Advances in the production of high-silicon electrical steel by thermomechanical processing and by immersion and diffusion annealing

Steel sheet with 6.5% Si is an excellent soft magnetic material, but its industrial production in low thickness still remains problematic or expensive. Using an adequate thermomechanical routing makes it possible to obtain steel with silicon up to 6.5% Si and thickness below 0.5 mm with excellent magnetic properties. Also a second production process is based on an immersion in a hypereutectic Al-Si bath at the adequate temperature in order to deposit a Si-rich layer on a steel substrate, followed by a proper diffusion annealing. The process is leading to homogenous concentrations of. e.g. 6.5% Si over the thickness being the power losses comparable with those industrially produced by chemical vapor deposition (CVD) method. (C) 2003 Elsevier B.V. All rights reserved.