The Influence of Cutting Edge Deformations on Magnetic Performance Degradation of Electrical Steel

Although it has been widely known that the cutting process of electrical steel brings deterioration effects to magnetic properties, it is still unclear how to evaluate the quality of the cutting process effectively. This paper investigates the performance degradation due to the punching process based on a needle probe instrument that incorporates three needle probes arranged in a way to pick up the flux around the area of the cutting edge and the flux of the unaffected center area. The amount of performance degradation can be obtained by comparing the edge and the center flux values. 50CS1300 samples with different punching clearances were produced, and measurement results were demonstrated. The power conversion losses imposed by the punching process were evaluated in terms of several measured parameters, including the magnetic flux density, the iron loss, and the copper loss. In addition, how different grain sizes affect the punching performance is also studied in this paper. Two materials with the same iron loss grade but different grain sizes were punched, and their magnetic properties were also examined.