Electrical Steel

Electrical Steel

Electrical Steel, also known as silicon steel sheet, is an indispensable soft magnetic alloy in power, electronics and military industries. It is also the largest metal functional material. It is mainly used as the iron core of various motors, generators and transformers. Its production process is complex and its manufacturing technology is strict. Foreign production technologies are protected in the form of patents, which is regarded as the life of the enterprise. The manufacturing technology and product quality of electrical steel plate is one of the important symbols to measure the production and scientific and technological development level of a country’s special steel.

Classification of Electrical Steel

Electrical steel plates are divided into two categories: oriented electrical steel plates and non oriented electrical steel plates. The development of electrical steel plate is a chromium free steel plate with high conductivity and high corrosion resistance. It is said that this chromium free corrosion-resistant high conductivity steel plate is coated with a thin chromium free coating on its surface, which can not only provide corrosion resistance but also improve its conductivity. A new type of electrical steel plate developed by Nippon Steel.

Performance Advantages of Electrical Steel

Generally, motors, transformers and other electrical components are required to have high efficiency, low power consumption, small volume and light weight. Electrical steel plate usually takes the core loss and magnetic induction strength as the magnetic guarantee value of the product. The requirements for the performance of electrical steel plate are as follows:
1. Low core loss (PT)
2. High magnetic induction (b)
3. Requirements for magnetic anisotropy
4. Good washability
5. The surface of the steel plate is smooth, flat and uniform in thickness
6. Good insulating film performance
7. Small magnetic aging phenomenon

Industry Application

Electrical steel has a history of hundreds of years. Electrical steel includes electrical steel with Si < 0.5% and silicon steel with Si content of 0.5 ~ 6.5%. It is mainly used as iron core of various motors, transformers and ballasts. It is an indispensable and important soft magnetic alloy in power, electronics and military industry. Electrical steel is the most used in magnetic materials, and it is also an important metal functional material for energy saving. The manufacturing process and equipment of electrical steel, especially oriented silicon steel, are complex, the composition control is strict, the manufacturing process is long, and there are many factors affecting the performance. Therefore, the product quality of oriented silicon steel is often regarded as an important symbol to measure the manufacturing technology level of a country’s special steel, and has won the reputation of “art product” in special steel.

Electrical Steel FAQS

What is electrical steel coil?

Electrical steel has a history of more than 100 years, including electrical steel with Si<0.5% and silicon steel with Si content of 0.5~6.5%

Two types, mainly used as iron cores of various motors, transformers and ballasts, are indispensable in power, electronics and military industries

Less important soft magnetic alloy. Electrical steel is the most widely used in magnetic materials and is also an important metal functional material for energy conservation Material. Electrical steel coil refers to the steel coil supplied by finished products in coiling state.

How did electrical steel develop?

The development history of electrical steel is divided into the following stages:

1. Development stage of hot rolled silicon steel (1882-1955)

The permeability of iron is thousands to tens of thousands of times higher than that of air. When the iron core is magnetized, the magnetic flux density is high

It produces a magnetic field far stronger than the external magnetic field. Ordinary hot-rolled low carbon steel plate is the first soft magnetic material with iron core applied in industry

Material. In 1898, the United States and Germany began to produce hot-rolled silicon steel plates. In 1905, the United States had mass production. In a very short time, it has completely replaced the ordinary hot-rolled low-carbon steel plate to manufacture motors and transformers, and its iron loss is more than half lower than that of ordinary low-carbon steel.

During the period of 1906-1930, it was the manufacturers and users who analyzed the cost, mechanical properties and motor and transformer design of hot-rolled silicon steel plate

It is the stage of unifying understanding, improving product quality and increasing output in manufacturing reform.

2. Development stage of cold rolled electrical steel (1930~1967)

This stage is mainly the development stage of cold-rolled ordinary oriented silicon steel (GO) plate. In 1930, American Gauss adopted cold rolling

A large number of experiments have been carried out with the annealing method to find out the manufacturing process of the oriented silicon steel strip coil with the grain magnetization direction parallel to the rolling direction. In 1933, Gauss produced 3% Si steel with high magnetic properties along the rolling direction by twice cold rolling and annealing. In 1934, Gauss applied for a patent and published it publicly. In 1935, Armco Steel Co., Ltd. cooperated with Westinghouse Electric Co., Ltd. to produce according to Gauss patented technology. After that, Armco Steel adopted technologies such as rapid analysis of trace carbon and continuously improved manufacturing process and equipment to gradually improve product quality. From 1963 to 1967, the United Kingdom, Japan and other countries successively stopped producing hot-rolled silicon steel

Plate. Hot rolled silicon steel plate is gradually replaced by cold rolled non-oriented electrical steel and cold rolled oriented silicon steel plate.

