Non-destructive testing is very useful in the materials industry to gather information on the characteristics of all types of substances. In this post we tell you what these analyzes consist of, what are their main modalities and how they are applied in the different productive sectors.

What is non-destructive testing?

Non-destructive testing (NDT) is the set of tests that are carried out on materials in a harmless way, that is, without affecting their structure, operation and original shape, so that they keep their performance intact once the studies are completed. This is its main advantage compared to destructive tests, which render the analyzed elements useless for later use.

As a material characterization technique, the objective of non-destructive testing is to determine the physical, chemical or mechanical properties of the different substances and to verify that they comply with the legal and quality requirements established in current regulations. The nature of the parameters to be obtained is what dictates what types of non-destructive testing must be used for each purpose.

Types of non-destructive testing

There are various formulas to classify these tests. Depending on the physical method of analysis used to characterize the samples, we find the following examples of non-destructive tests:

·      Visual inspection

Visual inspection of materials is the most basic type of non-destructive testing. It is used to see fissures, splashes, stains, cracks and any other pathology appreciable with the naked eye or with the help of glasses and magnifying equipment.

·      Penetrating liquids

They are used to detect leaks and irregularities in the surfaces of materials. To do this, a fluorescent or colored liquid is applied to the outside, observing capillary leaks in the damaged areas.

·      Electromagnetic waves

The characterization of materials is produced by their interaction with electromagnetic waves such as X-rays, gamma rays, ultraviolet, infrared and microwaves. The most common tests are industrial radiography and thermography, which analyze structures by measuring the absorption of ionizing and infrared radiation, respectively; as well as non-destructive tests with concrete using georadar waves.

·      Acoustic waves

Ultrasound and high frequency acoustic waves are also applied to detect flaws such as cracks or pores based on the variations in their trajectory in all types of materials, including metals.

·      Subatomic particles

It consists of analyzing the structures of materials by exposing them to subatomic elements, such as neutrons, protons and beta particles. The result of the interaction is a reliable indicator of the existence of failures in the compounds.

·      Magnetic particles

They are used to study irregularities in ferromagnetic materials. In this process, an electric current is induced and metallic powder is spread on the surface to diagnose the affected areas, where the accumulation of dust by permeability takes place.

·      Induced currents

Also known as “Eddy current” or “Foucault’s currents”, this method is based on the induction of a current on a conductive material to measure the impedance gradients that cause its discontinuities, detecting both the volume and the depth of these.

What is non-destructive testing used for?

The applications of the different types of non-destructive testing are very numerous and are present in a wide variety of production areas. In the automotive and aeronautical industries they are used, for example, to control the reliability of car and aircraft components, including chassis and engines. The same happens with industrial machinery parts for the manufacture of all kinds of products.

On the other hand, in the construction sector, non-destructive tests on concrete are key to guaranteeing the resistance of buildings and infrastructures. Additionally, these tests are also used to examine paint coatings, plumbing leaks, or faults in electrical wiring and power systems.

Given its great potential to characterize materials without causing damage, non-destructive testing is a key engineering technique in the materials industry. If you want to know more details about the technological procedures used in this field, we invite you to stay tuned to our blog.