Selecting the best non destructive testing company can be a difficult task, especially if it’s not something you commonly get involved in. Non destructive testing (NDT) is the process of inspecting an asset to determine integrity in a non invasive manner. Often inspection is spurred by regulations, notification from a government body, or personal duty of care and responsibility. Whatever the reason there are many different degrees of inspection and many options regarding how thoroughly or quickly your assets condition can be determined depending on the techniques and experience the company involved employs. If you are looking for more tips, check out SalemNDT eddy current machines.
In terms of techniques there are various basic forms of NDT that are offered by almost all NDT suppliers.
Magnetic Particle Inspection (MPI) – this involves the application of a background contrast paint, spraying a solution containing magnetic particle then moving a powerful magnet across the surface whilst analysing the movement of the magnetic particles. Any surface breaking defects will be highlighted as the magnet is dragged across the surface.
Dye Penetrant Inspection (Dye Pen / DPI) – Dye penetrant is another common technique that relies on the application of dye to the test piece, which is left to soak, and then highlighted with contrast paint. Any surface breaking defects will hold the dye which will then seep into the contrast paint highlighting their location.
More advanced methods exist that can overcome some of the problems with the more common methods.
Eddy Current Testing (ECT) – Eddy current testing relies on a probe injecting a magnetic field into the test piece, as the field travels over the piece, disruptions in the field are measured and plotted as a change in phase on a portable screen connected to the probe. Looking for these disruptions leads to the defect locations. Eddy current is able to pick up both surface breaking and sub-surface defects due to the magnetic field being able to pass through the material. This property also extends to being able to pass through other coatings, such as paint and linings. Allowing the inspection of painted tank floors for example. ECT has applications on welds, pipelines, plates, condenser tubes, boiler tubes, heat exchangers amongst many more.
Ultrasonics – Ultrasonics are a very common inspection tool, often used for thickness checking due to the reliability and precision of this calculation. Due to this precision and reliability ultrasonics have naturally been applied to many different types of asset. IRIS is an ultrasonics based technique, and is perhaps the most effect tube inspection technique out there delivering very precise and detailed results. Arrays can be constructed to inspect further into a part, such as in the case of phased array ultrasonics. Overall ultrasonics are one of the top non destructive testing techniques.