Abstract: Residual stress caused by magnetic field treatment is studied through magnetostriction investigation. The external magnetic field is carried out for both stress relief and magnetostriction at the same time. Samples of steel 45 are produced by tungsten inert gas welding and different heat treatment temperature and time are used to modify stress levels. The magnetostriction in the magnetic treatment process is recorded and residual stresses before and after the action of magnetic are compared. Experiment results shows that magnetostriction behaviors with different stress levels are different obviously. However, a good coherence exists between the relative change of magnetostriction and that of residual stress. Thus residual stress relief during the magnetic treatment can be evaluated by magnetostriction investigation conveniently. To explain the relationship between magnetostriction and stress level, energy differential equations are constructed and energy boundary conditions are modeled. The results deducted from the established equations show that the product of magnetostriction variation caused by pulsed magnetic field and residual stress in macro scope is constant, which agrees well with experiment results.

Key words: Magnetic treatment, Magnetostriction, Residual stress