Reliable, inline monitoring of material properties is a crucial success factor for flat steel manufacturers. With high-strength steels in particular, it is often difficult to detect even the smallest deviations in production in time. The EMG IMPOC system provides customers with a scientifically validated tool that can be used specifically for ferromagnetic steels. It enables precise, non-destructive measurements directly in the line. This allows quality fluctuations to be detected before they become costly. In this article, we show how research and practice were brought together in the EU project "Product Uniformity Control".
EMG IMPOC: Inline measurement of material properties during production
EMG IMPOC played a central role in the EU project "Product Uniformity Control" [1] when it came to visualising material properties directly in ongoing production. The aim was to monitor the microstructure and mechanical properties of modern high-strength steels inline without having to rely on purely destructive tests. EMG IMPOC provided continuous electromagnetic signals over the entire length of steel strips. This made it possible to identify suspicious sections and examine them in more detail. Particularly important: EMG IMPOC responded reliably to the smallest differences in structure, which were hardly detectable in conventional testing methods. This made practical, highly sensitive inline control possible for flat steel manufacturers for the first time ever.
Scientifically validated results from the EU project "Product Uniformity Control"
The results of the project clearly demonstrate the scientific and practical value of EMG IMPOC. In direct comparison with ultrasonic methods, electromagnetic methods proved to be significantly more sensitive to changes in the microstructure. EMG IMPOC was able to detect even minimal strength changes of less than 2 % – values that were barely visible under a microscope, but which have a practical impact on the properties of the steels. In dual-phase steels, for example, a continuous increase in IMPOC signals was measured in the first 60 metres of a coil, which correlated exactly with a slight but relevant increase in strength. In microalloyed steels, on the other hand, EMG IMPOC clearly identified overheating above the austenitising temperature. This scientifically proves that EMG IMPOC is a reliable and practical extension to classic testing methods.
Advantages for flat steel manufacturers: keeping a reliable eye on material properties
EMG IMPOC offers flat steel manufacturers several advantages in everyday production. On the one hand, it enables the identification of strip sections with deviating material properties during the ongoing process. This allows potential quality problems to be detected and isolated at an early stage. Secondly, the high sensitivity of EMG IMPOC – up to four times stronger than the reaction in conventional tensile tests – and continuous measurement over the strip length provide a data basis that makes adaptive process control possible in the first place. Instead of working rigidly with fixed parameters, production lines can react dynamically to deviations. This increases process stability, reduces the scrap rate and increases yield. For end customers, such as those in the automotive industry, this also means consistently high quality of the steel products supplied – and strengthens the competitive position of manufacturers in the long term.
Areas of application and limitations
The EU project has also shown that EMG IMPOC has clearly defined areas of application. The technology is based on electromagnetic measurement methods and is therefore only applicable to ferromagnetic steels. It is precisely in this range of materials – from micro-alloyed to high-strength dual-phase steels, which are in high demand in the automotive industry – that EMG IMPOC has impressively demonstrated its strengths. Here, it was able to detect the smallest differences in the microstructure and correlate them with mechanical properties such as tensile strength and yield strength. However, there are limitations when it comes to non-ferromagnetic materials, where the physical basis for measurement is lacking. In addition, interpreting the results requires in-depth metallurgical knowledge in order to correctly interpret the relationships between signal curves, process conditions and material properties. In practice, this means that EMG IMPOC is a highly effective tool for flat steel manufacturers who produce ferromagnetic steels – and this is precisely where it offers the greatest added value.
Conclusion
Against the backdrop of increasing demands on quality, efficiency and resource conservation, the results of the European research project "Product Uniformity Control" have impressively demonstrated how EMG IMPOC is revolutionising the monitoring of material properties in flat steel production. With up to four times higher sensitivity compared to conventional methods, flat steel manufacturers can detect even the smallest deviations in the microstructure and control their processes in a targeted manner. This means less scrap, greater process reliability and consistently high product quality – especially for demanding grades such as high-strength steels. EMG IMPOC is therefore not only scientifically validated, but also a tried-and-tested instrument for the future of steel production.
For details and possible applications, please contact our sales team, our product manager Franziska Kneisel (franziska.kneisel@emg-automation.com) or visit our website.
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Reference
[1] Van den Berg, F. D., Kok, P. J. J., Yang, H., Aarnts, M., Meilland, P., Kebe, T., Stolzenberg, M., Krix, D., Zhu, W., Peyton, A. J., Martinez-de-Guerenu, A., Gutierrez, I., Jorge-Badiola, D., Malmström, M., Volker, A., Duijster, A., Wirdelius, H., Boström, A., Mocci, C., Vannucci, M., Colla, V., Davis, C., Zhou, L., Schmidt, R., Labbé, S., Reboud, C., Skarlatos, A., Leconte, V., & Lombard, P. (2018, June). Results of the European collaborative project "Product Uniformity Control" to improve the inline sensing of mechanical properties and microstructure of automotive steels. In 12th European Conference on Non-Destructive Testing (ECNDT 2018), Gothenburg, Sweden.