silicon steel
Fe-Si alloy with silicon content of 0.5% ~ 4.8%. It is a soft magnetic material widely used in electrical field. Silicon steel for electrical purposes is often rolled into large pieces or strips of standard size, commonly known as silicon steel sheets, which are widely used in motors, generators, transformers, electromagnetic mechanisms, relay electronic devices and measuring instruments.
Silicon is a good deoxidizer for steel. It combines with oxygen to convert oxygen into stable SiO2 _ 2 which is not reduced by carbon, thus avoiding lattice distortion of iron due to oxygen atom doping. When silicon becomes a solid solution in α-iron, it increases resistivity and helps to separate harmful impurity carbon. Therefore, after silicon is added to iron containing impurities, the magnetic permeability can be improved and the coercivity and iron loss can be reduced. However, the increase of silicon content will make the material hard and brittle, and the thermal conductivity and toughness will decrease, which is not conducive to heat dissipation and processing, so the silicon content of general silicon steel sheets is less than 4.5%.
Silicon steel sheets are divided into two types: cold-rolled and hot-rolled, and cold-rolled silicon steel sheets are widely used. Cold-rolled silicon steel sheet has excellent magnetic properties along the rolling direction, which not only has high saturated magnetic flux density and low iron loss under strong magnetic field, but also has good magnetism (large initial permeability) under weak magnetic field. This is because the cold rolling process reduces the impurity content in the steel plate, resulting in coarse grains of the steel plate, which leads to an increase in magnetic permeability and a decrease in hysteresis loss.
Silicon steel classification:
Hot rolled silicon steel sheet:
Hot rolled silicon steel sheet is made by melting Fe-Si alloy in open hearth or electric furnace, repeatedly hot rolling into thin sheet, and finally annealing at 800-850℃. Hot rolled silicon steel sheet is mainly used to manufacture generators, so it is also called hot rolled silicon steel sheet for motor.
However, due to its low availability and high energy consumption, the relevant departments have strongly demanded elimination in recent years. Cold-rolled non-oriented silicon steel sheet: cold-rolled non-oriented silicon steel sheet is mainly used for generator manufacturing, so it is also called cold-rolled motor silicon steel. Its silicon content is 0.5%-3.0%, and it is cold-rolled to the thickness of the finished product. The supply state is mostly 0.35mm and 0.5mm thick steel strip. Bs of cold-rolled non-oriented silicon steel is higher than that of oriented silicon steel; Compared with hot-rolled silicon steel, it has uniform thickness, high dimensional accuracy and smooth surface, thus improving the filling coefficient and magnetic properties of the material. Cold rolled oriented silicon steel sheet;
Cold rolled oriented silicon steel strip is mainly used in transformer manufacturing, so it is also called cold rolled transformer silicon steel. Compared with cold-rolled non-oriented silicon steel, the magnetism of oriented silicon steel has strong directionality; It has excellent high permeability and low loss characteristics in the easy-magnetized rolling direction. The iron loss of oriented steel strip in the rolling direction is only 1/3 in the transverse direction, and the ratio of magnetic permeability is 6: 1. The iron loss is about 1/2 of that of hot rolled strip steel, and the magnetic permeability is 2.5 times that of the latter. Representation method of silicon steel sheet brand:
DR5 10-50 represents the iron loss value ... from the nominal thickness (expanded 100 times)+code A+ iron loss guarantee value (the value obtained by expanding the iron loss value at 50HZ frequency and the maximum magnetic flux density 1.5T 100 times).
DR5 10-50 stands for hot-rolled silicon, with an iron loss of 5. 1 and a thickness of 0.5 mm ... Features: the density of aluminum is low, with a specific gravity of 2.7, which is about1/3 of copper; Cold rolled non-oriented silicon steel strip (sheet) with good electrical conductivity, thermal conductivity, plasticity and cold toughness
Representation: DW+ iron loss value (when the frequency is 50HZ, the peak value of magnetic induction of sine wave is 1.5T). ) 100 times+100 times the thickness value. For example, DW470-50 stands for cold-rolled non-oriented silicon steel, with an iron loss of 4.7w/kg and a thickness of 0.5 mm. Now the new model stands for 50W470.
