一、序言 1950年Forster博士提出铁磁金属缺陷的录磁探伤方法(国外称磁象法),至今已有三十多年的历史。基本原理是首先将被检查工件磁化,铁磁金属工件中如存在缺陷,则在其工件的表面就产生散射磁场,使紧贴在金属表面的记录介质(如磁带)磁化。此时位于缺陷上部的磁介质产生了与缺陷相对应的剩余磁化强度,这样缺陷信号就被记录下来。磁介 I. Preface In 1950, Dr. Forster proposed the method of magnetic detection of ferromagnetic metal defects (foreign said magnetic imaging method), has been more than thirty years of history. The basic principle is that firstly the workpiece to be inspected is magnetized. If there is a defect in the ferromagnetic metal workpiece, a scattering magnetic field is generated on the surface of the workpiece to magnetize a recording medium (such as a magnetic tape) close to the metal surface. At this point in the upper part of the defect in the magnetic medium produces a defect corresponding to the residual magnetization, so that the defect signal is recorded. Magnetic medium