Experimental and Numerical Study of HSLA Steel Fatigue and Pitting Corrosion Behavior.

This paper presents an experimental and numerical study of the fatigue-corrosion behavior of the high strength low alloy steel known as HSLA steel in marine environment. Based on a case study of steel removed from of hull ship after about 1300 h of service in seawater, microstructural fatigue-corrosion indicators are detected such as micro-cracks, micro-pits, and beach marks. In addition, the mechanical properties decreased dramatically. Pitting corrosion acts as the main phenomena leading to the metal deterioration. This is confirmed through electromechanical calculation and potentiodynamic curves. Since, the environment is harsh and out of our control, a numerical study of the effect of pitting and the coupling between fatigue and pitting corrosion is held. The results show that the geometry of corrosion defect is responsible for the propagation of the pit and can lead to the crack formation. von Mises stress propagation is controlled too by the corrosion potential distribution. [ABSTRACT FROM AUTHOR]