Product-Specific Phased Array Training: Ensuring PAUT Efficiency by Supporting Proficiency
Nondestructive testing is not only a best practice in many industries: it’s a requirement. The use of phased-array ultrasonic scanners to detect subsurface flaws and defects in important equipment helps companies prevent asset failures, accidents, and liability.
Manufacturing, transportation, aviation, power generation, and oil and gas companies all rely on ultrasonic nondestructive testing. For many of these industries, testing requirements are codified in national laws and international standards. In order to meet these requirements, companies should provide in-house technicians with certified phased-array training, or turn to third-party NDT solutions.
What is Phased Array Ultrasonic Testing?
“Phased array” is a type of ultrasonic testing, so understanding phased array techniques specifically requires understanding ultrasonic testing broadly. The purpose of ultrasonic testing is to allow technicians to look inside solid structures, without taking them apart. This allows technicians to identify flaws such as cracks, holes, honeycombs, coating thicknesses, and other phenomena which may cause a large structure or asset to fail. By identifying these anomalies, companies can repair, replace, or simply remove service equipment that is at risk of failure.
Ultrasonic testing works by transmitting waves of ultrasonic energy into and through solid objects. One method collects the reflection of these waves and interprets wave variations in order to form an image of the object’s interior. As different materials—or holes in materials—reflect ultrasonic waves differently, wave variations provide consistent signals which can be reliably interpreted.
The other method, time-of-flight diffraction, pushes ultrasonic waves through objects and collects them on the other side. Similar to using reflectance, this transmission method interprets wave variations produced as the ultrasonic energy diffracts through the object. Both methods are effective; each has pros and cons.
Phased Array Vs. Simple Ultrasonic Testing
But what is phased array—does it rely on reflectance or diffraction? Actually, the answer is “either.” Phased array ultrasonic (PAUT) refers to the method used to introduce ultrasonic waves into an object, not the method of collection and interpretation. Early forms of ultrasonic testing used a single wave emitter, or transducer, to introduce ultrasonic energy. While effective, this method could only scan small slices of objects at a time. A single comprehensive scan required significant amounts of time and energy. As such, the method imposed large costs on organizations employing it as a means of routine maintenance.
Phased array ultrasonic improves on earlier methods by using multiple transducers—this is the “array.” These transducers are controlled by software on the ultrasonic testing device, which determines the most effective timing of ultrasonic pulses. The timing of these pulses—the phasing—helps create resonance effects.
Phased array ultrasonic can image much greater swaths of objects at a time than single-emitter testing. As a result of controlled phasing, the path of the ultrasonic beam can also be adjusted without moving the transducer probe, allowing faster, easier testing as well.
Finding Effective Phased Array Ultrasonic Training
How to successfully operate phased array ultrasonic equipment in accordance with the relevant codes and standards is not something a person can learn on YouTube. Due to the variability, complexity, and specificity inherent in the task, only knowledgeable, conscientious technicians can perform PAUT scans successfully. In addition to understanding ultrasonic principles, the different material properties of objects being scanned, and the operation of ultrasonic equipment, technicians must also understand all relevant standards and means of documenting compliance. Learning to do so takes time, practice, and expert guidance. Finding the right training program, therefore, becomes critical for success.
Keep in mind that different manufacturers provide different phased array ultrasonic equipment. While the principles behind each different brand’s equipment are the same, the operation can differ significantly.
The most qualified trainers will come from the equipment manufacturer. However, certified third-party NDT training companies provide a useful alternative. For example, Zetec offers training courses on the equipment we manufacture. Additionally, other companies also provide phased array ultrasonic training using Zetec equipment.
NDT equipment manufacturers and third-party training companies provide various levels of training in ultrasonic testing techniques. Basic courses cover ultrasonic testing itself; others focus on the details of ultrasonic testing for specific applications, like pipeline welds or high temperature hydrogen attack (HTHA). More advanced courses cover phased array ultrasonic testing in detail. Multiple levels of courses are offered in PAUT due to the tiered complexity of technician and managerial responsibility.
Phased array ultrasonic and other NDT training programs should be attended on a rotating, continual basis. New employees will require training in order to get up to speed. More experienced employees will require training to learn new aspects of ultrasonic testing or to refresh their knowledge of older ones. Training requirements are found in the relevant legal codes and standards, and training programs have been developed to meet these standards.
Phased-array training is indispensable for companies required to perform these scans. Some of the most appropriate training resources will come from the manufacturer of the equipment used in your company. However, certified third-party training providers who train on the same equipment can be an acceptable and effective alternative.