《NAS-4006 1984.pdf》由会员分享，可在线阅读，更多相关《NAS-4006 1984.pdf（4页珍藏版）》请在三一文库上搜索。
1、NATIONAL AEROSPACE STANDARD B H B AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA, INC, 1725 DE SALES STREET, N.W, WASHINGTON, D. C. 2 W 6 . . - S . , . . . . 5 Q COPYRIGHT 1984 AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA, INC. ALL RIGHTS RESERVED FED. SUP CLASS MFFP 1. SCOPE AND CLASSIFICATION 1.1 Scop
2、e - This specifjcation covers the requirements for aluninun coatings on fasteners or fastener systems. 1.2 Clamaification - Aluminum coatings under this specification shall be of one class only; .0002- .O005 inch inthicknemm. 2. APPLICABLE DOCUMENTS MILITARY STANDARDS MIL-STD-105 Sampling Procedures
3、 and Tables for Inspection by Attributes MIL-STD-1312 Fasteners, Test Method INDUSTRY STANDARDS ASTM B-281 Acetic Acid-Salt Spray (Fog) Testing. MILITARY SPECIFICATIONS MIL-A-8625 Anodic Coatings for Aluminum and .Aluminum Alloys MIL-R-81294 Remover, Paint, Epoxy System 3. REQUIREMENTS 3.1 Materials
4、 - The materials used 6hall be such as to produce coatings which meet the requirements of thia mpecification. 3.2 Preparation - The basis metal shall be free from defects that will be detrimental to the appearance or the protective value of the coating. 3.2.1 Parts shall be atress relieved prior to
5、coating if they have been subjected to operations causing detrimental remidual stresses. Temperatures to which the parts are heated and time at temperature shall be auch that maximum stress relief is obtained without affecting properties of the material. 3.2.2 Any residual compressive stress inducin
6、g operation such as shot peening, fillet rolling, ar thread rolling shall follow the stress relieving. 3.2.3 Before coating, parts shall have chemitally clean surfaces prepared with no evidence of erosion, pitting, intergranular attack, or unintentional abrasion. .LIST OF CURRENT SHEETS I NO. I REV.
7、 CUSTODIAN NATIONAL AEROSPACE STANDARDS COMNITTEE THIRD ANGLE PROJECTION PROCUREMENT SPECIFICATION TITLE CLASSIFICATION SPECIFICATION NOXE ALUMiNUM C O A T I N G NAS 4006 I SHEET 1 OF 4 USE OF OR RELIANCE UPON THIS DOCUMENT OR ANY NATIONAL AEROSPACE STANDARD IS ENTIRELY VOLUNTARY AIA DOES NOT QUALIF
8、Y SUPPLIERS OR THE SUITABILITY OF ITEMS FOR ANY PARTICULAR APPLICATION. OR (2) THE EXISTENCE OF OR APPLICABILITY THERETO OF PATENT OR TRADEMARK RIGHTS, CERTIFY CONFORMANCE OF ITEMS PRODUCED UNDER NATIONAL AEROSPACE STANDARDS. AIA MAKES NO REPRESENTATION OR CLAIM RESPECTING (1) -,-,- AEROSPACE INDUST
9、RIES M O N - O F M E R C A , INC, i n s M SALES STREET, N.W, WASHINOTON, D. c. 3.3 Procedure requiremanta of tbia apecification. 3.3.1 Parta may be coated by any auitablc technique capable of producing a coating meeting the 3.4 General Requirementa 3.4.1 Unleaa otherwiae apecified, the coating proce
10、aa ahdl be performed after al1 machining. forming, or other metal working proceaaea have been completed. applied prior to final coating. 3.4.2 The coating may be applied directly to the part aurface oz m y have a b a c coat or naah plate 3.5 Detail Requirementa 3.5.1 Thickneaa - Unleaa otherwiae ape
11、cified, the coating tbickneaa ahall be O. 0002 to O. O005 inches on all viaible aurfacea which Lan be touched by a ball O. 75 inch in dameter. 3.5.1.1 Coverage - The recess, in shank or head, may be bare in titanium or corrosion resistant materials only. 3.5.2 Appearance - The coating ahall be amoot
12、h, uniform, and r h l l be h from Pin holes, pomsity, u i a t e m , nodules, pita or other burtul i r p r i . C t i O M . 3.5.3 Adhesion - The coating ayatem ahall be continuoualy bonded to the baaia metal. The adhesion of the coating ahall be auch that when eumined at a magnificatirm of approximate
13、ly 4x, it doer not ahow between the c.oating-d the b a i # metal ia the aurface of the baria metal before coating. aeparation from the bauainet-al at the interface when aubjected to the teata dcacribed in 4.6.2. The interface 3. 5.4 Fluid Remirtmce - Tketoating shall ahow no evidence of bliatering o
14、r lor# of adheaion when exposed to phoaphate eater hydraulic fluid ar rpecified in 4.6.4. Aluminum caatinga containing organic component. shall not aec;rease more than two pencil hardneaa unita after cxpoaure when compared to the unexposed coating. when exposed to MIL-R-81294 paint rtripper aa apeci
15、fied in 4.6.5. Aluminum coatings containing organic component. ahall not decreaae more than two pencil hardnera unita after cxpoaure when compared to the unexpoaed coating. 3.5. 5 Paint Stripper Resistance - The coating ahall ahow no evidence of bliatering or lona of adherion 3.5.6 Embrittlement - T
16、he coated faatenera ahall ahow no evidence of cracking in the head to ahank fillet or thread areas when cxpoaed and eumined aa apecified in 4.6.6. 3.5.7 Corrosion Protective Propertier - When teated aa apecified in 4.6. 7, the counterainka and rurface area of the dummy blocka around the aluminum coa
