Standard Practice for Liquid Penetrant Testing

Standard Practice for Liquid Penetrant Testing 1. Scope* 1.1 This practice establishes the minimum requirements for conducting liquid penetrant examination of nonporous metal, and nonmetal components. NOTE 1—This practice replaces MIL-STD-6866. 1.2 The penetrant examination processes described in this practice are applicable to in-process, final, and maintenance (in-service) examinations. These processes are applicable for the detection of discontinuities, such as lack of fusion, corrosion, cracks, laps, cold shuts, and porosity, that are open or connected to the surface of the component under examination. 1.3 Caution must be exercised in the usage of elevated temperature with components manufactured from thermoplastic materials. Also, some cleaners, penetrants, and developers can have a deleterious effect on nonmetallic materials such as plastics. Prior to examination, tests should be conducted to ensure that none of the cleaning or examination materials are harmful to the components to be examined. 1.4 Units—The values stated in either SI units or inchpound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 All areas of this practice may be open to agreement between the cognizant engineering organization and the supplier, or specific direction from the cognizant engineering organization. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 The following documents form a part of this practice to the extent specified herein: 2.2 ASTM Standards:2 D95 Test Method for Water in Petroleum Products and Bituminous Materials by Distillation D2512 Test Method for Compatibility of Materials with Liquid Oxygen (Impact Sensitivity Threshold and PassFail Techniques) D6304 Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric Karl Fischer Titration E165 Practice for Liquid Penetrant Examination for General Industry E543 Specification for Agencies Performing Nondestructive Testing E1135 Test Method for Comparing the Brightness of Fluorescent Penetrants E1316 Terminology for Nondestructive Examinations E2297 Guide for Use of UV-A and Visible Light Sources and Meters used in the Liquid Penetrant and Magnetic Particle Methods E3022 Practice for Measurement of Emission Characteristics and Requirements for LED UV-A Lamps Used in Fluorescent Penetrant and Magnetic Particle Testing 2.3 ASNT Standards: 3 ANSI/ASNT-CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing 2.4 Military Standards:4, 5 MIL-STD-792 Identification Marking Requirements for Special Purpose Components QPL-AMS-2644 Qualified Products List, Inspection Material, Penetrant MIL-STD-45662 Calibration System Requirements 2.5 ANSI/ISO/AIA Standards:6 ANSI/NCSL Z540-1 General Requirement for Calibration Laboratories and Measuring Test Equipment ISO 10012 Measurement Management Systems— Requirements for Measuring Measurement Process and Measuring Equipment NAS 410 Certification and Qualification of Nondestructive Test Personnel 2.6 SAE Standard:7 AMS 2644 Inspection Material, Penetrant AMS 2175A Castings, Classification and Inspection of 2.7 DoD Contracts—Unless otherwise specified, the issues of the documents that are DoD adopted are those listed in the issue of the DoDISS (Department of Defense Index of Specifications and Standards) cited in the solicitation. 2.8 Order of Precedence—In the event of conflict between the text of this practice and the references cited herein, the text of this practice takes precedence. 3. Terminology 3.1 Definitions: 3.1.1 The terminology relating to liquid penetrant examination that appears in Terminology E1316 shall apply to the terms used in this practice. 3.2 Definitions of Terms Specific to This Standard: 3.2.1 aerospace—any component that will be installed on a system that flies. 3.2.2 cognizant engineering organization (CEO)— Reference Terminology Standard E1316. 3.2.3 component—the part(s) or element(s) of a system described, assembled, or processed to the extent specified by the drawing. 3.2.4 final examination—the final examination performed for the acceptance of the item. Any change to the item’s surface such as machining, grinding, welding, heat treatment, or etching by subsequent manufacturing operation, may render the previous examination invalid, requiring reexamination of all affected surfaces, unless otherwise approved in the contract. 3.2.5 in-process—that which occurs during manufacturing before a component is in final form. 3.2.6 in-service—refers to components that are in use or storage for their intended function. 3.2.7 linear indication—penetrant indications with at least a three to one length to width ratio. 3.2.8 reprocess—repeat, after cleaning, the application and appropriate processing of penetrant, emulsifier (as required), and developer (as required). 3.2.9 rounded indication—penetrant indication whose length to width ratio is less than three-to-one. 3.2.10 supplier—the organization contracted to supply the material, parts, or assembly. 3.2.11 turbine engine critical components—any component on turbine engine designated by the manufacturer as “critical.” 4. Significance and Use 4.1 This practice establishes the basic parameters for controlling the application of the liquid penetrant method. This practice is written so it can be specified on the engineering drawing, specification, or contract. It is not a detailed how-to procedure to be used by the inspector and, therefore, must be supplemented by a detailed procedure that conforms to the requirements of this practice. Specification E165 contains information to help develop detailed requirements. 5. Classification 5.1 Penetrant examination processes and materials are classified in accordance with the material classification contained in AMS 2644. Penetrant systems covered by this practice shall be of the following types, methods, and sensitivity levels: 5.1.1 Type: 5.1.1.1 Type I—Fluorescent dye. 5.1.1.2 Type II—Visible dye. 5.1.2 Method: 5.1.2.1 Method A—Water washable. 5.1.2.2 Method B—Post-emulsifiable, lipophilic. 5.1.2.3 Method C—Solvent-removable. 5.1.2.4 Method D—Post-emulsifiable, hydrophilic. 5.1.3 Sensitivity—(These levels apply to Type I penetrant systems only. Type II penetrant systems have only a single sensitivity and it is not represented by any of the levels listed as follows): 5.1.3.1 Sensitivity Level 1 ⁄2 —Very low. 5.1.3.2 Sensitivity Level 1—Low. 5.1.3.3 Sensitivity Level 2—Medium. 5.1.3.4 Sensitivity Level 3—High. 5.1.3.5 Sensitivity Level 4—Ultrahigh. 5.2 Developers shall be of the following forms: 5.2.1 Form a—Dry powder. 5.2.2 Form b—Water-soluble. 5.2.3 Form c—Water-suspendable. 5.2.4 Form d—Nonaqueous for Type I fluorescent penetrant. 5.2.5 Form e—Nonaqueous for Type II visible dye. 5.2.6 Form f—Specific application. 5.3 Solvent removers shall be of the following classes: 5.3.1 Class 1—Halogenated. 5.3.2 Class 2—Nonhalogenated. 5.3.3 Class 3—Specific application. 