PT LEVEL III NOTE 1. A hydrometer measures specific gravity. 2. ASTM D95 test is for determining water content in a penetrant or emulsifier. 3. A fluorometer measures fluorescent intensity by evaluating quantitative values for the emitted light of fluorescent materials. 4. Water tolerance test is a test used to measure the sensitivity of a penetrant to water contamination based on the amount of water. 5. A scratch on a smooth surface makes a drop of penetrant moves faster. 6. Contact angle of penetrant is smaller on aluminum than SS or chrome plate. 7. 100W (high pressure mercury vapor) ultraviolet light is used to background after water wash test. 8. The penetrant system monitor is designed to be used daily. 9. Quenched cracked aluminum blocks are for low to medium sensitivity check. 10. Penetrant in aerosol containers are affected by leakage of propellant. 11. Do periodic unannounced audit to determine a penetrant shop’s operation if proper or not. 12. QC of aerosol cans in long term storage is to weigh them every 2 years from date of manufacture. 13. Lipophilic (B) emulsifiers are supplied in ready-to-use form, while hydrophilic emulsifiers are in a concentrate (5-30%) and must be diluted. 14. Lipophilic (B) uses DIFFUSION, hydrophilic (D) used surfactant. 15. Hydrophilic is more sensitive than lipophilic. 16. Lipo should be checked for contamination by a removability test. 17. Hydrophilic emulsifier concentration should be checked by a refractometer test or colorimetry. 18. Parts are generally dipped into a tank of lipophilic emulsifier, withdraw and drain for a specific time. Emulsification time depends on the viscosity of the emulsifier. 19. Hydrophilic emulsifier can be applied by immersion and spray; emulsification time is directly related to its concentration. 20. The frequency of the process control depends on the workloads. 21. Performance test a. Process a known defective part and compare the result with the known and acceptable result b. Use cracked panels or blocks 22. OSHA minimum flash point 93C/200F degree without ventilation. 23. Penetrant waste in sewer can a. Leaves oil slick b. Deplete oxygen 24. Water washable penetrants can be removed from water by a. Reverse osmosis b. Absorption materials c. Activated carbon 25. Properly formulated penetrant effluent will float on the water in a tank. 26. New slow solubility penetrants disperse in water and do not undergo emulsification. 27. PT is a physical chemical process. 28. Ultraviolet light with a proper filter will NOT cause permanent damage to human tissues, eyes or blood cells. 29. Blotting: the action of a developer in soaking up the penetrant in a discontinuity, so as to cause the maximum bleedout of the liquid penetrant for increased contrast and sensitivity. 30. Dry powder developers are applied to dry part surfaces by air suspension, electrostatic spraying or part immersion. It should not be used with visible penetrant. 1
31. Water soluble developer (aqueous soluble) (powder dissolved in water) can be applied by dipping, flowing solution onto a part, or spraying solution over a part. 32. Water suspendible developers (aqueous suspendible) (powder does not dissolve in water, remains in suspension until it precipitates onto the parts) are applied like water soluble but they are harder to remove because they do not dissolve in water. 33. All aqueous developers contain biocides, corrosion inhibitors and wetting agents. 34. Non-aqueous (solvent suspendible) developers usually in aerosol cans and are the most sensitive developers. 35. The generally accepted minimum time period for becoming accustomed to the dark is 1-5 minutes. 36. NO one single property determines if a material will or will not be a good penetrant. (e.g. viscosity, surface tension, wetting ability.) 37. The speed of a penetrant penetrating a surface flaw is influenced the greatest by viscosity. (not by capillary action) 38. When using post-emulsification penetrants, difficulties incurred during the washing operation can be overcome by completely reprocessing the part from surface preparation on and by using a longer emulsifier time if allowed. 39. A commonly used method of checking on the overall performance of a liquid penetrant system is by comparing sections of artificially cracked specimens. (Not by determining viscosity or wettability) 40. Characteristic to be considered when selecting the type of penetrant to be used is the sensitivity level. (Not the removal characteristics or cost of the penetrant) 41. High viscosity makes penetrant from a crack harder to be removed by spray water wash. 42. The most desirable objectives governing the cleaning operations when removing surface penetrant are to remove no penetrant from defects and leaves a minimal of residual penetrant on the part surface. 43. When removing excess post-emulsifiable penetrant in a production situation involving relatively large irregularly shaped parts, you may use a coarse spray. (do not use hot water immersion) 44. Nonaqueous wet developer generally preferred when it is essential to use the most sensitive developers. (not dry developer??) 