Advanced NDT Techniques

1.Conventional Ultrasonic TestingConventional ultrasound has been commercially used for about 50 years.

sound Waves are generated by using a piezoelectric materials.

These sound waves are then pass through the Test materials.

In the case of any delaminations , disbounds or porosity it cause a reflection back from the materials.

Test piece

crack

0 2 4 6 8 10

initial pulse

crack echo

back surface echo

UT Instrument Screen

Working Principle

2.Phased Ultrasonic TestingFor Phased Array, the physics remains exactly the same than with

conventional UT.

The main differences come from the fact that the crystal is splitted into multiple ones and each of these crystals are driven by a pulser-receiver circuitry.

Phased Ultrasonic TestingBeam Steering

It has the ability of controling the angle at which beams are fired

Delays

Phased Ultrasonic TestingBeam Focusing

Ability to concentrate the beam to area smaller than the apperture

Delays

Phased Ultrasonic TestingLinear Scan – Corrosion Example

Delays

Phased Ultrasonic Testing(Advantages)

It gives the ability to steer and focus the beam.

Main Advantages

No safety issue Full waveform recording Automated reporting Best for Critical Weld inspection Covers all angles of conventional UT

3. TOFDTOFD Stands for Time of Flight Diffraction

It is replacement of Radiographic Technique to avoid radiographic health hazards.

It was originally developed as a sizing technique for the nuclear industry in the 70’s

The combination of Phases – Array and TOFD is becoming a very popular and efficient inspection technique.

How TOFD Works?TX RX

Lateral wave

LW

Upper tip Lower tip

Back-wall reflection

BW

TOFD Typical ScanPorosity

Porosity may image in many forms whether individual or cluster

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• Acoustic emission (AE) is the sound waves produced when a material undergoes stress (internal change), as a result of an external force.

• This occurrence is the result of a small surface

displacement of a material produced due to stress waves

4.Acoustic emission

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• Compressed Air Leak Detection• Steam Trap Inspection• Valve Leak Detection• Pressure & Vacuum Leak Detection• Heat Exchanger, Leaks• Tanks, Pipes, Leak Testing• Wind Noise/Water Leaks• Gear/Gear Box Inspection

Major Application

Other Applications

Castings Forgings

Welds Composites

Applications