Effect of Heat Treatment Process on the Fatigue Behavior of AISI 1060 Steel

This experimental study investigated the effects of quenching and tempering heat treatment on fatigue behavior and also tempering temperature and time holding of AISI 1060 steel. At first, the specimens were austenitized at 800˚C for 1 hour, and then were quenched in the water bath of 25˚C temperature. After that, tempering process was done at the temperature of 250˚C, 450˚C and 650˚C for 1 and 2 hours. The results of mechanical properties indicated that hardness, tensile strength and fatigue limit was decreased with increasing the holding time and tempering temperature. Scanning electron microscope (SEM) results showed that crack propagation in the tempered specimens at the 250˚C temperature in the 1 hour was slower than in the specimens in the higher temperature and higher period time. As well, with increasing of the tempering temperature, germination areas of fatigue crack was increased and crack propagation was done faster.