November 2020 - ArcelorMittal Global R&D has published a new paper which outlines the benefits of electromagnetic materials such as steel in modern electrified transport solutions. The paper, by ArcelorMittal Global R&D researchers Sigrid Jacobs and Jan Rens, outlines efficient steel solutions for the electromagnetic propulsion and braking systems of highspeed transport such as Hyperloop. Advanced steels offer many advantages in this application including very high resistivity, a lower skin effect, and less overheating. The latter is a particularly important consideration in systems such as Hyperloop which uses a maximum-efficiency approach to design. The transport system fulfils the goals of the EU’s Green Deal which aims to integrate eco-design and circular economy principles into new transport solutions which have minimal environmental impact.

Advanced steels examined in the paper are either laminated or bulk steels. They offer achievable combinations of permeability/saturation and resistivity. These steels also exhibit a positive impact on machine performance in terms of force development, flux redistribution, and losses. They are particularly useful in applications which are ruled by the presence of high frequency fields.

ArcelorMittal Global R&D’s approach is based on advanced material characterisation techniques. They include:

• High field-magnetisation measurements
• Identification of Preisach distribution based on multiple hysteresis measurements and JMAG’s Play/Stop models
• Eddy current analysis including skin effect
• Gradient material measurements of thin layer samples

The results show the importance of selecting the right active materials for machines and their structural parts. Linear machines for highspeed applications have specific material issues which are linked to skin effect. They also have modelling issues linked to boundary conditions and complex topologies. The combination of these phenomena can be difficult to master. But as this paper shows, ArcelorMittal has the inhouse skills and world-leading expertise to resolve these issues.