Effects of stress on magnetically induced velocity changes for surface waves in steels

Abstract

Results of an experimental investigation of the effects of uniaxial stress on the magnetically induced velocity changes for 5-MHz surface (Rayleigh) waves in specimens of ASTM A-36, SAE 4340, and HY-80 steel are described. Like the magnetically induced velocity changes for ultrasonic shear and longitudinal waves, the magnetically induced velocity changes for surface waves exhibited characteristic stress effects which were dependent on the magnitude and the sign (tensile or compressive) of the stress as well as on the relative orientation of the stress, the magnetic field, and the wave propagation directions. The observed characteristic stress effects indicated potential applicability of the magnetically induced velocity changes for surface waves to nondestructive measurements of residual surface stresses in ferromagnetic structural steels.