THE EFFECT OF MECHANICAL AND ELECTRICAL DISCHARGE CUTTING TECHNOLOGIES ON THE MAGNETIC PROPERTIES OF NON-ORIENTED SILICON IRON STEELS

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 x 30 mm(2). The magnetic properties were measured with a single strip tester in the range of frequency from 10 divided by 400 Hz at 1 T peak magnetic polarization.