Compared with regular steel, electrical steel is used because it handles magnetic flux more efficiently and keeps core loss lower. That is why it is commonly selected for transformers, EV motors, and other electrical equipment.

What sets it apart from regular steel is its magnetic performance. It is designed to carry magnetic flux efficiently while keeping core loss low, which is why it is widely used in power equipment, EV motors, and industrial machinery.

Key Takeaways

Electrical steel is an iron-silicon alloy made for magnetic cores.
Silicon increases electrical resistivity and helps reduce eddy current loss.
GOES is mainly used in transformers, while NGOES is more common in motors and generators.
Grade selection depends on operating frequency, efficiency targets, flux density, and manufacturing conditions.
Electrical steel is typically used in thin insulated laminations to limit parasitic currents.

What Makes It "Electrical"? The Science Behind Silicon Steel

Electrical steel performs differently from ordinary steel because of its chemistry and grain structure. It is engineered for magnetic applications where low core loss and high permeability matter.

The Role of Silicon

Silicon is the key alloying element in electrical steel. Typical silicon content ranges from about 1% to 6.5%, while many commercial grades are around 3.2%. Higher silicon content improves electrical resistivity, which helps reduce eddy current loss. In practice, however, pushing silicon too high can make the material more brittle and harder to roll into thin gauges.

Understanding Core Loss

Core loss mainly comes from two sources: hysteresis loss and eddy current loss.

Hysteresis loss occurs when magnetic domains inside the steel repeatedly reorient under alternating current. Material chemistry and grain structure both affect how much energy is lost in that process.

Eddy current loss comes from induced currents inside the core itself. These currents do not contribute useful output; they mainly generate heat. That is why electrical steel is produced with higher resistivity and used in thin insulated laminations.

High Magnetic Permeability

Electrical steel also has high magnetic permeability, so magnetic flux can pass through the core more easily. In practical terms, this helps improve transformer and motor efficiency while keeping equipment size under control.

GOES vs. NGOES

Electrical steel is generally divided into two main categories: grain-oriented electrical steel (GOES) and non-grain-oriented electrical steel (NGOES). The difference mainly comes down to grain orientation and the directionality of magnetic properties.

Feature	Grain-Oriented Electrical Steel (GOES)	Non-Grain-Oriented Electrical Steel (NGOES)
Grain Structure	Crystals are aligned in the rolling direction. This creates a "preferred" path for the magnetic field.	Crystals are randomly oriented. This gives uniform magnetic properties in all directions.
Key Property	Very high permeability and low loss only in the rolling direction.	Good, uniform magnetic properties in every direction. It is isotropic.
Primary Application	Static equipment where the magnetic field direction is known and fixed. Example: Power & Distribution Transformers.	Rotating equipment where the magnetic field direction is always changing. Example: Electric Motors, Generators, Alternators.
Cost/Process	More complex and expensive to make due to a special heating process.	Less complex and cheaper to produce.

Choosing the Right Grade

GOES for transformers and NGOES for motors is a useful rule of thumb, but actual grade selection still depends on frequency, loss targets, flux density, and processing conditions.

Beyond the Basics: Factors Influencing Your Choice

Operating Frequency: Standard grades are typically used around 50 or 60 Hz. In higher-frequency applications, including some power electronics and high-speed motors, thinner laminations are usually needed to control rising eddy current loss.

Flux density: Every grade has a saturation limit. The selected material needs to handle the required magnetic flux density without approaching saturation too early.

Efficiency targets: Higher-efficiency motors, including IE4 and IE5 designs, often require premium grades with lower core loss. These materials usually cost more upfront, but they can improve operating efficiency over time.

Mechanical stress and stamping: Cutting and stamping can degrade magnetic performance, especially near the edges. For that reason, processing conditions and grade selection need to be considered together, particularly in applications sensitive to loss.

A Quick Note on Electrical Steel Grades

Grades are often identified by designations such as M-19 or M-47. In general, a lower number indicates lower core loss, so M-19 is typically more efficient than M-47. This kind of designation is useful when comparing technical data sheets and narrowing material choices.

