In view of the frequent slipping and strip breakage problems of high magnetic induction oriented silicon steel (Hi⁃B steel) during the high⁃speed rolling process of the twenty⁃high reversing cold rolling mill, this article systematically analyzes the slipping mechanism and main influencing factors based on the actual production conditions of the production line. Research shows that slippage is mainly caused by factors such as the significant decrease in work roll surface roughness with increasing rolling passes, excessive pass reduction, mismatch of front and rear tension systems, and excessive oil film thickness due to high emulsion concentration. To this end, three key process optimization measures were proposed: increasing the initial roughness and grinding groove depth of the work roll by adjusting the grinding process parameters to enhance the friction between the roll and the strip; optimizing the tension system, appropriately increasing the front tension and reducing the rear tension to expand the front slip zone and stable deformation zone; reducing the emulsion concentration and controlling the oil film thickness. After implementing the above measures, the slippage and strip breakage rates during the cold rolling process of Hi⁃B steel were significantly reduced, and rolling stability and production efficiency were effectively improved.

For grain⁃oriented silicon steel, sufficient secondary recrystallization during high⁃temperature annealing is the key to ensuring good magnetic properties. The initial microstructure before high⁃temperature annealing has a significant impact on whether secondary recrystallization can proceed properly, so the initial microstructure before high⁃temperature annealing needs to be strictly controlled. To investigate the effect of pre⁃annealing on the initial microstructure before high⁃temperature annealing, and the impact of different initial microstructures on secondary recrystallization and magnetic properties, pre⁃annealing treatment and interrupted high⁃temperature annealing sampling experiments were conducted on grain⁃oriented silicon steel. The results showed that: the microstructure after 550 ℃ pre⁃annealing remained in the rolled state, with no primary recrystallization occurring; the initial microstructure before high⁃temperature annealing had a high intensity of γ texture {111}<112>, and during high⁃temperature annealing, Goss grains grew fully, resulting in a final product with high magnetic induction and low iron loss. After 640 ℃ pre⁃annealing, part of the primary recrystallization occurred in the microstructure. After 700 ℃ pre⁃annealing, the microstructure was fully recrystallized, with a stronger α texture {112}<110> and {110}<112> (brass texture) that hindered the growth of Goss grains during secondary recrystallization, leading to poor magnetic induction and higher iron loss in the final product. Therefore, grain⁃oriented silicon steel should be pre⁃annealed at temperatures below 550 ℃ before high⁃temperature annealing to retain more of the rolled microstructure, increase the proportion and intensity of favorable Goss texture, thereby promoting the growth of secondary recrystallized grains and improving magnetic properties.

This paper investigated the effect of the calcium oxide (CaO) content in magnesium oxide (MgO) coatings on the quality of the forsterite substrate formed on grain⁃oriented silicon steel. Using scanning electron microscopy (SEM), the study examined the impact of different CaO concentrations on both the substrate morphology and the surface condition of the finished steel strip. The results demonstrated that the CaO content in MgO was a critical factor for the final substrate quality. Specifically, as the CaO mass fraction was increased from 0.2 % to 0.5 %, the hydration rate of the MgO layer post⁃drying rose from 1.01 % to 1.92 %. The increase in CaO corresponded with a coarsening of MgO particles and poorer uniformity in the substrate layer, which macroscopically manifested as surface oxidation on the steel strip. The mechanism suggests that higher CaO content introduces more water into the MgO slurry. Consequently, during the high⁃temperature annealing phase in a bell furnace, steam trapped at the coil edges as it escapes between layers leads to additional oxidation along the strip edges, causing the observed defects.

This paper systematically demonstrates the necessity and feasibility of phasing out conventional grain⁃oriented silicon steel (CGO) during the "15th Five⁃Year Plan" period from the perspective of high⁃quality development of China's silicon steel industry. The article first reviews the technical evolution of CGO silicon steel from Goss's invention in 1933 to the present, pointing out that the copper⁃containing medium⁃temperature QRD process currently widely adopted in China represents backward production capacity in terms of magnetic properties, resource utilization, energy consumption, and production organization. The paper elaborates on the legal basis for eliminating CGO from five dimensions: first, CGO uses Cu2S as an inhibitor, leading to copper resource waste and scrap steel recycling difficulties; second, the medium⁃temperature heating process has high energy consumption and low yield rates; third, product magnetic properties fail to meet the GB 20052⁃2024 new energy efficiency standards and the demands of high⁃end fields such as ultra⁃high voltage and new energy; fourth, equipment standards lag behind smart manufacturing requirements; and fifth, disorderly capacity expansion triggers market "involution" and vicious competition. The article further analyzes the practical significance of phasing out CGO for supporting ultra⁃high voltage construction, serving emerging fields such as national defense, military industry, and low⁃altitude economy, and promoting industrial technology upgrading. Four policy recommendations are proposed: explicitly prohibiting CGO hot⁃rolled coil production through national industrial policies; promoting equipment upgrading and transformation of cold⁃rolling enterprises; optimizing the standard system to raise industry thresholds; and strengthening the supporting role of standards and quality.

