Effect of Single Overload on Fatigue Crack Growth Rate of 2205 Duplex Stainless Steel

The fatigue crack growth test of 2205 duplex stainless steel at overload ratios of 1.0, 1.5, 2.5 and 3.5 was carried out by using an electro-hydraulic servo fatigue tester. The effect of single overload on the fatigue crack growth rate was studied. The results show that the bigger the overload ratio was, the longer the stagnation time of crack growth of 2205 duplex stainless steel was and the greater the reduction of fatigue crack growth rate was. When the overload ratio was less than 3.5, the crack tip passivated or closed due to the single overload, and the fatigue crack growth rate dropped obviously or even stagnated temporarily. When the overload ratio was 3.5, the crack tip deflected and bifurcated, and the fatigue crack growth stopped completely.