A new type of non-oriented electrical steel sheet, NKB-CORE, has been developed by NKK through the application of a unique ultra-low sulfur technology. This type of steel sheet shows: (1) low hysteresis loss; (2) high magnetic flux density; (3) excellent punching property, and (4) low production cost. The low core loss was obtained by reducing the sulfur content in steel and suppressing surface nitriding. The high magnetic flux density was obtained by reducing silicon and aluminum content. This paper describes the material design of NKB-CORE, and presents the application of this material to motors for electric power steering systems for automobiles.

Non-oriented electrical steel sheets, Ultra low sulfur, Hysteresis loss, Magnetic flux density, Electric vehicle motor, Electric power steering, Surface nitriding, punching property, Sb, Segregation