ArcelorMittal Europe – Flat Products

Online client newsletter | June 2019

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Electrical steels for automotive

New iCARe® 420 Save grades boost the power density of efficient traction motors

While the driving range of electric vehicles (EVs) can be enhanced by installing more batteries, this is costly for consumers. Another approach is to optimise the entire electric powertrain as one by considering the performance, weight, and cost of all its components and materials. Additional improvements in driving range can be achieved by utilising advanced electrical steels such as ArcelorMittal’s iCARe® range. Now there’s a new member of the iCARe® family: iCARe® 420 Save which combines low losses with improved and guaranteed yield strength, resulting in an increase in the power density and energy efficiency of electric traction motors.

Electrical steels are found in every part of a modern vehicle – from the small motors which drive mirrors and seats to the larger machines that are used in the propulsion systems of hybrid or full EVs. Traction motors and generators in those alternative drive trains are particularly dependent on highly efficient electrical steels.

Example of a typical rotor and stator for an interior permanent magnet synchronous machine

iCARe® is ArcelorMittal’s range of innovative electrical steels for the automotive market

New iCARe® 420 Save family released

The iCARe® range already includes three families of electrical steels for different applications. The steels in the iCARe® Speed family offer the highest mechanical strength, making them ideal for compact, high-speed rotors with higher power density. But to obtain these high mechanical strength values, the magnetic power losses of ArcelorMittal’s iCARe® Speed grades are slightly impacted. For this reason, iCARe® Speed grades are only approved for rotor applications in synchronous machines.

To overcome this limitation, a new iCARe® family was recently launched by ArcelorMittal. Known as
iCARe® 420 Save, the new grades are low loss electrical steels which have an improved guaranteed yield strength of
420 megapascals (MPa).

Improved mechanical stress calculations allow designers to create smaller electrical machines

The iCARe® 420 Save family offers higher mechanical strength than standard iCARe® Save grades, but without any detrimental effect on its magnetic properties (such as magnetic power losses). This makes iCARe® 420 Save the best choice to enhance the magnetic properties of stators, while providing the necessary mechanical properties needed for rotors. Another advantage is that both stators and rotors can be punched from the same grade of iCARe® 420 Save, which reduces cost.

ArcelorMittal has already begun commercial production of iCARe® 420 Save at our mill in St-Chély d’Apcher (France). The steels can be shipped almost anywhere in the world.

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