Identification of microstructure effects in magnetic loss behaviour of 3.2% SiFe NO electrical steels by means of statistical power loss model

In this work systematic experiments were carried out to attempt the identification of microstructural effects (texture, grain size) on the polarization dependence of internal coercive field V₀ and hysteresis loss P_hys, determined by statistical power loss model (SPLM). Experiments were performed on 0.35 mm thick 3.2 wt% SiFe non-oriented (NO) electrical steel, with different grain size and almost the same crystallographic texture. From each material Epstein samples were cut at different angles to the rolling direction (RD). Loss separation and fitting process was carried out, according to the SPLM, for determining V₀ and P_hys as a function of the polarization. Three synthetic parameters were proposed in the 0.3 T-1.2 T polarization range, where the model was found to be valid: two coefficients P⁰_(hya) and n(1) to represent the hysteresis loss according to an exponential law and an average value of the internal coercive field V^(avg/)sub 0/ over the investigated polarization range. The dependence of V^(avg/)sub 0/, P⁰_(hys) and n(1) on the grain size and texture has been clearly identified, resulting in a single texture dependent behavior for both quasistatic and dynamic properties. All the results obtained from fitted P_hys values were confirmed by quasi-static measurements. A theoretical model, based on the measured orientation distribution function (ODF) has been proposed to reproduce the obtained texture dependence