Oriented silicon steel is the core material of transformer

Silicon steel is an extremely low-carbon ferrosilicon alloy material with a silicon content of 0.5% to 4.5%. It has the characteristics of high magnetic permeability, low coercive force, and large resistivity. According to different production processes, it can be divided into hot-rolled silicon steel and cold-rolled silicon steel. According to the different grain arrangement directions in silicon steel, cold-rolled silicon steel can be divided into non-oriented silicon steel and oriented silicon steel. Among them, oriented silicon steel is mainly used in the manufacture of transformers (cores). It is the core material of transformers and can also be used in large motors ( hydropower, wind power) and other fields. Grain-oriented silicon steel consumes less electric energy per unit mass, which can reduce power losses in transmission and distribution lines and achieve energy-saving effects. Its magnetism has strong directionality and has superior high magnetic permeability and low loss characteristics in the rolling direction that is easy to magnetize. , is a key functional soft magnetic material to improve transformer performance. The main processing procedures of grain-oriented silicon steel include normalized pickling, cold rolling, decarburization annealing, magnesium oxide coating, stretching, etc. The technical difficulties are reflected in the front-end, back-end and full-process management, among which the front-end raw material coil smelting technology The difficulty accounts for about 40%, the difficulty of subsequent pickling, cold rolling, decarburization annealing and other processes accounts for 40%, and the technical difficulty of the whole process management accounts for about 20%. The performance of grain-oriented silicon steel is generally defined by indicators such as iron loss and magnetic induction, and can usually be distinguished by grade. Magnetic induction intensity: When the magnetic induction of oriented silicon steel is less than 1.88T, it is generally oriented silicon steel (CGO), and when the magnetic induction is greater than or equal to 1.88T, it is high magnetic induction oriented silicon steel (HiB).

Iron loss: When the magnetic induction intensity changes sinusoidally and its peak value and frequency are specific values, the total power absorbed by the unit mass of the material is expressed by the symbol P (10Bm/f) and the unit is W/kg. The naming rules of grain-oriented silicon steel grades include manufacturer, thickness, magnetic induction intensity and guaranteed iron loss value. For example, B30P105 represents high magnetic induction oriented silicon steel with a nominal thickness of 0.30mm, and the guaranteed iron loss value P17/50 is not greater than 1.05W/kg.

The grade of oriented silicon steel is the performance index of oriented silicon steel. The smaller the number, the higher the grade and the better the performance (on the one hand, the lower the loss of oriented silicon steel, the higher the magnetic induction, which can reduce the power loss of the transformer; on the other hand, it makes The volume and weight of the core of a transformer with the same capacity can be reduced, and silicon steel sheets, electromagnetic wires and insulating materials can be saved). Head

The top grades are mainly 90 and above, mainly 90, 85, 80, etc. Taking Baosteel's grain-oriented silicon steel as an example, a comparison of typical characteristics between ordinary grain-oriented silicon steel material B30G120 and magnetic domain-refined grain-oriented silicon steel material B23R085 shows that the magnetic domain-refined grain B23R085 has a unit loss of 25.92% lower than the conventional grain-oriented B30G120 silicon steel sheet; the magnetization intensity is increased. 0.02T; the excitation power is increased by 0.2VA/kg, and the performance level has been greatly improved.