Texture Control During the Manufacturing of Nonoriented Electrical Steels

Abstract

Methods of modern quantitative texture analysis are applied in order to characterize the crystallographic texture of various non-oriented electrical steel grades in view of their relation with the magnetic properties of the steel sheet. A texture parameter is defined which quantifies the density of‹100›easy magnetic directions in the sheet planes. An extensive correlation study revealed the relation of this parameter with the hysteresis losses, determined at an induction of 1.5 T, and with the induction measured at an applied external field of 25 A/cm. It is shown that the latter magnetic property is the more texture dependent, whereas the former one is more sensitive to the grain size of the steel. Also various strategies for texture control are critically reviewed. It is shown that the conventional manufacturing process only provides poor tools for optimizing the texture of the final product. In order to obtain a quantum-leap improvement of the magnetic quality of the texture, in combination with other important microstructural features, nonstandard processing strategies are required, such as cross-rolling, two-stage cold rolling, or surface annealing.

Effect of Aluminium Addition on the Magnetic Properties of a Semi-Processed Electrical Steel

“…Regarding crystallographic texture, Figure 3 shows the main texture fibers for electrical steels, i.e. three suitable components for magnetic properties: alfa fiber (<110>//RD), cubic fiber (<100>//ND) and RD' fiber ({hkl}<001>), and an unsuitable component: gamma fiber (<111>//ND) 8 . The evaluation of the area under the "fiber curves" by mathematical numeric integration, according to the Simpson's rule 10 , can be seen in Figure 4.…”

“…The latter effect is important for weakening the formation of ND//{111} texture ("gamma fiber"), which is not suitable for magnetic properties 1,8,9 .…”

Description of anisotropy of magnetic properties for chosen grades of electrical steels

“…The problem of texture optimisation is of a great practical interest to metallurgists and materials science engineers, cf. for example [21][22][23][24][25]. Simultaneously, it should be remembered that the magnetic properties of ready-made parts of magnetic circuits may usually be worse than the properties of steels themselves due to stresses introduced during subsequent material processing [26][27][28].…”

Local Magnetic Properties in Non-oriented Electrical Steel and Their Dependence on Magnetic Easy Axis and Misorientation Parameters

“…These have included the magnetic texture factor (MTF), [6] the A parameter, [7][8][9][10][11][12] and texture calculations based on the formula for magnetocrystalline anisotropy. [13][14][15][16] However, these texture parameters are typically directional, in that they are calculated with respect to a magnetization direction of interest, typically the RD.…”