Silicon steel is commonly known as silicon steel sheet or silicon steel sheet. It is an indispensable low-carbon ferrosilicon soft magnetic alloy in the power, electronics and military industries. It is also the metal functional material with the largest output. Its output accounts for about 1% of the world's steel output. It is a ferrosilicon alloy with a silicon content of 0.8%-4.8%, which is hot and cold rolled into a silicon steel sheet with a thickness of less than 1mm. ·Adding silicon can increase the resistivity and maximum permeability of iron, reduce coercivity, core loss (iron loss) and magnetic aging. It is mainly used as the core of various motors, generators and transformers.

 

　　Silicon steel sheets can be divided into low silicon and high silicon according to their silicon content.

 

　　Low silicon wafers contain less than 2.8% silicon, which has certain mechanical strength and is mainly used to manufacture motors, commonly known as silicon steel sheets for motors;

　　The silicon content of high silicon wafer is 2.8%-4.8%. It has good magnetic properties but is relatively brittle. It is mainly used to make transformer cores, commonly known as transformer silicon steel sheets. There is no strict boundary between the two in actual use, and high-silicon wafers are often used to manufacture large motors.

 

　　Cold rolling can be divided into two types: non-oriented grain and grain orientation: cold-rolled sheets have uniform thickness, good surface quality, and high magnetic properties. Therefore, with the development of industry, hot-rolled sheets have a tendency to be replaced by cold-rolled sheets.

 

　　Cold-rolled silicon steel sheet is divided into two kinds of steel strips: non-oriented grain and grain oriented.
　　 Non-oriented grain cold-rolled strips are usually used as iron cores for motors or welding transformers; grain-oriented cold-rolled strips are used as iron cores for power transformers, pulse transformers, magnetic amplifiers, etc. The cold-rolled oriented thin silicon steel strip is made of 0.30 or 0.35mm thick oriented silicon steel strip, which is then pickled, cold rolled and annealed.
　　The cold-rolled non-oriented silicon steel sheet is the hot-rolled steel billet or continuous casting billet into a coil with a thickness of about 2.3mm. Cold-rolled electrical steel strip has the characteristics of flat surface, uniform thickness, high stacking coefficient, good punching performance, etc., and has higher magnetic induction and lower iron loss than hot-rolled electrical steel strip.
　　Using cold strip instead of hot rolled strip to manufacture motors or transformers, its weight and volume can be reduced by 0%-25%. If cold-rolled oriented tape is used, the performance is better. Using it instead of hot-rolled or low-grade cold-rolled tape can reduce transformer power consumption by 45%-50%, and transformer performance is more reliable.

 

　　Non-oriented silicon steel sheet is a silicon steel sheet with a non-oriented deformation texture crystalline structure formed according to a certain production process.

 

　　In the early 1920s, William (Williams) studied single crystals in ferrosilicon and found that um=1400000 in the {100} direction of the easy axis of magnetization. He believed that it should be excellent in the {100} axis in the polycrystalline plate. Performance.
　　 In 1926, the Japanese Honda Mao discovered that the crystallographic direction of iron is the easiest to magnetize, or the direction of the crystal grain cube edge is the easiest to magnetize direction.
In 1934, the American NPGoss successfully developed oriented silicon steel sheets in the laboratory. He used a combination of cold rolling and high temperature heat treatment to make the crystal grains in the silicon steel sheets arranged in an orderly manner along the rolling direction. magnetic.
　　 In 1935, Goss published an article in "TransAmer.Soc.Metals", introduced the research results, and applied for a British patent (No. 442211).
　　 In the same year, Armco of the United States began industrial production of cold-rolled oriented silicon steel sheets. In the 1940s, both Armco and Allegheny produced high-quality oriented silicon steel sheets for transformers. Armco's brand name is Tran-cor (Westinghouse called Hipersil); Allegeny's brand name is Silicon (GE Company called Corosil).
　　 In 1953, Japan tried to produce cold-rolled oriented silicon steel sheets.
　　 In 1958, Japan introduced Armco’s patented technology to start the industrial production of cold-rolled oriented silicon steel sheets, and on this basis, continuous improvements have made the performance of Japanese cold-rolled silicon steel sheets reach the highest level in the world.
　　 The single-oriented silicon steel sheet has low magnetic permeability in the direction perpendicular to the rolling direction. In order to overcome this shortcoming, the German vacuum melting company invented the dual-oriented silicon steel sheet in the 1940s.
　　 In 1957, GE and Westinghouse in the United States also produced dual-oriented silicon steel sheets almost simultaneously. In the 1960s, the Kawasaki and Yawata factories in Japan also successfully developed dual-oriented silicon steel sheets. Its magnetic properties in the rolling direction and the vertical direction are similar to those of the single-oriented silicon steel sheet in the rolling direction. The crystal grains of this silicon steel sheet are cubic.
In 1968, Japan’s Nippon Steel Plant began to industrially produce high-permeability oriented silicon steel sheets. Its commercial name is "Orientcore Hi-B", or "Hi-B" for short; in 1972, large-lattice high-permeability oriented silicon steel was developed In 1981, a small-lattice high-permeability oriented silicon steel sheet was further developed; in 1982, Japan began to produce surface laser irradiation treatment (ZDKH) high-permeability oriented silicon steel sheet, which further reduced iron loss.
　　 In 1988, Japan developed a high-permeability oriented silicon steel sheet using mechanical methods to form the micro-stress method (ADMH). Views on the development of grain-oriented silicon steel sheet from Nippon Steel Corporation. In the 1950s, the performance of single-oriented silicon steel sheets in several countries. ·Between 1955 and 1975, the quality of oriented silicon steel sheet and non-oriented silicon steel sheet in Japan changed. From 1880 to 1970, the declining curve of core steel sheet iron loss.

