| 摘要 |
PURPOSE:To demagnetize the residual magnetism of a special steel by a method wherein the magnetic flux acting on a material to be demagnetized is so controlled as to vary as positive negative demagnetization negative. CONSTITUTION:U character type magnets consisting yokes 5, magnetic poles 6, 7 and exciting coils 8 are equipped on a frame 10 extending nearly over the whole length of the steel material 1 interposing a nonmagnetic material 9 between them to form the demagnetizing device. When the steel material 1 is an ordinary steel, the demagnetization can be performed simply by making one cycle of the demagnetizing current -i to flow against the magnetizing current +i. When the steel material 1 is the special steel, the demagnetization can be performed comparatively effectively by making one cycle of the demagnetizing current -i' to flow against the magnetizing current +i. Moreover when the special steel is Chrome-molybdenum steel, etc., two cycle demagnetization reversing the polarity proves effective. Namely it forms the demagnetizing pattern of magnetizing +i cut demagnetizing -i' cut reverse directional magnetizing -i cut reverse directional demagnetizing +i' cut. Accordingly even in the special steel, the residual magnetism can be demagnetized. |