3. Development stage of high magnetic induction oriented silicon steel (1961~1994)

In 1961, Nippon Steel first trial-produced AlN+MnS comprehensive inhibitor with high

Magnetically oriented silicon steel. In 1964, it began trial production and was named Hi-B, but its magnetism was unstable. After 15 years of continuous

The manufacturing process of Hi-B steel has been improved, and the Z8H brand was officially produced in 1968. Since 1979

At first, Nippon Steel and Kawasaki adopted the technology of increasing silicon content, reducing the thickness of product steel strip and refining magnetic domain

New grades of 0.30, 0.27, 0.23 and 0.18 mm high magnetic induction oriented silicon steel have been produced.

What are the classification of electrical steel?

1. Hot rolled silicon steel plate Hot rolled low silicon steel (hot rolled motor steel) – silicon content: 1.0-2.5% nominal thickness: 0.50mm
2. Hot rolled high silicon steel (hot rolled transformer steel) – silicon content 3.0-4.5%, nominal thickness 0.35mm and 0.50mm
3. Non-oriented electrical steel low carbon electrical steel – silicon content:<0.5% nominal thickness 0.50mm and 0.65mm
4. (cold rolled motor steel) silicon steel – silicon content>0.5-3.2% nominal thickness 0.35mm and 0.50mm
5. (Cold rolled transformer steel) High magnetic induction oriented silicon steel – silicon content 2.9-3.3%, nominal thickness 0.30mm and 0.35mm
6. In addition to the types of products listed above, there are also some special electrical steel plates, such as 0.15mm and 0.20mm thick 3% Si cold-rolled non-oriented silicon steel strip and 0.025, 0.05 and 0.1mm thick 3% Si cold-rolled oriented silicon steel strip

What are the performance requirements of electrical steel coil?

Generally, motors, transformers and other electrical components are required to have high efficiency, low power consumption, small size and light weight. Generally, the core loss and magnetic induction strength of electrical steel plate are used as the magnetic guarantee value of the product. The requirements for the performance of electrical steel plate are as follows:

1. Low core loss (PT)

Core loss refers to the invalid electric energy consumed when the core is magnetized under the 50Hz alternating magnetic field, which is referred to as iron loss for short.

Also known as alternating loss, its unit is W/kg. This kind of invalid electricity consumed by various obstacles due to the change of magnetic flux

It can not only lose electric energy but also cause the temperature rise of the motor and transformer. Iron loss of electrical steel (PT)

It includes hysteresis loss, eddy current loss (Pe) and abnormal loss (Pa). Low iron loss of electrical steel plate, which can be saved

It can save a lot of electric energy, prolong the working time of the motor and transformer, and simplify the cooling device. Due to electrical steel plate

The power loss caused by the iron loss accounts for 2.5%~4.5% of the annual power generation of each country, so the total amount of electrical steel plate produced by each country

It is to try every possible way to reduce the iron loss, and take the iron loss as the most important indicator to assess the magnetism of the product

The value is used as the basis for classifying product brands.

2. High magnetic induction intensity (B)

Magnetic induction intensity is the number of magnetic lines of force passing through the unit cross-sectional area of the iron core, also known as magnetic flux density, which represents the

Magnetization capacity, in T. The magnetic induction strength of electrical steel plate is high, and the exciting current of iron core (also called no-load current)

Reduce the copper loss and iron loss, which can save electric energy. When the power of motor and transformer is constant, the magnetic induction strength

High, the design Bm can be increased, and the sectional area of the iron core can be reduced, which reduces the volume and weight of the iron core, and saves electricity

The consumption of steel plates, wires, insulating materials and structural materials can reduce the total loss and manufacturing cost of motors and transformers

This is also beneficial to the manufacture, installation and transportation of large transformers and large motors.

The design Bm of oriented silicon steel is up to 1.7~1.80T, close to B8 value, so B8 is taken as the guarantee value of magnetic induction. electric machinery

The design Bm is about 1.5T, which is close to the B50 value of cold-rolled non-oriented electrical steel, so the cold-rolled non-oriented silicon steel uses s50 as the magnetic field

Guaranteed value. The magnetic induction of hot-rolled silicon steel is lower, and B25 is usually taken as the guarantee value.

