Corrosion Mapping / C-Scan Inspection
Corrosion mapping is an ultrasonic technique which maps and identifies variations in material thickness due to corrosion. Corrosion is the deterioration of a metallic material by chemical (or electrochemical) attack. This is normally caused by the environment (most often water), and sometimes by another material. There are several types of corrosion:
- Uniform corrosion that extends evenly across the surface
- Pitting corrosion that is uneven and has smaller deep areas (pits)
- Exfoliation corrosion that moves along layers of elongated grains
- Inter-granular corrosion that grows along grain boundaries
To perform corrosion mapping an automatic or semi-automatic scanner is used to scan an inspection surface, using various ultrasonic techniques including pulse echo, eddy current and phased array. Corrosion mapping is widely used in the oil, gas and nuclear industries for the inspection of pipework, pressure vessels, storage tanks and reactors. In the Aerospace sector, corrosion mapping is often referred to as ‘C-Scan’ for the inspection of composite materials. Results for corrosion mapping provide a high degree of repeatability and the advantage of position and size data for every flaw which can be compared for repeat scans of the same area to track flaw growth or corrosion rates both generally and for individual pits. The following illustrations are courtesy of James Fisher IMS and show the results of corrosion mapping inspections –
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Corrosion mapped 8" carbon steel bend
Sample evidence of corroded areas detected with ultrasonic corrosion mapping
The Phoenix range of Standard and high temperature corrosion mapping transducers complement the compression wave probe range...
Tracer is a versatile freehand scanning system that calculates and outputs accurate X-Y positional data for corrosion mapping or c-scan...
The MapMan – OH scanner is a two-axis manual X-Y scanner designed for use with the Olympus HydroFORM probe. MapMan is fully encoded...
Swipe is a two-axis manually-operated X-Y scanner which enables quick C-Scan inspection of flat or curved components with unlimited travel...
The MagScan is a compact magnetic dual-axis motorised scanner which can be used on flat plate and on pipes as small as 4″ OD. The MagScan can...
Sp-Arc is a unique mapping tool for measuring wall thickness longitudinally along small bore...
R-Evolution is an ultrasonic array probe housed in a lightweight water-filled roller, delivering fast immersion quality C-scan inspections in the palm of your hand.
SAW Bug is a motorised, magnetic-wheeled buggy that can carry up to six ultrasonic TOFD and/or phased array transducers.
WrapIt is a flexible ultrasonic phased array probe that conforms to the shape of the component.