What Are the Properties of Silicon Steel?

Silicon steel is regarded as a ferrosilicon soft magnetic alloy with extremely low carbon content. Generally, the silicon content is 0.5%-4.5%. The addition of silicon in iron greatly improves the physical properties of silicon steels. Therefore, silicon steels have the following desirable properties for supporting the generation, distribution, and consumption of electricity.

What Are the Properties of Silicon Steel?

1. Low Iron Loss

Iron core loss refers to the ineffective electric energy consumed when the iron core is magnetized under an alternating magnetic field of ≥50Hz. It is often referred to as iron loss, also called alternating loss, and the unit is W/kg. This kind of ineffective electric energy consumed due to various obstacles to the change of magnetic flux not only loses electric energy through the heating of the iron core but also causes the temperature rise of the motor and transformer. Generally speaking, the iron loss of silicon steel includes three parts: hysteresis loss, eddy current loss (Pe), and abnormal loss (Pa). Silicon steel has low iron loss, which can not only save a lot of electric energy but also extend the operating time of the motor and transformer and simplify the cooling device. Since the power loss caused by the iron loss of silicon steel accounts for 2.5% to 4.5% of the annual power generation in various countries, countries producing silicon steel always try every means to reduce iron losses, and use the iron loss as the most important indicator to evaluate the magnetic properties of silicon steel products: the lower the iron loss, the higher the grade, and the better the quality.

2. High Magnetic Sensitivity

Magnetic induction intensity is the number of magnetic field lines passing through the unit cross-sectional area of the iron core, also called magnetic flux density. It represents the magnetizing ability of the material, and the unit is T. The increase in magnetic induction intensity means that the magnetic field formed under the same conditions of the iron core is strengthened, thereby reducing the excitation current, copper loss, and iron loss, and improving the energy conversion efficiency. Moreover, the total magnetization intensity of the iron core is the product of its magnetic induction and area, so the iron core Bm increases, and the cross-sectional area can be reduced accordingly, which reduces the quality of the iron core and copper wires, thereby reducing the iron loss and cost of electrical appliances.

3. Uniform Thickness & Smooth Surface

Silicon steels are required to be flat in finish and uniform in thickness, which is mainly used to improve the lamination coefficient of the iron core. A high lamination coefficient can increase the effective utilization of space in the iron core, reduce the air gap, and reduce the excitation current. A 1% decrease in the lamination coefficient of silicon steel is equivalent to a 2% increase in iron loss and a 1% decrease in magnetic induction.

4. Hardness

Hardness is one of the quality characteristics of silicon steels. When modern automatic punching machines are punching the steel, the requirements for hardness are more stringent. When the hardness is too low, it is not conducive to the feeding operation of the automatic punching machine. At the same time, it is easy to produce excessively long burrs and increase assembly difficulties. To meet the above requirements, the hardness of silicon steel must be higher than a certain hardness value. For example, the hardness of 50AI300 silicon steel is usually no less than HR30T hardness value 47.

The hardness of silicon steel increases as the grade increases. Generally, the more silicon content is added to high-grade silicon steel, the effect of solid solution strengthening of the alloy makes the hardness higher.

5. Excellent Insulation Film Performance

The surface of silicon steel is chemically coated, and then a thin film is attached to it, which can provide insulation, rust prevention, and lubrication functions. The insulation reduces the eddy current loss between the silicon steel cores; the rust resistance prevents the silicon steel from rusting during processing and storage; and the lubricity improves the punching performance of the silicon steel and extends the life of the mold.

6. Small Magnetic Aging

The phenomenon that the magnetism of ferromagnetic materials changes with use time is called magnetic aging. This phenomenon is mainly caused by impurity elements such as carbon and nitrogen in the material. When the carbon and nitrogen content in the silicon steel is less than 0.0035%, the magnetic aging effect is significantly reduced.

7. Good Processability

Users have a heavy punching and shearing workload when using silicon steel products, so these steels are required to have good punching properties, which is also important for micro and small motors. Good punching performance can increase the life of the punching die and scissors, ensure accurate punching and shearing sheet dimensions, and reduce punching and shearing sheet burrs.

8. High Electrical Resistivity

In comparison to iron, silicon steel shows a significant increase in resistivity. This increase reduces core loss by minimizing the eddy current component, hence improving energy efficiency.

Conclusion

Silicon steel is a widely used material in the manufacturing of cores of generators, motors, and transformers. This is due to its numerous favorable properties, including low iron loss, high magnetic permeability, flat finish, uniform thickness, and good processing performance. Gnee Steel is a professional silicon steel product distributor and exporter from China. If you have some doubts about silicon steel or want to buy silicon steel products, welcome to contact us for more details.