TASK 70-32-19-220-001
1 . General.
A.The enhanced visual inspection process is intended for in-process weld inspections. It is a localized process using fluorescent penetrant inspection materials and techniques, limited to small specific areas for inspection. It is not intended as a substitute for final acceptance inspection. It is convenient to use as an in-process inspection during welding. The process may be performed by certified welders with the additional inspection training described below.
B.If visible color dye penetrant has been used on parts which are to be subsequently inspected with fluorescent penetrants, the contamination by the dye may prevent reliable fluorescent penetrant inspection. Any color dye indications evident by white light visual inspection shall be considered valid indications even if not detectable by ultraviolet light.
C.Titanium alloy parts are subject to stress corrosion cracking when residues of halogen containing compounds remain on a part that is subsequently subjected to elevated temperatures typical of welding, heat-treating, or engine operation. These parts must be thoroughly cleaned with nonhalogen compounds after exposure to any halogen containing compound to prevent the cracking and possible failure of parts.
D.Personnel Requirements.
(1)Personnel performing this inspection must be certified in accordance with American Welding Society AWS D17.1, or locally approved welder certification program.
(2)As part of, or in addition to, the above certification process; personnel performing this inspection shall receive classroom instruction on the fluorescent penetrant process to include basic theory, application techniques, and necessary quality control procedures. Additional training shall include proper etching technique and safety procedures. The training shall include practical training in the use of this procedure and personnel must demonstrate proficiency in use and control of inspection equipment, inspection of in-process welds, and evaluation of indications before approval is granted.
(3)The classroom and practical training in etching and enhanced visual inspection shall be approved by a Level III inspector certified in fluorescent penetrant inspection in accordance with National Aerospace Standard (NAS-410), American Society of Non Destructive Testing (ASNT-TC-1A), Air Transport Association (ATA 105) or other locally approved certification programs.
2 . Equipment.
Subtask 70-32-19-220-001
A.Inspection booth, darkroom, or black cloth hood (for remote locations) to prevent excessive admission of white light.
NOTE:
Excessive white light may interfere with detection of a rejectable size indication. A test part having a known defect can be used to evaluate effectiveness of white light shielding.
B.Ultraviolet lamp to detect fluorescent indications. The ultraviolet (black) light source used for the detection of fluorescent indications shall have an intensity no less than 1000 microwatts per sq. centimeter when measured at 15 in. (381 mm). The black light should be checked on a weekly basis or before use, whichever is less frequent.
C.White light lamp for visual inspection of parts. The lamp should be capable of providing a minimum of 100 ft-candles of white light at the inspection surface.
D.Time piece for timing operations.
E.Tools for inspection personnel.
(1)Three-power and 10-power magnifying lenses.
(2)Cotton swabs or small fine hair art brush to apply solvents for evaluating questionable indications.
3 . Materials.
Subtask 70-32-19-220-002
A.All materials are used at ambient temperature. The materials that follow can be used for this class of inspection:
(1)Class D post-emulsifiable penetrant inspection systems as follows:
Approved products for this inspection process are in Qualified Products List QPL-AMS-2644 (latest revision). QPL specifications are available from ASSIST-Acquisition Streamlining and Standardization Information System. Refer to the List of Suppliers in Step 4 of 70-80-00.
For this class of inspection, only use the approved materials that follow:
Type I - Fluorescent Dye
Method D - Post-emulsifiable, Hydrophilic
Sensitivity Level 3 - High
NOTE:
Hydrophilic remover concentration is 20 percent maximum unless otherwise noted in the QPL for the dip method, and 5 percent maximum for the spray method.
NOTE:
Non-aqueous wet developers are approved for use in aerosol spray only. You can substitute a developer from one manufacturer for another manufacturer's developer.
CAUTION:
TITANIUM PARTS REQUIRE THE USE OF NON-HALOGENATED SOLVENTS OR MANUFACTURERS' NON-HALOGENATED SOLVENT.
(2)Solvents as follows:
 
Solvents
Consumable Product Ref. No.
 
Isopropyl alcohol (halogen-free)
C04-035  
 
MEK (halogen-free)
C04-001  
 
Acetone (halogen-free)
C04-003  
4 . Procedure.
Subtask 70-32-19-220-003
A.Parts must be cleaned of all traces of oil, grease, carbon, rust scale prior to penetrant application. Use one of the approved solvents to pre-clean the surface. Allow time for solvent to evaporate.
B.Apply penetrant oil with soft-bristle brush, cotton swab or spray application. Allow a minimum of 15 minutes for penetration.
CAUTION:
INDICATIONS OF DEFECTS CAN BE LOST BY USE OF EXCESSIVE SOLVENT.
C.Wipe off excess penetrant with a clean cloth using a solvent.
D.Apply either dry powder or NAWD as a fine thin coating at ambient temperature to a dry surface. Allow a minimum of 10 minutes for developer to absorb penetrant before inspecting part.
E.Evaluate any indication to the required in-process weld inspection standards.
CAUTION:
TITANIUM ALLOY PARTS ARE SUBJECT TO STRESS CORROSION CRACKING WHEN RESIDUES OF HALOGEN-CONTAINING COMPOUNDS REMAIN ON A PART THAT IS SUBSEQUENTLY SUBJECTED TO ELEVATED TEMPERATURES TYPICAL OF WELDING, HEAT-TREATING, OR ENGINE OPERATION. THESE PARTS MAY BE THOROUGHLY CLEANED WITH NON-HALOGEN COMPOUNDS AFTER EXPOSURE TO ANY HALOGEN-CONTAINING COMPOUND TO PREVENT THE CRACKING AND POSSIBLE FAILURE OF PARTS.
F.Remove all residues by spraying, wiping, or soaking with approved solvents.