What is silicon steel?

28 Nov 2023
Reading Volume :
GNEE Steel Silicon Steel Coil
1. What is silicon steel
Silicon steel refers to Fe-Si soft magnetic alloy, also known as electrical steel. The mass percentage of Si in silicon steel is 0.4%~6.5%. It has excellent magnetic properties with high magnetic permeability and low iron loss value. It has low core loss, high magnetic induction intensity, good punchability, good surface quality of steel plate, and good performance of insulating film. Etc. Silicon steel is mainly used to prepare the iron cores of various electric motors, generators and transformers. It is an indispensable metal functional material in the electric power, electronics and military industries. As the most widely used soft magnetic alloy, electrical steel is widely used in various aspects of the real economy, and improving its overall performance and manufacturing level has a very important role and significance in the development of the national economy.
oriented silicon steel
2. Production process
According to the production method, it can be divided into hot-rolled electrical steel and
cold-rolled electrical steel. Hot-rolled silicon steel sheets have been phased out in recent years due to their backward properties.
The most widely accepted method is to classify silicon steel into non-oriented and oriented according to the degree of crystal orientation aggregation.
Cold-rolled non-oriented silicon steel refers to an alloy of 0.5% to 4.0% (Si+Al), which is cold-rolled to 0.65mm, 0.5mm and 0.35mm and then annealed and coated. Compared with oriented silicon steel, its grain texture type is more diffuse, with more uniform magnetic properties in all directions, and low magnetic anisotropy. It is mainly used as iron core laminations for various types of motors and generators. The thickness accuracy, dimensional tolerance grade and surface smoothness of cold-rolled products have all reached a high level, thereby improving the lamination factor of the product and the magnetic properties of the material.
Single oriented electrical steel refers to Goss orientation, and double orientation refers to cubic
oriented electrical steel. The preparation process of the latter is extremely complicated, and it is difficult to industrialize at present, so the oriented silicon steel refers to the Goss orientation in a broad sense. Oriented silicon steel has high magnetic permeability and low loss characteristics in the <001> direction of easy magnetization, which meets the magnetic permeability requirements of static power equipment. Single-oriented silicon steel can be divided into CGO steel and Hi-B steel according to the difference of inhibitor and magnetic induction. Among them, the average grain orientation deviation angle of CGO steel is about 7°, and the saturation magnetic induction value B8 is above 1.82Tesla, which is mainly used for the manufacture of small and medium-sized transformers. The average grain orientation deviation angle of Hi-B steel is about 3°, and the B8 value is above 1.90Tesla. It is mainly used in the manufacture of various large-scale transformers, choke coils and other high-end electromagnetic components in the power industry.
non oriented siicon steel
3. Performance index of silicon steel
The electrical steel laminated iron core and the copper wire do work through electromagnetic induction, and the iron core acts by forming an alternating magnetic field. The core performance of electrical equipment, such as power, volume, efficiency, quality and overall operating cost, is determined by its own energy consumption and the magnetization ability of the iron core during the operation of the iron core. Therefore, the performance indicators of electrical steel require the following items:
1) Core loss P:
In the process of excitation and demagnetization, the extra electric energy consumed by the electrical steel core is converted into heat, which is called iron loss, and the unit is W/kg, which is the main basis for classifying product grades. Iron loss consists of hysteresis loss Ph, eddy current loss Pe and abnormal loss Pa. The three iron losses correspond to grain size, favorable texture ratio and strip quality, respectively. Therefore, the proportions of these three losses in oriented and non-oriented electrical steels are different. For example, the iron loss of non-oriented silicon steel is mainly Ph, and that of oriented silicon steel is mainly Pe. According to different use conditions, the guaranteed iron loss value of non-oriented silicon steel is P1.5/50, that is, the electric energy consumed when the silicon steel sheet is magnetized to 1.5T under a 50Hz alternating magnetic field, while the corresponding guaranteed iron loss value of oriented silicon steel is P1 .7/50.
cold rolled silicon steel
2) Magnetic induction intensity B:
Magnetic induction intensity, also known as magnetic flux density, is a technical index to measure the magnetization ability of magnetic materials per unit area. The increase of the 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 of the iron core is the product of its magnetic inductance and the area, so the Bm of the iron core is increased, and the cross-sectional area can be reduced accordingly, which reduces the quality of the iron core and copper wire, thereby reducing the iron loss and cost of electrical appliances. The guaranteed magnetic induction value of non-oriented silicon steel is B50, that is, the magnetic induction intensity under a magnetic field of 5000A/m, while the magnetic induction of oriented silicon steel is B8, and the magnetic induction unit is Tesla. Different electrical steels use different magnetic induction strength standards.



 
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