Hydrogen Uptake of Duplex 2205 at H2 Partial Pressures up to 100 bar

AbstractMicrobiological methanation is investigated in an underground natural gas reservoir. Since H2 is involved in the process, hydrogen embrittlement of steel must inevitably be considered. Therefore, a routine for testing has been developed and a unique autoclave test bench was designed to simulate field conditions. The 2205 duplex stainless steel (UNS S31803) was investigated. Constant load tests (CLTs) and immersion tests with subsequent hydrogen analyses were performed. The specimens were exposed to different partial pressures of H2 under both dry and wet conditions (with brine). Additionally, the influence of CO2 under wet conditions was covered. Tests were performed at two different temperatures (25 °C and 80 °C) and lasted for 30 days. In general, the duplex stainless steel shows a good resistance to hydrogen embrittlement, but a significantly higher hydrogen uptake was obtained compared to other steel grades.

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Hydrogen Embrittlement of Steels in High Pressure H2 Gas and Acidified H2S-saturated Aqueous Brine Solution

BHM Berg- und Hüttenmännische Monatshefte ◽

10.1007/s00501-021-01143-w ◽

2021 ◽

Author(s):

Anton Trautmann ◽

Gregor Mori ◽

Bernd Loder

Keyword(s):

Hydrogen Embrittlement ◽

Stainless Steels ◽

Austenitic Stainless Steels ◽

High Strength ◽

Hydrogen Uptake ◽

Constant Load ◽

Carbon Steels ◽

Hydrogen Gas ◽

Gas Reservoir ◽

Load Tests

AbstractMicrobiological methanation is planned in an underground natural gas reservoir. For this purpose, hydrogen is stored, which can lead to hydrogen embrittlement of steels. To simulate these field conditions, autoclave tests were performed to clarify the amount of absorbed hydrogen and to test whether this content leads to failure of the steels. Constant load tests and immersion tests with subsequent hydrogen analyses were performed. Tests under constant load have shown that no cracks occur due to hydrogen pressures up to 100 bar and temperatures at 25 °C and 80 °C. In these conditions, the carbon steels absorb a maximum of 0.54 ppm hydrogen, which is well below the embrittlement limit. Austenitic stainless steels absorb much more hydrogen, but these steels also have a higher resistance to hydrogen embrittlement. In H2S saturated solutions, the hydrogen uptake is ten times higher compared to hydrogen gas, which has caused fractures of several steels (high strength carbon steels, Super 13Cr, and Duplex stainless steel 2205).

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Investigation of the Passivity, Hydrogen Embrittlement and Threshold Stress of Duplex Stainless Steel

Volume 1: Regulations, Codes, and Standards; Current Issues; Materials; Corrosion and Integrity ◽

10.1115/ipc1996-1858 ◽

1996 ◽

Author(s):

Mirko Gojić ◽

Mirjana Metikoš-Huković ◽

Ranko Babić

Keyword(s):

Stainless Steel ◽

Hydrogen Embrittlement ◽

Duplex Stainless Steel ◽

Passive Film ◽

Threshold Stress ◽

Significant Degree ◽

Constant Load ◽

Stress Cracking ◽

Sulfide Stress ◽

Sulfide Stress Cracking

The electrochemical behavior of duplex stainless steel has been studied in various environments. Its passivity state was investigated in borate-buffer using cyclic voltammetry and impedance spectroscopy techniques. The susceptibility towards sulfide stress cracking and hydrogen embrittlement were tested at a constant load under cathodic polarization in the NACE solution saturated with H2S and 0.5 M sulfuric acid solution containing As203 as a promoter. SEM analysis accompanied these investigations. It is proposed that the highly protective quality of the passive film formed on the investigated duplex stainless steel may be associated with the presence of multiple oxidation states (Cr3+ and Cr6+) formed in the solid state along with (CrO42- and MoO42-) anions and the great variety of possible bridging ligand states (OH−, H2O, O2−). This leads to a significant degree of bonding flexibility and supports amorphous i.e. glassy structure of the passive film. Therefore, the stresses that would be associated with epitaxy, are easily alleviated without the creation of long-range defect structures. The investigated duplex stainless steel shows high resistance to hydrogen embrittlement and sulfide stress cracking. The embrittlement index was determined to be 26%, while the threshold stress amounts to 84% of the yield strength.

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