Device to improve iron loss properties of grain-oriented electrical steel sheet

A device to improve iron loss properties of a grain-oriented electrical steel sheet as the steel sheet travels, within a transport mechanism for transporting the steel sheet, along a feed direction (X) of the transport mechanism, the steel sheet having a width (w) measured in a transverse direction (Y) orthogonal to the feed direction (X), the device comprising:

• a measuring device that measures a variable sheet passing speed (v1) of the steel sheet travelling in the feed direction (X) through the transport mechanism;
• and
• an irradiation mechanism for irradiating a surface portion of the surface of the grain-oriented electrical steel sheet as the surface portion advances past the irradiation mechanism, the irradiation mechanism configured to scan a high-energy electron beam along the surface portion from a first edge of the steel sheet to an opposite second edge of the steel sheet in a direction angled relative to the transverse direction (Y),
• an angle (θ) of the scan with respect to the transverse direction (Y) corresponding to the measured sheet passing speed (v1) on the feed path, and
• the irradiation mechanism configured to adjust the angle (θ) of the scan in proportion to the measured sheet passing speed (v1), so as to maintain an irradiation pattern of the electron beam on the surface portion of the steel sheet that keeps pace with the measured sheet passing speed (v1),
• wherein the angle (θ) of the scan of the electron beam is θ=tan−1(v1/v2),
• wherein v1 is the measured sheet passing speed of the steel sheet, and
• wherein v2 is a scanning rate of the electron beam in the transverse direction (Y) of the steel sheet.