With the rapid development of new energy vehicles, smart grids, and renewable energy, the demand for low⁃iron⁃loss silicon steel has been continuously increased by the market. The thinning of silicon steel thickness is regarded as an irreversible trend in product development, while greater challenges are posed to production processes by this thickness reduction. In recent years, the preparation and development of thin⁃gauge silicon steel have become a research focus. The production processes for thin⁃gauge silicon steel were summarized in this paper: oriented silicon steel is divided into primary recrystallization, secondary recrystallization, tertiary recrystallization, and twin⁃roll thin⁃strip continuous casting methods; non⁃oriented silicon steel is categorized into conventional processing, asynchronous rolling, twin⁃roll thin⁃strip continuous casting, and planar flow casting methods. Meanwhile, the current production status of thin⁃gauge silicon steel was introduced and future development directions were proposed, which can provide references for the research and development of thin⁃gauge silicon steel.

As a functional material, silicon steel has been widely used in the core manufacturing of electrical equipment, mainly using the magnetic properties of silicon steel sheet. In recent years, thanks to the development of silicon steel and rapid development of production technology, various silicon steel products with different processes have appeared on the market. How to identify and select suitable silicon steel to manufacture different types of core is become more and more popular. In this paper, the magnetic properties of oriented silicon steel, the relationship between the no⁃load characteristics of transformer and the magnetic properties of silicon steel sheet, and the effect of core structure on the service conditions of silicon steel sheet were discussed. Considering the serving properties of silicon steel sheet under working conditions, the effects of temperature change, harmonic field and DC bias on the properties of silicon steel sheet and core structure were analyzed.

The microstructure evolution of copper⁃containing oriented silicon steel under different secondary cold rolling reduction rates was studied using electron backscatter technology (EBSD), and the loss characteristics were analyzed based on a loss separation model. The results showed that the decarburization annealed sample completely finished recrystallization, with an average grain size of about 10 μm; when the sample rolled to the thickness of the finished product, as the cold rolling reduction rate increases, the width of the deformation zone gradually decreases, and the orientation density of the {111}<112>fiber texture first increases and then decreases; when the cold rolling reduction rate is 62.3 %, the density of {111}<112> beneficial texture orientation reaches 7.1. In addition, the sample showed a lower content of the ∑3 unbeneficial grain boundary and a higher content of the ∑9 and ∑13b beneficial grain boundaries. The hysteresis loss of finished sample is low, resulting in an excellent magnetic property (P1.7/50=0.890 W/kg, B800=1.884 T).

Oriented silicon steel has the characteristics of high permeability and low core loss along its rolling direction, so its application in electric motors can significantly increase the torque density and efficiency of the motor. However, the motor will be subject to a variety of temperature factors during operation, affecting the magnetic properties of oriented silicon steel, so it is important to study the effect of temperature on the performance of the oriented silicon steel motor for its design and optimization. Therefore, this paper focused on oriented silicon steel motors to investigate the effect of temperature on its silicon steel material and motor performance. The experimental results showed that the core loss and saturation magnetism of silicon steel materials decrease with increasing temperature, and the core loss and saturation magnetism of oriented silicon steel are more significantly affected by temperature. At the same time this paper based on the material test data, the use of finite element method to further study the change rule of oriented silicon steel motor performance under the influence of different temperatures. Simulation results showed that the high temperature on the core loss of the oriented silicon steel motor is more significant, and compared to the core loss of oriented silicon steel at room temperature, the core loss at high temperature decreases by 6.9 %.

