Influence of Dynamic Tension Load on Weak Magnetic Signals and Metal Magnetic Memory Effects of Ferromagnetic Samples

Weak magnetic signal changes and metal magnetic memory effects of steel tensile samples under the excitation of geomagnetic field were studied.Two kinds of sinusoidal tensile load cycles were applied on the samples and the magnetic signals changes were recorded.The results indicated that the cycle index did not affect the magnetic signals in elastic loading processes.When loading goes into the plastic range, polarity of the magnetic signals reversed and the magnetic field changed dramatically near the position where necking finally occurred.And the magnetic distribution curves acquired zero value with a large gradient at the position.