Nondestructive Testing/Examination (NDT/NDE)
has been defined as comprising those test methods used to examine an object,
material or system without impairing its future usefulness.
Generally, NDT/NDE is carried out in one
of the following circumstances:
•
As an aid for monitoring the quality of
jobs during manufacture. In this case NDT is used to check the quality of components
during manufacture. The presence of manufacturing imperfections and defects may
be detected. The physical characteristics and the severity of such
imperfections and defects may also be assessed.
•
Critical defect assessment. This use of
NDT normally involves an in-depth examination of known defects in a structure
in order to provide detailed information for "fitness for purpose"
assessments and fracture mechanics calculations.
•
During in-service inspection. In this
case NDT methods are used in order to detect any physical deterioration in a
component or structure that might occur under service conditions. NDT methods
are most usually employed to detect cracking, or crack propagation from
existing defects. Such cracking is commonly associated with some form of
fatigue.
Purpose of NDT/NDE:
•
Flaw Detection
•
Flaw Location Determination
•
Dimensional Measurements
•
Structure and Microstructure
Characterization
•
Leak Detection
•
Estimation of Mechanical and Physical
Properties
•
Stress (Strain) and Dynamic Response
Measurements
•
Material Sorting and Chemical
Composition Determination
When is NDT/NDE Methods
Used?
There are NDT/NDE
applications at almost any stage in the production or life cycle of a component.
•
To monitor, improve or control
manufacturing processes
•
To test incoming materials
•
To verify proper processing such as heat
treating
•
To assist in product development
•
To verify proper assembly
•
To inspect for in-service damage
