The Third Group of Spacial Distribution of Magnetic Leakage Field Yielded by A Rectangular Slot on The Workpiece Surface

摘要

The objective of this study was to explain quantitatively a surprising phenomenon?a?athe magnetic polarity in a slot on the workpiece surface after discontinuation of longitudinal magnetization is opposite to it, when the specimen is being magnetized, that is,the magnetic residual field shows negative values. On the basis of uniform distribution of magnetic charges along all edges of a cuboid magnetic medium in the stable condition of magnetization and the demagnetization law of ferromagnetic materials( after removal of magnetizing field the difficult degree of the returning of a magnetic dipole back to its original orientation before magnetization depends on the magnitude of the mechanical reacting force and mechanical moment affected by this magnetic dipole in stable condition of magnetization ),they are known that after discontinuation of longitudinal magnetization rear magnetic charges excited during the magnetization may be remained along the bottom edges of the throughout rectangular slot on a cuboid steel component,and that there will appear unlike magnetic charges opposite to those,which had existed at the magnetization along the rest edges and over the lateral surfaces of the slot. Thereby this strange phenomenon was clarified. The spacial distribution gragh of the magnetic leakage field calculated and plotted along the symmetrical axis of the slot basically conformed to the third group of curves obtained from Dr. F. F.rster?ˉs experiment made in 1985.