Does the coating influence the X-ray inspection

Radiographic testing: non-destructive testing of components

The Radiographic examination is an imaging process to test materials without destroying them. With the help of X-rays or gamma rays, the density and thickness of a workpiece is determined and its defects are identified.

Synonym (s): X-ray testing, non-destructive material testing, imaging test methods


The advantage of X-ray inspection is that the inside of a component can be inspected without damaging it. When radiographic examination will be voluminous errors identified. This test method is used, for example, after welding for weld seams on sheet metal or pipes. Here it is tested whether the weld seam is intact. Other components and cast parts made of metal can also be examined with this non-destructive material testing method. The component is X-rayed.

In order for the radiographic test to work properly, the radiation must be matched to the component. This means that the radiation intensity, wavelength and exposure time must be adapted to the thickness and density of the workpiece.

Detecting defects in a weld seam using radiographic / X-ray testing.

This is how radiographic testing works

In contrast to other rays, electromagnetic X-rays have a very high penetration capacity and are therefore very suitable for non-destructive testing of materials. They are also known from medical technology. Both in medical technology and in testing technology, the way X-rays work is the same:

The radiation is directed onto the component to be tested. The electromagnetic waves penetrate the component and leave an image of the component in the form of an X-ray image on a radiographic film that is attached behind the component. On the X-ray you can then see whether and where there are defects on the component. Because the denser and thicker the workpiece, the less radiation comes through it and the brighter this area is on the radiograph. If there are cracks or inequalities in the material, this is indicated by the different brightness. In this way, cracks, pores, cavities, etc. can be found quickly.

The X-ray test is reproducible. This means that you can carry out the test procedure again later and get the same result.

Illustration possibilities

There are different variants of radiographic images that arise during the test procedure:

X-ray film

This is the X-ray image as we know it from doctor series. The radiographic film is a coated film sheet. During the test, the differences in the blackening of the film show where there are differences in the seal in the workpiece and what shape and position a possible defect may have. This imaging method is suitable for gamma radiation and X-ray radiation, for. B. for testing a weld seam and for testing cast parts.

Area detector (digital radiography)

Here the test results are converted with the help of area detectors and displayed in digital form.

Sensor foil / image plate

The X-ray image is also digitally saved with the sensor film. The film absorbs the radiation with the help of sensors. The result is transferred to a computer with an imaging plate scanner.

Luminescent screen

The luminescent screen is a powder-coated plate that is irradiated through the test piece. The test piece and any faults can then be seen on the powder coating. This process is suitable for plastic and light metal. It can also be used with steel - but only up to a thickness of 20 millimeters. The radiation exposure for the observer is high.

Image intensifier

Image intensifiers can be used to reduce radiation exposure for the observer. With the help of a camera, the X-ray image is recorded and transmitted so that the observer can view the image in a place protected from radiation.

Material examinations, reports & certifications

How the results of the radiographic test are to be evaluated depends largely on the legal standards. There are test specialists who carry out these assessments based on the DIN rules. In addition, training as a materials tester can be completed.

Radiographic Testing Standards

Some standards are listed below:

  • DIN EN ISO 19232
  • DIN EN ISO 17636
  • DIN EN 12681
  • DIN EN ISO 5579
  • DIN EN ISO 11699

Training as a materials tester / tester for non-destructive materials testing (NDT)

In order to become a tester for non-destructive material testing according to DIN EN ISO 9712, the NDT training must be completed. It includes the areas of radiographic testing, binding testing, ultrasonic testing, magnetic particle testing and visual testing. In the case of retraining measures, the examiners receive an IHK degree as part of their training.

The NDT training for certification and qualification according to DIN EN ISO 9712 is offered by:

GSI SLV

The Society for Welding Technology International - GSI for short - represents welding technology on an international level. The GSI cooperates with the SLV (welding training and research institute), which has several branches in Germany. There is, for example, the SLV Halle or the SLV Fellbach. They all offer various training courses in the field of welding technology in Germany and are specialists in non-destructive component tests.

DGZfP

The DGZfP is the German Society for Non-Destructive Testing e.V. The association is internationally recognized and takes care of the research, development, application and dissemination of non-destructive testing methods. At DGZfP Bildung und Training GmbH, training and qualification tests in accordance with DIN EN ISO 9712, DIN 54161 and DIN EN 4179 are offered.