Procedure for a Dye Penetrant Test
- Clean the surface. First, inspectors clean the surface they plan to test so that the surface is open and any defects...
- Apply the dye penetrant. The penetrant that inspectors use is made just for this purpose, and it’s typically sprayed...
- Remove extra penetrant and apply remover. Remove any excess penetrant with a dry rag.
What are three limitations to dye penetrant testing?
Primary disadvantages:
- Only surface breaking defects can be detected.
- Only materials with a relatively nonporous surface can be inspected.
- Precleaning is critical since contaminants can mask defects.
- Metal smearing from machining, grinding, and grit or vapor blasting must be removed prior to LPI.
- The inspector must have direct access to the surface being inspected.
Is penetrant testing still relevant?
Penetrant testing is still relevant in industry today for a variety of reasons including: • Large areas such as aircraft structures or complex shapes can be inspected in less time and more economically than with other methods. • The versatility of inspected materials such as ceramics, glass, plastics and most metals compared to other methods.
What is penetrant testing (PT)?
Penetrant Testing (PT), also called Liquid Penetrant Inspection (LPI) or Dye Penetrant Inspection (DPI), is one of the oldest and simplists NDT methods where its earliest versions (using kerosene and oil mixture) dates back to the 19th century. NDT methods can generally be classified into two categories: conventional and advanced.
What are the required properties of a penetrant?
- The material must be absorptive, to perform blotting action
- It must have a fine texture but not be too fine, as this may block imperfections
- For colour contrast penetrants it must mask out background contours and colours
- It must be easily and evenly applicable
- It must form a light and even coat
What is the basic step for doing penetrant examination?
The principle of liquid penetrant testing is that the liquid penetrant is drawn into the surface-breaking crack by capillary action and excess surface penetrant is then removed; a developer (typically a dry powder) is then applied to the surface, to draw out the penetrant in the crack and produce a surface indication.
How many steps are there to a dye penetrant inspection process?
six basic stepsThere are six basic steps to follow when using the dye penetrant solvent removable method.
What is dye penetrant method?
The dye penetrant method of inspection is a nondestructive test for defects open to the surface. It may be used on such materials as aluminum, magnesium, brass, copper, cast iron, steel, stainless steel, carbides, stellite, certain plastics and ceramics.
Which is the correct order for the liquid penetrant?
Which is the correct order for the liquid penetrant test? Explanation: Firstly surface is cleaned. Penetrant is applied and surface flow is made visible. Finally, surface is inspected.
What are the 4 methods of penetrant systems?
The four methods are listed below: Method A - Water Washable. Method B - Post-Emulsifiable, Lipophilic. Method C - Solvent Removable.
What are three major groups of penetrant process?
A penetrant material has the capacity to enter the crevices opening on the surface of a material. Fluorescent or visible penetrant with color contrast are used with one of the following three penetrant processes, namely, water washable, post-emulsifying, and solvent removable.
What is the difference between liquid penetrant and dye penetrant?
Dyes Vs. With dye penetrant, the liquid penetrant itself is the indicating material. The subject material in magnetic testing must be magnetized, whereas liquid penetrant techniques may be used on a wider variety of materials.
Which defect Cannot be detected by dye penetrant?
Leaks, cracks and forging defects are some defects which can be identified by using dye penetrant test. But, for detecting non-metallic inclusions, one will have to do a magnaflux test.
How long should the soak time be for dye penetrant testing?
The penetrant is allowed "dwell time" to soak into any flaws (generally 5 to 30 minutes). The dwell time mainly depends upon the penetrant being used, material being tested and the size of flaws sought.
Which penetrant method is easiest to use in the field?
Since visible dye penetrants do not require a darkened area for the use of an ultraviolet light, visible systems are more easy to use in the field.
When performing a liquid penetrant test the surface of the part under inspection should be?
Surface Preparation: One of the most critical steps of a liquid penetrant inspection is the surface preparation. The surface must be free of oil, grease, water, or other contaminants that may prevent penetrant from entering flaws.
What are the uses of liquid penetrant test?
Liquid or dye penetrant testing (PT) is a non-destructive material testing method which uses capillary forces to find surface cracks or pores and make them visible. It can detect surface-breaking flaws such as cracks, laps, porosity.
On which of the following materials would a liquid penetrant test method not be effective?
a. Penetrant testing cannot be used on ferromagnetic material. 2.
How is the correct emulsifier contact time determined?
The optimal emulsifier contact time is dependent on a number of variables that include the emulsifier used, the emulsifier concentration, the surface roughness of the part being inspected, and other factors. Usually some experimentation is required to select the proper emulsifier contact time.
1. Prepare
Clean the part by spraying SKC-S onto the surface. Next, wipe the part dry with a clean cloth.
2. Penetrant
Apply the penetrant to the test area. Allow the penetrant to dwell for 10-30 minutes. Then, remove the excess penetrant by wiping the part down using a clean dry cloth.
3. Developer
Apply the developer to the test area. Allow the developer to dwell for 10-60 minutes.
Related Blog Entries
The next revision of ASTM E1417 has been published, and a lot is changing. Here are several changes that you should be aware of.
How long does it take for a penetrant spray to work?
In the second step, the technician applies penetrant spray can to the surface which is in sharp red color. The technician needs to wait for 5 to 15 minutes depends on test procedure. In this time, the penetrant liquid enters to the crack (normally is not visible).
How many spray cans are there for a sanitizer test?
The 3 spray cans (aerosol) are provided for this test. First one is named cleaner. The technician sprays the cleaner to the test object and then cleans the surface with non-used rag or cloth. The sprayed material is evaporated rapidly. So the technsion needs to clean the surface instantly.
What is the fifth step of ASNT?
