Evaluation of Tensile Residual Stress in Welded Steel Plates Using Acoustically Stimulated Electromagnetic Response

Residual stress is one factor involved in the degradation and damage of industrial products. It is important to understand the magnitude and distribution of residual stress to maintain the integrity of a product. Magnetic measurements are a potential nondestructive method for evaluating residual stress in steel because the hysteresis properties are sensitive to stress. In recent years, spatial mapping of local magnetic hysteresis loop has been performed by using the acoustically stimulated electromagnetic (ASEM) method, which obtains the conversion coefficients from local hysteresis parameters to tensile stress. In this study, we demonstrate the evaluation and spatial imaging of tensile residual stress through local hysteresis parameters using welded steel specimens. We confirm that local coercivity can be used for evaluating residual tensile stress in the high-stress region. In addition, the spatial distribution of residual stress is well visualized by imaging the ASEM response signals due to remanent magnetization.