Electrical Steel – The Forgotten Material in Electrification

GNEE Electrical steel

Much effort has been made in examining the supply chain of commodities related to electrification: everything from copper to aluminium to critical battery materials such as lithium, nickel and cobalt. One overlooked material, however, is electrical steel. A small, niche segment of the steel industry – everything with a motor and every transformer contains electrical steel. Many questions have been raised regarding the capacity of steelmakers to produce sufficient volumes of electrical steels, particularly as increasing efficiency standards and more challenging applications drive the need for higher-quality, lighter gauge material. The high levels of required capex, combined with complex, somewhat secretive production methods (with some IP issues as well) and finally the potential for materials substitution with a new generation of amorphous steels have left this segment of the market in flux.

In most applications, steels are selected on the basis of mechanical properties – yield and tensile strength, hardness, toughness, n-values, and so on. Although mechanical properties are also important for electrical steels, it is the magnetic properties that are the key differentiator. High flux density (permeability), which is the amount of magnetisation produced in a material by an electric field) and low core loss, the amount of (unwanted) heat generated by an alternating magnetic field are the most important attributes of electrical steel.

Grain oriented electrical steel

Electrical equipment with rotating parts (such as motors) require steels with isotropic (non-oriented) properties such as fully-processed non-grain oriented electrical steel (NGOES) or semi-processed cold-rolled motor laminates (CRML, a product little seen outside of North America). Stationary electrical equipment (primarily transformers) utilises anisotropic grain-oriented electrical steel (GOES), where proper texture and material alignment allows for significantly higher flux density in the rolling direction.
As transformers are the sole major consumers of GOES, the market for this product is significantly smaller compared to NGOES, accounting for approximately one-third of the demand.