Non destructive Evaluation (NDE) Techniques

NDE technology refers to an array of non destructive techniques (NDT) and processes to monitor, probe and measure material response. The measured response is related to a desired material property or test object attribute by interpretation. The main NDT methods are:

• Visual inspection

• Liquid penetrant inspection

• Magnetic particle inspection

• Radiographic inspection (X-ray and gamma ray)

• Eddy current inspection

• Ultrasonic inspection

• Thermographic inspection

Although each method is dependent on different basic principles in both application and output, repeatable and reproducible NDE results depend on specific understanding and control of the:

• Material composition (magnetic, non-magnetic, metallic, non-metallic ...)

• Part thickness, size and geometry

• Material condition (heat treatment, grain size ...)

• Inspection scanning rate

• Fabrication method (casting, forging, weldment, adhesive or brazing bonded ...)

• Surface condition (rough, plated, bright, scaled ...)

• Nature or use of the part (critical, non-critical, high or low stress ...)

• Human factors

No NDE process or procedure produces absolute discrimination of anomalies but the end output of a procedure may be quantified and the anomaly or flaw detection capability may be measured, analyzed, quantified and documented.