Determination of the critical pitting temperature of corrosion resistant alloys in H2S containing environments

The study aimed at developing a test method allowing to evaluate the critical pitting temperature of corrosion resistant alloys in H2S containing environments. ASTM G150 method is indeed not appropriate in sour environment due to the oxidation of H2S at high applied potential and to the decrease of H2S partial pressure as the temperature increases. The study underlines that critical pitting temperature measurement is possible in H2S-containing environments but that the determined temperature is probably not potential independent. The methodology can however be used to rank different alloys provided the selection of a test media representative from service conditions.