Steel pipes rust and eventually fail. To preempt disasters, oil companies and others have created computer models to predict when replacement is needed. But if the models themselves go wrong, they can be modified only through experience, a costly problem if detection comes too late.
Now, researchers at Sandia National Laboratories, the Department of Energy’s Center for Integrated Nanotechnologies and the Aramco Research Center in Boston, have found that a particular form of nanoscale corrosion is responsible for unpredictably decreasing the working life of steel pipes, according to a paper recently published in Nature’s Materials Degradation journal.
Using transmission electron microscopes, which shoot electrons through targets to take pictures, the researchers were able to pin the root of the problem on a triple junction formed by a grain of cementite – a compound of carbon and iron – and two grains of ferrite, a type of iron. This junction forms frequently during most methods of fashioning steel pipe.