代炼钢实践已经发展到减轻大多数有害影响，但夹杂物对最终产品的性能是有害的，它们堵塞了从二次炼钢到连铸过程阶段的钢液的浸入式入口和计量喷嘴，并且它们影响了铸造过程中的溶质偏析/显微组织演变。目前，这些问题的解决方法是：(a)在钢包冶金过程中溶解液态氧化物系统（渣）中的夹杂物，(b)钙处理以控制形状，以及(c)频繁更换sens。这些缓解策略中的每一种都有其自身的后果，对产品质量产生负面影响。考虑到夹杂物对钢材质量的影响，有必要对从钢包炉到铸件的二次炼钢工艺流程进行优化。

Micro-particles in steel, also known as inclusions, are highly undesirable. Although modern steelmaking practices have been developed to mitigate most of the deleterious effects, inclusions are detrimental to the properties of the final product, they clog the submerged entry and metering nozzles that transfer molten steel from secondary steelmaking to the continuous casting process stages, and they affect solute segregation / microstructure evolution during casting. At present, these issues are dealt with by (a) dissolving inclusions in a liquid oxide system (slag) during ladle metallurgy, (b) calcium treatment for shape control and (c) frequent replacement of the SENs. Each of these mitigation strategies has their own consequences that negatively impact product quality. Given the impact of inclusions on steel quality, there is need to optimize the secondary steelmaking process stream from the Ladle Metallurgy Furnace (LMF) to the cast product. In this collaborative study with Gerdau and Laurel steel, a suite of fundamental models will be developed that predict steel cleanliness in a wide range of steelmaking practices and products in the LMF, nozzle clogging based on interactions between the melt and the inner surface of the SEN, and subsequent compositional segregation and microstructure development during continuous casting. The models will be verified against plant data and samples taken from the industrial sponsors. Long-term, this set of models will form the basis of an online tool for optimizing the secondary steelmaking process stream. As the models are based on the fundamentals of thermochemistry, transport phenomena, and solidification, a modification procedure will be developed enabling application for any Canadian steel mill.