6. General Practices 6.1 Responsibility for Examination—Unless otherwise specified in the contract or purchase order, the cognizant engineering organization is responsible for the performance of all examination requirements as specified herein. The cognizant engineering organization may specify more stringent requirements than the minimum specified in this practice when necessary to ensure that a component meets its functional and reliability requirements. Except as otherwise specified, the supplier may utilize his own facilities or any other facilities suitable for the performance of the examination requirements specified herein. The purchaser reserves the right to perform any of the examinations set forth in this practice where such examinations are deemed necessary to ensure that supplies and services conform to prescribed requirements. 6.2 Specifying—When examination is required in accordance with this practice the orders, contracts, or other appropriate documents shall specify the criteria by which the acceptability of components is to be evaluated. Engineering drawings or other applicable documents shall indicate the acceptance criteria for the entire component; zoning may be used. Examination on a sampling basis shall not be allowed unless specifically permitted by the contract. 6.3 Personnel Qualification—Personnel performing examinations to this practice shall be qualified and certified in accordance with ASNT Personnel Qualification SNT-TC-1A, ANSI/ASNT-CP-189 or NAS 410 for military purposes, or as specified in the contract or purchase order. 6.4 Agency Qualification—The agency performing this practice may be evaluated in accordance with Specification E543. 6.5 Materials: 6.5.1 Qualified Materials—Only materials listed or approved for listing on QPL-AMS-2644 (reference AMS 2644) shall be utilized for penetrant examination. Materials not conforming to the requirements of AMS 2644 may be used only when a waiver is obtained from the cognizant engineering organization. 6.5.2 Liquid Oxygen (LOX) Compatible Materials— Penetrant materials tested in accordance with Test Method D2512 and passing at 70 ft·lbf [95 J] or higher, shall be used on LOX wetted surfaces that cannot be thoroughly post-cleaned. Use of these materials shall be in accordance with the material supplier instructions and shall require approval of the cognizant engineering organization when such materials do not meet the requirements of AMS 2644. 6.6 Equipment and Facilities—Processing equipment used in the penetrant examination process shall be constructed and arranged to permit a uniform and controlled operation. The equipment shall meet all applicable national and local safety requirements as well as the requirements specified herein. 6.6.1 Viewing Areas—Areas where parts are reviewed shall be kept clean at all times. For visible dye examination, Type II, the lighting system shall provide at least 100 fc [1076 lx] of visible light when measured at the examination surface. For stationary fluorescent dye examination, Type I, the ambient visible light background shall not exceed 2 fc [21.5 lx] at the examination surface. The black lights shall provide a minimum of 1000 µW/cm2 at the examination surface. Black lights shall meet the requirements of 7.8.4.1. Viewing areas for portable fluorescent dye examination shall utilize dark canvas, photographer’s black cloth, or other methods to reduce the visible light background to the lowest possible level during examination and black light intensity shall meet the above requirements. 6.6.1.1 Where lamps are physically too large to directly illuminate the examination surface, special lighting, such as UV pencil lights, or UV light guides, or remote visual examination equipment shall be used. When using a borescope, the image viewed must have sufficient resolution to effectively evaluate the indication. Light intensity shall be measured at the expected working distance and shall be a minimum 1000 µW/cm2. 6.6.1.2 LED UV-A lamps used for evaluation purposes shall comply with Practice E3022. 6.6.2 Drying Oven—When components are oven dried, the dryer must be a forced-air recirculating type. In automated systems, where parts are dried by radiant heat and forced air, the travel speed of the system shall be such as to preclude overdrying of parts. The forced air does not have to be recirculating but must preclude contamination of the parts. The temperature shall be controlled with a calibrated device capable of maintaining the oven temperature at 615°F [8.3°C] of the temperature for which it is set. The oven shall not exceed 160°F [71°C]. The temperature indicator shall be accurate to 610°F [5.6°C] of the actual oven temperature. 6.7 Written Procedures—All liquid penetrant examination procedures are similar for many components, a master written procedure may be utilized that covers the details common to a variety of components. All written procedures, including technique sheets for specific parts shall be approved by an individual who is a qualified and certified Level III for penetrant examination in accordance with the requirements of 6.3. As a minimum, the following information is required either in individual procedures, specific technique sheets, or a master procedure, or a combination thereof: 6.7.1 Details of the precleaning and etching process, including the materials used and specification or other document controlling the examination process, the drying parameters and the processing times. If these operations are performed by other than examination personnel, details concerning the operations may be specified in other documents but must be referenced in the procedure(s). Reference Test Method E165 for detailed cleaning methods and instructions. 6.7.2 Classification of the penetrant examination materials required in accordance with Section 5 and AMS 2644. 6.7.3 Complete processing parameters for the penetrant examination materials including concentrations, application methods, dwell times, drying times, temperatures, and controls to prevent excessive drying of penetrant or overheating of component, as appropriate. Reference Practice E165 for additional details. 6.7.4 Complete examination/evaluation requirements including light intensities (both examination and ambient), the accept/reject criteria and the method and location of marking. Reference Practice E165 for additional details. 6.7.4.1 When battery-powered lights are used, define the frequency for verifying intensity and documentation required. 6.7.4.2 When the examination is performed in accordance with this Standard Practice, engineering drawings, specifications, technique sheets, or other applicable documents shall indicate the accept/reject criteria by which the components are judged acceptable. 6.7.5 Identification of the components or areas within a component to be examined in accordance with the procedure. 6.7.6 Complete postcleaning procedures. If postcleaning is performed by other than examination personnel, details concerning this operation may be specified in other documents, but must be referenced in the procedure. Reference Test Method E165 for additional details. examinations where subsequent fabrication/forming operations remove the surfaces inspected. 