Hydrogen Induced Cracking (HIC) can be a major issue for line pipe exposed to sour environments. In this study, influence of the test solutions on HIC evaluation was investigated from the view point of corrosion. Electrochemical measurements were employed to compare corrosion behavior of line pipe steels between the 0.93N acetate buffer solution and the conventional 0.05N acetate solution.
Oil and gas wells are highly corrosive environments because they contain H2S and CO2. The 13Cr martensitic stainless steel is widely used in the oil and gas industry because of high good corrosion resistance in CO2 gas wells. Generally, the addition of Mo increases the passivity of steel. However, the role of Mo in passive films has not been completely clarified.
In the oil and gas industry, oil country tubular goods or line pipes are exposed to wet H2S environments (sour environments) in some cases. The presence of H2S in the sour environment enhances hydrogen entry into the steel due to the catalytic action of H2S. The absorbed hydrogen enhanced by H2S affects hydrogen embrittlement. Hydrogen-induced cracking (HIC) is a hydrogen embrittlement phenomenon observed in sour conditions.
In linepipes for transportation of natural gas, suppression of hydrogen induced cracking (HIC) caused by H2S contained in the transportation medium is an important issue. HIC is a phenomenon in which hydrogen atoms generated by a corrosion reaction penetrate steel and are accumulated in the central segregation part and inclusions in the steel, internal pressure is increased by gasification, and finally cracks occur.