On the possibility of estimating the elasticity limit and residual deformations in ferromagnetic metals using the parameters of electromagnetic-acoustic transformation

Abstract

The approaches to nondestructive testing by the electromagnetic-acoustic transformation (EMAT) of Rayleigh waves within the region of the elasticity limit and at the beginning of the region of plastic deformations under tension of ferromagnetic metals and alloys are discussed. It is shown that these approaches must be varied for materials having the magnetostriction with an opposite sign and also for different tasks: either a material is tested under a load or after removing a load. It is proposed to monitor the displacement of the maximum of the EMAT-efficiency field curve with the use of the magnetization bias field and the amplitude of the received signal depending on a tensile load. The possibilities of constructing calibration curves and testing without them are demonstrated.