6.9.3 The maintenance or overhaul examination of turbine engine critical components shall be done only with Type I, Methods C or D (solvent removable or post emulsified, hydrophilic) processes and either sensitivity Levels 3 or 4 penetrant materials. 6.8 Examination Sequence—Final penetrant examination shall be performed after completion of all operations that could cause surface-connected discontinuities or operations that could expose discontinuities not previously open to the surface. Such operations include, but are not limited to, grinding, welding, straightening, machining, and heat treating. 6.8.1 Surface Treatment—Final penetrant examination may be performed prior to treatments that can smear the surface but not by themselves cause surface discontinuities. Such treatments include, but are not limited to, vapor blasting, deburring, sanding, buffing, sandblasting, lapping, or peening. Performance of final penetrant examination after such surface treatments requires that etching be included in the precleaning operation unless otherwise agreed on between the cognizant engineering organization and the NDT facility. 7. Specific Practices (Fig. 1) 6.10 Records—Results of all final penetrant examinations shall be recorded. All recorded results shall be identified, filed, and made available to the cognizant engineering organization upon request. Records shall provide for traceability to the specific part or lot inspected. As a minimum, the records shall include: identification of the procedure used, disposition of the examination; identification of the inspector’s examination stamp, electronic ID or signature; and the date of examination. Records shall be kept for a minimum of three years or as otherwise specified in the purchase order or contract. 7.1 Surface Preparation—All surfaces to be examined shall be clean, dry, and free of soils, oil, grease, paint and other coatings (except as allowed by 6.8.2), corrosion products, scale, smeared metal, welding flux, chemical residues, or any other material that could prevent the penetrant from entering discontinuities, suppress dye performance, or produce unacceptable background. Cleaning methods, including etching, selected for a particular component shall be consistent with the NOTE 2—Final penetrant examination should always precede peening. 6.8.2 Surface Coatings—All coatings and other surface conditions, such as, paint, plating, corrosion, etc. shall be removed from the area to be examined prior to penetrant examination. The penetrant examination shall precede any surface finish, such as anodize, except for inservice parts that may be examined without removing the anodize. 6.9 Material and Process Limitations—Not all penetrant sensitivity levels, materials, and process methods are applicable to all examination requirements. The sensitivity level shall be adequate for the intended purpose of the examination. Unless there is an approval for deviation given by the cognizant engineering organization, the following selections are mandatory or forbidden, as indicated: 6.9.1 Forms a and b (dry powder and water soluble) developers shall not be used with Type II (visible dye) penetrant systems. This is not intended to prohibit the use of a Form f developer that has been qualified with a particular Type II system in accordance with AMS 2644. 6.9.2 Type II penetrant examination shall not be used for final acceptance examination of aerospace products. In addition, Type II penetrant examination shall not be used prior to a Type I penetrant examination of the same surface. This is not intended to eliminate the use of in-process Type II FIG. 1 Process Flow Chart contaminants to be removed and shall not be detrimental to the component or its intended function. 7.1.1 One or more appropriate cleaning methods such as solvent cleaning, vapor degreasing, ultrasonic cleaning, aqueous-based cleaning, or methods agreed upon with the cognizant engineering organization shall be used for the removal of oils, greases, and waxes, and as the final step before penetrant examination. If etching is required, the parts shall be appropriately cleaned, then etched and delivered to penetrant examination. 7.1.2 Chemical cleaning shall be used for the removal of paints, varnishes, scale, carbon, or other contaminants that are not removable by solvent cleaning methods. (Warning— Caution should be exercised when using chemicals because they may irritate the eyes or skin.) 7.1.3 Mechanical cleaning shall be used for the removal of soils and other contaminants that cannot be removed by solvent or chemical cleaning methods. 7.1.4 Grit blasting without etching may be an acceptable cleaning method if it can be demonstrated that a sufficiently fine abrasive (150 grit or finer) will not cause peening and can be removed by a detergent or alkaline cleaner. 7.1.5 Etching, unless otherwise specified, shall be performed when evidence exists that previous cleaning, surface treatments, or service usage has produced a surface condition that degrades the effectiveness of penetrant examination. Etching processes shall be developed and controlled to prevent damage to the component under test. Etching is not required for those features such as close tolerance holes, close tolerance surfaces, faying surfaces, etc., where the function of the component or assembly would be degraded. Etching is not required for intermediate examination when the surface(s) are not retained in the final part/component configuration or when the final penetrant examination is preceded by etching. 7.2 Penetrant Application—Unless otherwise specified, the entire surface of the component shall be covered with penetrant. Large components may be examined in sections. Penetrant shall be applied by spraying, dipping, brushing, or other method to provide coverage as required. The component, penetrant, and ambient temperatures shall all be in the range from 40 to 125°F [4 to 52°C] unless otherwise specified. 7.2.1 Penetrant Dwell Time—The dwell time, unless otherwise specified, shall be a minimum of 10 min. For temperatures between 40 and 50°F [4.4 and 10°C], dwell time shall be a minimum of 20 min. It is recommended to rotate or otherwise move components as necessary, during dwell to prevent pooling of the penetrant. For dwell times greater than two hours, the penetrant shall be reapplied as required. 7.3 Penetrant Removal: 7.3.1 Method A Process—Water-washable penetrants shall be removed with a manual or automated water spray, or a manual wipe, or an air agitated immersion wash. 7.3.1.1 Manual Spray—For handheld spray guns water pressure adequate to remove the penetrant shall be used but shall not exceed 40 psi [275 kPa]. Water temperature shall be between 50 to 100°F [10 to 38°C]. When hydro-air nozzles are used the air pressure shall not exceed 25 psi [172 kPa]. A coarse spray shall be used with a minimum distance of 12 in. [30 cm], when possible between the spray nozzle and the part. Washing shall be conducted under appropriate illumination. Caution shall be exercised to ensure that over-washing does not occur. If over-washing occurs, the component(s) shall be thoroughly dried and reprocessed. After rinsing, drain water from the component and utilize repositioning, suction, blotting with clean absorbent materials, or filtered shop air at less than 25 psi [172 kPa] to prevent pooling in cavities, recesses, and pockets. (Warning— Over-removal of the surface penetrant shall require that the component be cleaned and reprocessed. A good indicator of over-wash or over-removal of the surface penetrant is evidenced by the total lack of residue that may occur on all or a specific area of the part, see Test Method E165.) 