The effects of nozzle sizes (Φ2 mm, Φ1.5 mm, Φ1 mm and Φ0.7 mm) on the microstructure and properties of Fe-6.5 % Si high silicon steel ribbon during rapid solidification were studied. The results showed that with the decrease of nozzle size, the ordered phase decreases, the continuous length of ribbon increase obviously, but the thickness and width of ribbon decrease, the grain size decreases, and the microhardness decreases. The saturation magnetization (Ms) of ribbon decreases gradually with the decrease of nozzle size, and the coercivity (Hc) increases gradually, but the magnetic properties do not change much overall. The quality of the high silicon steel ribbon made under the Φ1mm nozzle is better.

The textures of medium temperature reheated grain oriented silicon steel containing copper during decarburization annealing and secondary cold rolling were quantitatively analyzed by EBSD technique, and the evolution of textures and plastic deformation during different passes of secondary cold rolling was studied. The results showed that {111}〈112〉texture, {111}〈110〉 texture and {112}〈110〉 texture are the main texture components in decarburization annealing and secondary cold rolling. In the surface and subsurface layer, the volume fraction of {111}〈112〉 texture and {111}〈110〉 texture increases with the increase of cold rolling passes, while the volume fraction of {112}〈110〉 texture increases at first and then decreases with the increase of cold rolling passes. Different from other positions, the {112}〈110〉 texture occupies the highest volume fraction in the central layer, and when the cumulative deformation is higher than 58 %, it transforms to the {111}〈110〉 texture. The {001}〈110〉 texture increases after the first cold rolling, and then tends to be stable with the increase of cold rolling pass, but the texture volume fraction of the central layer is higher than that of other positions. With the increase of secondary cold rolling passes, the geometric dislocation density increases, the degree of plastic deformation increases, and the geometric dislocation density of the surface layer and the subsurface layer is higher than that of the central layer.

The effects of coating thickness, coating type, and welding process on the welding performance of non-oriented silicon steel were investigated through metallographic microscopy and electron backscatter diffraction (EBSD).The results indicated that：under the conditions of this experiment, the coating thickness was directly proportional to the percentage of welding foaming area, and the organic matter in the coating was the main factor affecting welding foaming. During the welding process, the microstructure gradually grows from equiaxed grains to columnar grains, ultimately forming larger and more uniform large grains.

The production practice of non-oriented silicon steel on FTSR production line was introduced in this paper, which can save energy and reduce carbon by up to 30 %. Adopting low-temperature heating technology for slab below 1 100℃ to save energy, emissions were reduced, and the solid solution and precipitation of the second phase particles were controlled. A reasonable hot rolling process has been developed, which ensures the driving force for recrystallization of hot rolled coils through high finishing and coiling temperature, forming more favorable textures for electromagnetic performance. The produced non-oriented silicon steel has excellent electromagnetic properties and good profile.

In order to ensure the overall strength of the stator, the assembly method of interference fit is mostly adopted between the stator tooth and stator yoke of the splicing motor, and the stress generated by this fitting method on the silicon steel sheet will affect the performance of the motor. In this paper, through the finite element simulation analysis and experimental verification method, the performances were compared on the motors respectively using two kinds of fit modes of interference fit and gap fit between tooth part and yoke part, and the influence law of compressive stress on the electromagnetic performance of silicon steel was obtained.

In response to the increasing occurrence of residual quality defects resulting from emulsion on the surface of electrical steel chilled strip, a field investigation was conducted. The working efficiency of equipment was enhanced through process parameter debugging and modification. Aging equipment pipelines were replaced to minimize emulsion pollution caused by running, bubbling, dripping, and leaking. Additionally, a compressed air purging device was added to improve the capacity of the purging system. By installing splash guard and reducing purging difficulty, the emulsion spots have been resolved. This improvement enhanced the surface quality of strip steel and reduced fuel consumption.

In the process of improving the production capacity and operating speed of old silicon steel heat treatment units, due to the fact that most units far exceed the original design speed limit, the stability of the looper was greatly affected, resulting in significant tension and speed vibration of the strip steel in the looper. By analyzing the principle of indirect tension control of the looper, a looper vibration suppressor was designed based on the feedforward principle, which effectively suppressed the problem of looper vibration and was applied to similar units with significant results.

In viewing of the problems of low accuracy and low efficiency in existing automated winding systems, a new method of automatic coiling on the twenty high rolling mill coiler was proposed in this paper based on laser rangefinder and visual recognition. Firstly, the diameter of the material taken by the coiling machine is measured in real-time using a laser rangefinder, providing accurate data on the width of the steel coil. The diameter of the steel coil is obtained through the laser rangefinder and the car lifting encoder. Then, through visual recognition technology, the inner diameter of the steel coil and the core shaft of the coiling machine are compared, and the height deviation value of the steel coil is accurately adjusted to increase the success rate of automatic coiling.

The weld joint tearing fault on walking beam base was analyzed and calculated, and the corresponding improvement methods were proposed in this paper. The practice showed that these methods can improve the weld joint strength of the walking beam base, and can provide an analysis and calculation method for the weld joint strength verification of similar welded structural components.