Abstract
Corrosion fatigue crack growth behavior of HT 80 steel was studied in synthetic sea water under various frequencies and potentials for the purpose of corrosion fatigue life prediction. In general, the slower the load frequency was, the faster the crack growth rate was. When ΔK<5MPam1/2 or ΔK>20MPam1/2, crack growth curves under various frequencies were parallel to each other, but when 5MPam1/2<ΔK<20MPam1/2, the acceleration of the crack growth rate cased by intergranular cracking was observed on the parent metal but not on the weld metal. The crack growth rate at 0.3Hz was minimum at potential of -0.7V (Ag/AgCl) in all tested ΔK regions. There was a good correlation between the acceleration rate of the crack growth and the transition rate from the bare metal to the steady-state metal. The corrosion fatigue life was estimated by using the crack growth curves and the theoretical curve well fitted to the experimental data. From this, it is proved that the corrosion fatigue life can be predicted if the crack growth properties at low ΔK regions is understood properly.