 

　　Both are cold-rolled silicon steel sheets, but the silicon content is different. The silicon content of cold-rolled non-oriented silicon steel sheet is 0.5%-3.0%, and the silicon content of cold-rolled oriented silicon steel sheet is above 3.0%.

 

　　(1) Non-oriented silicon steel sheets have relatively lower process requirements than oriented silicon steel sheets. Non-oriented silicon steel sheets are hot rolled steel billets or continuous casting billets into coils with a thickness of about 2.3 mm.
　　 When manufacturing low-silicon products, hot-rolled coils are pickled and then cold rolled to a thickness of 0.5mm at a time.
When manufacturing high-silicon products, the hot-rolled strip is pickled (or normalized at 800-850°C and then pickled), then cold rolled to a thickness of 0.55 or 0.37mm, annealed at 850°C in a hydrogen-nitrogen mixed atmosphere continuous furnace, and then It is cold rolled to 0.50 or 0.35mm thickness with a small reduction rate of 6-10%. The cold rolling with this low reduction ratio can increase the grain size during annealing and reduce the iron loss.
　　(2) Both cold-rolled sheets are finally annealed at 850°C in a continuous furnace under a 20% hydrogen-nitrogen mixed atmosphere, and then coated with an insulating film of phosphate and chromate. After cold rolling to the thickness of the finished product, most of the steel strips in the supply state are 0.35mm and 0.5mm thick.
　　 The Bs of cold rolled non-oriented silicon steel is higher than that of oriented silicon steel. Oriented silicon steel sheet requires low oxide inclusion content in steel, and must contain C0.03-0.05% and inhibitors (second phase dispersive particles or grain boundary segregation elements). The role of the inhibitor is to prevent the growth of primary recrystallization grains and promote the development of secondary recrystallization, thereby obtaining high [001] orientation.
　　 The inhibitor itself is harmful to magnetism, so after the inhibition is completed, it must be subjected to high temperature purification annealing. When using the second phase inhibitor, the heating temperature of the slab must be increased to make the original coarse second phase particles solid solution, and then the fine particles will be precipitated during hot rolling or normalization in order to enhance the inhibition effect.
　　The thickness of the cold rolled product is 0.28, 0.30 or 0.35mm. The cold-rolled oriented thin silicon steel strip is made of 0.30 or 0.35mm thick oriented silicon steel strip, which is then pickled, cold rolled and annealed.
　　 Compared with cold-rolled non-oriented silicon steel, oriented silicon steel has much lower loss than non-oriented silicon steel, and has strong magnetic directionality; it has superior high magnetic permeability and low loss characteristics in the rolling direction of easy magnetization. The iron loss of the oriented steel strip in the rolling direction is only 1/3 of the transverse direction, the magnetic permeability ratio is 6:1, and the iron loss is about 1/2 of that of the hot-rolled strip, and the magnetic permeability is 2.5 times of the latter. .

