A normalization of corrosion fatigue behaviour: an example using an offshore structural steel in chloride environments

A normalized presentation of the metal fatigue process is proposed and applied to the corrosion fatigue behaviour of an offshore structural steel under different loading conditions. Corrosion fatigue development in this steel under different stress levels and frequencies is presented in both 'normal' and 'normalized' terms. Experimental results on pitting and corrosion fatigue-crack growth are used to introduce the new normalized presentation approach, which may be employed to illustrate the corrosion fatigue behaviour of any given metal/environment system. This allows a description of the initiation and growth of defects to be made, involving both time-dependent and cycle-dependent stages. It is suggested that a set of dependencies between fatigue-characterizing parameters may be presented in graphic form and used as a 'fatigue certificate' for any given metal/environment system.