A Guide to Probes and Scanners for Ultrasonic Corrosion Mapping of Pipelines and Tanks

Dave J. post image

By Dave Jankowski, product sales leader at GE Inspection Technologies 

Ultrasonic phased-array corrosion mapping assists in quickly scanning, detecting, profiling and sizing of pitting and erosion in pipes and tanks. Encoded scanning data allows a high degree of repeatability and ensures 100% coverage to compare asset conditions and track corrosion rates over time.

Conducting accurate, precise corrosion inspection takes more than just an ultrasonic flaw detector or A-scan thickness gauge– selecting a scanner, probe and accessory configuration for your application is a critical part of inspection planning. The right setup can make or break your inspection.

The NDT equipment industry offers a variety of scanners and probes to improve inspection productivity when mapping large surfaces for wall thickness and metal loss. This is a snapshot of the technologies available and their recommended applications.

Robotic and Motorized Scanners

Robotic or motorized corrosion scanners, such as Fast UT from GE Inspection Robotics, are particularly useful for inspection in confined spaces or overhead pipe runs, where it is unsafe or impractical to introduce a live inspector. During a maintenance turnaround where time is critical, it is often desirable to avoid the time delays and costs associated with ventilation, rigging, scaffolding or hole watch. The use of a robotic scanner or crawler can pay for itself in a single turnaround.

When selecting a robotic scanner, it’s important to ensure compatibility with your existing UT flaw detector, and to ensure that the device is certified as  intrinsically safe when it will be operating in highly hazardous environments.

Manual Scanners

Manual scanners operate in much the same way as a motorized scanner, but with the requirement of a live inspector to physically move and operate them. Because they have fewer moving parts they can be very reliable. However to ensure accurate encoding of the scanned surface area, they require strong magnets and precision mechanics. It is advisable to train operators on manual scanning carefully to ensure consistent procedures.

High quality UT instruments such as GE’s Mentor UT are compatible with a variety of commercially available aftermarket scanners and robotic systems to meet virtually any corrosion mapping need.

DM Array Probes

For corrosion inspection and mapping, it is recommended to use a multi-element array probe, such as GE’s DM phased array probes. They provide comprehensive linear coverage and excellent resolution of backwall corrosion and pitting. Curved or flat wear bars can be added to the probes to extend probe life, ensure alignment, and aid acoustic coupling to the inspection surface. The larger surface area of multi-element probes allows inspectors to cover more surface area faster, and an advanced C-scan image display provides a visual representation of wall thickness loss.

Because corrosion mapping often takes place in challenging field conditions or at high temperatures, it’s important to consider the quality of probe construction when choosing a probe supplier.

Conventional DM Probes

When initial corrosion mapping of a pipe or tank wall identifies irregularities, inspectors are often called on to conduct more specific point inspections or thickness measurements using conventional UT. To maximize inspector productivity, the best phased array UT instruments are equipped with a conventional channel so these spot-checks can be conducted with the same instrument.

Conventional dual element transducers are recommended for spot-checking and measuring remaining wall thickness in corrosion application. Dual element transducers generate sound waves with one element and receive with another – in a ‘V-path’ orientation, which increases sensitivity when examining corroded or pitted back walls.


For productive and precise corrosion inspection, software can be just as important as probe and scanning hardware. Today a new generation of “app-based” UT flaw detectors operate much like a smartphone, allowing users to customize their device interface and build error-reducing guided inspection procedures. These “apps” can automatically identify compatible probes, improve calibration consistency and lock-out unnecessary device parameters, ensuring more reliable and repeatable inspection data. In addition, remote collaboration and live streaming via wireless internet streamlines reporting and allows experts to offer second opinions on tough inspection calls.

With the right combination of probes, scanners, software and accessories, today’s NDT inspectors are speeding up corrosion inspections and improving accuracy.

Learn more about GE’s newest ultrasonic corrosion mapping instrument atwww.mentorut.com and download our popular corrosion inspection probe and scanner configuration guide at:https://www.gemeasurement.com/download/mentor-ut-probe-scanner-and-accessory-guide

Dave Jankowski is the NDT Portable Products Sales Leader for GE Inspection Technologies. He holds a masters’ degree in materials engineering from Case Western Reserve University.


