Development of multiple applications based on new magnetic sensors in steel industries – Demams

The target of the project was to develop new magnetic sensors to help measure process variables in steel production, such as velocity or elongation.

Uniovi developed high sensitive magnetic sensors for a harsh environment.

A non-contact speed-measuring device based on the developed sensor was installed in the continuous annealing line of Aceralia. The system used a magnetic marker and two sensors separated more than 2 cm from the strip, working on a differential principle to improve accuracy. A more or less 0.5% accuracy figure was obtained additionally the line deceleration system has been improved.

The measuring principle is based on counting the time taken by the magnetic mark to cross the distance between marker and sensor (CSM), or two sensors (Aceralia) . The BFI principle is based on computing a phase shift of several waves of th esame frequency embedded in the distance. A PLL keeps the frequency at its correct value.

in skin-pass mills, thickness reductions of as low as 0.1% are normal, resulting in the corresponding velocity increase, therefore a very high resolution was required.

BFI and CSM developed an elongation measuring system for skin-pass mills. CSM used the technology provided by Uniovi whilst BFI used PLL-based technology, but, in both, the equation of mass flow conservation was considered.

CSM obtained a more or less 1.0% accuracy figure in a mill processing ferritic stainless steel.

Although the system proved to be affected by the effect of surrounding magnetic fields and by magnetic mark speading, following some recommendations and improvements, the system could be interesting for industrial use.