What are the different types of penetration dyes?
Penetrant types in Dye Penetration Test 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.
What is a dye penetrant inspection?
Dye penetrant inspection. Dye penetrant inspection (DP), also called liquid penetrate inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to check surface-breaking defects in all non-porous materials (metals, plastics, or ceramics).
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. Fig. 2: Typical Dye Penetrant Test Kit Penetrant characteristics in Dye Penetrant Test
What type of light will the Inspector use for visible dye?
The inspector will use visible light with adequate intensity (100 foot-candles or 1100 lux is typical) for visible dye penetrant.
What is the color of the developer on dye penetrant method?
4. Application of Developer: After excess penetrant has been removed, a white developer is applied to the sample.
Which liquid is used in liquid penetrant testing?
Application of a penetrant liquid (dipping, spray, brush) Removal of excess penetrant (solvent, water)
What is red dye penetrant?
Chemtools Red Dye Penetrant is formulated to seep into any micro cracks present in a weld seam. Locates surface-breaking defects in all non-porous materials including plastics, ceramics and most metals. This product is also referred to Dye Penetrant Inspection (DPI) or Liquid Penetrant Inspection (LPI).
What are the different Penetrants used dye penetrant test?
three basic types of penetrant: Colour contrast. Fluorescent. Dual purpose (fluorescent / colour contrast)
Where can we use liquid penetrant inspection?
Liquid penetrant testing can be applied to any non-porous clean material, metallic or non-metallic, but is unsuitable for dirty or very rough surfaces. Surface cleaning is a vital part of the penetrant testing technique.
How do you use liquid penetrant?
More videos on YouTubePenetrant. Apply the penetrant to the test area. Allow the penetrant to dwell for 10-30 minutes. ... Developer. Apply the developer to the test area. Allow the developer to dwell for 10-60 minutes.Inspect. Examine the part for any bright, clear indications.
How do you use red penetrant dye?
0:203:27Dye Penetrant Inspection - YouTubeYouTubeStart of suggested clipEnd of suggested clipIn the second step that penetrant is applied to the test piece usually a red colored low viscosityMoreIn the second step that penetrant is applied to the test piece usually a red colored low viscosity oil due to the penetrance high surface wetting capability it penetrates into the defects and cracks.
What is dye penetrant made of?
The dye penetrant composition may include an extender, preferably an isoparaffinic solvent consisting essentially of a mixture of isoparaffins having a chain length of about 10 to about 17 carbon atoms, and an average chain length of about 13 to about 14 carbon atoms.
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 of the following is not used as penetrant color?
Penetrants of which colour are not used? Explanation: The application of penetrant is one of the steps of inspection of dye penetrant test. It is an important feature that one must take care of, that the penetrant used, must not be of red colour, as defects are identified using red colour.
Which type of materials are commonly inspected using the dye penetrant inspection?
Dye penetrant inspection can be applied to both ferrous and non-ferrous materials and all non-porous materials (metals, plastics or ceramics). It is commonly used to detect defects in castings, forgings and weldments.
What is the minimum visible light intensity required for examination using visible penetrant?
100 fca) Visible penetrant indications can be examined in either natural or artificial light. 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.
What is emulsifier in liquid penetrant testing?
An emulsifier is an agent that enables removal of excess post emulsifiable penetrant on part surfaces with water. Proper emulsification and rinse times allow removal of excess surface penetrant while any penetrant in discontinuities is not removed.
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.Method D - Post-Emulsifiable, Hydrophilic.
What is developer in liquid penetrant testing?
The purpose of a developer is to effectively pull the penetrant back out of a defect to allow it to be seen by an inspector. The action of pulling it back to the surface also allows the penetrant to spread along the surface around the defect, thus magnifying the strength of the indication.
What is difference between DPT and LPT?
Dye Penetrant Test (DPT) is one of the most inexpensive non-destructive test (NDT) methods, used to check the surface irregularities of any component. This test method is popular by many names, which are as follows; Liquid Penetrant Inspection (LPI) Liquid Penetrant testing or Liquid Penetrant test (LPT)
What are the steps of liquid penetrant inspection?
Below are the main steps of Liquid Penetrant Inspection: 1. Pre-cleaning: The test surface is cleaned to remove any dirt, paint, oil, grease or any loose scale that could either keep penetrant out of a defect or cause irrelevant or false indications.
