RELATIONSHIP BETWEEN DISSIPATED ENERGY AND FATIGUE LIMIT FOR AUSTENITIC STAINLESS STEEL

Recently, rapid prototype modeling is required in industry due to accelerated production cycles. Therefore, effective fatigue life design method is required taking the place of conventional laboratory fatigue test based on 10 million stress cycles. Therefore, fatigue limit estimation based on energy dissipation measured by infrared thermography has been getting an increasing attention, because of its time and cost effectiveness. This technique has been welcomed mainly in automotive industries for evaluating fatigue limit of steel for automobile bodies. However the fundamental principle of this method has not been clarified yet. In this study, fatigue test is conducted for austenitic stainless steel. Temperature change due to dissipated energy, martensite fraction and strain are continuously measured to discuss energy dissipation mechanism related to plastic strain and transformation of microstructure during fatigue test.