Non-Destructive Testing (NDT) also referred to as NDE (Non-Destructive Evaluation/ Examination) and NDI (Non-Destructive Inspection), is a family of specialized technical inspection methods providing information about the condition of materials and components without destroying them.
NDT examines actual production pieces and reveals the presence of flaws which can be evaluated against accept/reject criteria. It is one of the major tools of quality control and is firmly entrenched in quality programs of industries such as aerospace, automotive, defence, pipe line, power generation, preventive maintenance, pulp and paper, refinery and shipbuilding.
There are several established NDT methods currently in industrial use. New methods are being constantly researched and developed, and many of the established ones have their effectiveness and efficiency enhanced by conversion to electronic, computerised, or robotic operation.
Forming the core of NDT are six basic methods:
- Visual testing (VT)
- Liquid Penetrant testing (PT)
- Magnetic Particle testing (MT)
- Radiographic testing (RT)
- Ultrasonic testing (UT)
- Eddy Current testing (ET)
Standards for qualification and certification of NDT personnel have been implemented e.g. International Standard ISO 9712 and European Standard EN473. Company-operated examination/certification scheme of NDT personnel has also been applied, such as recommended practice “ASNT SNT-TC-1A” issued by American Society for Non-destructive Testing (ASNT).