This paper describes the development of an instrument to analyze the phase transformations of hot strip steel using an electromagnetic sensor. The sensor exploits variations in the electrical conductivity and magnetic permeability of the steel to monitor microstructure evolution during processing. The sensor is an inductive device based on a H-shaped ferrite core, which is interrogated with a multi-frequency impedance analyzer (MFIA) containing a digital signal processor (DSP). An overview of the instrument and measurements from a range of carbon steels sample are presented. The results verify the ability of the instrument both to monitor the micro-structural changes and to reject variations in liftoff distance between the sensor and the hot strip.
This paper presents an analytical model which describes the inductance change when a double air-cored coil sensor is placed next to a conducting plate. Analysis of the analytical model reveals that the phase signature of such sensor is virtually lift-off independent. This finding is verified by numerical evaluations. This paper also finds that the phase signature of a ferrite U-cored sensor can be approximated by that of a double aircored sensor of similar size, and therefore possesses similar lift-off independent property. Measurements made with a sample U-cored sensor next to plates of non-magnetic and magnetic materials verified the theoretical results .
Control of molten steel delivery in continuous casting is critical to ensure stability of the meniscus and satisfactory mould flow patterns, which in turn are determinants of steel cleanness and surface quality. Considerable effort has been expended over the last 10 years in optimizing the design of the metal delivery system, particularly the pouring nozzle, to enable the consistent production of high quality steel at high throughput. This paper looks forward to possible systems that are capable of topographically imaging the distribution of molten steel flows in these applications. The paper will concentrate on the feasibility of using electromagnetic methods. The paper will present some initial results and an overview of the image reconstruction process used will also be included.The paper will conclude with a discussion of possible future developments, such as the use of a tomographic or multifrequency approach, future research on the reconstruction image procedures and the potential for visualisation and flow measurement. There is a need for further research in this area and some priority areas for future work will be suggested.Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/24/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx
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