Effect of tempering temperature on monotonic and low-cycle fatigue properties of a new low-carbon martensitic steel

The relationship between tempering temperature and low cycle fatigue (LCF) is not clear. New low-carbon martensitic steels under different tempering temperatures (320 °C, 350 °C, 380 °C) are tested for tensile mechanical properties, LCF, and microstructure. The results show that the monotone mechanical properties of martensite steels decrease with the increase of tempering temperature. The microstructure shows that the width of the laths increases, the residual austenite is decomposed, and the dislocation density decreases. A damage hysteresis fatigue life prediction model considering tempering temperature is proposed and the fatigue performance is evaluated. The fatigue performance parameters show that the fatigue damage capacity (W0) decreases and the damage transition index (β) increased. The established fatigue life model can predict the fatigue life at different tempering temperatures.