Penetrant Inspection

This method is used for local examination of sections of seam joints. The surface of the specimens must first be cleaned and degreased. Then a penetrant solution is applied along the joint. Capillary action pulls the solution into any defect open to the surface. The penetrant on the surface is rinsed with a solvent, leaving the penetrant in the defects. A developer is then applied to draw back the penetrant to the surface. Because the penetrants are brilliantly colored, each defect is easy to see.  

---

Surface Crack Detection Using Magnetic Particle Techniques and Penetrant Inspection Method. 

Due to the well known human shortcomings the probability of finding flaws using Magnetic Particle Inspection (MPI) or Liquid Penetrant Inspection (LPI) can be restricted to only 60-85% and the inspection reproducablity is difficult. 

Magnetic Particle inspection Liquid Penetrant Inspection... 

Klaus Abend "Fully automated Dye-Penetrant Inspection of Automotive Parts", 1998 SAE Int. Congress and Exposition, Detroit 23 - 26 Feb. 1998. 

Quantitative determined visual recognition for usual inspections, indicate that for indications with lengths over about 1.5 mm tbe probability of recognition is about 100 %. This is also applied to the penetrant inspection. This does not include the so called "human factor" which means that it cannot be guaranted that the inspector detects all indications for instance not always observing the inspection surface with full concentration. 

When comparing the magnetic particle- and penetrant inspection with other visual methods it appears that our viewing eonditions are not so bad, compared with other methods. In radio-graphie the contrast on the film is mueh lower. In ultrasonies and eddy current the presentation times on the screen is shorter and the contrast is lower. 

R. C. McMaster, ed., "Liquid Penetrant Inspection," Nondestructive Testing Handbook, Vol. 2, 2nd ed., American Society for Nondestmctive Testing, Columbus, Ohio, and the American Society for Metals, Cleveland, Ohio, 1982. 

Dye penetrant inspection of the hardware to determine the extent of distress in order to develop material requirements and repair techniques. 

D ye penetration inspection. This is a simple technique, requiring a minimum of operator training. In the hands of a skilled operator, it is capable of detecting fine cracks such as chloride stress corrosion cracks in austenitic stainless steels and fatigue cracks. 

Practice for Liquid Penetrant Inspection Method Practice for Magnetic Particle Examination Quality Standard for Steel Castings and Forgings for Valves, Flanges and Fittings and Other Piping Components — Magnetic Particle Examination Method... 

When radiographic, ultrasonic, magnetic particle, or hquid penetrant inspection of welds or materials is required or specified, the criteria in 4.2.2.2 through 4.2.2.5 shall apply unless other criteria are specified by the purchaser. Cast iron may be inspected in accordance with 4.2.2.4 and 4.2.2.5. Welds, cast steel, and wrought material may be inspected in accordance with 4.2.2.2 through 4.2.2.5... 

Liqnid penetrant inspection shall be in accordance with Section V, Article 6, of the ASME Code. 

A552 Liquid penetrant inspection of connection welds NOZZ LP c 1 1 lyes (true) Oi no (telse)... 

Liquid Penetrant Inspection Useful to find surface discontinuities. Can be used with any material that has a reasonably smooth nonporous surface. 

Magnetic Particle Inspection Useful to find surface discontinuities and some discontinuities very near the surface in ferromagnetic materials. More sensitive than liquid penetrant inspection. 

Liquid penetrant inspection Section V, Articles 6 and 24 of the AS ME Code Section VIII, Division 1, Appendix 8 of the ASME Code Section VIII, Division 1, Appendix 7, of the ASME Code... 

Failure Investigation. The clamp was nonmagnetic and the stamped identification on the side of the U-shaped shells indicated that they were fabricated from forged 304 austenitic stainless steel. Visual examination of the fracture surfaces revealed they were entirely brittle and exhibited a very coarse fracture morphology. Liquid penetrant inspection revealed the presence of additional cracks in the fractured half of the clamp. There was no cracking present in the high-strength steel fasteners. 

Figure 28.5 Penetrant inspection/photographs of chromate conversion coated controls and plasma polymer coated AA 2024-T3 ([2B]).

