Evaluation of fatigue damage using a magnetic measurement technique

A series of strain-controlled fatigue tests were performed on 0.1 wt% C Fe-C alloy samples under different strain amplitudes. The measured coercivity of these samples was found to behave differently in the initial and final stages of fatigue. In the intermediate stage of fatigue it was found that coercivity tended to increase, while initial and maximum permeabilities tended to decrease. This could be related to the changes in the surface structure which were observed by SEM. The present results indicate that hysteresis parameters are related to the accumulation of fatigue damage, and therefore it is possible to develop a magnetic measurement technique for monitoring fatigue damage in steel components.