The magnetic properties of 0.15-3%Si non-oriented electrical steel sheets were measured at temperatures ranging from 4 K to 200°C. Except for the 3%Si sheet, all the sheets were more easily magnetized at higher temperatures. The hysteresis losses increased at lower temperatures, but the changes were less than those due to the crystalline grain size. The eddy current loss can be estimated as WRTeρRT/ρT,where WRTe, ρRT, and ρT are the eddy current loss at room temperature and the electric resistivities at room temperature and T°C, respectively. The magnetic properties of a 6.5%Si steel sheet were also measured at the same temperatures.The 6.5%Si steel was the easiest to magnetize at room temperature. The change in the eddy current loss with temperature was proportional to those of resistivities,but the hysteresis loss increased very markedly at lower temperatures, because of the large change in magnetostriction.
