What is NDT (Non-Destructive Testing)
1: Introduction
'Non-destructive testing (NDT)' is testing, but materials without destroying them. The materials after inspection do not change in their size, shape, physical or chemical properties.
There are six major NDT methods viz., visual and optical aids, radiography testing, ultrasonic testing, eddy current testing, magnetic particle testing and dye penetrant testing. These are regularly used by industry.
Each of these methods, has its own flaw detection capability and therefore no method can replace other methods. These methods are discussed in brief.
2: Types of NDT Methods
Commonly employed NDT methods can be broadly divided into two groups :
i) Methods for detection of internal defects
ii) Methods for inspection of surface/sub-surface defects