Modeling microstructural effects on hysteresis loops with the same maximum flux density

Abstract

Microstructural attributes such as grain size d and dislocation density /spl zeta//sub d/ affect the hysteretic magnetic properties of steels because they affect domain wall movement and pinning. In an earlier paper, a model was proposed for computing hysteresis loops based on the effect of grain size and dislocation density. In that paper, hysteresis loops were compared that all had the same maximum field H/sub max/. The result was that coercivity departed from linear relationships with inverse grain size (viz. 1/d) and /spl zeta//sub d//sup 1/2/ for large values of 1/d and /spl zeta//sub d//sup 1/2/. The same was true of hysteresis loss W/sub H/, except that hysteresis loss even showed a peak, first increasing and then decreasing with increasing 1/d and /spl zeta//sub d//sup 1/2/. This kind of behavior had not been seen by experimenters, particularly core-loss people. It was learned that the core-loss experimenters compared hysteresis loops of the same maximum flux density B/sub max/ instead of the same H/sub max/. In this paper, we use the model previously formulated to produce hysteresis loops with the same B/sub max/. Indeed, the appropriate linear relationships are found. The paper also addresses effects of uniaxial anisotropy on these microstructural magnetic effects and why two hysteresis parameters are affected by microstructural variation.