Mentor: The Right Tool for the Job


By Timothy Humphrey, general manager at GE Oil & Gas

To the person with a hammer everything looks like a nail, but to be effective and efficient you really need the right tool for the job.  This week I’m proud to announce that after three years of development, GE can provide NDT inspectors with a new tool, and more importantly the right tool for the job.  Gone are the days when every inspection job looks like a nail.  This new platform is built to provide the right tools for their inspection jobs all in one toolbox.  This toolbox is called “Mentor”.

With the official launch of the Mentor UT portable ultrasonic flaw detector in Pennsylvania this week, we are adding another member to the Mentor platform of NDT portables.  Now inspectors can pick up a GE ultrasonic, eddy current or remote visual inspection instrument and be confident they are all excellent NDT inspection devices, easy to use, share common software, user interfaces, and connectivity.

We began the Mentor journey because we realized that the NDT and inspection industry was changing, and these changes called for a move toward more reliable, connected and smart inspection hardware and software.  In the next decade, an estimated 3.5 million manufacturing jobs will open up due to industry growth, a retiring workforce and lack of technically skilled applicants.  In the Ultrasound inspection industry is estimated that the average age of a Level III inspector is 55 years old.  This presents a challenge and an opportunity for those of us in the NDT world.  The inspection industry must determine the best way to train the next generation of inspectors to ensure that industry knowledge, critical expertise and lessons learned are maintained.  We see believe one way to address this issue is through the use of advanced technology, giving inspectors the tools and resources they need – which is how the Mentor concept was born.

The award-winning Mentor platform of NDT products is designed to help new and less experienced inspectors make better decisions, faster. These products, with the features and functionalities they share, help organizations embrace the industry shift toward digitization, improve inspection productivity, contribute to long-term equipment reliability.   Mentor is by for the simplest product available on the market and was built to help accelerate the training curve for new inspectors, leverage expertise of Level III inspectors driving efficiency for our customers.

Mentor products, across all inspection modalities share a common set of features that set them apart from any other inspection product on the market, essentially these features are what it means to be a Mentor:

  • Guided inspection “apps” – Inspection procedures, training, demonstration videos, help documents and drawings can be built into all Mentor inspection devices. This improves consistency and reduces training costs. Don’t ask an inspector to guess about how to conduct an inspection – provide step-by-step procedures or embed a demo video. Custom apps are easy to create using GE’s desktop Mentor Create software.
  • Intuitive glove-friendly touchscreen interface — Just like your smartphone, operating a Mentor device just makes sense, and interface features are common across devices. Rather than adjusting manual dials or buttons, navigating a Mentor device is fast, easy and intuitive for inspectors at all levels. Selecting, dragging and scaling screen features is easy, and reduces levels of awkward and confusing analog menus.
  • Wireless connectivity. Mentor instruments are the only commercially available NDT portables with standard onboard Wi-Fi. Secure wireless connectivity streamlines reporting and analysis, makes software updates easier and enables real-time remote collaboration with off-site experts. Need a second opinion on a tough call? Now your field technicians have a Mentor.
  • Easy to use: Mentor devices are just easy to use.  We have a team of experts and engineers who work to understand the challenges inspectors face and find innovative ways to build the “smarts” into the instrument to help make the inspector’s job easier.  We want to make sure the inspector’s expertise is focused on the work they are doing, not on the product they are using.

We understand the ongoing challenges and changes facing businesses in the NDT industry today, and we know the Mentor platform of advanced NDT portable products will save you time and money. This week we put another tool in our toolbox, taking another critical step in our journey.  We are committed to work hard on the next releases and software updates for the Mentor platform.  Our relentless focus on improving the customer experience through simplicity and innovation is what makes Mentor the leading brand in the NDT and inspection industry.

Tim Humphrey is the General Manager of GE’s NDT Portables product line. He has more than 25 years of industrial experience, primarily in the aerospace and automotive industries.