The influence of chemical composition: The fundamental composition of silicon steel consists of three major elements. The first type is alkaline alloying elements such as Si, Al, Mn, etc; The second category includes impurity elements such as C, S, N, O, Ti, Zr, etc; The third category includes trace elements such as Sb and Sn.

The influence of the first type of element

Si, Al, and Mn are useful alloying elements that can reduce the magnetic anisotropy constant K1 and saturation hysteresis stretching constant λ s, and are easier to magnetize, resulting in a decrease in pH. In addition, these elements can also add resistivity, so Pe decreases. So adding the content of the first type of element can significantly reduce iron loss. But when these elements are too high, the material becomes brittle and cannot be cooled.

The influence of the second type of element

C. S, N, O, Ti, Zr and other harmful elements can form small dispersed carbides, sulfides, nitrides and oxides in steel, preventing the growth of annealed grains in finished products. The lower the content of magnetic functional elements in steel, the better.

The influence of the third type of element

Adding a small amount of Sb and Sn to non oriented silicon steel can improve the texture of the non oriented silicon steel plate after recrystallization annealing, significantly adding favorable texture components (100) and (110), significantly reducing (111), and then reducing iron loss and improving magnetic induction. Adding a small number of such elements can suppress the composition of internal oxide and nitride layers and improve magnetic function.

grain size

Large grain size, small number of grain boundaries, low domain wall resistance, and reduced hysteresis loss. On the other hand, with larger grain size and larger magnetic domain scale, eddy current losses and abnormal losses increase. Therefore, in order to reduce total iron loss, there exists a suitable critical grain size.

Impurities, inclusions, and internal stresses

The inclusions and impurity elements in non oriented silicon steel sheets should be minimized as much as possible, which is a more important measure to improve magnetic properties. They not only prevent the movement of domain walls to add hysteresis loss and coercivity, but also make magnetization difficult due to the decrease in surrounding static magnetic energy. They also have a poor impact on particle growth and texture composition. Any internal stress in the silicon steel plate adds coercive force.

Crystal pattern

In oriented silicon steel, improving B8 significantly reduces hysteresis loss. Regarding non oriented silicon steel sheets, (100) has a higher planar pattern, lower hysteresis loss and P15, followed by (110) pattern, and (111) pattern is the worst.

steel plate thickness

Usually, as the thickness of the steel plate decreases, the hysteresis loss increases. However, the thickness of eddy current loss decreases significantly. Therefore, there is also a suitable critical thickness for total iron loss. The surface of the steel plate is smooth and flat, with reduced free magnetic poles, decreased static magnetic energy, decreased wall resistance, and decreased hysteresis loss and coercivity.

Article source: Transformer silicon steel sheethttp://www.cheungshun.com/