Zerstoerungsfreie Mess- und Prueftechnik
© Fraunhofer FHR
Zerstörungsfreie Mess- und Prüftechnik unterhalb der Oberfläche

Non-destructive measuring and testing technology below the surface#

Non-destructive measuring and testing technology below the surface

What is non-destructive testing?#

Non-destructive testing (NDT) methods are used to test components for defects or to record quality characteristics and material properties of components. Non-destructive testing means that the testing process does not influence or reduce the suitability of the material, component or product for the intended use in any way.

Non-destructive testing makes use of physical measurement technology and uses the entire spectrum of possible interactions known from physics. The data acquisition is done by means of suitable sensors adapted to the respective task. For the presentation and evaluation of the test results  imaging techniques are increasingly used.

Many, technically highly relevant questions, such as the strength of materials or components, cannot be solved  by observing or measuring properties on the material surface, but require a "look" into the interior of the material or component. This is done by selecting a suitable physical measurement technique which is capable of generating the desired measurement signals from the inside of the component. The high relevance of such measurement techniques can also be seen in the portfolio of standard NDT methods, which predominantly have material-penetrating capabilities, such as X-ray or ultrasonic methods.

Non-destructive testing imaging technologies#

The technologies of non-destructive testing are diverse.

Technologies

Selection of fields of application of imaging non-destructive testing#

  • Detection of near-surface defects in objects (heat flow thermography)
  • Inspection of weld seams, weld points and joints (thermography)
  • Detection of defects inside materials such as voids, cavities, pores, cracks, foreign bodies (X-ray technology)
  • Reconstruction of 3D volumes including all internal structures (X-ray technology)
  • Dimensional measurement as a supplement to tactile measurement technology with coordinate measuring machines and/or mechanical gauges (X-ray technology)
  • non-contact coating thickness measurement, e.g. of multi-layer coatings (terahertz)
  • detection, identification and localization of externally invisible material defects in composite materials (terahertz)
  • Detection of defects we blowholes, pores, metallic and non-metallic inclusions, cracks, delaminations (ultrasound)
  • Detection of material defects (discontinuities) such as hardness cracks, blowholes, layer separations, lift-offs, corrosion layers (eddy current)
  • Material characterization of ferromagnetic materials (steel, iron) (micromagnetic methods)
  • Incoming inspection of raw materials and recyclates for plastics, sealants, adhesives (magnetic resonance)