Sandia scientists have discovered that a particular form of nanoscale corrosion decreases the life-span of steel pipes used by the Oil and Gas industry.
Steel pipes are known to eventually rust and fail; to keep potential disasters in check, oil companies have created computer models to predict when replacement is needed.
One burning issue is that if these models themselves go wrong, they can be modified only through experience – a costly problem if detection comes too late.
Sandia has now come up with a solution to this problem: They have made use of transmission electron microscopes to pin the root of the problem.
These microscopes shoot electrons through targets to take pictures, and in one such experiment, the scientists were able to locate an anomaly on a triple junction formed by a grain of cementite and two grains of ferrite.
According to the scientists, the disorder in the atomic structure of those triple junctions made it easier for the corrosive solution to remove iron atoms along that interface.
The corrosive process stopped when the triple junction had been consumed by corrosion, but the crevice left behind allowed the corrosive solution to attack the interior of the steel.
“We thought of a possible solution for forming new pipe, based on changing the microstructure of the steel surface during forging, but it still needs to be tested and have a patent filed if it works,” said Sandia’s principle investigator and lead microscopist Katherine Jungjohann. “But now we think we know where the major problem is.”
According to Aramco senior research scientist Steven Hayden, “This was the world’s first real-time observation of nanoscale corrosion in a real-world material – carbon steel – which is the most prevalent type of steel used in infrastructure worldwide.”
“Through it, we identified the types of interfaces and mechanisms that play a role in the initiation and progression of localized steel corrosion.”
Hayden adds that the work is already being translated into models used to prevent corrosion-related catastrophes like infrastructure collapse and pipeline breaks.
Image and content: Pixabay/Sandia Labs
