Some important effects of the water jet and laser cutting methods on the magnetic properties of the non-oriented silicon iron sheets

Nowadays it is very important to use non-oriented electrical alloys, which must have a very good quality and must be cut through a proper method that leads to a minimum energy loss value. The manufacturers of the electrical machines want to minimize the damage of the magnetic properties during the cutting process, in order to produce high efficiency motors or generators. In this paper are presented two non-conventional cutting technologies, which are used in the prototype production of the magnetic cores. These two methods have significant effects on the area near the cut edge; the water jet produces important burs and oxidation of the material and the laser cutting generates high local thermal stresses that increase the total energy losses of the magnetic core. There were tested steel samples of fully processed non-oriented alloys (NO FeSi) grades, M400-65A and M800-65A, with an area of 300 × 30 mm2. The magnetic properties were measured with a laboratory single strip tester in the range of frequency from 10 ÷ 400 Hz at 1 T peak magnetic polarization.