In this paper, the effect of rare earth Ce content on the morphology, composition, type and size distribution of inclusions in W350 non-oriented silicon steel was investigated by means of ICP-MS (inductively coupled plasma mass spectrometry), SEM/EDS (scanning electron microscope-energy Dispersive Spectrometer), and ASPEX (automated SEM/EDS inclusion analysis). The results showed that with the increase of Ce content in the steel, the modification sequence of inclusions was CeAlO₃→Ce₂O₂S→Ce_xS_y. The type and size distribution of inclusions in the steel obviously changed with the difference in added Ce content. When the added Ce content in the steel was 10 ppm, 14 ppm, 20 ppm and 30 ppm respectively, the rare earth inclusions were mainly CeAlO₃-Ce₂O₂S. Furthermore, when the added Ce content increased to 60 ppm, the rare earth inclusions were mainly Ce₂O₂S with a small amount of CeAlO₃ contained in part inclusions. When the added Ce content increased continually to 95 ppm, the rare earth inclusions were mainly Ce_xS_y-Ce₂O₂S. The critical Ce content for the conversion between CeAlO₃ and Ce₂O₂S was 41 ppm. To ensure that inclusions transform from CeAlO₃ to Ce₂O₂S, the Ce content in the steel should be greater than 41 ppm. Under the current experimental conditions, it was found that when the Ce content was 20 ppm, the number density and proportion of inclusions in the steel were lower, and their average size was larger. When the added Ce content increased to 95 ppm, the number density of inclusions in the steel significantly increased, which deteriorated the steel cleanliness.

In order to study the effects of rare earth La–Ce alloying treatment on the characteristics of inclusions in non-oriented silicon steels, industrial experiments were conducted studying the composition, morphology, size and quantity of inclusions in W350 non-oriented silicon steel during the RH (Ruhrstahl-Hereaeus) refining process and tundish process, after rare earth treatment. The products were analyzed by means of ICP-MS (inductively coupled plasma mass spectrometry), SEM/EDS (scanning electron microscope-energy dispersive spectrometry), and ASPEX (automated SEM/EDS inclusion analysis). The research results showed that the types of inclusions in experimental steel changed significantly after rare earth treatment. The types of inclusions after RE (rare earth) treatment are typically rare earth composite inclusions that are mainly composed of (La, Ce)Al₂O₃, and conventional inclusions. The addition of rare earth promotes the agglomeration of inclusions; the morphologies of the inclusions are mostly blocky, and some are distributed in long strips. After rare earth treatment during the RH refining process, the number of inclusions with sizes of 1.0~3.5 μm in the experimental steel is increased, and the average size of the inclusions is 2.66 μm. In addition, the number of inclusions larger than 4 μm in the specimens increases due to the collision and growth of inclusions caused by the RH circulation. After rare earth treatment during the tundish process, the number of micro inclusions with sizes of 1.0~2.5 μm in the specimen steels decreases, while the number of inclusions larger than 5 μm increases. The size distribution of micro inclusions in hot-rolled sheets after rare earth treatment was studied using TEM (transmission electron microscopy). In the specimens without rare earth, the content of micro inclusions (≤1 μm) is 51,458.2/mm² and the average size is 0.388 μm. In the specimens with rare earth added, the content of micro inclusions (≤1 μm) is 24,230.2/mm² and the average size is 0.427 μm. Compared to sheet produced by the original process, the iron loss of the 0.35 mm finished experimental sheet is reduced by 0.068 W/kg, and the magnetic induction is increased by 0.007 T. The iron loss of the 0.50 mm finished experimental sheet is reduced by 0.008 W/kg, and the magnetic induction is increased by 0.004 T. After rare earth treatment, the average size of micro inclusions increases and the magnetic properties are obviously improved.

The effects of cold rolling reduction on the microstructure, recrystallization behavior, and magnetic properties of 3.0%Si-0.8%Al-0.3%Mn steel were studied by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). With the reduction rates of 78%, 85% and 87% in the cold rolled sheet, the width of the deformation band becomes narrower, the number of intragranular shear bands decreases, and the proportion of grain boundaries increases. The intensity of the α and γ fibers texture in the cold rolled sheet is enhanced, and the annealed sheet is dominated by the γ fibers texture and the content increases from 26.0% to 34.5%. During the recrystallization process, the Goss and γ-grains nucleate first. The λ-grains nucleate mainly at the grain boundaries of the deformed α-grains, and the α-grains ultimately recrystallize. With the increase in the cold rolling reduction rate, the γ-grains develop into the main texture due to a large amount of nucleation at the deformation band and grain boundary. The λ-grains with a high mobility do not have a numerical advantage, and the increase in the texture content is very small. The content of the unfavorable γ fiber texture in the annealed sheet increases, the magnetic induction intensity B50 decreases, Pe and Pt decrease significantly, and the critical grain size with the lowest iron loss decreases from 136.2 to 109.4 μm.

