Corrosion Mapping Made Better

Frédéric Reverdy

Senior Application and Products Engineer

Controlling corrosion and erosion is one of the essential engineering tasks required to ensure the long performance of critical components and infrastructure. One way to measure these damage mechanisms is to use a technique called ultrasonic corrosion mapping. Corrosion mapping consists of scanning the surface of the test piece and measuring the remaining material thickness for each position. It can be done using a conventional ultrasonic testing (UT) probe or a phased array one (PAUT).

In this blog, we’ll look at the new solutions, both hardware and software, proposed by Eddyfi Technologies to perform successful corrosion mapping inspections, combining high probability of detection of corroded areas like pitting with high productivity.

While corrosion mapping with conventional UT probes offer an easy solution, the drawback is often productivity as the probe must be scanned in both directions across the component to obtain a thickness map. Using a coarser resolution can improve the scanning speed but to the detriment of resolution, which can lead to missing small indications such as pitting. Due to a larger footprint, PAUT probes can cover a larger surface at higher speeds leading to a significant time reduction. The ability to collect high-resolution data at increased scanning speeds improves the probability of detection, enhances imaging, and improves defect characterization.

Using the synergy and complement of two of its product lines, Eddyfi Technologies has developed the perfect ecosystem for ultrasonic corrosion mapping: Silverwing scanners combined to M2M PAUT systems.

Hardware

The Silverwing R-Scan Array PAUT system is the perfect solution for the inspection of complex geometry components including curved surfaces (starting at 100mm/4in), flat plates, pipelines, and restricted access areas. The R-Scan Array utilizes the water-column concept which eliminates the need for a wedge, thus providing the benefits of improved signal consistency, accuracy, and limited dead zone. This concept offers enhanced surface conformance and improved coupling. The scanner is equipped with clickers that allow operators to conveniently increment the position of the probe along the index axis and re-initialize the encoders.



The R-Scan Array can also be used as a scanning head on the RMS scanner, providing an automated corrosion mapping solution. The robust, field-proven RMS robotic scanning head has been successfully deployed on various assets such as storage tanks, pressure vessels, pipelines and other critical structures in harsh environments including oil and gas, offshore, and mining assets. The association of the RMS with the M2M Mantis™ and M2M Gekko® PAUT systems improves scanning capability up to 10 times faster than conventional corrosion mapping.


The water box inside the R-Scan Array, called the Aqualock, is detachable. It can be used with semi-automated scanners, providing another manual corrosion mapping solution with encoders in both directions.


Software

The scanners developed by Eddyfi Technologies have been designed to work in conjunction with the cutting-edge Mantis and Gekko PAUT systems.

Scanner control

Capture™ software includes all the tools necessary to perform semi-automated and fully automated corrosion mapping inspections. All scanners are pre-configured within Capture libraries for fast and easy inspection setup. The RMS control software has been embedded in the Mantis and Gekko and functions seamlessly with the phased array data capture and analysis software. It allows operators to position the RMS and start scans directly from the PAUT screen.


Setup

The water-column concept eliminates the need for a wedge, thus providing perfect coupling and better near-surface resolution. Capture software provides:

  • Gate synchronization for up to four gates per group with the interface echo
  • Interface echo straightening
  • Synchronized Time Corrected Gain (TCG) to maximize the second backwall echo
  • Thickness information from the difference between two peaks

With a Pulse Repetition Frequency (PRF) of up to 20 kHz and 40 kHz, respectively, the Mantis and Gekko offer scanning speeds of over several hundred mm/s providing optimum productivity. The 16-dB dynamic range ensures that the peak amplitudes are measured despite an apparent echo saturation on screen.


Eddyfi Technologies’ PAUT systems can also handle any type of dual array probes (DLA). By separating the emission from the reception, the configuration removes the front surface echo resulting in an increase in near surface resolution. Capture can calculate delay laws directly on the equipment allowing operators to adjust the aperture and focus on the fly.

TFM

Both the Mantis and Gekko offer real-time Total Focusing Method (TFM). The focus capability of TFM allows the detection of small pitting that could be missed by conventional UT and electronic scanning.


The large spread generated by the Full Matrix Capture (FMC) allows better detection of the backwall contour where a conventional UT and electronic scan would simply miss data due to the fact that they are both using straight beams.


Data analysis

The indicators in the top banner and in analysis have been revised to provide as much information as possible. You can display:

  • The minimum depth within an area (delimited by the cursors) or the entire C-scan
  • The position of those minima
  • The remaining thickness in millimeters or %

With the release of its latest version, Capture now offers a stitching tool that allows merging various 2D mapping inspections. By selecting different files, Capture checks their compatibility (same type, transducer, etc.) and creates a larger file. Analysis can then be conducted on the large file. Capture considers the index and scan offsets to correctly reposition the various C-scans and recalculate the corresponding B-scans, D-scans, Topview, Sideview, etc.


By exploiting the synergies between its different product lines, Eddyfi Technologies proposes advanced solutions for technicians performing corrosion mapping inspections. Both the modularity of scanners and integration with Capture software enable operators to easily setup their inspections quickly and efficiently. Capture has all the tools to use probes with a water box, such as the R-Scan Array, as well as DLA probes. Adding TFM helps detect smaller indications and measure remaining wall thickness for complex backwalls. Finally, analysis can be performed on the equipment using various tools such as C-Scan stitching.

Stay ahead of the competition with our Beyond Current solutions for corrosion mapping inspections. Contact us for more information today.

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