MAGNETIC-PROPERTIES OF HIGH-PERMEABILITY THIN GAUGE NONORIENTED ELECTRICAL STEEL SHEETS

Magnetic properties of high permeability thinner gauge non-oriented el ectrical steel sheets are investigated from the viewpoint of applicati ons in the audio frequency range. The steel sheets 0.75 mass% Si - 0.3 mass% Al (0.20, 0.35 and 0.50 mm in thickness) were prepared, includi ng the hot-band annealing prior to the cold-rolling for the purpose of controlling the texture. The stress-relief annealing was carried out before the characterization. The flux density at applied field of 5000 A/m is 1.76 T for 0.2 mm-thick sheet. The decrease of the thickness f rom 0.5 mm to 0.2 mm results in the 67% reduction of the core loss mea sured at the flux density of 1.0 T and the frequency of 1 kHz. The cor e losses measured at 1.0 T, 400 Hz and 1.0 T, 1 kHz are 15.7 W/kg and 57.9 W/kg. The RMS exciting force of the developed sheet (0.2 mm in th ickness) at 1.6 T, 400 Hz was about one-fourth as large as that of a c onventional 3 mass% Si steel sheets. Their results would indicate that such high permeability thin gauge steel sheet could be utilized in th e audio frequency application, in particular, in the motor cores of th e electric vehicles.