SIDER C.N.D. » Services

Radiographic and gammagraphic inspections (RT)

admin — Mon, 05 Jan 2015 10:09:30 +0000

Radiographic and gammagraphic inspections are methods of non-destructive tests that use ionizing radiation in order to verify the integrity of pieces or parts of them. This is done by the radiography of the affected area that is the projection of the piece image on the film that will be characterized by darker areas (lower opacity of the material to radiation ) and lighter areas ( most of opacity) ; this difference in the localized density of the component creates differences in the blackening of the film areas allowing us to detect the presence of defects that will appear (with the exception of special cases) such as areas most exposed of the film itself . These type of controls are based on the use of x-rays generated by x-ray equipment (emitting directional or panoramic beam) or gamma rays emitted by radioactive isotopes (such as Cobalt -60 , Iridium -192 and Selenium -75; the most used elements in industrial gammagraphy) .These techniques are generally used for the detection of defects in the production of pipe welds, carpentry welds, materials in general, castings, electronic cards and sometimes even on works of art allowing qualitative inspection of volumetric type of the structural characteristics and ensuring the identification of defects also lying within the pieces.

Ultrasonic test and thickness measurements (UT)

admin — Mon, 05 Jan 2015 10:14:51 +0000

Ultrasounds are elastic waves (or mechanical vibrations ) which spread in the materials with a stated velocity depending on material characteristics and on kind of wave used. As well as the light, ultrasonic waves may undergo reflections, refractions, diffractions , diffusions in the passage from a means to another one.

Just these features , in conjunction with known speed of propagation and the angle of incidence of the ultrasound beam , allow the identification of discontinuities within the pieces examined, their location and depth. This method of investigation , that is volumetric, permits the control of high thicknesses in less time and cost than the industrial radiography though it is less reliable for the inspection of low thicknesses . The most used techniques are the a-scan control that involves checking with traditional oscillogram, phased array , in which you can electronically set the parameters of the ultrasonic beam , TOFD which exploits the phenomenon of the wave diffraction for the detection of flaws.

The thickness measurements represent a particular application of the more general ultrasonic method. The time between the emission of the pulse and its reception by the probe, given a propagation speed and a known angle (0 °) allows to know the thickness of the piece with centesimal precision .

Magnetic particles inspection (MT)

admin — Mon, 05 Jan 2015 10:17:33 +0000

The magnetic particles inspection allows to detect the presence of surface and sub-surface ( a few millimeters) discontinuities inside of ferromagnetic materials by exploiting the phenomenon of ferromagnetism .Consequently to the magnetization of the piece, induced by the special equipment and following the application on its surface of a ferromagnetic product ( liquid or powder ) , the latter will tend to concentrate at the points where the magnetic field undergoes a deviation ( due to ” reluctance “of the material , in correspondence of discontinuity ) allowing to detect the presence and shape of the defects ( eg . cracks) that will become now clearly visible. This control technique can also be used with fluorescent products highlighted by the use of a UV lamp called ” black light ” allowing to obtain a higher sensitivity control.

Penetrant test (PT)

admin — Mon, 05 Jan 2015 10:21:52 +0000

The penetrant test (PT) generally consists in the use of a red liquid with particular characteristics of viscosity and capillarity named “dye penetrant” and another white coloured called detector that allow the detection of defects opening on the surface of ferrous and non-ferrous materials. After applying the red liquid on the piece to be examined and having waited a few minutes for its penetration in discontinuities , it will be carefully removed from the surface, and the developer will be applied on the same giving evidence of flaws, recalling on the surface the part of dye penetrant that had not been previously removed by cleaning the piece ( because trapped in the discontinuity ) . Any defect will appear in red and will be visible to the eye and evaluated . It is possible, alternatively to this type of products, to use fluorescent liquids with a UV lamp to obtain a more reliable result.

Visual inspection (VT)

admin — Mon, 05 Jan 2015 10:23:25 +0000

The visual inspection is an essential method to ensure a high quality standard of the product. You can get useful information about the quality of the surfaces examined , their geometry , the finish, the presence of wear, corrosion , etc . as well as on the presence of visible defects to the naked eye . It is possible also using tools such as microscopes or lenses ( to identify very small details) or mirrors , borescopes and endoscopes that allow the inspection of areas otherwise not accessible .

Leak detection (LT)

admin — Mon, 05 Jan 2015 10:24:40 +0000

The leak detection, performed using vacuum box equipment, is essential to check for leaks or defects extended trough the tickness of components such as welding of open tanks that can not be pressurized directly and vessels. After applying a special liquid like soapy water on the area to be tested , a depressurization by compressed air will be applied on the same; any leak becomes clearly visible because the air recalled from the opposite surface will cause the production of bubbles allowing to localize the areas to be repaired.

Chemical tests “on site” (XRF – OES)

admin — Tue, 23 Dec 2014 23:20:17 +0000

Chemical tests “on site” have the big advantage to perform the analysis with great versatility and speed directly at the customer site . For this purpose can be used XRF equipment (PMI – Positive Alloy Material Identification) for a generally qualitative analysis of the products and OES equipment (Optical Emission Spectroscopy) for a control also quantitative of the elements of the material subjected to analysis without the need to take samples from the analyzed piece. In both cases it is actually possible to obtain the chemical composition of the product , but the OES method, besides being much more accurate , allows the reading of elements which are otherwise undetectable, such as carbon.

Ferrite content analisys

admin — Mon, 05 Jan 2015 10:36:48 +0000

The ferrite content analisys is performed on austenitic or duplex steels in order to determine, by magnetic induction, the ferrite contained amount . This test is normally required because a too high percentage of the same could create problems of metallurgical nature.