In situ steel solidification imaging in continuous casting using magnetic induction tomography

Abstract

The solidification process in continuous casting is a critical part of steel production. The speed and quality of the solidification process determines the quality of the final product. Computational fluid dynamics (CFD) simulations are often used to describe the process and to design its control system but, so far, there has been no tool that provides an online measurement of the solidification front of hot steel during the continuous casting process. This paper presents a novel magnetic induction tomography (MIT) solution, developed in the EU-funded SHELL-THICK project, to work in a real casting setting and to provide a real-time and reliable measurement of the shell thickness in a cross section of the strand. The new MIT system was installed at the end of the secondary cooling chamber of a casting unit and tested over several days in a real production process. MIT is able to create an internal map of the electrical conductivity of hot steel deep inside the billet. The image of electrical conductivity is then converted to a temperature profile that allows the measurement of the solid, mushy and liquid layers. In this study, such a conversion is done by synchronizing in one time step the MIT measurement and the thermal map generated with the actual process parameters available at that time. The MIT results were then compared with the results obtained with the CFD and thermal modelling of the industrial process. This is the first time in situ monitoring of the interior structure has been carried out during a real continuous casting.

Magnetic Induction Tomography Sensors for Quantitative Visualization of Liquid Metal Flow Shape

“…Operating frequency of 130 Hz (penetrating 24 depth through GaInSn) is chosen. This particular operating frequency was also successfully applied in previous work on steel imaging [17].…”

Noninvasive Conductivity and Temperature Sensing Using Magnetic Induction Spectroscopy Imaging

“…Correspondingly, the observation of temperature profile of hot steel inside the billet has been attempted. Internal map of electrical conductivity which is related to the measurement of the solid, mushy and liquid layers was reported [10]. The study synchronises the magnetic induction tomography (MIT) and the thermal map from the actual process parameters.…”

A Review on Fast Tomographic Imaging Techniques and Their Potential Application in Industrial Process Control

“…Early industrial applications of MIT focused on its use in liquid metal diagnostics [ 45 ] and some theoretical studies focused on its possible use in metal solidification, both in the field of steel continuous casting. Application for metal flow imaging was further investigated in [ 46 ] and use in a real continuous casting solidification was demonstrated in [ 47 ]. The injection of argon gas and stoppers opening in submerged entry nozzles in steel production can be controlled via the liquid metal flow regime identified by the MIT sensors.…”