INTRODUCTION
This non-destructive testing technique, also known as
liquid penetrant inspection (LPI), is a cost-effective method
used to locate surface breaking flaws such as cracks,
porosity, laps, seams and other surface discontinuities. Dye
penetrant inspection can be applied to both ferrous and
non-ferrous materials and all non-porous materials (metals,
plastics or ceramics).
OBJECTIVES
To perform liquid penetrant on material (metal) surface.
APPARATUS / SPECIMEN
I. Dye penetrant kit consists of cleaner, penetrant and
developer.
II. Different metal components of different forming /
treatment processes.
THEORY
Liquid pentrant testing is one of the oldest and simplest
NDT methods where its earliest versions (using kerosene
and oil mixture) dates back to the 19th century. This method
used to reveal surface discontinuities by bleed-out of a
colored or fluorescent dye from the flaw. The technique is
based on the ability of a liquid to be drawn into a “clean:
surface discontinuity by capillary action. After a period of
time called the “dwell time”, excess surface penetrant is
removed and a developer applied. This acts as a blotter that
draws the penetrant from the discontinuity to reveal its
presence.
The advantage that a liquid penetrant spection offers over
an unaided visual inspection is that it makes defects easier
to see for the inspectors where that is done in two ways.
It produces a flaw indication that is much large and easier
for the eye to detect than the flaw itself. Many flaws are so
small or narrow that they are undetectable by the unaided
eye (a person with a perfect vision can not resolve features
smaller than 0.08 mm)
To improves the detect-ability of a flaw due to the high level
of contract between the indication and the background
which help to make the indication more easily seen (such
as a red indication on a white background for visible
pentrant that glows under ultraviolet light for flourecent
pentrant).
Liquid penetrant testing is one of the most widely used NDT
methods. Its popularity can be attributed to two main factors:
its relative ease of use and its flexibility. It can be used to
inspect almost material provided that its surface is not
extremely rough or porous. Materials that are commonly
inspected using this method include; metals, glass, many
ceramic materials, rubber and plastics.
However, liquid pentrant testingcan only be used to inspect
for flaws that break the surface of the sample (such as
surface cracks porosity, laps, seams, lack if fusion, etc).
PROCEDURES
The general steps can be summarized as follows:
1. Surface Preparation : Wipe the tet surface clean from oil,
grease, water or other contaminants that may prevent
penetrant from entering flaws.
2. Penetrant Application: Once the surface has been
thoroughly cleaned and dried, the penetrant materials is
applied by spraying onto surface.
3. Penetrant Dwell: The pentrant is left on the surface for a
sufficient time to allow as much penetrant as possible to be
drawn from or to seep into defects
4. Excess Penetrant Removal: remove excess Penetrant
from the surface of the sample while removing as little
penetrant as possible from defects.
5. Developer Application: Apply a thin layer of developer to
draw penetrant trapped in flaws back to the surface where
it will be visible
6. Indication Development: The developer is allowed to
stand on the part surface for a period of time sufficient to
permit the extraction of the trapped penetrant out of any
surface flaws. This development time is usually minimum of
10 minutes. Significantly longer time may be necessary for
tight cracks.
7. Inspection; Perform visual inspection under appropriate
lighting to detect indications from any flaws which may be
present.
8. Clean Surface: The final step in the process is to
thoroughly clean the part surface to remove the developer
from the parts that were found to be acceptable.
RESULTS AND OBSERVATION
Record your observation on detected defects.
DISCUSSION
Discuss the activity and observation being made.
From our experiments or practices, it is to learn how
to aimed at detecting defects in iron with the naked
eye without using advanced technology, using
manual methods can also detect defects in the iron.
by using the manual we can also clearly identify the
defects in the metal and we are learning a new
knowledge to identify defects in metal
CONCLUSION
In conclusion, we are pleased with this experiment
because it is practically flawed and it is successful
because it gives good opinions.
We use manual methods without the use of machines to
improve our knowledge and experience because using our
own hands to succeed in this experiment, we can detect
defects in metal more clearly with the naked eye. although
the metal used is not very noticeable, but we can still see
the defect.
In conclusion, this color dye is easy to detect with blemishes
and is easy to use at laboratories, workshops and so on. at
least by using liquid color we can easily detect defects in
metal. The cost is not very expensive and affordable but it
can give the defect a very good and clear result.
APPENDICES
REFERENCE
i. http://www.intertek.com/non-destructive-testing/dye-penetrant-
inspection/
ii. https://www.slideshare.net/shakiwan/dye-penetrant-test
iii. https://en.wikipedia.org/wiki/Dye_penetrant_inspection