Against the backdrop of the carbon peaking and carbon neutrality goals, the optimization of magnetic properties of non⁃oriented silicon steel is pivotal for improving the energy efficiency of power equipment. In this paper, two types of non⁃oriented silicon steel with a thickness of 0.35 mm were taken as the research objects. Based on the iron loss separation model, the total iron loss was decomposed into hysteresis loss (Ph), eddy current loss (Pe) and anomalous loss (Pa), and the influence laws of grain size, microstructure homogeneity and recrystallization texture on each loss component were investigated. The results showed that compared with steel A having a smaller average grain size, a strong {001}<130> texture and a weak {111}<112> texture, the steel B with a larger average grain size, poor microstructure homogeneity and a strong {001}<120> texture exhibits a lower Ph but a higher Pa. This work elucidates the intrinsic correlation between microstructure and texture characteristics and iron loss components, and provides theoretical support for the microstructure and texture regulation as well as magnetic performance optimization of non⁃oriented silicon steels used under different operating frequencies.

To optimize the high⁃temperature oxidation control and scale removal process of non⁃oriented silicon steel in industrial production, low⁃grade industrial BW1300 hot⁃rolled non⁃oriented silicon steel was selected as the research subject. Through physicochemical analysis, its alloy composition was determined, and characterization methods such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and X⁃ray diffraction (XRD) were used to systematically study the thickness of oxidation scales, phase composition evolution, and the effects of different heating regimes on the structure of oxidation scales during high⁃temperature oxidation, with a focus on analyzing the role of alloying elements and oxidation mechanisms. The results show that at 1 150~1 177 ℃, the bonding force between the oxide scale and the substrate is relatively low, making it easy to remove the scale, which is consistent with previous studies on the effect of temperature on oxidation layer adhesion. When the temperature exceeds 1 177 ℃, Fe2SiO4 and FeO form a eutectic liquid phase, leading to rapid thickening and a loose structure of the oxide scale. This study supplements the specific oxidation characteristics of industrial BW1300 silicon steel, enriches the research system of high⁃temperature oxidation of non⁃oriented silicon steel, and its conclusions are close to industrial production practices, providing a theoretical basis and technical support for the optimization of scale removal processes and the control of oxidation defects.

Faced with the pressures of quality improvement, efficiency enhancement and green manufacturing in the iron and steel industry, innovation in rolling process is the key to boosting the competitiveness of non⁃oriented electrical steel. Taking a 20⁃high rolling mill as the research platform, this paper conducted an integrated study on reduced⁃pass rolling of high⁃grade non⁃oriented electrical steel. Combining material testing, finite element simulation and rolling experiments, it reveals the influence law of silicon content on the key rolling characteristics, establishes a "material⁃process⁃equipment" collaborative optimization technology system, proposes a reduction strategy of "large reduction in the early passes, small reduction in the later passes, and stable reduction in the middle passes", develops a dynamic flow and temperature control technology for emulsion, and optimizes the coordinated model of flatness and tension. The results showed that on the premise of ensuring magnetic properties, flatness accuracy and surface quality, the number of rolling passes reduced from 6 to 5 can achieve production increase and cost reduction.

This paper introduced the structure and process mechanism of the cleaning section equipment of the silicon steel continuous annealing unit. Through process parameter optimization experiments and combined with EMG cleanliness detection experimental data, the influences of alkaline solution concentration, temperature, brush roller current and other parameters on cleaning quality were revealed. The research results show that when the temperature of the alkali solution is controlled at 60⁃80 ℃, the concentration at 2 %⁃5 %, the brush roller current at 9⁃11 A, the extrusion pressure at 2⁃4 MPa, the cleaning time at 10⁃30 s, and the spray beam angle at 45°, the surface fluorescence unit of the strip steel can be reduced to below 15 μW/cm2, effectively avoiding secondary problems such as furnace roller nodules, and providing reference for process optimization of similar production lines.