Stress Dependence of Magnetic Hysteresis Properties Through Acoustically Stimulated Electromagnetic Response in Steel

It is known that magnetic hysteresis properties are sensitive to stress. This indicates that magnetic measurements have a potential tool to evaluate residual stress in steel. However, its applications of magnetic measurement techniques are very limited because it is difficult to probe local hysteresis properties in conventional magnetic measurements. In recent years, however, the spatial mapping of local magnetic hysteresis behaviors becomes possible by ultrasonic focusing and scanning. The principle of this technique is based on the generation and detection of acoustically stimulated electromagnetic (ASEM) response. Here we investigate the stress dependence of magnetic hysteresis properties through the ASEM response in steel. Using a tensile testing machine, we have measured the stress dependence of hysteresis parameters such as coercivity, ASEM response due to remanent magnetization and so on. We found that coercivity is an appropriate index to convert from magnetic hysteresis properties to the values of residual stress.