Pulse-echo is an ultrasonic non-destructive testing (NDT) technique using ultrasonic pulsed waves to find defects in materials. Ultrasonic waves are mechanical vibrations and have a frequency greater than 20,000 Hz. There are two methods of receiving ultrasonic waveforms: reflection and attenuation. In reflection or pulse-echo mode, a transducer performs both the sending and the receiving of the pulsed waves as the “sound” is reflected back to the device (see Figure 1). Reflected ultrasound comes from an interface, such as the back wall of the object or from an imperfection within the object. A flaw detection system shows these results in the form of a signal with an amplitude representing the intensity of the reflection and the distance, representing the arrival time of the reflection (see Figure 2).

(T) – Transducer

(R) – Receiver

Pulse-echo NDT technique is ideally suited for locating flaws and defects in the most common materials used in manufacturing and for weld inspection and pipeline integrity. Pulse-echo can be used across a wide range of industries including:

Nuclear Power
Rail and
Offshore Oil, Gas
and Petrochemical
Aerospace and

Advantages of TOFD Inspection Method

  • Speed of detecting discontinuities
  • Accurate positioning and sizing of discontinuities
  • Reproducibility and accuracy proven to <0.5mm
  • Offers a higher probability of detection (POD)
  • Improved risk reduction and calculation due to higher POD
  • Data collected in B-scan or D-scan format to improve detection of discontinuities
  • Planar discontinuities, which are not perpendicular to measured surfaces can be detected
  • Inspections can be performed above 200°C
  • Permanent digital records with graphic images

Can’t find a solution that suits your rail industry inspection requirements?

If our current solutions do not meet your exact requirements, we can modify an existing system, or design a completely new customised solution for your needs, should the situation demand. Contact us with a brief outline of your NDT inspection requirements and we can provide an initial proposal for a solution that best suits your needs. Or call to discuss your corrosion mapping requirements: Tel:[AB1]  +44 (0) 1925 826000 or Email: sales@phoenixisl.com