The ferrosilicon alloy with preferred grain orientation after deformation and recrystallization annealing is primarily used for manufacturing various transformers, fluorescent lamp ballasts, and stator cores of steam turbine generators. About 40% of the electrical energy lost in the transmission and distribution system is consumed in transformers, with iron and copper losses each accounting for about 50% of the total transformer losses. Therefore, continuously reducing the iron loss of oriented silicon steel and achieving high efficiency and cost savings in transformers is a very important part of the overall carbon reduction project.

The magnitude of iron loss is directly related to the quality of the silicon steel used to manufacture the iron core. Although many efforts have been made to reduce iron loss, recent work indicates that further reduction of iron loss can be achieved through the following methods.

(1) Remove the magnesium silicate substrate to make the surface of the steel plate smoother, promote the mobility of 180 ° domain walls, and ensure the uniformity of magnetization. Using MgO chloride or Al2O3 as the main isolation agent in production can produce steel plates with smoother surfaces.

(2) Thinning the steel strip can further reduce eddy current losses. Nowadays, many products are produced and used with thicknesses of 0.27mm and 0.23mm. Laboratory homework instructions. Assuming the thickness is reduced to 0.15mm, the iron loss of the trademark product can be reduced by about 50% compared to the currently used 0.23mm thickness.

(3) Through laser irradiation, mechanical scoring, toothed roller processing, or plasma spraying, the surface of oriented silicon steel is treated to have defects perpendicular to the rolling direction, which can refine magnetic domains and reduce abnormal eddy current losses.

During this period, laser processing has shown better application prospects. Because the abnormal eddy current loss is proportional to the magnetic domain width, refining the magnetic domain width can reduce iron loss. Laser processing technology utilizes its rapid heating and cooling characteristics to draw lines on the surface of oriented silicon steel sheets, causing fine plastic deformation and high-density dislocations in the heating zone, reducing the length of the main domain wall, and simultaneously generating residual tensile stress, achieving the intention of refining magnetic domains and reducing iron loss. The homework indicates that laser processing has a significant effect on reducing iron loss, and the larger the initial value of iron loss, the greater the percentage of iron loss reduction after laser processing.

The experimental results indicate that the distance between laser points should not be too small, otherwise adjacent laser effect zones will stack with each other, causing a significant release of the original coating tensile stress and reducing the effect of reducing iron loss. Other than that, silicon steel sheets processed by laser cannot be further treated at temperatures above 800 ℃.

The current problem with laser processing is that it may simply cause damage to the insulation coating on the surface of silicon steel sheets or be damaged due to bending deformation of the sheet. The problem of damaged coatings is often addressed by the re coating method in foreign countries. There are homework assignments in China indicating that the problem of surface coating damage in pulse laser processing mainly depends on the pulse width and its peak power. Increasing the pulse width and reducing the peak power can defeat this question. When the pulse width is increased to 750 μ s, only mild laser processing marks are needed on the surface, and the insulation is not damaged at all. Based on this estimation, continuing to increase pulse width and reduce peak power may address the issue of coating damage caused by pulsed laser processing.

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