Non-Destructive Testing - NDT

Power & Utilities

Hertel expertly carries out non-destructive materials testing or NDT. This NDT makes it possible to assess the condition of materials without damaging them.

Non-Destructive Testing - NDT

To be able to carry out reliable testing, a number of factors are involved. A large number of physical limitations, the surface condition, geometry and accessibility of the object to be assessed must be weighed up. This is why only expert and certified testers can carry out NDT. Our testers hold the relevant SKO certificates and are certified in accordance with EN473/SNT-TC 1A level 2.

Hertel carries out the following forms of Non-destructive testing:

Ultrasonic testing

Ultrasonic testing is carried out using sound waves. Sound moves in a straight line in metal. At a transition between two materials sound waves are reflected. This phenomenon is used to detect irregularities. All materials that can be penetrated by ultrasonic waves are suitable for this method: metal, aluminium, copper, stainless steel etc.

Ultrasonic testing enables faults deep in the material to be detected in different materials over their whole thickness, without having to carry out destructive tests. Ultrasonic testing is also faster than radiography.

 Applications: wall thickness measurements, crack detection, weld examination, detection of corrosion/erosion.

Magnetic testing

 Magnetic testing makes it possible to identify faults on and directly below the surface. This can only be done in magnetisable grades of steel. Material is tested using a magnetic field and test ink. Cracks, binding faults etc. interfere with the magnetic field.

 Applications: surface-examination of welds, high-pressure steam piping, welding of supports, lifting lugs, stay rope attachments etc.

Penetrant testing

Penetrant testing is a surface-examination that can be carried out on all non-porous materials. A liquid - a 'penetrant' - is applied to the material surface. This penetrant then penetrates through into the damage. Another substance - the developer - shows where the penetrant has been absorbed into the damage.

Applications: all non-porous materials, surface testing of welds new build or maintenance, welding of supports, lifting lugs, stay rope attachments etc.