 

　　The grains of oriented silicon steel are arranged in an orderly manner, while the grains of non-oriented silicon steel are arranged in a disorderly manner. Non-oriented silicon steel is mainly used in stators and rotors of motors, compressors, and large-scale hydro-generator sets. Oriented silicon steel is generally used in transformer cores and some motors.
　　 Generators and transformers have the same requirements for silicon steel sheets: both require low iron loss, good magnetization characteristics, and high lamination coefficient, but transformers generally use oriented silicon steel sheets. Non-oriented silicon steel sheets for generators.

 

　　Due to the different performance characteristics of the two, there is a difference in the direction of use: the main purpose of cold-rolled non-oriented silicon steel sheet is for generator manufacturing, so it is also called cold-rolled motor silicon steel. The main purpose of cold-rolled oriented silicon steel strip is for transformer manufacturing, so it is also called cold-rolled transformer silicon steel.

 

　　1. Low iron loss. The most important indicator of quality, all countries in the world classify grades by iron loss value. The lower the iron loss, the higher the grade and the higher the quality.
　　2. High magnetic induction intensity. In the same magnetic field, a silicon steel sheet that can obtain a higher magnetic induction, the motor or transformer core made of it has a small volume and weight, and relatively speaking, it can save silicon steel sheet, copper wire and insulating materials.
　　3, the stacking factor is high. The surface of the silicon steel sheet is smooth, flat and uniform in thickness, and the stacking factor of the manufactured iron core is improved.
　　4. Good film development. This is even more important for the manufacture of small and micro motor cores.
　　5. The surface has good adhesion and weldability to the insulating film, which can prevent corrosion and improve the punching property.
　　 6. The phenomenon of magnetic aging is small. ·Silicon steel sheets must be delivered after annealing and pickling.

 

　　The hot-rolled silicon steel sheet for electricians is made of ferrosilicon soft magnetic alloy with low carbon loss and is hot-rolled into a sheet with a thickness of less than 1mm. Hot-rolled silicon steel sheet for electricians is also called hot-rolled silicon steel sheet. Hot-rolled silicon steel sheets can be divided into low-silicon (Si≤2.8%) and high-silicon (Si≤4.8%) steel sheets according to their silicon content.

 

　　2. Cold rolled silicon steel sheet for electrician (GB2521-88)

　　It is made of electrical silicon steel with a silicon content of 0.8%-4.8% and is made by cold rolling. Cold-rolled silicon steel sheet is divided into two kinds of steel strips: non-oriented grain and grain oriented. Cold-rolled electrical steel strip has the characteristics of flat surface, uniform thickness, high stacking coefficient, good punching performance, etc., and has higher magnetic induction and lower iron loss than hot-rolled electrical steel strip.
　　Using cold strip instead of hot rolled strip to manufacture motors or transformers, its weight and volume can be reduced by 0%-25%. If cold-rolled oriented tape is used, the performance is better. Using it instead of hot-rolled or low-grade cold-rolled tape can reduce transformer power consumption by 45%-50%, and transformer performance is more reliable.
　　 is used to manufacture motors and transformers. Generally, the non-oriented grain cold-rolled strip is used as the state of motors or welding transformers; the grain-oriented cold-rolled strip is used as the iron core of power transformers, pulse transformers, and magnetic amplifiers. Steel plate size: thickness is 0.35, 0.50, 0.65mm, width is 800-1000mm, length is ≤2.0m.

 

　　The grades of hot-rolled silicon steel sheets for household appliances are represented by J (home) D (electric) R (hot rolled), namely JDR. The number after JDR is the iron loss value*100, and the number after the horizontal line is the steel plate thickness (mm)*100. Hot-rolled silicon steel sheets for household appliances have slightly lower requirements for electromagnetic properties, and the minimum iron loss value (P15/50) is 5.40W/kg. Usually delivered without washing.
　　 Differential motors used in various electric fans, washing machines, vacuum cleaners, range hoods and other household appliances.

 

　　Oriented silicon steel sheet is off-white;

 

　　Take a piece of silicon steel sheet and fold it twice by hand. If it is oriented, the off-white slag will fall off, and it will break if it is repeatedly folded two or three times. The non-oriented silicon steel sheet is difficult to break even if it is folded ten times.