What is the procedure of DP test?
Cast railroad wheels were dipped in used oil, dried off, and then coated with powder chalk or suspension of chalk in alcohol. Once the wheels were dry, any oil stored in the flaw would bleed out into the chalk and be detected. This was called the oil and whiting method.
What is the correct order of liquid penetrant test?
Explanation: Firstly surface is cleaned. Penetrant is applied and surface flow is made visible. Finally, surface is inspected. –> Inspection.
Which of the following steps in dye penetrant test is Important Step Number 3?
In the third step, the technician removes penetrant liquid from the surface by rag or cloth and uses back and forth rubbing to clean the surface. No red color should be visible after cleaning. Then technison takes a clean rag and sprays some cleaner on a cloth and then cleans the surface one more time.
When DP test is done?
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.
What are the materials needed for dye penetrant inspection?
It may be used on such materials as aluminum, magnesium, brass, copper, cast iron, steel, stainless steel, carbides, stellite, certain plastics and ceramics.
What is the disadvantage of dye penetrant inspection?
With this method, only surface breaking defects can be detected. It is possible to inspect only materials with relatively nonporous surface. It is necessary to pre-clean the material since contaminants can mask defects.
What is the disadvantage of liquid penetrant test?
Liquid penetrant testing has the following disadvantages: Extensive, time-taking pre-cleaning critical—surface contaminants can mask defects. Sensitive to surface-breaking defects only. Direct connection to the surface under test necessary.
Why we do DP test?
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 the purpose of dye penetrant testing?
Dye Penetrant Inspection (DPI) is widely used to detect surface breaking flaws. 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.
How to prepare a welding job for DP test?
Prepare job ready for DP test depend upon manufacturing method used for example. consider welded joint to be examined. Grind start end points,high points. Clean the job using cotton waste using thinner,detergent,water chemical cleaners etc. Depend on type of penetrant used.
How is liquid penetrant used in dye penetration test?
A suitable liquid penetrant is applied to the surface of the component under examination and is permitted to remain there for sufficient time to allow the liquid to penetrant into any defects open at the surface. After the penetrant time, the excess penetrant, which remain on the surface, is removed.
What is the standard method for fluorescent penetrat inspection?
Standard Test Method for Fluorescent Penetrat Examination using Water Washable Process. 4.1 A liquid penetrant which may be a visible or a fluorescent material is applied evenly over the surface being examined and allowed to enter open discontinuities. After a suitable dwell time, the excess surface penetrant is removed.
How is developer used to test for entrapped penetrant?
A developer is applied to draw the entrapped penetrant out of the discontinuity and stain the developer. The test surface is then examined to determine the presence or absence of indications.