45. The best method of drying after the application of a wet developer is normally drying with circulating air at a maximum of 71C/160F degree. ‘ 46. An advantage of post-emulsifiable methods over water-washable methods is their sensitivity is easier to control. 47. The type of penetrant to be used on an investment casting should be post-emulsifiable fluorescent for maximum sensitivity and water-washability. 48. If modular equipment has been obtained for a penetrant inspection system using fluorescent post-emulsifiable penetrant and wet developer, the dryer should be placed after the developer tank. 49. Filters for ultraviolet lights effectively remove visible light from the energy given off by the mercury arc. 50. The use of a 100W spot bulb with a plain filter for color contrast penetrants produces a high intensity narrow beam. 51. Wetting ability is measured by contact angle. The smaller the contact angle, the better the wetting ability. (not related to surface tension) 52. A network of interconnecting jagged lines appearing in hard fired, unglazed ceramic products would be an indication of thermal shock. 53. Porosity indications in ceramics would appear essentially the same as porosity indications in metals. 54. When performing an evaluation of the fluorescent ability of a penetrant, the value that is normally sought is the relative amount of light emitted by the fluorescent material compared to other penetrants. (the comparison blocks and panels) 55. Cold temperature of test objects and penetrant material is undesirable because of higher viscosity. 56. The contrast ratio of the red dye and a white developer is normally about 10-1 or 20-1. 2
57. When utilizing the fluorescent post-emulsifiable penetrant method and performing the rinse cycle, to prevent overrinsing, discontinue the rinse as soon as the surface penetrant is removed from the part. 58. Sulfur, halogen or chlorine may be detrimental to stainless steel or titanium metals or alloy surfaces under high temp servicing or processing. 59. If the liquid penetrant pulls away leaving bare surfaces, the part is not clean enough. 60. If wet aqueous developer is to be used in water washable penetrant inspection, it should be applied to the wet part surfaces following water rinsing, then the part is dried as soon as the excess penetrant has drained off the part. 61. One advantage of hydrophilic over lipophilic is its improved control of pollution caused by liquid penetrant process waste materials in the prerinse process because penetrant is lighter than water so it floats atop of water and can be collected before drain to sewers. 62. Water washable and postemulsification types of penetrant should not be used on the same object. 63. Fluorescent liquid penetrants should not be applied to test objects that retain traces of visible dye penetrants or processing materials from prior testing and vice versa. 64. For lipophilic emulsifier, the diffusion rate (emulsification time) varies depending on the viscosity of the emulsifier. 65. Wet aqueous developers are not recommended to be used with water washable penetrant because the wetting agents in these developers act like hydrophilic remover which can remove entrapped penetrant indications. 66. Wet aqueous developers contain wetting agent which can cause foaming. 67. Wet aqueous developers are susceptible to attack by bacteria and fungi. 68. Dry powder, water suspended and water soluble are supplied in powder form. 69. Flaw entrapment efficiency refers to the ability of a penetrant to produce an indication that is large enough to be seen. 70. This combination of physical properties of a liquid has the most effect on its penetrating properties: capillarity, wettability and surface tension. 71. Plating is not a method for working wrought metals. 72. Water washable fluorescent penetrant is recommended for production inspection of casting. 73. Postemulsification fluorescent penetrant is recommended for production testing of forgings. 74. Nonaqueous developer is best choice for stress corrosion. 75. For water washable penetrant inspection, the wash nozzle should provide a coarse brisk spray. 76. A heat treatment crack would most likely show a fine, blue white indication OR a bright yellow-green indication???(page 37 in study guide) 77. Usual lipophilic emulsifier dwell time is 1-3 minutes. 78. Small indications that are easiest to see: wide, short indications. 79. The property that controls the rate of penetration of the penetrant into a discontinuity is viscosity. (surface tension, volatility and wetting action have nothing to do with the rate of penetration. 80. It is recommended that sulphur and chloride content be limited to 1.0%. 81. Application that provides the greatest sensitivity: dip the part in penetrant, remove and drain for the remainder of the dwell time. 82. The best technique for applying wet developer is spraying. 83. False indications are caused by the process, not by the part. 84. Flaw entrapment efficiency reflects the ability to form an indication large enough to be seen. 85.
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