Advanced science.  Applied technology.


Sulfide Stress Cracking (SSC) Testing

Hydrogen sulfide (H2S) is a naturally occurring gas that can be deadly to humans and corrosive to oil and gas equipment, especially in the presence of water. The National Association of Corrosion Engineers (NACE) test method TM0177 is widely used to qualify metals for resistance to sulfide stress cracking and stress corrosion cracking in H2S environments. Southwest Research Institute (SwRI) has a facility dedicated to NACE TM0177 Method A, providing sulfide stress cracking (SSC) testing and assessments of resistance of metals to SSC in H2S sour gas environments.

NACE TM0177 Method A Laboratory

NACE TM0177 Method A tensile testing with uniaxial tensile loading

SwRI’s Method A testing laboratory allows triplicate samples to be run on multiple materials or heats. Glass vessels and proof ring assemblies are enclosed in a customized sealed glove box under nitrogen blanket. The exposures are typically performed at a user-specified actual yield strength (AYS) as determined by mechanical test data of the specific material heat. We use stringent safety protocols to perform projects in highly aggressive H2S-based environments at low and high pressure and temperatures.

At room temperature, the SSC failure mechanism is believed to be a form of hydrogen embrittlement. The specimen is exposed under load to an acidified (pH 2.6 – 2.8) and buffered brine solution (5 wt% NaCl + 0.5 wt% acetic acid) that is saturated with 100% H2S gas. Testing is performed at 24 °C (75 °F) ±3°C (±5°F). The environmental cracking susceptibility is evaluated based on a failure/no-failure test result after a 30 days exposure test.

NACE Corrosion Test Lab

Visit Stress Corrosion Cracking to learn about other test methods or specialized R&D services that address sulfide stress cracking and environmental cracking. In addition to Method A testing, SwRI can investigate failed parts on-site using optical methods, SEM, XRD, or X-ray, as well as non-destructive techniques such as Eddy current and microtomography (to obtain 3D rendition of internal damage).

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Or call Dr. Elizabeth Trillo at +1 210 522 4210.