Effects of rare earth (La+Ce) on inclusions in hot-rolled band of 3.0∼3.3%Si-0.8∼1.0%Al non-oriented silicon steel was studied using industrial trials, scanning electron microscope (SEM) and thermodynamic analysis. Furthermore, combining Heterogeneous Nucleation Theory with Edge-to-Edge Matching (E2EM) model, the formation mechanism of complex inclusions was also investigated. Rare earth (La+Ce) would promote the spheroidization and coarsening of inclusions, and then transform into regular and near circle morphology composite inclusions of rare earth. The low content of rare earth (21 ppm) mainly deoxidized and modified Al₂O₃ inclusions, and formed (La,Ce)AlO₃ inclusions. Increasing of rare earth (29–45 ppm) would promote the formation of (La,Ce)AlO₃-(La,Ce)₂O₂S and (La,Ce)₂O₂S inclusions, reduce the sulfide precipitation, and promote a gradual transformation of the core of composite inclusions from (La,Ce)AlO₃ to (La,Ce)AlO₃-(La,Ce)₂O₂S and (La,Ce)₂O₂S, which agreed well with the thermodynamic analysis. However, rare earth (29–45 ppm) had a weak metamorphic effect on Al₂O₃ inclusions generated by temperature drop and secondary oxidation. LaAlO₃, CeAlO₃, La₂O₂S and Ce₂O₂S could be the heterogeneous nucleation core of AlN, Al₂O₃, MgO-Al₂O₃, typical composite inclusions with (La,Ce)AlO₃ and (La,Ce)₂O₂S as the core would ultimately form.

The effects of trace Ce on the microstructure and texture of non-oriented silicon steel during recrystallization and grain growth were examined using X-ray diffraction and electron backscatter diffraction. Additionally, this study focused on investigating the mechanisms by which trace Ce influences the evolution of the {114} and γ-fiber textures. During the recrystallization process, as the recrystallization fraction of annealed sheets increased, the intensity of α-fiber texture decreased, while the intensities of α*-fiber and γ-fiber textures increased. The {111} grains preferentially nucleated in the deformed γ-grains and their grain-boundary regions and tended to form a colony structure with a large amount of nucleation. In addition, the {100} and {114} grains mainly nucleated near the deformed α-grains, which were evenly distributed but found in relatively small quantities. The hindering effect of trace Ce on dislocation motion in cold-rolled sheets results in a 2–7% lower recrystallization ratio for the annealed sheets, compared to conventional annealed sheets. Trace Ce suppresses the nucleation and growth of γ-grains while creating opportunities for α*-grain nucleation. During grain growth, trace Ce reduces γ-grain-boundary migration rate in annealed sheets, providing growth space for {114} grains. Consequently, the content of the corresponding {114} texture increased by 6.4%, while the γ-fiber texture content decreased by 3.6%.

The cold-rolled non-oriented silicon steel sheets with a Si content of 2.4 wt.%, produced by continuous and reversible cold rolling, were used as the experimental material. The effects of annealing temperature on the microstructure, texture, and magnetic properties were studied by optical microscopy, an X-ray diffractometer, and a magnetic property measuring instrument. The experimental results showed that the dominant texture components at the surface of both sheets were almost the same, i.e., α and γ fibers. After annealing at 920 °C for 30 s, a complete recrystallization occurred in both sheets. When annealing below 1070 °C, the average grain sizes of continuous cold-rolled sheets were slightly higher than those of reversible cold-rolled ones. Additionally, for all specimens, the recrystallization texture components were γ fiber, as well as weak α fiber, λ fiber, and Goss texture. Additionally, the difference was the texture intensity. The iron losses of the finished products of continuous cold rolling were lower than those of the finished products of reversible cold rolling with the increase in annealing temperature, and the magnetic induction was higher than that of the finished products of reversible cold rolling.