Investigation of the limits of statistical power loss model for 3.2% SiFe electrical steels. II. Role of crystallographic texture

In many experimental works it has been proved that the results obtained by the statistical power loss model of Bertotti (SPLM) [l] on different qualities of SiFe electrical steels are markedly influenced by the non-magnetic properties of the material. This work intends to give a systematic contribution to the problem of texture effects on the polarisation dependence of internal coercive field Vo and hysteresis loss Phys, in the case of 0.35mm thick 3.2wt% SiFe non-oriented electrical steel. Six materials have been produced from the same composition to assure a wide variety of the average grain size, without significant changes in the crystallographic texture. Single sheet samples have been cut at different angles with respect to the rolling direction (RD), from 0° to 90°, with a step of 15°. Power loss has been measured between 10Hz and 400Hz. at densely distributed polarisation levels. Then, the SPLM was applied to separate the different loss contributions and to determine the Vo and Phys values as a function of polarisation. Based on the previously revealed polarisation dependence of these parameters [3,4], two single coefficients of power function representation, the Po(hys) coefficient and n(1) exponent have been found to represent the hysteresis loss, whereas the Vo field data have been synthesised by a simple average value Vo(avg), over the 0.3T-1.2T polarisation range. The grain size effect has been successfully separated from the effect of texture in both Po(hys) hysteresis and Vo(avg) field. Similar dependence on texture has been found for both quasi-static and dynamic responses in function of the magnetisation direction. These extracted textural effects have been compared with the power loss description proposed by Bunge [5,6] and with a texture-based "minimum force model" developed in this work. Both theoretical approaches, based on measured ODF of materials, resulted not fully satisfactory, probably due to their simple basic assumptions with respect to the real magnetisation mechanisms