Published on 21-Mar-2024

Understanding the various Ultrasonic Testing Methods

Understanding the various Ultrasonic Testing Methods

Sources - Indiamart

In a world full of technological wonders, NDT ensures the safety and reliability of the structures and materials on which we rely. Ultrasonic Testing Methods is a fascinating realm where sound waves play the leading role in NDT. Ultrasonic Testing is an NDT Method that uses ultrasonic waves to inspect materials without causing harm.

These waves penetrate materials, revealing internal structures and defects without a scratch. The tester sends ultrasonic waves into the material, setting the tone, and when a flaw is detected, it bounces back, revealing its location and size, similar to a musician detecting a sour note. Ultrasonic Testing comprises a few methods that are used to determine any flaws or irregularities in any material. Check them out.

What are the Advanced Ultrasonic Testing Methods in NDT?

Ultrasonic Testing Methods in NDT

In ultrasonic testing, each type plays a distinctive role, in ensuring the examination of materials. Whether it's the gentle touch, the deep dive, or the precision of phased arrays, ultrasonic testing methods offer a diverse range of tools for flaw detection.

Latest Inventions have given us advancement in technology, a few are given below:

  • Phased Array Ultrasonic Testing ( PAUT )
  • Time of Flight Diffraction Ultrasonic Testing ( TOFD )
  • Long Range Ultrasonic Testing ( LRUT )
  • Automated Ultrasonic Backscatter Technique
  • Internal Rotating Inspection Systems
  • Dry-Coupled Ultrasonic Testing
  • Rapid Ultrasonic Gridding (RUG)
  • Conventional Ultrasonics

1. Phased Array Ultrasonic Testing (PAUT)

Phased Array Ultrasonic Testing

A Phased Array Ultrasonic scanning unit involves many crystals arranged in a manner that sends sound waves in different directions inside the material. The sound from different crystals is timed by the computer at different phases – hence the name Phased Array (Timed elements & Arrangement of elements)

The major advantages of the technology are:

  • Inspection is quick since the manual to and fro movement by the user is not required.
  • More possibility of finding defects without using different angle probes, since a single probe scans in different directions.
  • PAUT gives multiple views of the defects through advanced presentation views such as B scan (depth of defect) view, C Scan View(Top view), S Scan view (sectorial view), and conventional A scan view (echo pattern ).

Complete scanning can be recorded and interpretation can be made later by many people. So the technology is believed to be a reliable process for inspection.

Read More, Phased Array Ultrasonic Testing: What, How & Where

2. Time Of Flight Diffraction (TOFD)

AQC-Ultrasonic Testing

The technology is used for Crack detection at a rapid rate. The method involves two Ultrasonic probes a “transmitter’ and a “receiver” attached to a fixture. The fixture can be operated manually or robotic. The technology finds defects by analyzing the time of sound travel and sound diffracted from the crack tips, hence the name “ Time of Flight Diffraction” The technology exactly locates the defect and measures the size of the defect.

3. Long Range Ultrasonic Testing / Guided Wave Testing

AQC Ultrasonic Testing

The Technology is used to scan a complete length of pipe for internal corrosion, cracks, or damages. Long Range Ultrasonic Testing involves multiple Probes fixed around the circumference of the pipe. The sound is sent in a manner that travels through the wall of the pipe up to the end (Flange ) of the pipe and returns back.

The low-frequency sound waves are sent to avoid loss of sound due to scattering. The sound reflected from the obstructions is shown on the screen. The A-symmetrical sound echoes are identified as defects and the locations of the defects is shown in the sweep range of the screen. The size of the defects is also can be interpreted by using Distance Amplitude Curve.

The major advantages of Guided Wave testing or Long Range UT are:

  • It is a speedy testing method, a long length of pipe can be scanned quickly
  • Full access to the pipe length is not required
  • Even Insulated or underground pipes can be scanned without excavation of the whole pipe length.
Explore the Long Range Ultrasonic Testing (LRUT)

4. Automated Ultrasonic Backscatter Technique