Production of High-Resistivity Electrical Steel Alloys by Substitution of Si with Al and Cr

Fe-3Si-3Al and Fe-4Si-4Cr (wt%) experimental alloys were processed to assess the electrical resistivity and workability effects of substituting Al and Cr for Si in high-Si electrical steel alloys. The experimental alloys were made by arc melting, and processed by hot rolling and cold rolling to produce strips. Samples were characterized by means of metallography, hardness, workability and resistivity. Results showed that the two alloys could be rolled down to 200 µm thickness (90% hot-rolled reduction and 80% cold rolled reduction) without crack formation in the strips. Hardness in the annealed condition and electrical resistivity were 228 HV/74 µΩ cm and 243 HV/85 µΩ cm, respectively, for the Fe-3Si-3Al and for Fe-4Si-4Cr alloys. The resistivity measured for Fe-4Si-4Cr was higher than the resistivity reported for the benchmark high-Si alloy, Fe-6.5Si. Both experimental alloys showed improvement on the workability compared to Fe-6.5Si since there was no edge cracking on the cold-rolled strips up to 80% reduction, and the hardness was approximately 35% lower.