ABSTRACT
The cracking mechanisms considered in this document all result from corrosion in the presence of H2S followed by hydrogen-uptake in the steel. For each of the cracking mechanisms there is a critical hydrogen uptake rate and/or hydrogen concentration in the steel below which cracking does not initiate. The hydrogen uptake is dependent upon a number of parameters of which the most important are:
hydrogen sulphide concentration;
pH; and
temperature.
