The document discusses penetrant testing, which is a non-destructive testing method used to detect surface-breaking defects in materials. It explains the principles and methodology of penetrant testing, including precleaning, applying penetrant, removing excess penetrant, applying developer, and interpreting results. The advantages and disadvantages are outlined. Proper procedures and standards are emphasized to ensure effective testing.

1. SIS Institute of NDT 1
Penetrant Testing
Introduction and Principles

2. SIS Institute of NDT 2
Principle
Capillary Action

3. SIS Institute of NDT 3
Methodology
 Precleaning
 Application of penetrant
 Penetration Time
 Removal of excess surface
penetrant
 Application of Developer
 Interpretation under normal or
ultra-violet radiation
 Post cleaning

4. SIS Institute of NDT 4
Advantages
 Relatively simple process
 Low capital cost
 Suitable for both metals and non-metals
 Establishment of procedures and
standards, less difficult
 Complex shapes and sizes can be
inspected
 Arrangement of discontinuities is not a
limitation

5. SIS Institute of NDT 5
Disadvantages
 Only surface defects can be
determined
 Less sensitivity compared to tother
NDT methods
 Not suitable for low density
metallurgical parts
 Low reliability
 Requires high degree of personnel
skill

6. SIS Institute of NDT 6
Procedure
 Follow the supplier's directions
 Standards specify test methods, eg
ASTM E165, ASME Section V, ISO 3879,
AS 2062
 All materials (penetrant, remover and
developer) should be from one supplier
as a kit
 Parts must be clean and dry and at the
correct temperature
 Precleaning requires removal of all oil,
grease, dirt, paint, slag, spatter
 Dry after cleaning by warming

7. SIS Institute of NDT 7
Penetrant
 Liquid with a high surface tension
is applied and wets the surface
 Soaking into surface flaws
 Coloured with a dye for visibility
 Fluorescent dyes for use with UV
illumination in a darkened cubicle
 Applied by dipping, flooding,
brushing or spraying
 Wait the specified dwell time

8. SIS Institute of NDT 8
Removing surplus
penetrant
 Water washable penetrants
are flushed with water
 Post emulsifiable penetrants
require the emulsifier to be
applied by dipping, flooding
or spraying
 Solvent removable
penetrants are first wiped up
with dry rags then with a rag
dampened with the solvent

9. SIS Institute of NDT 9
Developers
 Blot up dye from flaws revealing
their location
 Absorbent material with a colour
which contrasts the penetrant
 Developers may be suspended in
water or other liquid, or may be dry
powder
 Applied by dipping, immersing,
flooding, dusting or spraying
 Wait for a minimum dwell time of 7
minutes, or as specified

10. SIS Institute of NDT 10
Defects found by DPI
 Most are cracks, which can be
exceedingly fine
 Also finds inadequate penetration,
incomplete fusion, and pores that
are open to the surface
 Does not find buried flaws
 Overlap and undercut best seen by
visual inspection

11. SIS Institute of NDT 11
Precleaning
 What is Precleaning?
 Need for Precleaning?
 Methods of Precleaning
 Extent of Precleaning

12. SIS Institute of NDT 12
What is Precleaning?
 Cleaning before the actual
penetrant inspection
 The surface preparation is
mandatory as per the codes

13. SIS Institute of NDT 13
Need for Precleaning?
 Discontinuities may be closed
 Contaminant may retain some
amount of penetrant
 Contaminant may allow partial
penetration of penetrant

14. SIS Institute of NDT 14
Methods
 Mechanical Methods
 Chemical Methods
 Solvent methods
 Special methods

15. SIS Institute of NDT 15
Results of Improper
Precleaning
 No indications
 False Indications
 Cannot accurately determine the
extent of flaw