The influence of calcareous deposits on hydrogen uptake and embrittlement of API 5CT P110 steel

Abstract The effect of calcareous deposits on hydrogen uptake and embrittlement of API 5CT P110 steel was investigated using the electrochemical hydrogen permeation and slow strain rate techniques. A deposit with two distinct layers was formed at −1000 mV SCE , comprising an initial Mg-rich layer followed by a Ca-rich layer whereas at −1500 mV SCE the deposit was porous and rich in Mg. The formation of calcareous deposits did not significantly alter hydrogen uptake and embrittlement at −1000 mV SCE whereas at −1500 mV SCE they were increased. A mechanism was proposed to explain the different roles of calcareous deposits in hydrogen absorption and embrittlement.