Composition effects on core loss of Fe-Si-Al electrical steels

Fe-Si-Al non-oriented electrical steels were studied in the following composition range: Si= 1.5-2.1 m%; Al=0-3.0 m%; Mn=0.3 m%; Fe=R. (m%= mass %). Three minima were observed on the core loss vs. Al+Si content curve: First of them at 4.5 m% is the same as was earlier found by Perrier and Brissonneau and further two were found at 3.6 m% and 2.7 m%. It was realised that a more clear interpretation of this peculiar effect can be given by plotting the measured quantities vs. the Al/Si ratio (counted in at%): The 2:5, 1:2, 4:5, 5:4 and 5:3 ratios are prefered. It was found that more advantageous grain coarsening and texture development occured at these ratios, which resulted in more favorable loss behaviour.