Magnetic Materials Properties

Commonly, ferromagnetic or ferrimagnetic materials are considered magnetic materials, although other materials (diamagnetic and paramagnetic) also exhibit some magnetic properties. Magnetic materials can be classified into two categories: soft magnetic materials and hard magnetic materials [1].

Coercivity is assumed as the main criterion, and IEC Standard 404-1 recommends the coercivity of 1000 A/m as a value to distinguish both groups. This border is symbolic because both classes are completely different. From soft magnetic materials, we require the coercivity to be as small as possible while hard magnetic materials should have coercivity as high as possible [1].

There is also a subclass of hard magnetic materials called semi-hard magnetic materials (with coercivity between 1,000 and 100,000 A/m) [1].

Electrical GO steel is classified according to international standards based on the power loss. European standard EN 10107 uses the following nomenclature for the steel grades:

• First letter M for electrical steel
• Three digits after the first letter denote value of specific loss measured at 1.5 or 1.7 T
• Two further digits represent the thickness
• Last letter describes type of material: N, normal (loss measured at 1.5 T), S, reduced loss (loss at 1.7 T); P, high permeability (loss at 1.7 T)

For example, M097-30N means electrical steel (M) of normal grade (N) with material thickness 0.3 mm (30) and power loss at 1.5T not exceeding 0.97 W/kg.

Basic properties for the examples of GO SiFe steel according to EN Standard 10107 [1] are given in the spreadsheet "Classification of Electrical Steel according to Standard EN10107.xlsx". The standard determines maximum anisotropy of loss, which is tested using two sets of samples - one cut perpendicular and one parallel to the rolling direction.

This repository data on some electrical steel grades [1]:

M089-27N (conventional grain-oriented steel):

• Thickness: 0.27 mm
• Power loss at 1.5 T, 50 Hz: 0.89 W/kg
• Maximum polarization (Jmax): 1.9 T
• Coercivity (Hc): 15 A/m
• Maximum permeability (μmax): 40,500

M100-23P (high-permeability "HiB" grain-oriented steel):

• Thickness: 0.23 mm
• Power loss at 1.7 T, 50 Hz: 1.0 W/kg
• Maximum polarization (Jmax): 1.83 T
• Coercivity (Hc): 24.2 A/m
• Maximum permeability (μmax): 51,700

Magnetization curves are reconstructed for these steels as smooth splines and can be reused via SplineCloud API.

References

[1] S. Tumanski. Magnetic Materials from: Handbook of Magnetic Measurements. 23 Jun 2011, Measurements CRC Press,

https://www.routledgehandbooks.com/doi/10.1201/b10979-4