High-temperature annealing is a crucial process in the production of cold-rolled grain-oriented silicon steel, and extensive research has been conducted by practitioners over several decades, leading to significant advancements. The high-temperature annealing equipment, process, and microstructure growth mechanism of grain-oriented silicon steel were summarized based on the characteristics of the process and existing domestic and foreign researches. Furthermore, potential directions for future research in the high-temperature annealing process were proposed.

The cutting process will lead to the deterioration of the magnetic properties of the electrical steel, causing changes in the microstructure of the edge of the electrical steel. The cutting experiment was carried out on the non-oriented electrical steel sheet, and the effects of wire cutting and laser cutting processes on the magnetic properties of electrical steel were studied. The magnetic properties of wire-cut and laser-cut electrical steels were tested by using the test method of annular specimens, and the material model was constructed based on the measured data, and the material model was combined with the motor model under actual working conditions, and the motor loss was verified by simulation. The results showed that the wire cutting process has little effect on the magnetic properties of electrical steel, and the loss of electrical steel in the wire cutting process for motors is low.

The cause of cold-rolled broken strip of silicon steel was analyzed, so as to further improve the preparation process of silicon steel and reduce the probability of cold-rolled broken strip. The experimental results showed that the contents of brittle inclusions such as AlN and Al2O3 in the fractured part and unfractured part of cold-rolled broken strip are respectively 26.03 % and 29.65 % higher than those of the qualified samples, while the contents of plastic inclusions such as sulfides and complex nitrogen sulfides are 64.75 % and 56.14 % lower than those of the qualified samples. During the rolling process, brittle inclusions will form gaps around them, and these cracks will form cracks, forming long cracks under the action of rolling force, and eventually causing band breakage.In order to reduce the belt breakage, 0.03 %~0.05 % Sn element can be added to reduce the proportion of brittle inclusions in the inclusions, and meanwhile extend the duration of the argon blowing station during 2~3 min smelting, which can make the inclusions evenly distributed, and prevent the accumulation of brittle inclusions, and ultimately reduce the probability of cold-rolled broken strip.

The effects of cover annealing, continuous annealing, and combinations of different annealing methods on the magnetic permeability of 0.30 % Si non-oriented silicon steel were studied. The results showed that the higher cover annealing temperature (≥680 ℃) can obtain a higher permeability of μ1.0 (≥5 800 Gs/Oe), and combined with continuous annealing (≥790 ℃), it can obtain lower iron loss and higher permeability. The lower the first continuous annealing temperature is, the higher the improvement in various magnetic properties of the finished product will be, and under the condition of the second continuous annealing of 830 ℃, the magnetic induction of the finished product is basically stable. The increase of the magnetic permeability is not obvious in second lowtemperature continuous annealing, and the magnetic permeability is greatly improved when the second continuous annealing temperature above 770 ℃. On the whole, the better magnetic performance of the finished product is obtained in the methods of 680 ℃ cover annealing + 830 ℃ continuous annealing and the finished product + 770 ℃ continuous annealing.

Due to the recent strong demand for silicon steel market, the continuous annealing lines which have been in operation for 10 years have to increase the speed and improve the quality improvement. Because of the single layer of silicon steel getting thinner and thinner, the yield rate and the concession rate of the whole coiling process were more and more obvious affected by the coiling tension. By studying the principle of tension control and tension optimization schemes, a practical tension model for strip coiling was established, which gradually find out the torque accuracy and linearity of the asynchronous motor of the tension reel in weak magnetic region. The optimizations of the motor drive (inverter) and the PLC program make the torque accuracy (winding tension) meet the requirements of the coiling process.

A process parameter optimization strategy for reducing silicon steel iron loss was proposed by combining BP neural network and particle swarm optimization (PSO) algorithm. Firstly, a BP neural network was used to establish a prediction model for silicon steel iron loss, which has high fitting and prediction accuracy. Then, in terms of optimizing process parameters, the BP neural network prediction model was used as the fitness function, and the furnace temperatures of each section of the continuous annealing RTF furnace were selected as optimization variables. PSO algorithm was used to optimize these process parameters. The results showed that using BP neural network and PSO algorithm to optimize some process parameters can significantly reduce the iron loss of silicon steel, which has certain guiding significance.

The working principle of the inner cover pressure control system of silicon steel high temperature ring annealing furnace was described in detail. According to the operational experience of the operators in the actual production process and some actual situations encountered in production, the problems encountered in the field operation were sorted out, and the inner hood pressure predetection control method and operation specifications were formulated to realize the automatic early warning technology of the inner hood pressure of the high temperature ring annealing furnace, which effectively improved the pass rate of the inner hood pressure.

Aiming at the problems of complicated operation and low efficiency of traditional chemical analysis methods for the analysis of ferrosilicon alloy element content, the fusion sample preparation -X-ray fluorescence analysis method was developed and established. The results showed that using lithium carbonate melting agent to pretreat ferrosilicon alloy and melting at 1 050 ℃×15 min could avoid the damage of high temperature ferrosilicon sample to the platinum crucible, and the molten sample composition was uniform. The correlation coefficients of the analysis curves for ferrosilicon alloy elements by X-ray fluorescence analysis were all above 0.99, which were consistent with the standard sample results and the traditional national standard method, and the reproducibility of multiple analyses was within the tolerance range.Therefore, the analysis results were accurate and reliable. More importantly, a single analysis could quickly characterize the content of each element in ferrosilicon alloy.

A Sengimir rolling mill in the silicon steel department uses GE's MV7309 medium voltage inverter as the main drive. Since it was put into operation, the inverter has had several trip accidents caused by the difference between the positive and negative voltages on the DC side of the inverter of the right winder greater than the threshold, which affected the production efficiency. Starting from the NPP type topology and DC voltage regulation mode adopted by the inverter, this paper analyzed and gradually investigated the various causes that may cause the positive and negative voltage imbalance on the DC side, and completely solved the fault of DC positive and negative voltage imbalance of the right coiling inverter. The treatment of similar faults has strong reference significance.