Effect of Laminate Cutting and Annealing Treatment on the Magnetic Properties of Fe₄₉Co₄₉V₂Alloy

The Fe49Co49V2 alloy is a soft magnetic material commonly used in high-performance electrical machines in form of a laminate made of stacked thin sheets. Laminate preparation inevitably induces defects along the cut edge, which will deteriorate the magnetic properties of the alloy. Three laminate cutting methods, namely, punching, electrical discharge machining (EDM), and laser cutting, have been assessed for their impact on the magnetic properties of the laminates. The effect of annealing treatment before and after the cutting process was also studied. The magnetic properties of the ring laminate samples were measured under a frequency of 400 Hz at room temperature. The grain size and local misorientation were evaluated by electron backscattering diffraction (EBSD). Our study indicates that grain boundary and local misorientation within the grains are key considerations when assessing the deterioration of the soft magnetic properties. The mean grain size along the edge of laser-cut laminates with a post-annealing treatment was about 29.3{m}, larger than that in the center area of about 24{m}. This process route also exhibited the lowest fraction of local misorientation of greater than 0.5° along the edge area. As a result, laminates produced by laser cutting followed by a post-annealing treatment displayed the best magnetic performance among all investigated manufacturing routes.