Magnetic and insulating properties of electrical steel with a new insulating coating |
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Authors: | Nakamura M. Sugiyama T. Kitayama M. |
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Affiliation: | Hirohato Works, Nippon Steel Corporation, Fuji-cho, Hirohata-Ku, Himeji-Shi, Japan; |
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Abstract: | New inorganic-organic coatings for nonoriented electrical sheets have been developed. Smooth and dull sheets having surface roughnesses of 0.18 μm. H root mean square (rms) and 0.75 μm. H rms, respectively, were coated with different weights of a bichromate-emulsion resin solution. Another sheet having a surface roughness of 0.18 μm. H rms was treated with a bichromate-emulsion resin solution containing a dispersed polyethylene resin powder to provide surface roughness. Results indicated that this third sheet exhibits a higher lamination factor and surface resistivity than the coated sheet whose surface roughness is provided by the dullness of the sheet itself. Moreover, it has a lower core loss and requires less ac exciting current when used in welded motor cores at given thicknesses. When weldability is not a factor, then the smooth sheet having a surface roughness of 0.18 μm. H rms and treated with the inorganic-organic coating is the most suitable: it has the highest lamination factor, the least amount of core loss, and requires the least amount of ac exciting current. |
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