2. INTRODUCTION
It is simple,reliable and economical testing method of NDT , that
helps to locate and identify surface defects
It is used for inspecting defects in materials like Alumininum, Copper,
plastics, stainless steel, titanium or ferrous materials etc.
Defects which is to be inspected may be seams, forging laps,
porosity, cold shuts, fatigue crack, heat treat cracks etc.
It is a quick and accurate process for locating surface flaws
3. STEPS INVOLVED IN ZYGLO FLUORESCENT
PENETRANT TEST
There are six steps involved in this testing method
1. Part preparation or precleaning
2. Application of penetrant
3. Removal of penetrant
4. Part drying
5. Application of developers
6. inspection
4. 1.PART PREPARATION
Precleaning is done before application of penetrant and used for
effective inspection
It is used to remove rust, greese, oil, wax, paint etc. from the surface
of material
Thin cleaners like caustic and acid are used to remove paints
Aqueous cleaners are used to remove oil
Clean and completely dry part is to be inspected before applying
penetrant
5. 2.Application Of Penetrant
After cleaning of part,zyglo penetrant is applied by spraying,brushing
or immersing
After application a waiting time is required,for the penetrant action
takes place
This waiting time is called as Dwell time
Dwell time is depends on the material being inspected and the type
of defect
6. 3.Removal Of Penetrant
Zyglo testing involves four method for removing penetrants
a) Lipophilic method (Post emulsifier):
• In this method emulsifiers are usually applied on it by dipping it in a tank followed
by draining for 2-4 minutes
• Then it is wasged off with water
b) Hydrophilic method (Post Remover):
• The PR method prevents excessive penetrant removal because it only provides
limited solvent action
• A water spray pre-rinse removes excessive penetrant,when part is immersed in a
tank for 20 sec. to 5 minutes
• After immersion post-rins removes any remaining penetrant by water spraying
7.
8. Removal of penetrant cont……
c) Water washable:
• In this method, spray washing is done with water at temp. of 50-100 F
• Black light is used to determine the removal of penetrants
• Overwashing of penetrant is to be avoided in this method
d) Solvent removal method:
• This method is used when use of water as penetrant remover is
ineffective
9. 4.PART DRYING
It involves the drying of part with hot air dryer at temp.
below 160 F
Overdrying is avoided as overdrying can reduce
effectiveness of inspection
10. 5.Application of developers
Developers draws penetrants out of the cracks making
defects indication much more prominent
Zyglo method involves use of three types of developers:
a) Dry powder developer
b) Aqueous developer
c) Non-Aqueous developer
11.
12. 6.INSPECTION
After the application of developer ,a 10 min. dwell time for
developer is required
Then part placed in a dark area for inspection
For Zyglo fluorescent penetrant test MAGNAFLUX ZB-100F
Black light is used
13. POST CLEANING
After the inspection is complete, post cleaning is a
good idea
This step usually a water spray, removes most
inspection materials
Brushing is normally required to remove non-
aqueous developers
14. ADVANTAGES
High sensitive to small surface discontinuities
Large areas and large volumes of parts/materialscan
be inspected rapidly and at low cost
Parts with complex geometry shapes are routinely
inspected
15. DISADVANTAGES
Penetrant stains clothes and skin and must be treated with
care
The method is limited to surface defects
Training is required for the inspector
Post cleaning of acceptable parts or materials is required
16. SAFETY PRECAUTION
• Wear protective gloves to avoid skin irritation
• Do not smoke or eat while using NDT materials
• Wash hands thoroughly after using NDT materials
• Avoid clothing contact with NDT materials
• Avoid breathing spray mists, air borne powders and solvent vapors
• Store all NDT materials in closed containers well apart from open
flames or other heat sources