Effects of Cu Precipitates on Magnetic Properties of Nonoriented Electrical Steel

Tests to measure the effects of the precipitating size of Cu on the magnetic properties of nongrain-oriented (NGO) electrical steel were carried out. The hysteresis loss had a maximum value when the diameter of the precipitates was around the thickness of the domain wall and decreased rapidly with decreasing size of the precipitates. Alternatively, yield point (YP) rose steeply with reduction in the size of Cu precipitates. It can be confirmed that the precipitating Cu has an ability of rising over 100 MPa in YP without deteriorating core loss. Regarding the effects of Cu precipitates on the hysteresis loss, the surface tension effect might be dominant for the case in which precipitates are smaller than the domain wall thickness, and internal magnetic poles are effective for the larger precipitates.