Aiming at the problem that broken edge wave defects in hot-rolled grain-oriented silicon steel affect the stability of rolling and increase the amount of rework for levelling and cutting loss, the occurrence pattern of the broken edge waves defect in the hot rolling process of grain-oriented silicon steel, the wear of the F7 work roll in finish rolling, and the deviation of the strip steel in finish rolling were analyzed. It has been clarified that the local wear of the F7 work roll and the strip deviation between the finishing mill stands are the main causes of the broken edge wave defects in the hot rolling process of grain-oriented silicon steel. By optimizing the roll shifting range of the F7 work roll and controlling the strip deviation between finishing mill stands, the broken edge wave defects in the hot rolling process of grain-oriented silicon steel have been significantly improved. This has led to a reduction in the amount of rework on the hot rolling line and the yield loss caused by cutting during leveling.

The characteristics and influencing factors of iron loss distribution along rolling direction and transverse direction of large width oriented silicon steel coil were studied. The results showed that the iron loss along both the rolling direction and the transverse direction had obvious nonuniform distribution characteristics.The maximum iron loss along the rolling direction and the transverse direction both occurred in the innermost circle area and the area where the cold spot was located.With the changing position along the rolling direction, both the maximum and minimum iron losses along the transverse direction fluctuated, resulting in the fluctuation value of the transverse iron loss being closely related to the position along the rolling direction.It was concluded that the characteristics of iron loss distribution along the rolling direction and transverse direction of large width oriented silicon steel coil were mainly related to the non-uniform distribution of temperature field during high temperature annealing. The non-uniform distribution of temperature field resulted in significant differences in the secondary recrystallization process and purification annealing effect at different positions of oriented silicon steel coil.On the one hand, the secondary recrystallization grain size in the innermost ring and cold spot region of oriented silicon steel coil was significantly smaller than that in the outermost ring region, and the residual island grain in the innermost ring and cold spot region showed a gradient distribution along the transverse direction, while there was almost no island grain in the outermost ring region. On the other hand, the distribution gradient of N content in the innermost ring and cold spot region along the transverse direction was obviously larger than that in the outermost ring region.

Simulation shows that the proportion of 3rd harmonic content in the magnetic flux of the three-phase five-limb core and the three-phase wound core is about 17 %. These cores are recommended to be prepared using thin-gauge and low-loss grain-oriented silicon steel. The service properties of ultra-stable low-loss silicon steel (USL) and high magnetic induction oriented silicon steel (HiB) were studied under different harmonic orders and harmonic contents. According to the loss separation model, the losses of different silicon steels are divided into hysteresis loss, eddy current loss, and excess loss. Compared with HiB silicon steel of the same grade, USL silicon steel has a similar proportion of eddy current loss and a smaller proportion of excess loss. Under the same harmonic excitation, USL silicon steel with a lower proportion of excess loss is less affected by harmonic, because the excess loss of silicon steel is proportional to the frequency.

Decarbonization is one of the main causes of the “crisp edge defect” in the edge of low-temperature oriented silicon steel hot coils. To this end, the decarburization mechanism of low-temperature oriented silicon steel slabs was studied, and the evolution of the total decarburization layer depth of low-temperature oriented silicon steel slabs at different temperature stages was clarified. Based on this, a new anti decarburization coating was developed. Through laboratory experiments, on-site back billet experiments, and on-site promotion and application experiments, it was verified that the new anti-decarburization coating can significantly reduce the total decarburization layer depth of low-temperature oriented silicon steel hot-rolled edges and improve the quality of hot-rolled edges. The development and application of a new anti decarburization coating for low-temperature oriented silicon steel slabs have laid a favorable foundation for promoting burr rolling in downstream cold rolling processes.

The product series and core properties of POSCO non-oriented electrical steel for new energy vehicles were expounded. The patent  applications of POSCO in this field over the recent five years(2019-2023) were systematically analyzed, covering the characteristics of patent applications  and the analysis of core patents, thereby revealing the technical means and effects of its patent.

This paper takes the core stacking factor of drive motor lamination for new energy vehicles as the research object and conducts a systematic study. First, it elaborates on the impact of core stacking factor on motor performance, then introduces the definition and measurement methods of core stacking factor, and focuses on analyzing the influence mechanisms of key factors such as coating thickness, stamping burrs, material hardness, number of selfclinching points, welding pressure and weld quality on core stacking factor. This research provides a theoretical basis for improving the performance of drive motors in new energy vehicles.

As a green， low-carbon, and clean regulating power source in the power system, pumped storage serving is currently the most mature economically viable option and most suitable for  large-scale development，which can effectively meet the development needs of new power systems. AC excitation variable frequency technology represents a significant research focus in the field of variablespeed pumped storage power units. This article systematically studied the technical parameters, manufacturing process schemes, and product performance results of a new type  electrical steel material with high-strength and low iron-loss for iron cores based on the technical characteristics of double fed motor rotor iron core for AC excitation variable-speed pumped storage units. This has significant driving significance for the successful development of AC excitation variable-speed pumped storage units.

Aiming at the rolling problem of special steel grades caused by insufficient rolling capacity of tandem cold rolling mills, this study was carried out based on the rolling mechanism model (focusing on the rolling force model and combined with on-site actual production conditions. Under the condition of not increasing the number of existing mill stands, a small roll diameter rolling technology was proposed: reducing the stand roll diameter to decrease the unit rolling force, thereby improving the rolling capacity of the mill. The application results show that the implementation of this technology has a significant promoting effect on expanding the range of rolling varieties of the tandem cold rolling mill and releasing the rolling capacity, which provides a feasible path for the efficient rolling of special steel grades.

In the 1 780 mm hot rolling mill, Bengang uses advanced thirdgeneration "dual station coreless coiling" hot coil boxes to produce low to medium grade nonoriented silicon steel products. Compared with the conventional 1 700 mm hot rolling mill equipped with insulation covers, the finishing temperature control capability has been greatly improved, enabling the stable implementation of the lowtemperature tapping process. This significantly reduces the solid solution and precipitation of the second phase, avoids its fine dispersed distribution at grain boundaries, forms a favorable hotrolled plate structure foundation, lays the groundwork for obtaining an ideal grain size in the subsequent finished product annealing process, and thus achieves excellent magnetic properties. After the commissioning of the hot coil box, the average finishing temperature increased from 850 ℃ to 880 ℃. Compared with conventional units, the iron loss decreased by 8.3 % and the magnetic induction increased by 0.01 T.

Compatibility tests were conducted on silicon steel sheets with two types of refrigerant oilrefrigerant media to evaluate the compatibility of the sheets, including separate hightemperature and lowtemperature compatibility tests on individual silicon steel sheet components. Based on the test results, it was determined whether the components meet the compatibility requirements. The compatibility differences between the two media and silicon steel sheets were compared based on the test results, providing a basis for determining the applicability of silicon steel sheets in different media.