7.3.1.2 Automated Spray—For automated spray systems, the wash parameters shall be such that the requirements of 7.8.3 are met. Water temperature shall be maintained between 50 to 100°F [10 to 38°C]. 7.3.1.3 Manual Wipe—Excess penetrant shall be removed with a clean, dry, lint-free cloth or absorbent toweling. The remainder of the surface penetrant shall then be removed with a water-dampened cloth or towel. The surface shall not be flushed with water and the cloth or towel shall not be saturated with water. The component shall be examined under appropriate illumination to ensure adequate removal of the surface penetrant. The surface shall be dried by blotting with a clean, dry towel or cloth, or by evaporation. 7.3.1.4 Immersion—Immersion wash may be utilized if the water is air agitated and good circulation is maintained throughout the wash operation. Water temperature shall be maintained between 50 and 100°F [10 and 38°C]. 7.3.2 Method B Process—Lipophilic post-emulsifiable penetrant shall be removed by air agitated water immersion or with a water spray or hydro-air spray rinse after application of an emulsifier and an appropriate emulsifier dwell time. Water pressure and temperature and air pressure shall meet the requirements specified in 7.3.1.1, 7.3.1.2, and 7.3.1.4. 7.3.2.1 Lipophilic emulsifiers shall be applied by immersion or flowing. Lipophilic emulsifiers shall not be applied by spray or brush and shall not be agitated while on the surface of the component. Maximum dwell times, unless otherwise specified, shall be 3 min for Type I systems and 30 s for Type II systems, or as recommended by the manufacturer. Actual dwell times shall be the minimum necessary to produce an acceptable background on the component. 7.3.2.2 Rinsing—After the appropriate emulsifier dwell time, emulsification shall be stopped by immersion or water spray. For spray removal of the penetrant/emulsifier mixture, the parameters of 7.3.1.1, 7.3.1.2, and 7.3.1.4 apply. Dwell time in an agitated immersion rinse, if used, shall be the minimum required to remove the emulsified penetrant. Examine the components under appropriate illumination after rinsing. Clean and reprocess those components with excessive background. After rinsing, drain water from the component and utilize repositioning, suction, blotting with clean absorbent materials or filtered shop air at less than 25 psi [172 kPa] to prevent pooling. Caution shall be exercised to ensure that the air nozzle is held at a sufficient distance from the part to ensure that the developing indication is not smeared by the air blast. If over-emulsification is observed, the component must be cleaned and reprocessed. 7.3.3 Method C Process—Solvent-removable penetrants are removed by first wiping the excess penetrant with a clean, lint-free, dry cloth or absorbent toweling. The remainder of the surface penetrant is then removed with a solvent-dampened lint-free cloth or towel. The surface of the component shall not be flushed with solvent and the cloth or towel shall not be saturated with solvent. The component and cloth or toweling shall be observed under appropriate illumination to ensure adequate removal of the surface penetrant. Over-removal of the surface penetrant shall require the component to be cleaned and reprocessed. The surface shall be dried by blotting with a lint-free, dry cloth or towel, or by evaporation. Method C can also be used for water-washable penetrants using water or solvent for removal of excess penetrant. 7.3.4 Method D Process—Hydrophilic post emulsifiable penetrant shall be removed with a water prerinse, application of the hydrophilic emulsifier and then a postrinse. 7.3.4.1 Rinse—The water prerinse shall be applied for the minimum amount of time required to achieve removal of the bulk surface penetrant. The rinse parameters of 7.3.1.1 or 7.3.1.2 shall apply. (1) For spray application of the emulsifier, a water prerinse may be omitted. 7.3.4.2 Hydrophilic emulsifier shall be applied by immersion, flowing, or spray. Hydrophilic emulsifier shall not be applied by brush. Foaming application of hydrophilic emulsifier is permissible when approved by the CEO. (1) For immersion applications, the concentration, percent volume, shall be no higher than specified by the penetrant system supplier and shall not exceed that for which the system was qualified. While immersed, the emulsifier or part should be mildly agitated. Dwell time shall be the minimum required for adequate surface penetrant removal, but unless otherwise approved by the cognizant engineering organization, shall not exceed 2 minutes. (2) For spray or flowing applications, the concentration shall not exceed 5 %. Spray applications may include fixed spray nozzles, spray wands, pump sprayers, or spray bottles provided the concentration is tested and meets the requirments of 7.8.2.6. Dwell time shall be the minimum required for adequate surface penetrant removal, but unless otherwise approved by the cognizant engineering organization, shall not exceed two minutes per surface area. 7.3.4.3 Postrinse—After the application and dwell of the hydrophilic emulsifier, the component being examined shall be rinsed with water. The spray rinse parameters of 7.3.1.1, 7.3.1.2, and 7.3.1.4 shall apply. Evidence of over-removal shall require the part to be cleaned and reprocessed. Excessive background may be removed by additional (touchup) application of the hydrophilic emulsifier provided its maximum allowable dwell time is not exceeded. Additional rinsing of the touch-up area will be required after application and dwell of the hydrophilic emulsifier. If careful touch-up application of the hydrophilic emulsifier does not produce an acceptable background, the part shall be cleaned and reprocessed. Manual systems shall require the use of appropriate black light illumination to ensure adequate penetrant removal. 7.4 Drying—The components shall be dried prior to the application of dry developer, nonaqueous developer, or examination without developer. The components should be drained of excess water but not dried before the application of aqueous soluble or suspendable developers. The components shall be dried after the application of aqueous developers. 7.4.1 Drying Parameters—Components shall be air dried at room temperature or in a drying oven. Oven temperatures shall not exceed that specified in 6.6.2. Drying time shall only be that necessary to adequately dry the part. Components shall be removed from the oven immediately after drying. Components shall not be placed in the oven with pooled water or pooled aqueous solutions/suspensions. 