CONVENTIONAL NON-DESTRUCTIVE TESTING [NDT]

ASIGMA has more than 20 years of experience in the application of related methods. Our Technicians have the necessary knowledge and experience as well as the corresponding UNE-EN ISO 9712: 2012 certification.

ASIGMA offers inspection services through conventional NDTs, for the detection and sizing of discontinuities in materials using the following methods:

[PT] LIQUID PENETRANT INSPECTION

It is probably the most used method due to its speed. This method is able to detect discontinuities that emerge from the surface of non-porous solids.

For this, the method uses a liquid, specially formulated based on products derived from hydrocarbons, which contains in its composition a series of pigments that give it its characteristic red or fluorescent color. During the process and after an exhaustive preparation of the surface of the piece, the penetrant is applied and it is allowed to act during the penetration time, so that, by capillarity, it penetrates the discontinuities. Then, the excess penetrant is removed and a layer of developer is applied, which provides a contrast background and contributes to the formation of indications due to the penetrant retained in the discontinuities. Observing the indications makes it possible to detect and locate all the discontinuities that may affect the intended use of the piece.

(MT) MAGNETIC PARTICLE INSPECTION

This method is used for both surface and subsurface control.

This NDT method is carried out by inducing a magnetic field in a ferromagnetic material and the subsequent application of iron particles (either dry or suspended in a liquid) on the surface of the tested object. Surface and subsurface defects alter the flow of the magnetic field within the part and force part of it to rise to the surface. Magnetic particles are attracted and concentrated where magnetic flux leaks occur, producing a visible indication of discontinuity on the surface of the tested material.

.Sensitivity is highest at surface discontinuities and decreases rapidly as depth increases.

(UT) ULTRASOUND INSPECTION

Volumetric test method that allows detecting internal discontinuities of materials. It uses electronically produced high-frequency sound waves that propagate both in solid and liquid materials and in many other materials at high speeds. Pressure oscillations that have frequencies above the audible range (greater than 20,000 Hz) are considered ultrasound.

In tests using the ultrasound method, high-frequency sound waves are transmitted to the material to detect imperfections or to locate changes in the properties of the material. The most widely used technique, within the ultrasound test, is that of pulse-echo, by means of which sound is introduced into the tested object. The reflections (echoes) coming from the internal imperfections or the geometric surfaces of the piece reach a receiver, which converts the mechanical pulse into an electrical pulse that, after having been suitably treated and amplified, is represented on the display screen. of the equipment, providing the inspector with information about the status of the tested piece.

The main applications are:

Quality control of structural materials

Detection of heterogeneities

Determination of properties

Thickness measurement

(VT) VISUAL INSPECTION

It is the most basic NDT method but no less important. Visual inspectors carry out tests with the naked eye or with the help of simple optical instruments, such as magnifying glasses and mirrors, to detect visible discontinuities on the surface of the part. Likewise, in Visual Inspection, complex optical systems can be used for remote inspection such as endoscopes equipped with image acquisition systems that allow to automatically recognize and measure the characteristics of a component and detect possible defects in it.

(ET) INSPECTION BY EDDY CURRENTS

The Induced Currents test consists of the application of an alternating magnetic field on the surface of a conducting sample, so that an induced electric current is generated on the surface of the same. The discontinuities of the material cause alterations in the flow of the eddy currents, whose representation on the display screen of the ET equipment alerts the inspector to the presence of a defect. Likewise, the Eddy Current test is sensitive to the variation of any of the properties of the material of the piece, such as electrical conductivity or magnetic permeability, allowing the test to be applied for the classification of samples and the measurement of non-conductive coatings on a conductive base, among others.