3. Requirements for magnetic anisotropy

The motor works under running condition, and the iron core is composed of stator and rotor laminated by toothed circular laminations

The electrical steel plate is magnetic isotropic, so it is made of non-oriented cold-rolled electrical steel or hot-rolled silicon steel. General requirements

Iron loss difference<8%, magnetic induction difference<10%.

The transformer works in a static state. The iron cores of large and medium-sized transformers are laminated with strips, and some distribution transformers

The transformer, current and voltage transformer and pulse transformer are made of winding iron core, which can ensure rolling along the electrical steel plate

It is made of cold-rolled oriented silicon steel because of the direction of blanking and magnetization.

4. Good lamination

When users use electrical steel plates, the workload of punching and shearing is very large, so it is required that electrical steel plates should have good punching property, which is particularly important for micro and small motors. Good punching property can improve the service life of the die and scissors, ensure the accurate size of the punching shear and reduce the burr of the punching shear.

The main factors affecting the punching property are: 1) Die or scissors materials. For example, tools for punching ratio of cemented carbide dies

The steel stamping die is more than doubled. 2) Distance between punch and die. The appropriate spacing is generally

5%~6%。 3) Type of lubricating oil for lamination. 4) Punch shape. 5) Type and quality of insulating film on steel plate surface. 6)

Hardness of steel plate, etc. The latter two factors are related to the quality of electrical steel plate.

What are the factors affecting the electrical steel loss?

1. Effect of chemical composition:

The composition of electrical steel basically includes three types of elements. The first category is basic alloy elements, such as

Si, Al, Mn, etc; The second is impurity elements, such as C, S, N, O, Ti, Zr, etc; The third category is trace elements such as Sb, Sn, etc.

2. Grain size:

The grain size is large, the number of grain boundaries is small, the resistance of domain wall movement is small, and the hysteresis loss is reduced. On the other hand, with the increase of grain size and domain size, eddy current loss and abnormal loss increase. Therefore, in order to reduce the total iron loss, there is an appropriate critical grain size.

3. Impurities, inclusions and internal stress:

Inclusions and impurity elements in non-oriented electrical steel should be reduced as much as possible, which is the most important measure to improve magnetism. it

They not only hinder the movement of the domain wall and increase the hysteresis loss and coercivity, but also produce

Closed domains make magnetization difficult. They also have a bad effect on grain growth and texture composition. In electrical steel plate

Any internal stress increases the coercivity.

4. Crystal texture:

In grain-oriented silicon steel, increasing B8 can significantly reduce hysteresis loss. For non-oriented electrical steel,

(100) texture is high, hysteresis loss and P15 are the lowest, (110) texture is the second, and (111) texture is the worst.

5. Steel plate thickness:

Generally speaking, the thickness of steel plate decreases and the hysteresis loss increases. However, the thickness is reduced and the eddy current loss is significantly reduced. because

This also has a reasonable critical thickness for the total iron loss.

Surface state of steel plate The surface of steel plate is flat and smooth, the free magnetic pole on the surface is reduced, the static magnetic energy is reduced, and the resistance of domain wall movement is reduced,

The hysteresis loss and coercivity are reduced.

What are the uses of electrical steel?

After punching, non-oriented electrical steel of medium and low grades can be welded or riveted into various iron cores. Electrical steel products can be widely used in the manufacture of electrical equipment such as small and medium-sized industrial motors, compressors in household appliances, power transformers, welding machine transformers and current stabilizers. At the same time, semi-organic and inorganic coatings can be applied to different occasions.

What is electrical steel sheet?

Electrical steel sheet is the general name of silicon steel, pure iron, permalloy and other electrical steel. It is an indispensable soft magnetic alloy for power, electronic and military industries, and also the largest output of metal functional materials. It is mainly used as the iron core of various motors, generators and transformers. The electrical steel sheet is added with silicon in low-carbon pure iron, which not only improves the hardness and resistance, but also maintains good soft magnetic properties. Iron core electrical steel B-FM is a standard alloy in the electrical steel series and belongs to free-cutting electrical steel. There are many kinds of electrical steel sheets with different properties. The common classification method is divided into cold rolled electrical steel sheet and hot rolled electrical steel sheet according to the process. The cold-rolled electrical steel sheet can be divided into oriented electrical steel sheet and non-oriented electrical steel sheet. The non-oriented electrical steel sheet can be divided into cold-rolled oriented low-carbon low-silicon electrical steel sheet and cold-rolled non-oriented electrical steel sheet.

What are the classifications of electrical steel sheet?

