Phased Array Ultrasonic Testing: Advantages and Disadvantages

For nondestructive testing (NDT), industries are increasingly adopting the use of phased array ultrasound testing (PAUT). It is replacing other conventional ultrasound and radiographic NDT methods with its high flaw detection and accurate measurement capabilities. For industries like aerospace, power generation, pipeline services and more, phased array ultrasound testing provides many advantages.

The Phased Array Ultrasound Testing Method

The phased array ultrasonic testing method operates with a series of small transducers in a single assembly which can be pulsed individually. The beams emitted from these individual transducers can thus be controlled and can be focused and swept along the material without the need for movement of the probe. The pulse timing for each transducer is computer controlled. The result obtained from the reflected pulse is analyzed to determine flaws in the material. The ability to optimize the angle and focal distance of the beam makes PAUT an effective method for determining material quality. PAUT can be done for volumetric applications including weld inspection, corrosion inspection, and material thickness measurement. 

Advantages of Phased Array Ultrasound Testing

Compared to other NDT methods, PAUT has many advantages, including:

Increased Flaw Detection Ability

In PAUT, a probe is used to steer and control the direction and shape of the beam generated from the transducers. Unlike eddy current technology, the surface can be scanned at diverse angles by steering the beam. The steered scanning and optimized controls allow for increased coverage to detect a flaw in the material. The material of complex geometry can be inspected by steering the beam at angles which may have been difficult if done manually.  

PAUT is also effective in determining material thickness. During the inspection, any change in the thickness of the material due to corrosion or erosion can be determined using ultrasonics. 

Increased Inspection Speed

A phased array probe uses multiple transducers which assist in the inspection of the larger surface in a short time. Multiple inspections can be carried out with a single probe which saves the time otherwise spent on setup reconfiguration and changing of the probe for each unique testing.

With a phased array system, the digital feedback can be received instantaneously. This helps in faster identification of flaws and in understanding the weld quality.

Reliability of Results

Phased array probes can provide the test results with an excellent repeatability factor. The ability to inspect complex geometry and detect flaws makes PAUT a reliable testing method.

Disadvantages of Phased Array Ultrasound Testing

Despite its many advantages, phased array ultrasound testing also has a few drawbacks:

Applicability

While PAUT has a wide range of abilities, it’s not a preferred testing method for the detection of surface cracks, metal fatigue, or bolt hole inspections compared to eddy current testing. Eddy current is ideal for testing surface flaws and tubing inspections while PAUT is highly effective in corrosion detection, composite materials and thicker welds. 

Complexity of Operation

PAUT equipment is far more advanced than conventional ultrasonic testing equipment with many capabilities.. Due to its multiple data optimization features, the equipment should be handled by a trained professional to eliminate the risk of inaccurate testing and to use the equipment to its full potential.  

Higher Initial Cost

Due to its advanced features, investing in PAUT equipment can have a higher initial cost compared to conventional ultrasonic testing systems. That being said, PAUT’s advanced capabilities can result in faster, more accurate and efficient inspections maximizing asset uptime. This ultimately can lead to a lower total cost of ownership with PAUT equipment. 

Phased Array Ultrasound Testing for Minimizing Risks

Industries trust phased array ultrasound testing as the nondestructive testing method for its many advantages—including efficiency with weld inspection and corrosion mapping. Phased array equipment optimized with appropriate software packages allows technicians to efficiently inspect and accurately visualize flaws. In industries like aerospace, power generation, oil and gas, a small flaw can be a major operational issue. By identifying the root cause with PAUT technology, asset teams can take appropriate measures to reduce the risks that may be associated with the flaw.

Zetec provides exceptional phased array ultrasound testing equipment for corrosion mapping and weld inspections. To find the NDT equipment which best suits your testing needs, contact us today!