Exam Question
Describe following non-destructive test methods:
(a) Dye penetration test - principle, and method in detail. (8)
(b) Magnetic particle testing - principle and method in detail. (8)
Class 4 (4th Engineer)
MEP
📅 Jun 2024
Reference Answer
### (a) Dye Penetration Test (DPT)
#### Principle
The Dye Penetration Test, also known as Liquid Penetrant Inspection (LPI), is a non-destructive testing (NDT) method used to detect surface-breaking discontinuities in non-porous materials. Its principle is based on **capillary action**, where a low surface tension liquid (the penetrant) is drawn into clean, dry surface-breaking flaws (e.g., cracks, porosity, laps, seams).
After a sufficient dwell time, the excess penetrant is removed from the surface. A developer is then applied, which acts as a blotter, drawing the trapped penetrant out of the flaw. This results in a visible indication on the surface that is significantly larger than the flaw itself, thus making it easily detectable under appropriate lighting.
#### Principle
The Dye Penetration Test, also known as Liquid Penetrant Inspection (LPI), is a non-destructive testing (NDT) method used to detect surface-breaking discontinuities in non-porous materials. Its principle is based on **capillary action**, where a low surface tension liquid (the penetrant) is drawn into clean, dry surface-breaking flaws (e.g., cracks, porosity, laps, seams).
After a sufficient dwell time, the excess penetrant is removed from the surface. A developer is then applied, which acts as a blotter, drawing the trapped penetrant out of the flaw. This results in a visible indication on the surface that is significantly larger than the flaw itself, thus making it easily detectable under appropriate lighting.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play