How Electrical Steel Is Made

The magnetic performance of electrical steel is closely tied to how it is produced. From steelmaking and rolling to annealing and coating, each stage affects core loss, permeability, and final consistency.

Hongwang's HiB Grain-Oriented Electrical Steel Production Process

Iron Making and Hot Metal Pretreatment
The process starts with iron making and desulfurization. Reducing sulfur at this stage improves steel cleanliness and helps support more stable downstream quality.
Converter Steelmaking and Secondary Refining
The molten iron is converted into steel, then refined further to control composition and remove remaining impurities. This stage is critical for achieving the chemistry required for electrical steel.
Continuous Casting
The refined steel is cast into slabs for the next rolling stages. Stable casting helps maintain internal quality and supports more consistent downstream processing.
Slab Reheating and Hot Rolling
The slabs are reheated and hot rolled into coils, preparing the material for further gauge reduction and subsequent structure control.
Cold Rolling
The strip is cold rolled to final gauge, which is one of the most demanding stages for thickness control. HWHG can produce gauges down to 0.18 mm, with other nominal thicknesses including 0.20 mm, 0.23 mm, 0.27 mm, and 0.30 mm.
Decarburization and Annealing
After rolling, the material goes through decarburization and annealing. These heat-treatment steps remove carbon and help form the grain structure needed for strong magnetic performance. For GOES, this stage is even more critical because it helps align the grains in the rolling direction, which directly supports better magnetic properties.
Insulating Coating
A thin insulating coating is applied to the surface to reduce eddy current loss when the sheets are stacked into laminations.
Final Quality Control

For thin-gauge products, quality control goes well beyond nominal thickness. At gauges from 0.18 mm to 0.30 mm, transverse thickness tolerance is controlled at 0 to +0.015 mm, longitudinal thickness tolerance at 0 to +0.02 mm, thickness deviation at ±0.02 mm, unevenness at ≤1.5%, and edge wave over 2 meters at ≤0.90 mm. These controls help ensure the strip remains stable and consistent in demanding applications.

Applications of Electrical Steel

Electrical steel is widely used in power equipment, rotating machines, and electromagnetic components where magnetic efficiency matters.

Power and distribution transformers: GOES is commonly used in transformer cores because it offers low loss and high permeability in the rolling direction.
Electric motors and generators: NGOES is widely used in rotating machines because its magnetic properties are more uniform in different directions.
Inductors, chokes, relays, and solenoids: Electrical steel is also used in a range of electromagnetic components for energy storage, filtering, and switching functions.

Common Questions About Electrical Steel

Is electrical steel the same as regular carbon steel?

No. Electrical steel is formulated for magnetic cores and low loss, while regular carbon steel is not.

Why is electrical steel laminated?

It is used in thin insulated laminations to interrupt eddy current paths and reduce loss.

Can electrical steel be welded?

Usually not. Welding heat can damage both the grain structure and the insulating coating, which reduces magnetic performance near the weld.

What does the "M" grade mean in electrical steel (e.g., M-19)?

In general, a lower M-number indicates lower core loss and a higher-efficiency grade.

Is silicon steel magnetic?

Yes. Electrical steel is a soft magnetic material, which means it can be magnetized and demagnetized with relatively low energy loss. That is why it is widely used in AC applications.

Final Note

Electrical steel is not the most visible part of a transformer or motor, but it has a direct impact on efficiency, core loss, and long-term operating stability. That is why grade selection, lamination design, and processing quality matter more than they may seem at first glance.

As requirements for efficiency, consistency, and performance continue to rise, electrical steel selection becomes more important in overall equipment design.

If you are evaluating electrical steel for transformer cores, motor laminations, or thin-gauge applications, HWHG can support your project with grade recommendations, thickness options, and technical details based on your actual requirements. Contact HWHG to discuss material selection, specifications, and application needs.

What Is Electrical Steel? A Practical Guide to Silicon Steel

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