The magnetic cores of electrical machines are cut especially through mechanical methods nowadays. In the zone near the cutting edge, a plastic deformation of the silicon iron steel will appear, with harmfull effect on the magnetic properties of the alloy. On the contrary, the electro-erosion cutting technology does not induce mechanical stresses in the cutting edge zone, because the material is removed from the work-piece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subjected to an electric voltage. There were tested different samples of non-oriented silicon iron steel (NO FeSi) grades, M400-65A and M800- 65A, with an area of 300 × 30 mm2. The magnetic properties were measured with a single strip tester in the range of frequency from 10 ÷ 400 Hz at 1 T peak magnetic polarization

Keywords: Non-oriented silicon iron, Mechanical cutting, Electrical discharge machining, Energy losses, Magnetic domains