Eddy Current Inspection
Eddy Current Inspection is a form of NDT inspection used to detect surface-exuding defects such as fatigue without having to remove protective coatings by grit blasting or needle gun. REEL has successfully applied this technique in the offshore industry worldwide over many years.
This effective method produces quick, highly sensitive results and can be used on most materials if sound transmission is good. High frequency sound pulses are emitted from a transducer above a sample of the material. The sound waves propagate through the sample, reflecting at interfaces and these reflected waves are monitored by a detector above the sample. The depth and type of flaws are ascertained using this method. The testing is carried out from one side of the sample only.
Magnetic Particle Inspection (MPI)
MPI is a proven and reliable method of detecting even the smallest surface, or near-surface, flaws in ferrous materials. The MPI inspection equipment establishes the magnetic field pattern of the material and pinpoints indications by identifying any distortion in that field.
Indications cause leakage of magnetic flux in the vicinity of the flaw and the equipment identifies build-ups of very fine iron particles that gather at the location of the leakage, however small it may be.
Dye Penetrant Inspection (DPI)
DPI is a simple method of detecting surfaceextruding flaws such as cracks or porosity. One step up from visual inspection, DPI offers advantages of large area coverage, speed and low cost.
Based on the principle that liquid is drawn into a surface-breaking crack by capillary action, dry powder developer is applied to the surface to draw out the liquid that has penetrated the crack and produce a surface indication.
Hardness is affected by composition of material and weld metal, metallurgical effects of welding processes, heat treatment and other factors.
A vital part of the inspector’s role is fully acquainting themselves with the limiting factors of various types of hardness machines.
REEL inspectors use three portable hardness meters, all used for highly polished machined surfaces and providing highly accurate hardness readings.
Visual inspection, with or without visual aids, is the original and still highly effective method of NDT. Many defects can be detected by careful direct visual inspection. Optical aids used include lowpower magnifiers, microscopes and telescopes.
Boroscopes, endoscopes and other fibre-optic devices are used for inspection of areas with restricted access. These devices can be used with television camera systems. High-speed visual inspection may be used for tubular components.