Ever more stringent European Union regulations are driving the market trend for electrical motors towards highest possible efficiency. This translates into a continuous quest for electrical steels with the lowest possible magnetic iron losses.

OCAS Gent, as research centre of the ArcelorMittal group in charge of R&D on electrical steels, has vast expertise in developing such advanced low loss electrical steel grades. The tendencies are clear: we optimist the chemical composition, grain size, crystallographic texture and minimize the crystallographic defects such as precipitates, and step-by-step, within industrial constraints, we achieve lower magnetic losses.

However, some crucial questions remain unanswered to prepare for long-term future actions: what are the lowest possible magnetic losses we can achieve? How much lower, compared to the current state-of-the-art? And which features have the biggest effect?

goal
With this thesis we want to tackle this issue from another angle, by micro-magnetic modelling. The main advantage of modelling is that the contributing microstructural features can be altered independently from each other; which is practically impossible by sample preparation for physical experiments.

Hence the purpose is to achieve clearer and separated insights into the hysteretic loss mechanisms with a numerical micro-magnetic approach, by modelling the effect of the electrical steel’s microstructure on the hysteretic behaviour of the local magnetisation, organised in magnetic domains.

EELAB has many years of experience with micro-magnetic computations. During the master thesis the aim is carry out different micro-magnetic numerical experiments of well-chosen microstructures - from perfect towards realistic structures - and to compare the resulting magnetic hysteretic behaviour.

Assisted by CMM, ab initio calculations can be carried out to determine the effect of the chemical composition on the physical material parameters such as magneto-crystalline anisotropy constants, which then serve as input parameters for the micro-magnetic computations. Primary focus is on one particular chemical composition of a highly alloyed electrical steel.