Kinetics of Magnetic Ageing of 2%Si Non-oriented Grain Electrical Steel

The effect of carbon content on the magnetic ageing index and Vickers hardness evolution on annealed samples of 2%Si non-oriented gram electrical steel was studied.Samples with 40 and 60ppm carbon content were subjected at ageing temperatures of200 and 225 degrees,respectively. During the ageing treatment, the cycle was interrupted on several time intervals in order to obtain the core loss and to determine Vickers hardness. The precipitates were characterized using scanning electron microscope (SEM). Using the software MatCalc, computer simulations of epsilon-carbide precipitation were performed and compared with experimental data from literature. The results for both carbon contents showed that the maximum hardness value was achieved in shorter time than that to achieve the maximum magnetic ageing, indicating that the critical size of precipitates more harmful to the magnetic properties is larger than the ones that maximize the hardness.