7.5 Developing—Unless otherwise specified, developers shall be utilized for penetrant examination. Type I penetrants that are qualified to AMS 2644 may be used without developer under either one of the following conditions: manufacturing examination of aluminum and magnesium castings classified by AMS 2175A as Class 3 or 4, or with the expressed approval of the cognizant engineering organization. Minimum and maximum penetrant bleedout times without developer shall be 10 min and 2 h respectively. When developer is used, components that are not inspected before the maximum bleedout time shall be cleaned and reprocessed. When developer is not used, components that are not inspected before the maximum bleedout time shall be reprocessed. 7.5.1 Dry Developers—Components shall be dry before the developer is applied. Dry developer shall be applied in such a manner as to contact all surfaces to be inspected. Excess dry developer may be removed after the development time by light tapping or light air blow-off not exceeding 5 psi [34 kPa]. Minimum and maximum developer dwell times shall be 10 min and 4 h, respectively. Dry developers shall not be used with Type II penetrants. 7.5.2 Nonaqueous Developers—Components, or areas requiring examination, shall be dry before application of the developer. Nonaqueous developer shall be applied by spraying. For Type I penetrants, the developer shall be applied as a uniform thin coating over the entire surface to be inspected. For Type II penetrants, the developer shall be applied over the entire surface to form a uniform, white coating to provide suitable color contrast for the penetrant indications. The uniformity and thickness of the developer coating is important for both types of penetrant systems. If the developer coating thickness is too heavy for Type I systems such that the metallic surface is completely masked, the component shall be cleaned and reprocessed. Unless otherwise specified, the minimum and maximum development times for nonaqueous developers are 10 min and 1 h respectively. For nonaqueous suspendable developer, the developer container shall be frequently agitated between applications. 7.5.3 Aqueous Developer—Aqueous soluble developers shall not be used with Type II penetrants or Type I, Method A penetrants. Aqueous suspendable developers can be used with both Type I and Type II penetrants. Aqueous developers may be applied to the component after rinsing. Developers shall be applied by spray, flowing, or immersion. The applied developer shall not be allowed to puddle and shall completely cover all surfaces to be inspected. Components shall be air dried or oven dried to the requirements of 7.4.1. Minimum and maximum development times, after the component is dry, are 10 min and 2 h. Aqueous suspendable developers must be either constantly agitated to keep the particles from settling out of suspension or they must be thoroughly agitated prior to use to ensure that particles are in suspension. 7.6 Examination—The interpretation area shall meet the appropriate requirements of 7.8.4.5. Components shall be interpreted before the maximum developing time, and if required by specific procedures, monitored periodically during the developing time. Components not interpreted before the maximum developing time shall be cleaned and reprocessed. 7.6.1 Type I Processes—Inspector’s vision shall be dark adapted for a minimum of 1 min prior to examining components. Longer times for more complete adaptation should be used if necessary. Inspectors shall not wear photochromic or permanently darkened lenses while processing or reviewing parts under black light. Black lights shall meet the requirements of 7.8.4.1. All areas of fluorescence shall be interpreted. Components with no indications or only nonrelevant indications shall be accepted. Components with relevant indications shall be evaluated with respect to the applicable acceptance criteria. Components with excessive background fluorescence shall be cleaned and reprocessed. 7.6.2 Type II Processes—All indications shall be interpreted. Components with no indications or only nonrelevant indications shall be accepted. Components with relevant indications shall be evaluated with respect to the applicable acceptance criteria. Components with excessive background shall be cleaned and reprocessed. 7.6.3 Evaluation—All indications found during the examination shall be evaluated in accordance with specified acceptance criteria. 7.6.3.1 Indication Verification—If allowed by the specific procedure, indications may be evaluated by wiping the indication with a solvent-dampened swab or brush, allowing the area to dry, and redeveloping. Redevelopment time shall be at least ten minutes, except nonaqueous redevelopment shall be three minutes minimum. If no indication reappears, the original indication is considered false. This procedure may be performed twice for any given original indication. 7.6.3.2 Discontinuity Removal—When allowed by the specific examination procedure, discontinuity(ies) may be removed by an approved procedure such as sanding, either powered or manual, or grinding to determine the depth and extent of the discontinuity(ies). After the mechanical operation, the area shall be cleaned, etched (if permitted), and reexamined. The process used for reexamination shall be at least as sensitive as the original process. 7.6.4 Sizing—If the acceptance criteria are written in terms of indication sizes, the indication size shall be measured. If the acceptance criteria is written in terms of discontinuity or flaw sizes, the discontinuity shall be measured. 7.6.4.1 Indication Sizing—When sizing indications for judgment against appropriate acceptance criteria, the penetrant indication shall be carefully evaluated under appropriate lighting (white light for visible dye penetrant and black light for fluorescent penetrant), after the required development or redevelopment time as applicable. Measure the indication size at its largest dimension with a measuring device and the appropriate light that meets the requirements of 6.6.1. 7.6.4.2 Discontinuity Sizing—When sizing discontinuities for judgment against appropriate acceptance criteria, the area may be carefully wiped with a solvent-dampened cotton swab or brush, ensuring rapid evaporation so that the area for examination is not flooded with solvent. Immediately measure the discontinuity using a measuring or comparison device and the appropriate light that meets the requirements of 6.6.1. 7.7 Postcleaning—Components shall be cleaned after examination to remove developers and other examination material residues if these are detrimental to subsequent operations or the components’ intended function. 