SCC of commercial steels exposed to high hydrogen fugacity

The commercial steels 1008, X65, X70, 4140 and 4145H were subjected to linearly increased stress test in the dilute pH 2.1 sulphate solution at their free corrosion potential and at increasingly negative applied potential values to −1500 mV. The increasingly negative applied potential increases the aggressiveness of SCC conditions because of increasing hydrogen evolved at the specimen surface. It was found that steels 1008, X65, X70 and 4145H resisted SCC for all applied potentials including −1500 mV. In some tests the potential drop was also recorded.