The main quality characteristics of silicon steel sheets include iron loss value, magnetic flux density, hardness, flatness, thickness uniformity, coating type and punching properties, etc.
1.Iron loss value
Low iron loss is the most important indicator of the quality of silicon steel sheets. Countries all classify grades according to the iron loss value. The lower the iron loss, the higher the grade.
2. Magnetic flux density
Magnetic flux density is another important electromagnetic property of silicon steel sheets, which indicates the ease with which silicon steel sheets are magnetized. Under the magnetic field intensity of a certain frequency, the magnetic flux passing through unit area is called magnetic flux density. Usually the magnetic flux density of silicon steel sheets is measured at a frequency of 50 or 60 Hz and an external magnetic field of 5000A/m. It is called B50, and its unit is Tesla.
The magnetic flux density is related to the collective structure, impurities, internal stress and other factors of the silicon steel sheet. Magnetic flux density directly affects the energy efficiency of motors, transformers and other electrical equipment. The higher the magnetic flux density, the greater the magnetic flux passing through the unit area, and the better the energy efficiency. Therefore, the higher the magnetic flux density of the silicon steel sheet, the better. Usually, the specifications only require the minimum value of the magnetic flux density.
3.Hardness
Hardness is one of the quality characteristics of silicon steel sheets. When modern automatic punching machines are punching sheets, the requirements for hardness are more stringent. When the hardness is too low, it is not conducive to the feeding operation of the automatic punching machine. At the same time, it is easy to produce excessively long burrs and increase assembly time. time difficulties. In order to meet the above requirements, the hardness of the silicon steel sheet must be higher than a certain hardness value. For example, the hardness of 50AI300 silicon steel sheet is usually no less than HR30T hardness value 47. The hardness of silicon steel sheets increases as the grade increases. Generally, the more silicon content is added to high-grade silicon steel sheets, the effect of solid solution strengthening of the alloy makes the hardness higher.
4. Flatness
Flatness is an important quality characteristic of silicon steel sheets. Good flatness is beneficial to film processing and assembly work. Flatness is directly and closely related to rolling and annealing technology. Improving rolling annealing technology and processes is beneficial to flatness. For example, if a continuous annealing process is used, the flatness is better than a batch annealing process.
5. Thickness uniformity
Thickness uniformity is a very important quality characteristic of silicon steel sheets. If the thickness uniformity is poor, the thickness difference between the center and edge of the steel sheet is too large, or the thickness of the steel sheet varies too much along the length of the steel sheet, it will affect the thickness of the assembled core. Different core thicknesses have large variations in magnetic permeability properties, which directly affect the characteristics of motors and transformers. Therefore, the smaller the thickness variation of the silicon steel sheets, the better. The thickness uniformity of steel sheets is closely related to hot rolling and cold rolling technology and processes. Only by improving rolling technology capabilities can the thickness variation of steel sheets be reduced.
6.Coating film
Coating film is a very important quality item for silicon steel sheets. The surface of the silicon steel sheet is chemically coated, and a thin film is attached to it, which can provide insulation, rust prevention and lubrication functions. The insulation reduces the eddy current loss between the silicon steel core sheets; the rust resistance prevents the steel sheets from rusting during processing and storage; the lubricity improves the punching performance of the silicon steel sheets and extends the life of the mold.
7. Film processing properties
Punchability is one of the most important quality characteristics of silicon steel sheets. Good punching properties extend the life of the mold and reduce the burrs of the punched sheets. The punchability is directly related to the coating type and hardness of the silicon steel sheet. Organic coatings have better punching properties, and newly developed coating types are mainly used to improve the punching properties of silicon steel sheets. In addition, if the hardness of the steel sheet is too low, it will cause serious burrs, which is not conducive to punching; but if the hardness is too high, the life of the mold will be reduced; therefore, the hardness of the silicon steel sheet must be controlled within an appropriate range.
Post time: Mar-19-2024