What is the Best Approach to Nondestructive Testing of Steel Structures?
When testing steel structures, nondestructive testing (NDT) inspectors need instruments that permit flexible scanning and deeper probing. For steel items, standard ultrasonic testing (UT) is no longer enough, as the angles of UT remain fixed without the ability to maneuver accordingly. Instead, specialists must use phased array ultrasonic testing (PAUT), which fosters multiple apertures with a single probe.
When combined with the correct instrumentation, PAUT can detect more flaws—including defects at awkward angles that would otherwise be easily overlooked. For certain challenging applications, analysts can also apply more advanced focusing techniques like the total focusing method (TFM) to detect anomalies on a more accurate level. Thus, combining PAUT and TFM is the most effective approach to the nondestructive testing of more challenging steel structures.
The Power of PAUT for Inspecting Steel Structures
PAUT is an improvement on standard UT for testing steel structures in several key ways:
- It allows multiple angles in a single testing phase
- It can customize inspection parameters
- It features an enhanced beam shape for comprehensive scanning
PAUT probes allow users to steer the wave beams throughout various parts of the steel structure. A flexible scanning regimen can also read flaws that would have gone unnoticed during a conventional UT scan.
PAUT offers sectorial scanning (or angular scanning), which allows NDT analysts to move the beam and find more flaws during the testing stage. Moreover, it speeds up inspection times while spotting hidden flaws that could have jeopardized asset operations or public safety.
Additionally, because PAUT allows an analyst to scan items efficiently in a single session, wedges and probes last longer and don’t need to be replaced as frequently as with other methods. A mobile PAUT unit can also scan large-scale infrastructure with ease, requiring no heavy equipment or immobile systems that restrict usability.
PAUT vs Radiography and Penetrant Testing
Though commonly used in the past, radiography is quickly losing ground as an acceptable NDT method due mainly to its inherent hazards. Radiography exposes NDT analysts to heavy doses of radiation, especially during longer testing intervals, and analysts need specialized skills in order to conduct radiographic testing.
Just as radiography exposes analysts to harmful radioactive waves, penetrant testing (PT) involves exposure to toxic chemicals that can endanger human health. The PT process also requires considerable preparation time, with inspections in some cases taking upwards of 30 minutes—and this is without taking into account the time and energy needed to analyze the complex data PT provides.
PAUT, on the other hand, requires no radiation or harmful chemicals whatsoever; the wavelength beams pose no hazard to analysts’ health. PAUT requires minimal setup and allows for quick, efficient inspections that even level 1 analysts can capably conduct. Furthermore, pairing PAUT with an instrument powered by industrially proven, code compliant software can help users sift through even large amounts of data more quickly and accurately than ever. In some cases, PAUT could also be coupled with advanced focusing techniques and time of flight diffraction (TOFD) to function at the highest level.
PAUT with TFM Features
To get the most out of PAUT, analysts should be provided with high-quality instrumentation that provides up to one million data points per frame. TFM can determine the exact type of flaw discovered and its potential impact on the structure at large to an impressively detailed degree. TFM is also capable of scanning broad areas, with every detail of the large area fully encapsulated on-screen in real time.
The spatial resolution of a scanned image provides a comprehensive profile of the area, and the user can tailor the scanning radius based on their needs. TFM allows digital optimization through prime focusing and expansive mapping. It’s also a key way to draft immaculate maintenance strategies that reduce costs and prevent operational mishaps.
The Most Effective Method for Nondestructive Testing of Steel Structures
In sharp contrast to more traditional NDT methods such as radiography and penetrant testing, phased array ultrasonic testing is clean, efficient, and thorough. It is also a much safer method, posing no potential harm to analysts whatsoever.
With its wide array of customization schemes for any testing scenario, it’s as flexible as it is precise, and has a variety of valuable applications in numerous industries, including construction, oil and gas, aerospace, and manufacturing. When conducting nondestructive testing of steel structures, there is no approach more effective than PAUT with TFM.
Zetec’s designers are industry-leading experts in ultrasonic and eddy current technologies, and we can help you navigate any of our NDT testing solutions or devices.