HYDROGEN PERMEATION THROUGH PROTECTED STEEL IN OPEN SEAWATER AND MARINE MUD

Hydrogen permeation through cathodically protected and unprotected BS 4360, grade 50D with various surface finishes and coatings was measure d over a 12-month period in open seawater and for a subsequent 6 month s in marine mud. Cathodically protected, uncoated steel showed the gre atest hydrogen permeation, and coated steels showed the least. Nonanti fouling coatings showed a rapid deterioration when buried in marine mu d with a significant increase in hydrogen permeation. Overall, the ant ifouling coating gave the lowest hydrogen permeation in both environme nts. Results were discussed in relation to possible hydrogen-induced c racking in the use of moveable (''jack-up'') offshore oil and gas plat forms.