Correlation between the Magnetic Properties and the Crystallographic Texture during the Processing of Non Oriented Electrical Steel

Abstract

The magnetic properties in electrical steels are strongly dependent on the crystallographic texture as well as other microstructural features such as grain size. Both, texture and grain size, are determined by the thermo-mechanical history of the material. This work regards a set of different thermo-mechanical paths applied on two types of non-oriented electrical steels containing 2.4% and 3.0%Si, respectively. The evolution of grain size, microstructure morphology and texture throughout processing were studied in detail by optical microscopy, X-Ray diffraction and Electron BackScatter Diffraction (EBSD). The impact of the texture on the magnetic properties was evaluated. This was done by the calculation of the magnetic anisotropy energy and the A parameter, i.e. a parameter defined in scientific literature that describes the magnetic "quality" of the texture, which can be correlated with the magnetic properties of the materials. Finally, the influence of further laser cutting on the crystallographic texture will be examined as well.

Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels

“…In contrast, when final annealing is performed at 1000 1C, the permeability is affected negatively due to the strong g-fiber texture developed (Fig. 7c), which affects the magnetization process [6,13,14,27]. In this case, the effect of texture on the magnetic properties is higher than that of the grain size.…”

“…On the other hand, the desirable texture that minimizes the in-plane energy losses of GNO electrical steels is the o1 0 04//ND fiber texture [11,12]. In contrast the so-called g-fiber texture, represented by o1 1 14//ND, is very detrimental for these steels because the lowest permeability axis, o1 1 14, is aligned parallel to the normal direction of the sheet and should therefore be avoided [13,14]. Residual stresses, grain size and carbide particles for instance have an important effect on the final mechanical properties [4,5].…”

Effect of Annealing Prior to Cold Rolling on the Microstructure Evolution and Energy Losses of Low-Si, Ultra-Low-C Hot-Rolled Electrical Steel

“…The texture that minimizes the in-plane energy losses of GNO electrical steels is the <100>//ND fiber texture [10,11]. In contrast, the γ-fiber texture, <111>//ND, usually produced as a result of recrystallization and grain growth of cold-rolled and annealing of low-C steels, is very detrimental for magnetic properties since the lowest permeability axis <111> is aligned parallel to the normal direction of the sheet [12,13].…”

Effect of Dissolved Carbon on the Recrystallization Texture Formation in Electrical Steels

“…Impurities such as carbon and nitrogen in steels have significant effects on the development of recrystallization texture, which determines the magnetic permeability of the electrical steels at high fields. 3,4) It is long being recognized that the magnetization is easiest in < 100 > and hardest in < 111 > crystallographic directions. 5) For non-oriented electrical steels, which are typically applied in rotary machine, in-plane isotropic magnetic properties are important.…”