For detection of more localized corrosion, such as crevice corrosion or SCC, other ultrasonic inspection techniques may be useful. Baseline data generated at the time of installation will also be helpful in evaluating results. One benefit derived from this type of inspection technique is that it can often be conducted with little or no interference with production. Periodic planned visual inspection of equipment utilized under conditions likely to cause stress cracking is also an effective technique, especially when combined with non-destructive inspection techniques such as dye penetrant inspection. It may be necessary to remove coatings or insulation from the equipment surface to facilitate inspection. 

Patching plaster, household Penetrants, inspection Peppermint oil Plating compounds Pyrotechnic ammunition flares, signals, flashlight bombs, and rockets... 

Postweld inspection for lamellar tears is difficult unless the tears penetrate to the surface (usually at the toe of the weld). Dye penetrant inspections are reliable for tears that penetrate the surface. For embedded tears, ultrasonic inspection is sometimes used, but tears are difficult to differentiate from noninjurious inclusions. 

LIQUID PENETRANT INSPECTION - A type of nondestructive inspection that locates discontinuities that are open to the surface of a metal by first allowing a penetrating dye or fluorescent liquid to infiltrate the discontinuity, removing the excess penetrant, and then applying a developing agent that causes the penetrant to seep back out of the discontinuity and register as an indication. 

Pigure 4 Hierarchical Task Analysis for the Top Level of Fluorescent Penetrant Inspection. 

Drury, C. G. (1999), Human Factors Good Practices in Fluorescent Penetrant Inspection, in Human Factors in Aviation Maintenance—Phase Nine, Progress Report, DOT/FAA/AM-99/xx, Nationtd Technical Information Service, Springfield, VA. 

A penetrant dye is sprayed onto the surface of the composite inspected. The liquid infiltrates cavities and is made visible by applying a developer to the surface. Defect size is indicated by the color intensity and the rapidity of infiltration of the liquid penetrant. Two types of penetrant, visible and fluorescent, can be used. Fluorescent dyes are visible under UV light, while the visual dyes are visible under normal light. The choice of the penetrant is function of the material tested and the sensitivity required. Automatic dye penetrant inspection systems exist that transfer and apply the dye, apply the revealing agent (or developer), and finally clean the part after testing. How ever. only specific shapes can be inspected automatically, and manual inspection is still required for most structures. 

In February 1998, while readjusting the setting of SG safety valves in cold state, water leak was observed in one of the bosses in experimental thermo well in the steam sub header of one of the SG modules. The leaking boss and plug were replaced with dummy piece and all other similar welds were checked for any defects by liquid penetrant inspection. Investigation revealed that failure is due to lack of heat treatment during fabrication. 

All pressure equipment should be tested or inspected periodically. The interval between tests or inspections is determined by the severity of the usage the equipment has received. Corrosive or otherwise hazardous service requires more frequent tests and inspections. Inspection data should be stamped on or attached to the equipment. Pressure vessels may be subjected to nondestructive inspections such as visual inspection, penetrant inspection, acoustic emissions recording, and radiography. However, hydrostatic proof tests are necessary for final acceptance. These tests should be as infrequent as possible. They should be performed before the vessel is placed in initial service, every 10 years thereafter, after a significant repair or modification, and if the vessel experiences ovrapressure or overtemperature. 

Liquid-Penetrant Inspection is a method of testing for surface defects or sub-surface defect with surface openings by relying upon a penetrant seeping into the defect. It is normally used for non-magnetic materials. 

All specimens have been machined/ inspected and delivered for testing. The join in the sic tensile rods became visible under ultraviolet light during dye penetrant inspection, whereas the join in SijN rods was not visible. Room temperature and high temperature testing procedures are being established and testing is expected to be completed by April 30/ instead of March 31, milestone date for end of characterization. The delay has been caused by several power failures and shutdowns. 

Penetrant inspection Good detection of defects or discontinuities open to the surface No graphic record in normal operation... 

Visual and other inspections (liquid penetration inspection in some case) are performed to pump casings during annual inspections. No cracks are found on the cast stainless steel casing of pumps and valves. 

---