| 摘要 |
PURPOSE:To perform demagnetization uniformly throughout overall length of shape steel and at one time without moving the shape steel, by a method wherein a demagnetizing cable is arranged throughout the overall length of the shape steel in the longitudinal direction. CONSTITUTION:A cable 6 is arranged along the bend of an angle steel 5 and throughout the overall length of the angle steel 5. The cable 6 is connected to a demagnetizing power source 4 and attenuating alternating current flows therein. The current is attenuated gradually from alternating current value sufficient to maintain the magnetic field beyond the saturated flux density of the angle steel. Finally, current flowing in the cable 6 becomes zero thereby so-called attenuating alternating current demagnetization is performed. In this constitution, the magnetic field generated around the cable 6 is applied to the angle steel 5 and alternating flux 7 passing through the angle steel 5 becomes as shown in broken line and a closed loop passing through edges A, B of the angle steel 7 is formed thereby the demagnetization is performed. This phenomenon can be produced uniformly and simultaneously throughout the overall length of the angle steel. |
