Probing and monitoring multiple forms of localised corrosion occurring concurrently on pipeline steels in marine environments

An electrode array probe, with a novel approach, has been specifically designed to enable the in-situ field monitoring of multiple forms of localised corrosion of steel exposed to marine environments. The initiation and propagation of localised corrosion within the crevice area as well as at the steel weldment were visualised and evaluated over one-year field exposure at two different marine locations in Australia. The results show the varied initiation and propagation behaviour of crevice corrosion and weldment corrosion on steel, which provide experimental evidence for ‘bi-modal’ behaviour and the change-over of corrosion modes in extended periods of marine exposure. • A novel corrosion probe enables the in-situ field monitoring of localised marine corrosion. • 61-week field monitoring of three types of co-existing localised corrosion in the sea. • Localised corrosion rates were significantly higher than general marine corrosion. • Experimental evidence has been obtained showing ‘bi-modal’ marine corrosion behaviour. • The new probe is a promising tool for localised corrosion monitoring in the sea.