Inspection dye penetrant

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

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

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. 

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. 

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. 

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. 

Special attention was given to the welding of stainless steel butt joints, of which there are approximately 2000 in the entire reactor. The inert-gas, nonconsumable-electrode method was u.sed almost entirely. Welds were inspected to considerably higher standards than required by the ASME code. In addition to being subjected to dye-penetrant inspection, every... 

ASTM G 46 also includes procedures for the nondestructive evaluation of pitied specimens. These include radiographic, electromagnetic, ultrasonic, and dye-penetrant inspection. These methods can be used to locate pits and to provide some information on thdr size, but they generally cannot detea small pits or differentiate bOween pits and other types of surface defects. 

Corrosion-fatigue cracks can be detected by nondestructive testing techniques such as magnetic particle inspection, radiography, ultrasonics, and dye penetrant. Corrosion-fatigue cracks may occur in numerous tubes simultaneously. Nondestructive testing of tubes at locations similar to those in which cracks are observed can be useftil. 

Positive pressure/submersion V acuum/ submersion Dye penetration Vapor/particle leak testing Visual inspection methods Light transmission tests... 

The traditional approach to evaluating the integrity of ampoules has been through 100% inspection by a vacuum dye penetration test. The basic procedure for the vacuum dye penetration test is to place racks of sealed ampoules in a dye bath, apply a vacuum for a period of time, remove and rinse the ampoules, and then inspect for dye penetration. 

A further complication in relation to the dye penetration lest is the possibility of microbiologically contaminated dye penetrating some of the ampoules and going unnoticed during inspection. Sterile dye solutions are usually specified for this test. 

Fig. 6. a) Surface inspection using a dye penetrant makes surface cracks visible. In 27 of 30 specimens of sample C cracks could be detected before strength testing. 

Preliminary testing is done next to uncover flaws in joining, and sometimes in the metal itself. Nondestructive test methods, such as ultrasonics and X- or gamma-ray inspection, are used on main welding seams Dye penetration, hydrostatic, or air-soap tests are also used to locals leaks and cracks. Helium or Freon leak detectors are necessary fok more critical leak testing, particularly on high-vacuum equipment. 

Hydrogen cracks are normally very fine and difficult to detect, even when they break the surface, which they often do not. For cracks which are present at the surface, magnetic particle inspection (MPI) is the preferred technique, although dye penetrant should be used if a non-ferritic filler (e.g. an austenitic stainless steel or a nickel alloy) has been used. The MPI technique has the advantage that when using DC, cracks just below the surface can be detected. 

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. 

The photothermal camera can be used in addition to, or in lieu of, traditional surface inspection techniques (dye penetrant, magnetic particle or eddy current examination). The principal characteristics of the "Standardized Flying-spot" technique used in the inspection process enable the photothermal camera to ... 

Caustic Storage Systems. Storage tanks require carefiil inspection before use. Figure 13.1, an example of an inspection checklist, indicates some of the important items. Visual inspection will detect many faults. Welds, especially at roof and floor fines, should be tested by dye penetration or in accord with rqrplicable codes. Ultrasonic... 

All full-penetration, pressure-containing welds are 100% radiographed to the standards of Section III of the ASME Boiler and Pressure Vessel Code. Weld preparation areas, back-chip areas, and final weld surfaces are magnetic-particle or dye-penetrant examined. Other pressure-containing welds, such as used for the attachments of nonferrous nickel-chromium-iron mechanism housings, vents, and instrument housings to the reactor vessel and head, are inspected by liquid-penetrant tests of the root pass, the lesser of one-half of the thickness or each 1/2-inch of weld deposit, and the final surface. Additionally, the base metal weld preparation area is magnetic-particle examined prior to overlay with nickel-chromium-iron weld metal. 

MQHS CMV-111604 Oxygen-rich atmosphere Reld-welded tubing assemblies scheduled inspections Personnel Property 1C Barriers adequate to prevent exposure Dye-penetrant insp on should beperfoimed initially and eveiy five years 2E ASME... 

Barriers/Controls 5) All tubing and/or equipment connections have been field welded to ensure an adequate seal. System is visually inspected on an annual basis and hydrostatically leak tested every 5 years. Controlled Risk Assessment 5) Barriers/controls considered adequate. The addition of a dye-penetrant analysis of all field joints would further reduce the possibility of hazard risk exposure. Enforced No Smoking policies around oxygen panels by the hospital staff and the patients will also decrease the risk potential. A Controlled RAC of2E is assigned. 

Dye-penetrant Used for surface defects. A liquid dye is applied to a clean, dry surface and allowed to penetrate surface cracks and dry. A developer put over the surface causes the dye to outline the defect dearly. Useful for nonmagnetic materials. Can be used on nozzles and surfaces difficult to inspect radiographically. Detects surface defects only. Not practical on rough surfaces. 

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