EFFECT OF MECHANICAL STRAINS ON THE MAGNETIC PROPERTIES OF ELECTRICAL STEELS

The magnetic properties of steel laminations used as magnetic cores in electrical machines are very sensitive to mechanical strains resulting from manufacturing operations. This study presents an experimental in situ characterization of a non-oriented Fe-3%Si steel, a FeCo2%V alloy and a high-purity polycrystalline nickel. The mechanical properties of study materials were determined under an monotonous uniaxial tensile test. Magnetic measurements were carried out under uniaxial tensile stresses approaching and exceeding the elastic limit (ye, as well as in the corresponding unloaded states. The deformation stages are clearly identified by the magnetic parameters. A linear relationship was found between the evolution of the magnetic behaviour and of the kinematic hardening X, representative of internal stress state of plastically strained specimens.