Abstract
Problem Statement (Relevance): This article describes a method for determining the depth of a meniscus that may occur in liquid steel caused by the electrodynamic forces present in an AC electric arc furnace (EAF). Such information can be helpful when assessing the degree of arc shielding or optimizing the furnace operation. Until recently, it used to take costly experiments to identify the parameters which characterize the effect produced by the arc on steel as there were no means to monitor them. Objectives: This paper aims to develop an approach to identify such parameters based on a large amount of process data accumulated under normal operating conditions. Methods Applied: The method is based on the correlation between the electrode movement and the changing electrical parameters of the furnace. A number of different arc models have been considered and a number of assumptions made as to the shape of meniscus, which can help estimate the effect of electrodynamic forces. The process data that was used for model calibration included 300 heats. Originality: This paper demonstrates the actual possibility of using simple models simulating the interaction between the AC arc and the liquid steel to identify the meniscus depth based on actual process data. The article also provides all the necessary mathware and algorithms. Findings: Based on the assumptions made, a mathematical expression was established that represented the relationship between the average depth of the meniscus and the effect produced by the arc on steel. Relasionships were established for the meniscus depth as a function of the electrical parameters in the instance of EAF-180 functioning at the site of Magnitogorsk Iron and Steel Works OJSC. Practical Relevance: Using the information about the meniscus depth, one can estimate what degree of arc shielding is required for different operating modes while tackling the power optimization tasks. Another important application is the opportunity to study disturbances as correlated with the level of steel in the furnace, which can serve as an indirect indication of the turbulence patterns.
Keywords
Electric arc model, submersion, axial electrodynamic forces, meniscus depth, arc column.
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