(2) cold-rolled oriented silicon steel strip (sheet)
Representation: DQ+ iron loss value (at the frequency of 50HZ, the peak value of magnetic induction of sine wave is 1.7T, which is the iron loss value per unit weight. ) 100 times+100 times the thickness value. Sometimes g is added after the iron loss value to indicate high magnetic induction intensity. For example, DQ 133-30 represents cold-rolled oriented silicon steel strip (sheet), with an iron loss value of 1.33 and a thickness of 0.3 mm. Now the new model is represented as 30Q 133.
(3) hot rolled silicon steel sheet
Hot rolled silicon steel sheets are denoted by DR, and are divided into low silicon steel (silicon content ≤2.8%) and high silicon steel (silicon content > 2.8%) according to silicon content.
Expression: DR+ iron loss value (the maximum magnetic induction intensity is 65438+iron loss value per unit weight at 0.5T after repeated magnetization at 50hz)+100 times the thickness value. For example, DR5 10-50 represents a hot-rolled silicon steel plate with an iron loss value of 5. 1 and a thickness of 0.5 mm ..
The brand of hot-rolled silicon steel sheet for household appliances is represented by JDR+ iron loss value+thickness value, such as JDR540-50.
2, the Japanese brand expression method:
(1) cold-rolled non-oriented silicon steel strip
Nominal thickness (enlarged 100 times)+code A+ guaranteed value of iron loss (enlarged 100 times when the frequency is 50HZ and the maximum magnetic flux density is 1.5T). For example, 50A470 indicates a cold-rolled non-oriented silicon steel strip with a thickness of 0.5mm and an iron loss guarantee value of ≤4.7.
(2) cold-rolled oriented silicon steel strip
Nominal thickness (expansion 100 times)+code g: for ordinary materials, and p: for highly oriented materials+guaranteed iron loss value (the value obtained by frequency 50HZ, maximum magnetic flux density 1.7T expansion 100 times the iron loss value). For example, 30G 130 represents a cold-rolled oriented silicon steel strip with a thickness of 0.3mm and an iron loss guarantee value of ≤ 1.3.
Coating:
The insulating coating on the surface of oriented silicon steel can be divided into three categories: organic coating, inorganic coating and semi-inorganic coating. The basic components of inorganic coatings are phosphate coatings and aluminum phosphate coatings, which contain colloidal silicon dioxide, magnesium oxide and boric acid. Inorganic coatings have good heat resistance and weldability, but poor stamping and adhesion. The basic components of semi-inorganic coating are phosphate, chromate, latex resin solution, dispersion promoter and surfactant, among which dispersion promoter and surfactant play an important role in coating quality. Semi-inorganic coating has good stamping and adhesion, but its heat resistance and weldability are not as good as inorganic coating.
A coating
A coating is a semi-organic thin coating, which has excellent stamping, corrosion resistance, freon resistance and high-rise resistance, especially welding performance, and is suitable for small and medium-sized motors and household appliances.
The EI cores of motors and small transformers are equivalent to the A 1 coating of Sichuan Railway and the T4 coating of WISCO. H-coating H-coating is a semi-organic thick coating with excellent stamping, corrosion resistance, freon resistance and high-rise resistance, which is suitable for small and medium-sized motors. Equivalent to A 1 coating of Sichuan Railway and T4 coating of WISCO.
D coating
D coating is an inorganic coating with excellent weldability and heat resistance, which is suitable for small and medium-sized motors, especially for stress relief annealing at higher temperature. Equivalent to C-4 coating of AISI and T3 coating of WISCO.
Unless otherwise specified, the surface insulation coating of steel grade design is coating. The energy loss of transformer caused by iron core is called iron loss, which includes two parts, hysteresis loss and eddy current loss. Hysteresis loss is the loss caused by "internal friction" in the process of repeated magnetization of iron core, which is related to iron core.
The properties of materials (permeability, coercivity) are related. Eddy current loss is caused by Joule heat generated by induced current in iron core. The eddy current loss can be greatly reduced by using the iron core formed by laminating thin silicon steel sheets coated with insulating paint.
The size of iron loss is not only related to the iron core itself, but also related to the power supply voltage. When the power supply voltage is constant, the iron loss is basically unchanged, regardless of the size and nature of the load current, so the iron loss is basically equal to its no-load loss.