In the case of non-demagnetization, longitudinal magnetization is more harmful than the remanence generated by circumferential magnetization because it produces magnetic poles at both ends of the workpiece. The circumferential magnetization (such as the magnetization of a round steel bar), the magnetic circuit is completely closed in the workpiece, and no leakage magnetic field is generated, but the circumferential magnetization of the remanent magnetic field inside the workpiece is larger than the longitudinal magnetization.
This can be confirmed by measuring the remanence in a deep longitudinal slot on the circumferentially magnetized workpiece, but the remanence on the surface of the workpiece is measured by a remanence instrument. The retention of remanence on the workpiece will have a great impact on the further processing and use of the workpiece.
For example:
(1) The residual magnetism on the workpiece will affect the accuracy and normal use of the magnetic compass and instrument installed near the workpiece;
(2) The residual magnetism on the workpiece will adsorb iron dust and magnetic powder, which will affect the roughness of the workpiece surface and the tool life during continued processing;
(3) The residual magnetism on the workpiece will bring difficulties to remove the magnetic powder;
(4) The residual magnetism on the workpiece will cause the arc to blow off during the arc welding process and the welding position to deviate;
(5) The residual magnetism of the oil circuit system will adsorb iron filings and magnetic powder, affecting the smooth flow of the oil supply system;
(6) The residual magnetism on the ball bearing will adsorb iron filings and magnetic powder, resulting in ball bearing wear;
(7) The remanence on the electroplating steel will cause the electroplating current to deviate from the expected flow area and affect the electroplating quality;
(8) When the workpiece needs to be magnetized several times, such as determining that the last magnetization will have an adverse effect on the next magnetization.