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Liquid penetrant inspection is a nondestructive testing method that does not harm the test piece and is commonly used on materials such as metals, glass, plastics and fired ceramics. This nondestructive testing method relies on the liquid penetrant seeping into the flaw, then forming a surface indication that is observed under special lighting after the penetrant is given time to "bleed out" from the flaw. Liquid Penetrant Inspection (LPI or PT) is very effective in detecting flaws that are open to the surface such as fatigue, quench or grinding cracks; forging cracks and bursts; overload and impact fractures; porosity; laps and seams.
The Process
At Laboratory Testing Inc., the first step in Liquid Penetrant Inspection is to thoroughly clean the surface to be inspected to be sure it is free of oil, grease, water, heat-treat scale, paint, plating and other contaminants that may prevent liquid penetrant from entering flaws. The part may also require etching if mechanical operations such as machining, sanding, or grit blasting have been performed because they can smear metal over the flaw opening and prevent the penetrant from entering.
Next, a red visible or fluorescent dye liquid penetrant is applied to the part by spraying, brushing or immersing in a penetrant bath. The liquid penetrant is left on the surface for a sufficient time to allow as much penetrant as possible to seep into a defect. Penetrant dwell time is the total time that the penetrant is in contact with the part's surface.
After the dwell time has elapsed, the excess liquid penetrant is removed from the surface. Depending on the penetrant method used, this step may involve cleaning with a solvent (solvent-removable), direct rinsing with water (water-washable), or first treating the part with an emulsifier (post-emulsifiable) before rinsing with water. When using the water-washable or post-emulsifiable methods, the part is placed in a low-temperature oven and allowed time to dry after rinsing.
A thin layer of developer is applied to the part to assist in drawing penetrant trapped in flaws back to the surface where it will be visible as indications. Developers may be applied by dusting (dry powder) or spraying (wet developers). These indications are larger than the actual flaw, and therefore, are more visible. When using fluorescent penetrants, indications must be viewed under darkened conditions with a high-intensity UV lamp. The final step in the process is to thoroughly clean the surface to remove any residues.
Advantages and Limitations
Liquid Penetrant Inspection offers a fast and relatively inexpensive means of surface inspection since large areas and quantities of parts or materials can be inspected quickly. The process is flexible for inspecting parts of almost any shape and for most materials that are not extremely rough or porous. This process is a nondestructive testing method which does not cause harm to the parts or products being tested. Indications are produced directly on the surface of the part and provide a visual representation of the flaw. Liquid penetrant inspection is highly sensitive to small surface discontinuities.
One of the major limitations of a penetrant inspection is that flaws must be open to the surface. Also, surface finish and roughness can affect inspection sensitivity. Pre-cleaning of parts is critical since contaminants can mask defects, and post-cleaning is required to remove residues.
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What are instrument leak test procedures?
Instrument leak test procedures vary depending on the type of instrument. It is very common to use either air or a liquid under pressure to check the instrument for leaks.
How car-ber hydro testing works?
The National Board of Boiler and Pressure Vessel Inspectors interprets and enforces the ANSI / ASME codes within the pressure vessel industry throughout North America. "The National Board" stipulates that all pipe welds must have a pressure leak test applied to each assembly before that particular assembly can be put into service. As per B31.3 of the ASME codes the preferred method of testing the integrity of welds is through application of Hydrostatic pressure. All other NDT testing methods e.g. radiography (X-rays), magnetic particle examination, liquid penetrate examination etc. are considered variances to B31.3. Most vessels, flanges, valves and other various pipe assemblies are tested at the manufacturer's facility; the only portion of an assembly that remains untested is the weld (tie-in point) which connects the various assemblies under field conditions. In other instances a leaking flange may require replacement as part of an on-going maintenance program (between turnarounds) creating the need to isolate and hydro-test the connecting weld. It is to these specific areas of the pipe assembly that CAR-BER has focused attention. Traditionally the method of testing welds which connect assemblies in the field involves filling the entire system with testing medium and pressurizing to a pre-determined value (usually 1 1/2 times the working pressure) and maintaining that specific pressure for a pre-determined time. Such a methodology requires extensive person-hours to blank and purge the entire assembly and requires large amounts of medium to perform the test. The requirement for large amounts of medium means that a significant amount of medium must be lost in order to register a noticeable change in pressure. The minuscule amounts of medium required for the CAR-BER equipment to perform, translates to very precise pressure readings should the slightest volume of medium escape the pressurized vessel during testing procedures
What is high pressure common rail test bench?
