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Non-Destructive Testing (NDT), also Non-Destructive Examination (NDE), covers all the processes and techniques which enable acquiring data related to the integrity and the health of a material or a part without altering or destroying it.

NDT is to materials what medical imaging is to the human body.


All branches of industry use NDT: aerospace, nuclear, petro chemistry, railway, automobile, metal industry, foundry… on parts of an equipment or an installation important for safety and availability. NDT has to reveal all the defects likely to decrease the availability, the safety of use and/or more generally the compliance of a part to the use for which it is intended.

NDT is applied to forging, rolled, molded, welded parts… in three cases:

  • The in-manufacturing inspection, which generally ends in the sorting of defective parts
  • The inspection upon reception of parts or installations to detect defects, define their nature and characterize them.
  • The in-service inspection to detect, define and size defects appearing during life and to follow their evolution in the time


Two types of defects:

  • Surface defects such as cracks, holes, pitting, wear…
  • Internal defects such as porosities, inclusions, subsurface cracking, thickness variations due to wear or to corrosion ..


In France, knowledge level and skills of operators are guaranteed by a certification system based on theoretical and practical examinations, managed by COFREND (The French Confederation for Non-Destructive Testing)

13 000 qualified operators in France.


The main NDT methods are: visual inspection, penetrant testing, magnetic testing, eddy current testing, ultrasonic testing, radiography, infrared thermography

Fiche Ultrasons 2015

Ultrasonics (UT)


Ultrasonic testing allows to detect internal defects by measuring perturbations of an ultrasonic wave.


Eddy current (ET)


Eddy currents are created in conductive materials. They allow to detect surface or sub-surface defects by measuring the perturbations of an electro-magnetic field.

Magnetic particles (MT)


Magnetic Testing (MT) is used on ferromagnetic materials It allows to detect surface breaking cracks. by accumulation of magnetic powder.

Radiography (RT)


Radiography is used on all types of materials with all thicknesses. It allows to detect internal defects in the thickness by measuring the attenuation of a radiation flux.

It uses the same principle as medical radiography.Because of radioprotection contraints,radiographic testing requires particular precautions and a specific certification.

Le ressuage (Penetrant Testing en anglais)

Penetrant testing (PT)


Penetrant Testing highlights surface breaking by capillary action.

La thermographie infrarouge

Infrared Thermography (IRT)


The infrared thermography is a method of non-destructive test based on the measure of the temperatures of surface which implements heat transfers principally by thermal conduction and radiation.
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