Why so many big companies choosing 0.1mm utral-silicon steel?

Did you know that the thickness of non-oriented silicon steel sheets can now be as low as 0.1mm? But why do we need to make oriented silicon steel sheets thinner? And what impact does this have on motor performance? Today's article by SHUNGE will take you to find out.

I. Characteristics of Non-oriented 0.1mm Ultra-thin Silicon Steel Sheets

The hallmark of non-oriented silicon steel sheets is their nearly uniform magnetic performance in all directions (isotropy), making them ideal for manufacturing rotating electric motors with continuously changing magnetic fields.

When the thickness is reduced to 0.1mm, it exhibits the following core features: 

1.Ultralow high-frequency losses

Key Advantage: This is the primary design goal for the 0.1mm thickness. According to electromagnetic theory, eddy current losses are directly proportional to the square of the material thickness. Decreasing the thickness from the common 0.35mm or 0.50mm to 0.1mm greatly suppresses eddy current losses at high frequencies.

Application Frequency: This makes it suitable for working frequency ranges extending up to 400Hz, 1kHz, or even above 2kHz, where conventional thicker silicon steel sheets would experience excessive core losses.

2.High Electrical Resistivity

The addition of silicon (Si) in silicon steel sheets inherently increases the material's electrical resistivity, thereby reducing eddy current losses. Combining the 0.1mm ultra-thin specification with high silicon content (typically around 3%) achieves excellent high-frequency performance.

3.High Permeability

Even at moderate magnetic flux densities and high frequencies, it maintains a high permeability, meaning it requires less magnetizing current to establish the magnetic field, resulting in high efficiency.

4.Moderate Saturation Flux Density

The saturation flux density (Bs) of non-oriented silicon steel ranges typically between 1.6T and 1.8T, lower than oriented silicon steel but adequate for most high-frequency applications. It's important to note that the addition of silicon slightly lowers the saturation magnetization.

5.Good Stamping Processability

Compared to more brittle materials like amorphous and nanocrystalline alloys, 0.1mm non-oriented silicon steel sheets still retain a degree of toughness and ductility, allowing for stamping into complex shapes using precise dies.

II. Types and Characteristics of Iron Cores Manufactured

Iron cores made from 0.1mm non-oriented ultra-thin silicon steel sheets are primarily in the form of laminated cores.

1. Iron Core Manufacture Process

Precision Stamping: Utilizing high-precision presses and dies to stamp the silicon steel coils into the desired shapes.

Lamination: Stacking numerous stamped thin sheets layer by layer and securing them into a sturdy core structure using riveting, welding, bonding, or self-locking methods.

Heat Treatment: Annealing in a protective atmosphere (such as nitrogen) to relieve stresses from the stamping process, restoring the material's optimal magnetic properties.

2. Types and Characteristics of Iron Cores

These iron cores are mainly used in applications needing high-speed rotation or high-frequency magnetic fields, with the key features as follows:

 3. Comparison with Other Materials

vs. Common Non-oriented Silicon Steel (0.35/0.50mm): At the same frequency, the iron loss of 0.1mm sheets is significantly lower than the latter, making it the natural choice for stepping into high-frequency and high-speed applications.

vs. Ferrite: The saturation flux density is much higher than that of ferrite, allowing it to handle larger power and avoid magnetic saturation under high-frequency currents. However, ferrite still holds advantages in higher frequencies (MHz level) and costs.

vs. Amorphous and Nanocrystalline: Better processability, usually higher saturation magnetization, especially with stable performance at high temperatures. While amorphous and nanocrystalline materials may have lower losses at specific high frequencies, they are more brittle, with different cost structures.

Summary

Non-oriented 0.1mm ultra-thin silicon steel sheets are a special type of soft magnetic material designed for high-frequency and high-speed applications. Their core value lies in extreme reduction of high-frequency eddy current losses through ultrathin sizing.

The laminated cores manufactured from these sheets are mainly used in:

Next-generation high-speed motors (such as those in new energy vehicles and aerospace) to achieve higher power density and efficiency.

Special high-frequency magnetic components (such as aviation and military power sources) to provide reliable performance in high-power and higher frequency requirements.

It serves as a key material linking traditional line-frequency motor technologies with future high-frequency power electronics technologies.