7.8 Quality Control Provisions—This section provides the controls necessary to ensure that the penetrant system, materials and equipment provide an acceptable level of performance. The frequencies of the required checks in Table 1 are based on a facility operating daily. For facilities operating less frequently, the frequency of daily and weekly checks and those required at the start of each shift may be reduced accordingly, but must be performed prior to processing of parts. Monthly and quarterly checks shall be performed at the same frequency as for full-time operations. The NDT facility may perform these process control operations or contract for their performance with an independent, laboratory. Records of tests, except as noted in Table 1, shall be maintained and available for audit by the customer, the cognizant engineering organization, or regulatory agencies. Penetrant materials that are provided ready-for-use and do not require mixing to a concentration, and are not recovered, or reused, or both, such as materials packaged in aerosol containers, closed drums or materials poured into containers for use and are not reused are not subject to the in-use penetrant requirements of 7.8.2. 7.8.1 New Material Conformance—Prior to being placed into use, the conformance of materials to the requirements of AMS 2644 shall be verified, usually by a certified report from the supplier. Use of materials not conforming to AMS 2644 shall require approval by the cognizant engineering organization prior to use and shall be allowed only when materials conforming to AMS 2644 are inadequate for the particular application. 7.8.2 Material Checks (In-Use)—The applicable tests specified in 7.8.2.1 through 7.8.2.9 shall be conducted on in-use materials at the intervals specified in Table 1. Operators shall be alert to any changes in performance, color, odor, consistency, or appearance of all in-use penetrant materials and shall conduct the appropriate checks and tests if they have reason to believe the quality of the penetrant may have deteriorated. Penetrant examination shall be conducted only after acceptable quality of materials has been established. 7.8.2.1 Penetrant Contamination—The in-use penetrant materials shall be viewed as specified in Table 1 to determine if any of the following conditions are evident: precipitates, waxy deposits, white coloration, surface scum, or any other evidence TABLE 1 Required Tests and Frequency Tests A Penetrant Contamination Penetrant Brightness Water Content— Water-Based Penetrant (Method A) Water Content— Non-Water-Based Penetrant (Method A) Lipophilic Emulsifier Water Content B Hydrophilic Emulsifier Immersion, Spray, or Flowing Concentration B Dry Developer Condition B Aqueous Developer Contamination— Soluble and Suspendable Aqueous Developer Concentration— Soluble and Suspendable Penetrant System Performance C Water-Washable Penetrant Removability Emulsifier Removability Comparative Penetrant Sensitivity Black Light IntensityB Black Light Integrity Special UV lighting Battery Powered UV-A lights Visible Light Intensity Light Meter CalibrationB Examination Area Cleanliness A Examination Area Ambient Light Intensity Water Wash Pressure CheckA Water Pressure Gage Calibration B Water Wash Temperature Check A Water Temperature Gage Calibration B Drying Oven CalibrationB Air Pressure Gauge Check Air Pressure Gauge Calibration Frequency Paragraph Daily Quarterly Weekly 7.8.2.1 7.8.2.2 7.8.2.3 Monthly 7.8.2.4 Monthly Weekly 7.8.2.5 7.8.2.6 Daily Daily 7.8.2.7 7.8.2.8 Weekly 7.8.2.9 Daily As required per 7.8.3 As required per 7.8.3 As required per 7.8.3 Daily Weekly Daily Prior to and after use Weekly Semi-annually Daily Quarterly Start of each working shift Semi-annually Start of each working shift Semi-annually Quarterly Start of each working shift Semi-annually 7.8.3 7.8.3.2 7.8.3.3 7.8.3.4 7.8.4.1 7.8.4.1 7.8.4.2 6.7.4.1, 7.8.4.2(1) 7.8.4.3 7.8.4.4 7.8.4.5 7.8.4.5 7.8.4.6 7.8.4.6 7.8.4.6 7.8.4.6 7.8.4.7 7.8.4.9 7.8.4.9 A Need not be recorded. The maximum time between verifications or checks may be extended when substantiated by technical data and approved by the Cognizant Engineering Organization. C Not required for Method C examinations. B of contamination or breakdown. When any of the above conditions are determined to be detrimental, the material shall be discarded or otherwise corrected, as appropriate. 7.8.2.2 Penetrant Brightness—Brightness tests of in-use fluorescent penetrants shall be conducted at the intervals specified in Table 1. Tests shall be in accordance with Test Method E1135 with a representative sample of the unused penetrant serving as the reference. Brightness values less than 90 % of the unused penetrant brightness are unsatisfactory and the in-use penetrants shall be discarded or otherwise corrected, as appropriate. 7.8.2.3 Water Content of Water-Based Water-Washable Penetrants—The water content of water-based Method A penetrants shall be checked at the intervals specified in Table 1 using a refractometer. The water content must be maintained according to the manufacturer’s recommendation. 7.8.2.4 Water Content of Non-Water-Based Water-Washable Penetrants—Water content of non-water-based Method A penetrants shall be checked at the intervals specified in Table 1 in accordance with Test Method D95, Test Method D6304, or Karl Fischer Method as described in Annex A1. If the water content of the in-use penetrant exceeds 5 %, the penetrant shall either be discarded or sufficient unused penetrant added to reduce the water content to below 5 %. 7.8.2.5 Lipophilic Emulsifier Water Content—Water content of lipophilic emulsifiers shall be checked at the intervals specified in Table 1 in accordance with Test Method D95, Test Method D6304, or the Karl Fischer method as described in Annex A1. If the in-use emulsifier exceeds the water content of the original (un-used) emulsifier by more than 5 % it shall be discarded or corrected, as appropriate. 7.8.2.6 Hydrophilic Emulsifier Concentration— Concentration of the emulsifier solution shall be checked at initial makeup, during additions and at the intervals specified in Table 1 using a refractometer. A longer period may be used if a plan justifying this extension is prepared by the NDT facility and approved by the CEO. Refractometer values obtained shall be compared to actual values obtained from known concentrations of emulsifier. For immersion applications, the concentration, as percent of volume, shall be no higher than that specified by the penetrant system supplier and shall not exceed that for which the system was qualified. For spray or flowing applications, the concentration shall not exceed 5 %. 7.8.2.7 Dry Developer Condition—Recycled or reused dry developer shall be checked as specified in Table 1 to check for fluorescence and to ensure it is fluffy and not caked. Caked dry developer is unsatisfactory and shall be replaced. To check for fluorescence, apply a thin layer of in-use developer to a 4-in. [10-cm] or greater flat test panel using the same method of application used for production parts, and observe under a black light. Dry developer exhibiting ten or more fluorescent specks in a 4-in. [10-cm] diameter circle is unsatisfactory and shall be replaced. The test panel selected shall be nonfluorescent and non-reflective and have a working surface color which provides a good contrast with the developer powder. 