Nanyang NanTai Experimental Equipment Co.,ltd High Pressure common rail test bench: 1.Application: Bosch, Delphi,Denso,Siemens common rail injector and pump. 2.Pump test: measure feeding and return volume,pump chamber pressure,feeding pressure,check sealing performance, and functions of ZME valve. 3.Injector test: measure the injected fuel quantity & return volume under full-loaded, idling, pre-injection and Emission status. 4. Check the sealing performance of the injector. 5. Check the solenoid valve. 6. Clean the injector and pump before testing. 7. Clean the ZME separately. 8. Testing 6 oil injectors in one setup. 9. Test electronic high pressure pump VP37 and VE37. 10.Testing pump nozzle & electronic unit pump by additional programming system & adaptor. 11.User can add and edit the data by themselves. 12.Save and print the testing results & customer information. Characteristics: 1. Full-automatic operation procedure, save the time to set up the data. 2. Germany flow sensor: flow range 0.008-2L/min, test precision 0.3%. 3. Bosch common rail system (original Bosch rail with DRV) is used. 4.Rail pressure is controlled accurately by DRV and ZME valve. 5. Industrial temperature controlling kit enables the temperature to be constant at 40±2°C 6. Original Bosch CP3 common rail pump is equipped. 7. Industrial computer with windows system. 8. Rich database:546 types of data. 9. Self-protection under following status:overheat, oil-mist, overpressure, low oil level, 10. Remote control is convenient for software upgrading and after-sale service. 11.Support Multi-language. Main technical parameters: 1. Power: 11kw, 15kw optional 2. Oil pump rotation speed: 0-4000rpm 3. Test rang of rail pressure: 0-2000bar 4. Test precision of rail pressure: ±0.5Mpa 5. Test precision of flow sensor: 0.3% 6. Measuring rang of flow sensor: 0.008-2L/Min 7. Temperature of test oil:40±2℃ 8. Filter precision of test oil: less than 5μ 9. Capacity of tank: 80L 10. Dimension: 1780X900X1800MM 11. Aggregate weight: 1000KG 12. Electricity: 380V, 50Hz, 3 phase
What did the assembly line improve and how did it affect the factory?
Automation testing is part of software testing that includes use of tools to verify actual results with expected outcomes by avoiding manual delays. Automation is fulfilling the requirement of present era through reduced manpower and maintaining consistency of product. The overall productivity can be enhanced by creating the test scripts once and execute them for every patch/update release. It will be beneficial in reducing manual efforts for every release. Automated testing services/Automation tools are not only simplifies the complex tasks by eliminating human error but also assist us in data collection and consolidation.Hope this information is helpful for you in affecting productivity through automation. Please let me know in case any query/concern.
What different material certificate and mill test certificate?
mill test cert manufacture and material goods
Who can perform Dye penetrant inspection?
Penetrant inspection should be performed by a certified NDT (non-destructive testing) laboratory by a certified (Level II or III) inspector. There are many criteria for succesfully passing Penetrant Inspection. This type of test is usually performed in accordance with some kind of industry standard usually specified on an engineering drawing or blueprint. Just look up NDT or non-destructive testing laboratories in your area and they should be happy to answer more detailed questions.
What is contact angle in penetrant test?
The contact angle is the angle in which the liquid interface meets the solid surface. The contact angle should be as small as possible to have an effective penetrant material.
Is it necessary to perform both non destructive and destructive testing?
NO. Destructive testing will destroy the test coupon on new welded construction, non-destructive tests are often done as well. Non-destructive testing will not destroy any repair made and is preferable to destroying a repair. HOWEVER: Pressure vessels repaired by welding MUST be tested by destructive (hydrostatic) testing as the design of the vessel has a built in factor of safety that ensures the vessel won't be destroyed at the pressure used for the test. If a destructive test is done then no NDT is required usually.
What does ASME Section V Article 6 say?
It Deals the liquid penetrant test. and its principal is capillary action
What are the advantages of no destructive testing?
The advantage of nondestructive tests is you still have something at the end of the test that is useful. A destructive test takes the product to its' breaking point and beyond.
What are the advantages of destructive testing?
the product can under go a full test range
Types of penetrating liquid used in liquid penetrant test?
Low molecular weight hydrocarbons - anything with a very low surface energy/contact angle/surface tension.
What is Non Destructive Testing of Concrete?
Non Destructive testing for concrete are types of tests that used to test the strength of the concrete. Some of the tests used are visual inspection,rebound hammer, and probe penetration.
Why water is only used for hydraulic testing of boiler?
because water is a liquid and simple for this test than all liquid
Difference between destructive testing and non destructive testing?
Destructive testing will render the part unusable for its intended purpose (e.g. it is cut up for analysis, or fatigue tested for life). Non destructive testing will, after testing, allow the part to be used for its intended purpose (e.g. test for leakage, flow, or resistance).
When conducting a penetrant test what does the spherical indications on the surface of a part mean?
Porosity
When is non destructive testing used?
Nondestructive testing is used when people want to test the durability of a material, component, or system without damaging it. It is commonly used in varied engineering, art, and medicine.