How long does it take to test for fluorescent dye?
Inspection of the test surface should take place after 10- to 30-minute development time, and is dependent on the penetrant and developer used. This time delay allows the blotting action to occur. The inspector may observe the sample for indication formation when using visible dye. It is also good practice to observe indications as they form because the characteristics of the bleed out are a significant part of interpretation characterization of flaws.
What is a DP inspection?
Dye penetrant inspection ( DP ), also called liquid penetrate inspection ( LPI) or penetrant testing ( PT ), is a widely applied and low-cost inspection method used to check surface-breaking defects in all non-porous materials (metals, plastics, or ceramics). The penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous components magnetic-particle inspection is often used instead for its subsurface detection capability. LPI is used to detect casting, forging and welding surface defects such as hairline cracks, surface porosity, leaks in new products, and fatigue cracks on in-service components.
How to apply DPI?
The penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has been allowed, the excess penetrant is removed and a developer is applied. The developer helps to draw penetrant out of the flaw so that an invisible indication becomes visible to the inspector. Inspection is performed under ultraviolet or white light, depending on the type of dye used - fluorescent or nonfluorescent (visible).
How long does it take for a penetrant to soak into a flaw?
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, the material being tested and the size of flaws sought. As expected, smaller flaws require a longer penetration time. Due to their incompatible nature, one must be careful not to apply solvent-based penetrant to a surface which is to be inspected with a water-washable developer.
What does it mean when a developer is bleed out?
Any areas that bleed out can indicate the location, orientation and possible types of defects on the surface.
What happens if you don't remove excess penetrant?
If excess penetrant is not properly removed, once the developer is applied, it may leave a background in the developed area that can mask indications or defects. In addition, this may also produce false indications severely hindering the ability to do a proper inspection.
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 many types of dye penetrant are there?
Again, depending on the detectability of defect indication, five types of dye penetrant is available:
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.
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 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.
Why is dye penetrant used in aviation?
As such, it is one of the most widely used inspection processes used in aviation. Because of its ease of use and wide availability, many in the industry take dye penetrant for granted, allowing anyone, under any conditions to inspect critical aviation parts without the benefit of proper training and controlled conditions.
What is a penetrant inspection?
Penetrants are useful only for surface breaking cracks in a solid and non-porous material. Its sensitivity is greater than that of magnetic particle inspection if it is applied properly. General instructions for use. According to Magnaflux, penetrant inspection is accomplished in five simple but critical steps.
What is post emulsifiable penetrant?
Post-emulsifiable penetrants are penetrants that cannot be completely removed from the part surface with water. They require a second processing step to convert the surface penetrant layer into a mixture that can be removed with water. Removing the excess penetrant may be the most difficult step in the entire process.
How long does it take to wash a penetrant off?
It requires washing the penetrant off with 65F to 75F water (30 to 120 seconds according to manufacturer's specs. General purpose dye-penetrant inspection kits are ideal for low volume inspections.
What controls are needed for liquid penetrant inspection?
These controls include such things as dwell time, rinsing practices, wiping practices, penetrant selection for the conditions and parts being inspected, black light intensity, etc.
Does Magnaflux have a spot check?
This is particularly important when using water-based cleaners. Magnaflux provides a Spotcheck Jr., which contains the clean er, penetrant, and developer in one unit. The desired degree of sensitivity and cost are usually the most important factors in selecting the proper penetrant method for a given application.
What type of penetrants are used to provide high contrast indications under normal light?
Type III penetrants consist of liquid penetrants containing dyes to provide high contrast indications under normal light and have fluorescence property that emits lights and exposes indications when exposed to black light.
What is liquid penetrant classification?
Liquid penetrant classification is divided into several categories which are: the type that categorizes based on the type of contrast dye used in the penetrant process, the method that categorizes based on the method used to remove the penetrant, the level that categorizes based on the sensitivity level of the process, the form that categorizes based on the type of developer and the class that categorizes based on the class of solvent remover.
What is the difference between method D and method B?
Method’ D’ penetrants are similar to Method ‘B’ Lipophilic Penetrants. The difference is the hydrophilic emulsifier method requires a water-based remover solution; hence, removing the excess surface penetrant occurs using a detergent action rather than an emulsification action.