7.8.2.8 Aqueous Developer Contamination—Soluble and suspendable aqueous developers shall be checked as specified in Table 1 for fluorescence and coverage. Immerse a clean aluminum panel, about 3 by 10 in. [8 by 25 cm] in the in-use developer, dry it, and observe it under a black light. Observed fluorescence or failure to uniformly wet the panel is unsatisfactory and the developer shall be discarded or otherwise corrected, as appropriate. 7.8.2.9 Aqueous Developer Concentration—Soluble and suspendable aqueous developer concentration shall be maintained and checked with a hydrometer or in accordance with the manufacturer’s instructions at the intervals specified in Table 1. Concentration shall be in accordance with the manufacturer’s recommendation and shall be replaced or corrected accordingly. 7.8.3 Penetrant System Performance—The penetrant system’s overall performance shall be checked as specified in Table 1. The check shall be performed by processing a known defect standard through the system using in-use penetrant, emulsifier (if used) and developer and appropriate processing parameters. The resulting indications will then be compared to the indications obtained using unused penetrant, emulsifier (if used) and developer. This comparison may be made with records of previously obtained indications or with a similar known defect standard processed with unused materials from a hold-out sample. When required by the CEO or when the sensitivity or performance of the in-use materials falls below the performance of the unused materials, the in-use materials shall be checked in accordance with paragraphs 7.8.3.2 through 7.8.3.4 as appropriate, prior to conducting any further penetrant examinations. Unacceptable materials shall be discarded or otherwise corrected in accordance with the manufacturer’s instruction. 7.8.3.1 Known Defect Standards—The known defect standard used shall be approved by the cognizant engineering organization. The user shall establish and document effective cleaning procedures based on the manufacturer’s instructions, if applicable. The user shall ensure that cleaning of the standards between uses is adequate and that physical changes in the standard that make it unrepresentative of the indications found using the hold-out sample are detected. 7.8.3.2 Water-Washable (Method A) Penetrant Removability—When required in accordance with 7.8.3, the removability of water-washable (Method A) penetrants shall be tested using a AMS 2644-specified test panel or any other commercially available grit blasted panel. The test shall be performed using a sample of unused penetrant serving as a reference. Place a streak of the unused reference sample on one portion of a panel and a separate streak of the in-use penetrant on a separate area of the panel. Allow the panel to drain for five minutes and then wash the panel using the temperature, pressure and wash times in use on the examination line. Dry the panel, coat with developer, and examine under UV light. If the background of the in-use sample is visibly greater than that of the reference, then the in-use penetrant shall be discarded or otherwise corrected, as appropriate. 7.8.3.3 Emulsifier Removability—When required in accordance with 7.8.3, the removability of the in-use emulsifier shall be tested using an unused sample of the same brand of emulsifier serving as a reference. The test shall be conducted using two test panels and processing parameters specified in AMS 2644 or any other commercially available grit blasted panel. The in-use emulsifier shall be used with the unused penetrant on one panel and compared to the reference system of unused emulsifier with unused penetrant on a second panel. Allow both panels to drain for five minutes and then wash using the temperature, pressure and wash times used on the examination line. Dry both panels, coat with developer, and examine under UV light. If the background is visibly greater than that of the reference system the emulsifier shall be discarded or otherwise corrected, as appropriate. 7.8.3.4 Comparative Penetrant Sensitivity—When required in accordance with 7.8.3, the comparative sensitivity of in-use penetrant shall be checked using the procedures in 7.8.3 except that the check shall be performed by comparing the in-use penetrant to the reference (hold-out) unused penetrant by processing both with unused emulsifier, if applicable, and unused developer. If the comparative sensitivity of the in-use penetrant is noticeably less than the reference penetrant, the in-use penetrant is unsatisfactory for use. penetrant or for determining the sensitivity level of the penetrant neither of which can be performed using a starburst-type panel. 7.8.4 Equipment Checks—The following equipment checks shall be conducted at the intervals specified in Table 1 and recorded, as required. Records shall be maintained and available for audit by the customer, cognizant engineering organization or regulatory agencies. The calibration of equipment shall be traceable to the National Institute of Standards and Technology (NIST) or other recognized national standards, where applicable. 7.8.4.1 Black Lights—Portable, hand-held, permanently mounted or fixed black lights used to inspect parts shall be checked for intensity as specified in Table 1 or prior to use, and after bulb replacement. A longer period may be used if a plan justifying this extension is prepared by the NDT facility and approved by the cognizant engineering organization. The minimum acceptable intensity is 1000 µW/cm2 (10 W/m2) at 15 in. [38.1 cm] from the front of the filter to the face of the sensor. Black lights shall be checked at the intervals specified in Table 1 for cleanliness and integrity and shall be cleaned, repaired or replaced as appropriate. (1) Black lights that use an UV-A LED source shall comply with the requirements of Practice E3022. NOTE—Some UV-A sources other than mercury vapor, for example, micro-discharge, LED, etc., have been shown to have emission characteristics such as excessive visible light, and UV intensity that may result in fluorescent fade, veiling glare, etc., all of which can significantly degrade examination reliability. (2) Since visible light contamination may interfere with UV-A inspection, it is recommended that a visible light contamination be taken at the viewing surface, when the UV-A lamp is on and is held at the angle and distance used for interpretation. The white light reading shall not exceed 2 fc [21.5 lx]. 7.8.4.2 Special UV Lighting—As specified in Table 1 or prior to use, the light intensity of UV pencil lamps, UV light guides, borescopes or remote UV examination equipment shall be measured at the expected working distance and shall provide at least 1000 µW/cm2 (10 W/m2) at the intended examination surface. When using borescopes or remote video examination equipment, the image or interpretation area being viewed shall have sufficient resolution to effectively evaluate the area of examination. (1) Battery powered black lights used to inspect parts shall have their intensity measured prior to and at the end of each use, inspection, shift or day as defined by the Written Procedures (see 6.7.4.1). The minimum UV light intensity shall be 1000 µW/cm2 at 15 in. [38.1 cm]. 