What is Non-Destructive Testing (NDT)?
Non-destructive testing is used to evaluate the integrity and properties of material or components without causing damage to the tested object. NDT consists of a variety of non-invasive inspection techniques used to evaluate material properties, components, or entire process units.
The techniques can also be utilised to detect, characterize, or measure the presence of damage mechanisms (e.g corrosion or cracks).
NDT is also commonly referred to as non-destructive examination (NDE), non-destructive evaluation (NDE), and non-
destructive inspection (NDI).
NDT methods can generally be classified into two categories: conventional and advanced. Each method has its own characteristic advantages and limitations.
What are the main Conventional NDT techniques?
Digital technology has greatly enhanced the convenience and accuracy to NDT processes, particularly in the areas of eddy current (EC) and ultrasonic (UT) techniques. Technical advancements are also significantly improving the efficiency and accuracy of NDT methods, especially in energy, aerospace, power generation, and other industrial applications.
While there are hundreds of methods available, the most common are:
- Consultancy/Level 3 Services
- Magnetic Particle Inspection
- Dye Penetrant Inspection
- Visual Inspection
- Ultrasonic Testing
- Radiographic Inspection
- Eddy Current Inspection
What are the main Advanced NDT techniques?
- Time of Flight Diffraction
- Phased Array
- Magnetic Flux Leakage
- Alternating Current Field Measurement
- Eddy Current Array
- Pulsed Eddy Current
- Internal Rotary Inspection System (IRIS)
- Corrosion Mapping
- Automated Ultrasonic Testing
What are the advantages of using NDT?
As no harm occurs to the items under test, NDT testing is a very valuable technique used for product evaluation, research and problem solving which can save both time and money.
Other benefits include:
- Mitigate environmental & operational risks
- Reduce downtime and out-of-commission assets
- Determine structural integrity
- Provide internal technical assurance controls
- Establish regulatory compliance
- Improve safety
What is the Difference Between Destructive and Non-Destructive Testing?
Unlike NDT, destructive testing destroys or changes the part during the test so that even if it passes the test it can no longer be used. Examples of destructive testing include bend testing, tensile testing. or macro sectioning. Non-destructive testing doesn’t damage or destroy the part and allows it to continue to be used after testing has finished.
Where is NDT used?
Depending on how broadly you define NDT you could say that it’s used in almost every industry in the world, since visual inspections take place in almost every workplace in some form or other.
That being said, there are specific industries that require NDT and have formalized processes for its use, as codified by those organisations such as API and ASME.
These industries include:
- Oil & Gas
- Renewables
- Power Generation
- Chemicals
- Mining
- Aerospace
- Automotive
- Maritime
- Mining