What is a water washable penetrant?
Water-washable penetrants are the type of penetrants formulated with an emulsifier mixed with the penetrant oil to permit direct removal with water spray, immersion, or manually wiping.
What is the sensitivity of a type I penetrant?
Type I penetrants have high sensitivity, which means excellent ability to detect small surface discontinuities. Type I’s high sensitivity is due to the highly visible indications the fluorescent penetrant will emit when exposed to blacklight even from a tiny quantity of penetrant at a tiny discontinuity.
What is the penetrant test sensitivity?
The penetrant test sensitivity is the testing process’s ability to measure the smallest discontinuity and display it as a clear indication.
What is a type 1 penetrant?
Type I penetrants consist of liquid penetrants that demonstrate the property of fluorescence when exposing to UV radiation. The fluorescence property of a chemical means certain chemicals’ capability to emit visible light when exposed to ultraviolet radiation (Blacklight).
What is a penetrant material?
Most standards insist that the penetrant materials used, should not contain contaminants that spoil the quality of weld and metals. ( contaminants such as Sulphur, Chlorine & halogens ) Penetrant materials are mostly suitable for materials with surface temperature less than 52°C.
What are the two types of inspections?
Dye penetrant inspection. The two types of inspections are 1) Visible Inspection and 2) Fluorescent Inspection. Visible inspection uses color contrast die and inspection carried out under white light, visible Light should have a light intensity of 1000 Lux.
What is the ASME section V?
The ASME Section V, Article 6, describes the requirements of Liquid Penetrant Test (PT)
What temperature is required for PT inspection?
Any PT inspection on elevated temperature (temperature other than 4°C to 52°C), should have special qualification on the Consumables. As described in the ASME BPVC section V- Article 6 – Mandatory Appendix 3.
How long does it take to interpret bleed out?
Interpretation should be completed between 10 to 60 minutes after development. Deeper the defect, wider the bleed out indication.
What is the most important part of a PT test?
Most essential part of the test is Pre-Cleaning. It is a critical step, because any left out dust, spatter, chips, burrs, oil, grease, rust, etc, shall mask the discontinuity and will not show –off during PT.
Overview
Principles
DPI is based upon capillary action, where low surface tension fluid penetrates into clean and dry surface-breaking discontinuities. The penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has been allowed, the excess penetrant is removed and a developer is applied. The developer helps to draw penetrant out of the flaw so that an invisible indication becomes visible to the inspector. Inspection is performed under ultraviole…
History
The oil and whiting method used in the railroad industry in the early 1900s was the first recognized use of the principles of penetrants to detect cracks. The oil and whiting method used an oil solvent for cleaning followed by the application of a whiting or chalk coating, which absorbed oil from the cracks revealing their locations. Soon a dye was added to the liquid. By the 1940s, the fluorescent or visible dye was added to the oil used to penetrate test objects.
Inspection steps
Below are the main steps of Liquid Penetrant Inspection:
1. Pre-cleaning:
The test surface is cleaned to remove any dirt, paint, oil, grease or any loose scale that could either keep penetrant out of a defect or cause irrelevant or false indications. Cleaning methods may include solvents, alkaline cleaning steps, va…
Advantages and disadvantages
The main advantages of DPI are the speed of the test and the low cost. Disadvantages include the detection of only surface flaws, skin irritation, and the inspection should be on a smooth clean surface where excessive penetrant can be removed prior to being developed. Conducting the test on rough surfaces, such as "as-welded" welds, will make it difficult to remove any excessive penetrant and could result in false indications. Water-washable penetrant should be considered …
Standards
International Organization for Standardization (ISO)
• ISO 3059, Non-destructive testing - Penetration testing and magnetic particle testing - Viewing conditions
• ISO 3452-1, Non-destructive testing. Penetrant testing. Part 1. General principles
• ISO 3452-2, Non-destructive testing - Penetrant testing - Part 2: Testing of penetrant materials
See also
• Fluorescent penetrant inspection
• Nondestructive testing
External links
• and Magnetic Particle Testing at Level 2, International Atomic Energy Agency, 2000(pdf, 2.5 MB).
• [1] - technical reports summarizing fluorescent penetrant inspection research efforts
• [2] - an article on how to perform a sensitive visible dye penetrant examination