In the fifth step, The ASNT Level II liquid penetrant inspector evaluates the test result based on the acceptance criteria indicated in the approved test procedure. Please note one indication might be considered imperfection and be rejected by one acceptance criteria and be accepted by another one. So it is imperative that the test be evaluated with right acceptance criteria.
What is a dye penetration test kit?
Dye penetration test kit contains all the required elements for performing dye penetration test. These kits are easily available in the market and contains the Penetrant, Cleaner and Developer as shown in Fig. 2 below.
What are the two types of penetrants in a dye penetrator?
Depending on the physical characteristics and performance of the penetrant materials, they are of two basic types: Type 1-Fluorescent Penetrants containing dyes that fluoresce under ultraviolet radiation and. Type 2-Visible Penetrants containing red color dye.
How to remove excess penetrant from a sample?
The excess penetrant needs to be removed from the sample surface. Depending on the dye penetrant type, The removal method is selected from water-washable, solvent-removable, lipophilic post-emulsifiable, or hydrophilic post-emulsifiable, etc. Emulsifiers are used for the highest sensitivity level, and it chemically reacts with the oily penetrant, thus making it easier to remove using water spray. The excess penetrant has to be removed thoroughly otherwise, on the application of the developer, it may leave a background in the developed area that can mask indications or defects. Also, while using solvent remover and lint-free cloth, care must be exercised not to spray the solvent on the test surface directly, because this can remove the penetrant from the flaws.
How many types of dye penetrant are there?
Again, depending on the detectability of defect indication, five types of dye penetrant is available:
What is a DPT test?
Dye Penetration Test (DPT) is one of the simplest and oldest Non-Destructive Inspection methods. Also, known as the Liquid penetration test, the Dye penetrant test is widely used to detect surface discontinuities like cracks, fractures, porosity, grinding defects, incomplete fusion, and flaws in joints. This test or inspection method is serving as an aid to finding irregularities in aluminum, cast iron, brass, steel and stainless steel, copper, magnesium, carbides, stellite, ceramics, and even certain plastic materials. So, the dye penetration test is suitable for both ferrous and non-ferrous materials and highly economic as compared to the other non-destructive inspection methods.
How long does it take for a liquid penetrant to penetrate a flaw?
Next, The liquid penetrant is applied on the specimen surface and allowed to soak into any flaws for its dwell time (generally 10 to 60 minutes). The dwell time varies depending on the used penetrant (viscosity: longer duration for high viscosity), test material, and the defect sizes (smaller flaw sizes require longer penetration time). Dwell time is normally provided by the penetrant manufacturers and depends on the following:
What are the advantages of dye penetration test?
The main advantages of dye penetration test are: small defects can be detected easily. suitable for a range of materials. Inspection is quick and can easily cover large areas and volumes. inspection of complex shapes can be performed easily.
How to remove penetrant from specimen?
After the elapse of penetrant dwell time, the excess penetrant is removed by water spray. Water at 60°F to 110°F and a pressure not exceeding 30 psi (210 KPa) is applied with droplet type sprayer specifically designed for penetrant removal. The nozzle of sprayer is held so that water strikes the surface of the specimen at an angle of approximately 45 degrees. Care is to be taken to avoid over-washing, which causes washout of penetrant from discontinuities. Other methods of referenced codes or specifications could also be used if applicable for the test surface conditions.
How long does a penetrant stay on the test surface?
c) Penetrant shall remain on the test surface for the entire dwell time period.
What temperature should a fluorescent water washable penetrant be?
The temperature of the penetrant materials and the surface of the part should be between 50°F and 100°F for fluorescent water washable penetrants and between 60°F and 125°F for visible penetrants.
Why not follow a visible penetrant examination?
Note: Caution - Fluorescent penetrant examination shall not follow a visible penetrant examination because visible dyes may cause deterioration or quenching of fluorescent dyes.
What is the minimum light intensity required for a penetrant?
Adequate illumination is required to ensure no loss in the sensitivity of the examination. A minimum light intensity at the examination site of 100 fc (1000 Lx) is recommended.
Is intermixing of penetrant materials from different families permitted by this procedure?
5.2 Intermixing of penetrant materials from different families (man ufacturers) is not permitted by this procedure.
Can you use penetrant cleaner on welded parts?
7.3 Unless otherwise recommended by the manufacturer, welded components or parts cleaned by Vapour degreasing, organic solvents or detergents, and properly protected from contamination, need not be re-cleaned with penetrant cleaner (remover) prior to application of the penetrant.
What Is The Principal of Dye Penetrant Testing?
- Based upon capillary action, low surface tension fluid can penetrate into clean and dry surface-breaking discontinuities. Penetrant which has entered a tight discontinuity will remain even when the excess is removed. Penetrant can be applied to the test component by dipping, spraying, or brushing. After reasonable penetration time has been allowed,...
Fluorescent Dyes
- The use of fluorescent dyes increases the sensitivity of the technique significantly. However, the technique is not applicable in extreme temperature because the penetrant vehicle, which is normally oil, will become excessively viscous below 5°C, causing an increase in the penetration time with a consequent decrease in sensitivity. Meanwhile, in temperature above 60°C, the penet…
Advantages and Limitation
- The advantages of Dye penetrant inspection are listed below; 1. All nonporous materials 2. Portable 3. Applicable to small parts with complex geometry 4. Simple 5. Inexpensive 6. Sensitive 7. Relatively low skill level (easy to interpret) The limitations are; 1. Will only detect defects open to the surface 2. Requires careful space preparation 3. Not applicable to porous surfaces 4. Tem…
Watch This Video on The Basic Principle of Dpi
- There you have it, short info about Dye penetrant inspection. If you have anything to add, please let us know in in the comment section below. And please share if you liked this article.