Non⁃oriented silicon steel is the core soft magnetic material of generators, motors and other equipment. Metallurgical defects are one of the important factors affecting its magnetic properties and product quality. The characteristics of inclusions significantly affect the magnetic properties of non⁃oriented silicon steel. In this paper, the influence law and mechanism of the type, shape, size and quantity of inclusions on magnetic properties were systematically sorted out, and the effective control technology of inclusions was summarized. The type, shape, size and quantity of inclusions are closely related to magnetic properties. In terms of type, the stress field generated by oxide inclusions ( such as Al2O3 ) significantly pins the magnetic domain wall and aggravates the hysteresis loss. Sulfide inclusions ( such as MnS ) change the magnetic domain structure and affect the magnetic permeability anisotropy due to the difference in morphology and distribution. Nitride inclusions ( such as AlN ) pin grain boundaries and dislocations in a small dispersed form, hindering the movement of magnetic domain walls. In terms of morphology, angular inclusions cause stress concentration and have a greater hindrance to the magnetic domain wall than spherical inclusions. In terms of size, fine inclusions ( < 1 μm ) lead to an increase in coercivity, an increase in iron loss, and a decrease in magnetic induction intensity by inhibiting grain growth and strong pinning effect. In terms of the number of inclusions, the increase of the volume fraction of inclusions will enhance the interaction, and the decrease of the spacing will lead to the superposition of the stress field, so that the iron loss will increase significantly.In terms of mechanism, inclusions affect magnetic properties in multiple dimensions by changing the energy state of magnetic domain wall, regulating grain boundary migration and recrystallization texture. In view of the regulation of inclusions, calcium treatment and rare earth treatment technology are mainly used at present. Through spheroidization and aggregation of inclusions, they are transformed into composite inclusions, which can increase the size and reduce the number, and effectively improve the magnetic properties of non⁃oriented silicon steel.

During the continuous casting of 600 grade non⁃oriented silicon steel, there is a phenomenon of submerged entry nozzle blockage. In severe cases, the fluctuation amplitude of the crystallizer liquid level can reach ± 5 mm, and the number of single nozzle casting furnaces is low, which seriously affects the smooth production and the quality of continuous casting billets. The microscopic analysis of the blockages at the slag line of the submerged entry nozzle was carried out in this paper, and the source of the blockages was traced according to the detection results of the energy spectrometer. And then related studies such as the substitution of RH high⁃quality alloys, the adjustment of alloying sequence, and the effect of RH desulfurizer on the ladle slag system were carried out. The results showed that the castability of continuous casting of 600 grade non⁃oriented silicon steel has been improved, and the number of furnaces poured by SEN has been increased from 5⁃6 furnaces/unit to 12⁃13 furnaces/unit.

The pre⁃fused RH flux has never been industrial application on big scale until Calderys put such product to silicon steel product lines. This paper introduced the whole process of developing RH desulphur fluxes from design by FactSage to industrial trials. In practical terms, Calderys’ pre⁃fused RH fluxes helped overcome the pulverization problem of CaO⁃CaF2 flux. By FactSage simulation, four new recipes were designed for production and industrial trials. The several trial results showed that the new recipe 3 containing a small amount of F element is the best one which increased desulphurization rate with max increase of 10 %. Additionally, pre⁃fused RH fluxes could control the non⁃uniform refractory corrosion of down snorkel well compared to CaO⁃CaF2 flux which is easy to cause non⁃uniform corrosion due to the content of free lime.

Based on the actual production conditions of non⁃oriented silicon steel, this paper explored the influence of carbon content on the electromagnetic properties of non⁃oriented silicon steel, revealed the key issue that excessive carbon content leads to an increase in iron loss and a decrease in magnetic flux density, and formulates corresponding solutions and preventive measures. According to the actual production of 50W1300 and the results of electromagnetic properties and hardness tests of the products, it can be known that when the carbon content exceeds 0.005 %, the iron loss value P1.5/50 increases from 5.653 W/kg to 6.422 W/kg, an increase of 13.60 %. The magnetic induction intensity B50 decreases from 1.766 T to 1.742 T, a reduction of 1.36 %. At the same time, the hardness of the finished product rises from HV105 to HV129, an increase of 22.86 %. In response to this problem, optimization strategies for the steelmaking and cold rolling annealing processes were formulated, successfully solving the situation that the low electromagnetic properties and the high hardness of the products due to excessive carbon content.

Silicon steel often has convex and coil collapse defects during the coiling process, which seriously affect the quality of the steel coil and reduce the yield rate of the steel coil. In order to analyze the causes of convex and coil collapse defects in the coiling process of silicon steel, a mathematical model was established firstly for the stress field during the steel coil coiling process, and the stress calculation method during the coiling process was analyzed. Secondly, the reel was physically modeled to determine the position of the strain gauge. Then, the strain gauge was installed on the silicon steel production line. The relationship between the strain of the steel coil during the coiling process and the coiling quality was analyzed through the values of the strain collected by the strain gauge over time. The data collected by the strain gauge lays a technical foundation for preventing convex and coil collapse in silicon steel coiling.