基于磁荷假说的圆钢棒退磁因子计算

由于椭球体的磁介质能在均匀外磁场中被均匀磁化，而有限长的圆柱体磁介质在均匀外磁场中的磁化是不均匀的，不符合《磁粉探伤》教材中所列举的圆钢棒退磁因子列举数值的实际情况。简要介绍了有关磁介质的两种理论，即磁荷假说以及安培分子环流假说。从磁荷假说入手，推导了圆钢棒退磁因子的计算公式。将推导所得退磁因子数值与教材中的列举数值进行了比较，结果发现，推导计算值与教材中的数据差距很大，因此有必要对教材中圆钢棒的退磁因子进行修正。

Calculation of Demagnetization Factor of the Round Steel Rod Based on Magnetic Charge Hypothesis

Because of the magnetic medium of the ellipsoid magnetized in the uniform external magnetic field was uniform magnetization, but at the same condition, the magnetic medium of the finite length of cylindrical was not uniform magnetization, the actual situation was inconsistent with the demagnetization factor values of round steel bar listed in Magnetic Particle Testing book. Two theories, magnetic charge hypothesis and ampere molecular hypothesis, were briefly described. Based on the magnetic charge hypothesis, the demagnetization factor formula of round steel rod was derived, and the values were calculated. The calculating values were compared with the lists of book, and it was found that, the values were different greatly between them, so it was necessary to amend the demagnetization factor value of round steel rod in the book.