Non Destructive Testing , NDT , is industrial method for analyzing the characteristics of material or finding the discontinuities in the material & Weld joints, without damaging the material.

NDT is otherwise called as, Non Destructive Evaluation –NDE, Non Destructive Inspection (NDI) and it a quantitative analysis method.

Whereas Destructive Testing is a Qualitative analysis method, to find the quality of the material such as Tensile strength, Elongation property, hardness value, Impact toughness, etc

The above mentioned qualitative properties cannot be found using NDT methods. This is  because in order to find the mechanical properties, it is required to apply load on the material. The load deforms the material  making them not usable.

But NDT Methods are used in such a manner, that the material can be reused after the testing.

This area answer some of the FAQ Frequently asked Questions

  • What is NDT?
  • What is the use of NDT?
  • What is Difference between Non Destructive Testing and Destructive Testing ?

There are various NDT Methods.

Which are mentioned one by one below :

Eddy Current testing:

Eddy Current Testing

Eddy Current uses the principle of electromagnetic Induction in Conductive materials, to detect defects.

The presence of any discontinuity will cause a change in eddy current field and corresponding change in phase and amplitude of the measured signal.

Eddy Current testing is generally used in surface defect inspection and tubing. Industries like aerospace and petroleum industry used these methods often.

Remote Field Testing:

Remote Field Testing is also an Electromagnetic testing method which uses a probe with electromagnet at it ends. The discontinuities which the remote field of the magnets encounters is indicated in the machine. The method is used for detecting cracks and corrosion in thin tubes such as in heat exchangers.

Remote Field Testing

remote field testing

 Ultrasonic Testing:

Ultrasonic Testing utilizes high frequency sound waves which is not audible to human ears. The defects are detected by analyzing the returned sound waves, which is displayed as echoes in the machine screen. The method has vast application and almost used in any material, to detect internal defects.

Ultrasonic testing

Phased Array Ultrasonic Testing (PAUT)

is an advanced Ultrasonic Testing method which multiple sound emitting elements, arranged in such a manner that it sends sound at different angles and different timings. The received sound gives more detailed view of the defects, method is applied in Oil & Gas, Aerospace, Aircraft manufacturing, Automobile & Railways.

Liquid Penetrant  Testing:

LPT is a surface defect detection method. It is used on any material except material with very rough surface finish and porous materials. The method uses special high contrast die which penetrates in to small defects using the principle of capillary action and the defects become visible during application of dry powder over the surface.

Liquid Penetrant Testing

Radiography Testing (RT) / X-Ray

Uses penetrating electromagnetic radiation to capture images of the material in a film or digitally using a flat panel detector.

The image shows both defects on the surface and internal, the method is applicable on all materials and has a vast application.

Radiographic testing

Magnetic Particle Testing (MT) / (MPI) / (MPT)

Uses Magnetic Filed to find defects in Surface and Near Surface. The method is applicable in Ferromagnetic materials only (i.e. the material with Fe, Co or Ni as major content in it), also the method is not suitable austenitic Steels. But it is a very efficient crack detection method.

Magnetic particle inspection


Visual Testing (VT)

Visual Testing is the Method of analyzing the defect which are visually visible. Also with aid of Magnifying glass or Video Boroscopes or mirrors for in accessible areas.

Visual Testing

There are several other Non Destructive Testing Methods ..


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