1. The cold-rolled non-oriented low carbon and low silicon electrical steel sheetrefers to the electrical steel with Si<1% (Si+AI)<1%. The nominal thickness is 0.5mm and 0.6mm, which is characterized by simple process and low manufacturing cost. This steel has low silicon content, high magnetic induction strength and high iron loss, and is mainly used to produce household motors and micro-motors (also known as fractional horsepower motors), small motors, ballasts and small transformers, etc. Cold-rolled non-oriented electrical steel sheet is a kind of ferrosilicon soft magnetic alloy with very low carbon content, which is a necessary magnetic material for the development of electric power, telecommunications and military industry. Cold rolled non-oriented silicon steel sheethas high quality of silicon and aluminum spoons, low iron loss and low magnetic induction strength. The cold-rolled non-oriented electrical steel sheet of medium and low grades can be used to manufacture electrical equipment such as small and medium-sized industrial motors, household appliances, spoon compressors, transformers and current stabilizers.

The oriented electrical steel sheet refers to a kind of cold-rolled electrical steel with silicon content of 2.9%~3.3%, and after special process treatment, most of the grains have the same orientation, thus the magnetic properties are extremely superior. The steel is divided into ordinary oriented electrical steel sheet and high magnetic induction oriented electrical steel sheet, which is mainly used to manufacture large transformers.

2. The silicon content of hot-rolled electrical steel sheetcan be divided into hot-rolled low silicon steel (1.0%~2.5%) and hot-rolled high silicon steel sheet(3.0%~4.5%)

It can be supplied in rolls, with many production processes and long cycle. Now it is being phased out in China. The electrical steel sheet usually takes the core loss and magnetic induction strength as the guarantee of product magnetism. Its performance requirements include: low core loss, high magnetic induction strength, smooth steel sheet surface and uniform thickness, good insulation film performance, small magnetic aging phenomenon, etc. Compared with hot-rolled electrical steel sheet, cold-rolled steel sheet has certain advantages. It is understood that the phenomenon that the magnetism changes with the use time is called magnetic aging

If it is caused by impurities such as carbon and nitrogen in steel. Electrical steel has high solid solubility of carbon and nitrogen at high temperature. When it is cooled rapidly from high temperature, carbon and nitrogen have no time to precipitate to form supersaturated solid solution. When the iron core is operated for a long time, especially when the temperature rises to 50C~80C, the excess carbon and nitrogen will precipitate as fine and dispersed tungsten carbide and Fe16N4 particles, which will increase the coercivity and core loss, leading to magnetic aging.

What are the differences between cold-rolled electrical steel sheet and hot-rolled electrical steel sheet？

1. High magnetism can save a lot of electric energy;
2. Smooth surface and high lamination coefficient;
3. Good lamination performance;
4. The surface is coated with insulating film for easy use;
5. Supplied in rolls, suitable for high-speed punching machine, with high utilization rate.

What are the advantages of electrical steel sheet?

Electrical steel sheet is a kind of special steel, which is usually used to manufacture electrical equipment. This steel is different from other types of steel in several aspects, which makes it very suitable for electrical applications.

Some main advantages of electrical steel sheet include:

1. Improve strength and durability: electrical steel sheetis more durable than other types of steel. This makes it very suitable for electrical equipment that often bears high stress and wear.
2. Improve conductivity: the high purity of electrical steel sheetmakes it an excellent conductor. This makes it very suitable for a wide range of electrical applications, including generator, motor and transformer components.
3. Enhanced corrosion resistance: the unique composition of electrical steel sheetalso enhances its corrosion resistance. This means that it can be safely used in the environment where other types of steel will corrode or decompose rapidly.
4. Reduce manufacturing costs: the improvement of electrical steel sheetperformance also leads to the reduction of manufacturing costs. This is because this kind of steel can be easily made into the required shape and size through a simple manufacturing process.
5. Wide use: electrical steel sheetis widely used and is one of the most widely used steel types in the market today.

What are the applications of electrical steel sheet?

Electrical steel sheet is a kind of special steel, which is usually used to manufacture electrical equipment. This steel is different from other types of steel in several aspects, which makes it very suitable for electrical applications.

Electrical steel sheet is a kind of general material with various properties and is suitable for many different applications. It has excellent magnetism and good formability, and is an ideal choice for the production of transformers and motors. Its strength and durability make it very suitable for use in power transmission lines, while its ductility makes it suitable for use in consumer electronics products such as loudspeakers. Finally, electrical steel sheet is an excellent choice to improve energy efficiency or reduce costs without sacrificing quality.