Gas and oil pipelines are prone to corrosion at points where electric currents flow from the metal into the surrounding earth. To avoid this, an insulating cathodic layer is applied to the pipelines and flanges.

However, this has proven useless during geomagnetic storms. Electrical discharges that occur at these times outstrip the protective potential of the cathodic coating – in fact, they make the problem worse. Geomagnetic storm activity is increasing across the globe. The result is an increase in the corrosion rate of pipelines and flanges.

For example, the central 1/3rd of the 800 mile Alaskan pipeline runs along the plane of the auroral electrojet, a natural current produced in the ionosphere in response to polar storms. To protect the pipeline, a weak counter-current is applied to the pipeline flanges so they have a net, negative potential in relation to the ground.

However, during a storm the electrojet can change polarity suddenly, and become extremely erratic (currents can leap from a few amperes to over 1000) all of which renders the so-called ‘cathodic protection’ useless. The result has been corrosion in the flanges and pipes.

The same story is true across the globe. Despite the extra cost, when it comes to underground pipelines, flanges and fittings it seems the use of high grade alloys, such as super duplex, are no longer a luxury.

We at ChemiPetro sell a wide range of high specification super alloys designed to minimise corrosion in applications like underground pipelines. Our flanges and pipe fittings are supplied at competitive prices meaning protection for minimal extra cost.