Electrical Steel (Silicon Steel)
A magnetic steel for laminations
Typical values for the temper in the title
Electrical steel is iron with silicon (usually up to about 3.5%) and very low carbon. Silicon raises electrical resistivity and lowers eddy current losses in AC, and thin sheet with an insulating coating lowers them further.
There are two types: grain-oriented steel, with very low losses in one direction, for transformers; and non-oriented steel, with similar properties in all directions, for motors and generators. It is the most common magnetic material in the world.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Density ρ | ≈7.65 | |
| Magnetic saturation Bs | ≈2.0 T (typical) | |
| Machinability | — | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Si silicon | up to about 3.5 | high electrical resistivity |
| C carbon | very low | |
| Fe iron | balance |
Standards: ASTM A677 (non-oriented), ASTM A876 (grain oriented), EN 10106 and EN 10107.
Conditions and product forms
Electrical steel is ordered by grade, which defines maximum losses (W/kg) at a given thickness.
| Condition | Properties | When to choose it |
|---|---|---|
| Non-oriented (EN 10106, ASTM A677) | similar properties in all directions | motors and generators |
| Grain oriented (EN 10107, ASTM A876) | very low losses in the rolling direction | transformers |
Applications
- Transformer laminations
- Motor laminations
- Generators
- Inductors and chokes
- Relays
Fabrication
Cutting
Laminations are stamped or laser cut. Cutting hurts properties near the edge, and sometimes they are annealed after cutting.
Coating
There is an insulating coating between layers. Do not remove it.
Direction
In grain-oriented steel, flux must flow in the rolling direction.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| Magnetic Pure Iron (Armco) | — / | Good | pure iron: for DC · material page |
| Hiperco 50 | — / | — | Hiperco 50: high saturation, expensive · material page |
| 48% Nickel-Iron (Permalloy 50) | — / | — | 48% nickel-iron: high permeability · material page |
Common mistakes
Using grain-oriented steel in a motor
Properties are good in one direction only.
Removing the insulating coating
Losses rise.
Using ordinary steel for laminations
Losses are much higher.
Equivalents, standards and supply
| Standards | ASTM A677 / ASTM A876 / EN 10106 / EN 10107 |
|---|---|
| Forms | coiled sheet · laminations |
| Producers | thyssenkrupp · voestalpine · Nippon Steel |
Learn more
Values are typical and for comparison only. For design, rely on the standard, the producer specification and the mill certificate. Sources: ASTM standards (B86, B386, B392/B393, B551, B708, B760 and others), producer data, and the METAL HUB materials database.
Updated: October 31, 2026