As corrosion is a major issue for many industries, numerous inspection and monitoring
techniques have been developed to assess corrosion level and integrity of metallic structures.
Amongst them, ultrasonic measurements are widely used to monitor or control wall thickness
and, in general, thickness loss by the corrosion of these structures. However, in most cases,
the accuracy of these measurements is in the order of hundreds of micrometers for corroded
materials. For laboratory corrosion tests such as accelerated corrosion tests developed by
automotive manufacturers, a higher accuracy level is needed and classical evaluation methods
such as weight loss measurements are normally used. However, these measurements are
destructive and do not provide information on the kinetics of degradation.
Following recent works by Ström and co workers, the aim of the present work was to qualify
the use of ultrasonic measurements for an accurate monitoring of steel corrosion during
accelerated corrosion tests and, more generally, during outdoor field exposures.
So, in this work, wall thickness of cold rolled steel panels was continuously monitored during
several accelerated corrosion tests. Results of ultrasonic measurements were compared to
classical evaluation methods (e.g. mass loss or micrometer). Ultrasonic measurements have
also been used on steel panels exposed in severe environments, e.g. on the deck of a ship.
The results of these experiments clearly showed that non destructive ultrasonic measurements
provided corrosion data as accurate as classical methods and, moreover, it allows direct and
in-situ measurements of the corrosion rate of steel.
Keywords: corrosion monitoring, ultrasonic, accelerated corrosion test, steel