7.8.4.3 Visible Lights—For Type II visible dye examinations, the lighting systems shall be checked at intervals specified in Table 1 to ensure a minimum of 100 fc [1076 lx] when measured at the examination surface. 7.8.4.4 Light Meters—Ultraviolet and visible light meters shall be calibrated at intervals specified in Table 1 in accordance with MIL-STD-45662, ANSI/NCSL Z540-1, or ISO 10012-1. 7.8.4.5 Examination Area—The interpretation area for stationary systems for Type I penetrants shall be checked as specified in Table 1 and shall be clean and free from excessive fluorescent contamination and excessive visible light background. The ambient visible light background shall be checked at intervals specified in Table 1 or when any changes, or construction, or both, in the interpretation area are made. Ambient visible light shall not exceed 2 fc [21.5 lx] at the examination surface. 7.8.4.6 Water Wash Operating Pressures/Temperatures— Indicators and controls shall be checked as specified in Table 1 to ensure proper settings. Non-compliant water pressure and temperature settings shall be adjusted to the proper settings prior to performing penetrant examinations. Indicators and controls shall be calibrated at intervals specified in Table 1 in accordance with MIL-STD-45662, ANSI/NCSL Z540, or ISO 10012. 7.8.4.7 Drying Oven Calibration—The temperature controlling device and the temperature indicating device, if separate from the controller, on the drying oven shall meet the requirements of 6.6.2 and shall be calibrated at intervals specified in Table 1 in accordance with the requirements of MIL-STD45662, ANSI/NCSL Z540, or ISO 10012. 7.8.4.8 Timers—Timing devices used to measure or monitor processing times, such as dwell times and eye adaptation times, need not be calibrated. 7.8.4.9 Air Pressure Gauges—Air pressure gauges that are used to regulate air pressure of hydro-air spray guns, removal of water prior to drying, and blow off of dry developer shall be checked and calibrated at intervals specified in Table I and in accordance with MIL-STD-45662, ANSI/NCSL Z540, or ISO 10012. move such identification, the records accompanying the component shall be marked or shall specify components to the applicable documents. The methods of marking are listed in 7.9.2. Marking shall conform to MIL-STD-792, unless otherwise specified. 7.9.2 Impression Stamping Ink Stamping, Dyeing, Laser Marking, Vibro Engraving, Peening or Etching—The specific method to be used shall be specified in the contract document (purchase order, drawing, specification, and so forth). If not specified, ink stamping shall be used. Marking shall be located in areas adjacent to the part number or an area specified by the contract documents. 7.9.3 Other Identification—Other means of identification, such as tagging, may be applied when the construction, finish, or functional requirements of the component preclude etching, dyeing, or stamping. Items such as bolts, nuts, or other small parts may be identified by conspicuously marking each package. 7.9.4 Symbols—Each component that has successfully passed examination shall be marked as follows: 7.9.4.1 When etching or stamping is applicable, symbols shall be used. The stamping may contain an identification symbol or supplier number of the facility and a unique number or symbol identifying the examiner. Except for specialized applications, use the symbol “P” to denote 100 % examination. All components, in the lot sampled, accepted on sampling basis shall be marked with the symbol “P” enclosed by an ellipse. 7.9.4.2 When dyeing is used, maroon dye shall be used to denote components accepted on a 100 % examination basis. Yellow dye shall be used to denote a sampling basis when sampling is permitted. 7.9 Marking and Identification—Components successfully passing the penetrant examination shall be identified and marked as follows: 7.9.1 Marking—Marking shall be applied in a manner and location that is harmless to the component, or its intended function, and to preclude removal, smearing, or obliteration by subsequent handling. When subsequent processing would re- 8. Keywords 8.1 dye liquid penetrant examination; dye penetrant examination; fluorescent liquid penetrant examination; fluorescent penetrant examination; liquid penetrant examination; liquid penetrant testing; nondestructive; nondestructive evaluation; nondestructive examination; nondestructive testing; penetrant examination; penetrant testing ANNEX (Mandatory Information) A1. METHOD FOR MEASURING WATER CONTENT A1.1 Scope and Application—This modified Karl Fischer volumetric procedure is a practical alternative to Test Method D95 for undiluted hydrophilic emulsifiers and water contamination of in-use lipophilic emulsifiers and Method A penetrants. The amount of sample used is adjusted to meet the water equivalent capacity of the titration agent employed (1 mL = 5 mg H 2O). For most materials required to meet the five percent (5 %) maximum allowable water content limit, 0.5 to 1.0 g sample size is sufficient. A1.2 Apparatus: A1.2.1 Buret, glass, 50-mL, A1.2.2 Flask, wide-mouth Erlenmeyer type, 250-mL, A1.2.3 Pipets, volumetric, two, 10-mL, A1.2.4 Weighing scale, reads to at least two decimal places, and A1.2.5 White paper. A1.4.5 Record titrant reading. A1.3 Reagents: A1.3.1 Buffer solution, Hydranal (Riedel de Haen) or Hydra-Point (J.T. Baker), 500 mL, A1.4.6 Place the flask on balance and add about 0.5 g of test sample, and record weight. Gently swirl flask to mix sample. A1.3.2 Titrant, Hydranal Composite 5 (Riedel de Haen) or Hydra-Point Titrant 5, 1 L, and A1.4.7 Place flask under buret and titrate back to the same yellow-brown color and record the reading. A1.3.3 Methanol, reagent grade, 500 mL. A1.4.8 Repeat and average % H2O readings. A1.4 Analytical Procedure: A1.5 Calculate Water Content as follows: A1.4.1 Charge buret with Hydranal titrant. % H 2O 5 @ consumption titrant 3 titer value 3 100# ÷sample weight A1.4.2 Pipet 10 mL of methanol into clean dry Erlenmeyer flask. A1.4.3 Pipet 10 mL of Hydranal buffer into the same flask and gently swirl to mix. A1.4.4 Place white paper below buret. Place the flask under the buret and slowly titrate, with gently swirling the Hydranal titrant into the flask until a light yellow-brown color persists (about 3 mL). (A1 .1) where: consumption = second buret reading of Hydranal Composite 5 Titrant minus the first buret reading, mL, titer value = 5 mg/mL H2O, mg/mL, and sample weight = weight of sample added, mg. A1.6 Repeat and average % H 2O readings. SUMMARY OF CHANGES Committee E07 has identified the location of selected editorial changes to this standard since the last issue (E1417/E1417M – 13) that may impact the use of this standard. (June 15, 2016). (1) Added E3022 to the list of Reference Documents. (2) Revised 6.6.1.2 and 7.8.4.1(1) to refer to E3022.