Influence of environmental factors on corrosion of ship structures in marine atmosphere

This paper deals with the modelling of the effects of relative humidity, chlorides, and temperature on the corrosion behaviour of ship steel structures subjected to marine atmospheres. A new corrosion wastage model is proposed based on a reference non-linear time-dependent corrosion model that is modified by the effect of different environmental factors contained in the marine atmosphere. The model assesses the corrosion degradation under stationary environmental conditions denoted as “short-term”. The long-term corrosion degradation is predicted by considering the succession of the various environmental conditions that can be present in the marine atmosphere during a ship lifetime and adding the corrosion damage incurred during each of them. Corrosion records (depending only on time) are used to calibrate the reference model while the effect of environmental factors in increasing or decreasing the corrosion rate is based on data published by other authors. A numerical example of a representative application of the new corrosion model is presented, to demonstrate how to apply the model.