## 2 Microstructure of Electrical Steel  
The magnetic characteristics of soft magnetic materials, as electrical steel categories, are intricately linked to the microscopic structure and texture of the subsequent steel. The  
Figure 1: The graph demonstrates occasional significant improvements in losses, which are often attributed to the introduction of new technologies in the manufacturing process [17]. microstructural limits that play a significant role in magnetic properties, such as magnetization curves, permeability, coercive force, and specific magnetic loss, primarily include grain size, inclusions, internal pressures, the magnetic friction value, and surface defects. These microstructural factors govern the behaviour of the domain walls (coercive force) and their motion, these factors are responsible for shaping a material's magnetic response, particularly at low- and medium-level magnetic fields. The crystalline structure further impacts magnetic behaviour, following various crystallographic guidelines. Specifically, [100] directions are even more susceptible to magnetization than other directional orientations. [110] or [111] or body-centred cubic (bcc) orientations (as depicted in Figure 2). In polycrystalline materials, the magnetic fabric influences the residual magnetic introduction and field rotation at high external magnetic field values. For rotary machines, the optimal texture of electrical steel is a cubic fibre texture, where most grains have a normal [100] orientation in the sheet-planning machine. To enhance magnetic permeability and minimize overall power loss, the preferred microstructure is a coarse-grained configuration exhibiting a [100]//ND texture (known as the \(\theta\)-fibre). This texture encompasses the cube, rotated cube, and all orientations where the [001] planes align with the sheet plane. This arrangement is advantageous due to its abundance of easy magnetization axes [001] within the sheet plane. Conversely, the [111]//ND (referred to as the \(\gamma\)-fibre) texture features hard magnetization axes [111] within the sheet plane, making it necessary to mitigate its presence in the final steel sheets [18; 19]. An even spreading of crystalline orientations along these fibres results in most permeability and magnetic properties at the sheet level, and this class of electrical steel is known as NOES. Further, in applications involving static electrical machines like transformers, it may be preferable to use a distinct Goss texture [110] and [001] orientation since the magnetic field can align with the [001] direction [20]. Such steels have electrically oriented grains. However, evaluating the effect of texture on magnetic properties presents challenges, as it is highly challenging to isolate its influence from factors like grain size or the presence of second-phase impurities in a material. As the silicon content rises, the manufacturing process experiences higher temperatures, causing a slowdown in the production of non-oriented cold-rolled electrical steel. Consequently, the duration the finished strip spends in a furnace increases, resulting in a larger initial grain size. This, however, leads to a decrease in iron loss and an increase in magnetic induction intensity. The strong [111] surface texture in the final product of the electrical steel stems from intensive cold-rolling deformation, and even with continuous annealing, the dominance of the [111] texture persists. The continuous annealing process transforms the silicon steel structure into equiaxed ferrite overall but does not eliminate the genetic traits of microstructure and texture. Adjusting the annealing process counteracts the adverse effects of larger grain sizes, thus enhancing the [100] and [Goss] textures along with magnetic properties. Similarly, in non-oriented electrical steel, strategic process adjust  
Figure 2: The magnetization curves for a single crystal of bcc iron [21]. ments increase [100] and [Goss] texture content, thereby decreasing iron loss and enhancing magnetic induction.