Effect of volum fraction of martensite on fatigue properties of 20B38 Dual phase steeel

Intercritical heat treatment is an important and effective operations on the mechanical properties of steel. This operation is easy and cost effective ways to achieve the desired mechanical properties such as strength and ductility. In this paper, we investigate the effect of Intercritical heat treatment on fatigue properties of microalloying boron steel. In order to achieve different dual phase microstructures with different amounts of martensite, the temperatures of 730, 750 and 770 0c wase selected as the Intercriticalcritical temperatures and valus of 52, 68 and 88 % by volume martensite obtained with the ferrite. To investigate the effect of tempering on fatigue properties, one series of samples were Tampere. The present study shows that the fatigue strength increases with increasing volume fraction of martensite and with tempering the fatigue strength will decrease.