The fabrication process of nonoriented electrical steels comprises: casting, hot rolling, cold rolling and final annealing. The developments of new technologies for fabrication hot band offers new possibilities. In this paper we will shortly describe the similarities and differences with respect to the evolution of microstructure (grain structure) and texture along the conventional processing route and thin strip casting. We will point out the most relevant features at the different processing steps, which are important for optimum texture and microstructure of the finally processed material. Thereby we will regard ferritic FeSi steels, where no homogenization of the microstructure appears due to the austenite -ferrite phase transformation.

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In this article, evolution of microstructure and texture in non‐oriented electrical steels along novel strip casting route and conventional route are comparatively investigated in detail. It demonstrates the similar and important role of the microstructure and texture prior to cold rolling to finally obtain desirable recrystallization microstructure and texture in both routes. In both routes, a high intensity of cube‐fiber texture and a low intensity of γ‐fiber texture can be acquired in hot strips by optimizing the hot rolling and thermal treatment parameters. Accordingly, after cold rolling and annealing, a lower intensity of γ‐fiber texture together with a higher intensity of cube‐fiber texture, which are favorable for high‐permeability materials, can be obtained in both routes. The desired large grain size in the finally annealed materials to obtain low magnetic losses may be gained by choosing appropriate annealing conditions after the first stage of recrystallization. The features of microstructure and texture are similar at comparable stages. The main differences in the regarded different processing routes are in the practical efforts. The detailed results and deeply corresponding discussion on how the microstructure and texture develop during cold rolling and annealing in differently processed samples will be given in the future work.

Due to the nonlinear material behavior and contradicting application requirements, the selection of a specific electrical steel grade for a highly efficient electrical machine during its design stage is challenging. With sufficient knowledge of the correlations between material and magnetic properties and capable material models, a material design for specific requirements can be enabled. In this work, the correlations between magnetization behavior, iron loss and the most relevant material parameters for non-oriented electrical steels, i.e., alloying, sheet thickness and grain size, are studied on laboratory-produced iron-based electrical steels of 2.4 and 3.2 wt % silicon. Different final thicknesses and grain sizes for both alloys are obtained by different production parameters to produce a total of 21 final material states, which are characterized by state-of-the-art material characterization methods. The magnetic properties are measured on a single sheet tester, quantified up to 5 kHz and used to parametrize the semi-physical IEM loss model. From the loss parameters, a tailor-made material, marked by its thickness and grain size is deduced. The influence of different steel grades and the chance of tailor-made material design is discussed in the context of an exemplary e-mobility application by performing finite-element electrical machine simulations and post-processing on four of the twenty-one materials and the tailor-made material. It is shown that thicker materials can lead to fewer iron losses if the alloying and grain size are adapted and that the three studied parameters are in fact levers for material design where resources can be saved by a targeted optimization.

The magnetic properties of non-oriented electrical steel, widely used in electric machines, are closely related to the grain size and texture of the material. How to control the evolution of grain size and texture through processing in order to improve the magnetic properties is the research focus of this article. Therefore, the complete process chain of a non-oriented electrical steel with 3.2 wt.-% Si was studied with regard to hot rolling, cold rolling, and final annealing on laboratory scale. Through a comprehensive analysis of the process chain, the influence of important process parameters on the grain size and texture evolution as well as the magnetic properties was determined. It was found that furnace cooling after the last hot rolling pass led to a fully recrystallized grain structure with the favorable ND-rotated-cube component, and a large portion of this component was retained in the thin strip after cold rolling, resulting in a texture with a low γ-fiber and a high ND-cube component after final annealing at moderate to high temperatures. These promising results on a laboratory scale can be regarded as an effective way to control the processing on an industrial scale, to finally tailor the magnetic properties of non-oriented electrical steel according to their final application.