17、ted faatenera ahall ahow no more corroaion than the correaponding arear with the cadmium plated faatener control blocka. General aurface corroaion on the back of the panela ahould not be conmidercd in cvalut ing the protective qualitiea of the coating, through the complete cleaning and coating cycle
18、 with parta ahall be capable of being heated in air aa apccified in 4.6. 3 without avidena of the coating blirtering or cracking. The adheaion after heating ahall meet the requiremcnta of 3. 5. 3. 3.5.8 Heat Rcaiatance - Coating on parta or on apecimena reprerenting parta that have been proceaaed 1
19、NAS4006. SHEET 2 USE OF OR RELIANCE UPON THIS DOCUMENT OR ANY NATIONAL AEROSPACE STANDARD I S ENTIRELY VOLUNTARY AIA DOES NOT QUALIFY SUPPLIERS OR THE SUITABILITY OF ITEMS FOR ANY PARTICULAR APPLICATION, OR (2)fHE UISTENCE OF OR APPLICABILITYTHERETO OF PATENT OR TRADEMARK RIGHTS. CERTIFY CONFORMANCE
20、 OF ITEMS PRODUCED UNDER NATONAL AEROSPACE STANDARDS. AIA MAKES NO REPRESENTATION OR CLAIM RESPECTING (1) -,-,- NATIONAL AEROSPACE STANDARD AEROSPACE INDUSTRIffi ASSOCIATION OF AMERICA, INC., 1725 De Sales Street. N. W., WashingtonD. C. 20036 - “ “ - 4. QUALITY ASSURANCE PROVISIONS Performance of al
21、l inspection requirements as specified herein. Except as otherwise specified, the Supplier may utilize his own facilities or any commercial laboratory acceptable to the procuring agency. The procuring agency reserves the right to perform any of the inspections set forth in this specification where s
22、uch inspections are deemed necessary to assure that the suppliers and services conform to prescribed requirements. 4.1 Responsibility for Inspection - Unless otherwise specified, the Supplier is responsible for the 4.2 Separate Test Specimens When coated parts are of such form as to not be readily a
23、daptable to made by the use of separate.tests specimens coated concurrently with the parts. The separate specimens a test specified herein. or are for destructive tests of small lot sizes, or as permitted herein, tests may be shall be approximately one inch wide, four inches long, and .O40 inch thic
24、k. The specimens shall be introduced shall be of the same basis metal and heat treat condition as the parts they represent. Separate specimens into a lot at regular intervals prior to the cleaning operations, and shall not be separated therefrom until after completion of the process. 4,3 Lot - A lot
25、 shall consist of coated articles of the same type, coated under the same conditions, and approximately the same sise and shape, submitted for acceptance at one time. 4.4 - Lassification of Tests 4.4.1 Qualification Tests - Materials submitted to this specification shall meet all the requirements of
26、 this specification prior to product and supplier approval. 4.4.2 Acceptance Tests - Coated parts shall be inspected for thickness, appearance, adhesion, and heat resistance prior to shipment of the lot. 4.5 Sampling - Sampling shall be i n accordance with level II of MIL-STD-105 unless otherwise sp
27、ecified herein. The acceptance quality level (AQL) shall be 4. O percent defective in accordance with MIL-STD-105. Published and distributed by: National Standards Association, Inc. Copyright, 1972, Aerospace Industries Association of America, Inc. 1321 Fourteenth Street, N. W. Washington, D. C. 200
28、05 vrith the requirements of 3.2 before coating and 3.5.2 after coating. 4.5.1 Visual Examination - Samples selected in accordance with 4. 5 shall be examined for compliance 4.5.2 Coating Thickness Samples selected from each lot in accordance with 4.5 OP four separately coated Specimens conforming t
29、o 4.2 shall be inspected for conformance to 3.5.1. If the number of articles in the lot is three or less, sampling shall be as specified by the procuring agency. If the coating thickness at any place on any article or specimen does not conform to the requirements of 3.5.1, the lot shall be rejected.
30、 the adhesion test to determine compliance with the requirements of 3.5.3. If the samples from 4.5.2 are not 4.5.3 .$dhesion - The parts or separate specimens used for thiclcness testing & I 4.5.2 may be used for used, sampling for adhesion tests shall be the same as required in 4.5.2. Failure of on
31、e or more of the test specimens shall constitute failure of the lot. 3.5.8. Samples used for items 4.5.2 and 4.5.3 may be used for heat resistance. Failure of one or more of the test specimens shall reject the lot. 4.5.4 Heat Resistance - A set of four parts or four separate specimens shall be teste
32、d for compliance with 4.6 Test Methods specified in test number 12 of MIL-STD-1312. For qualification testing, the microscopic test method shall be used 4.6.1 Thickness - Determination of coating thickness for acceptance shall be made by either of the methods on actual parts. Published and distribut
33、ed by: National Standards Association, Inc. 1321 Fourteenth Street, N. W. Washington, D. C. 20005 Copyright, 1972, Aerospace Industries Association of America, Inc . -,-,- A I A I N A S NAS*40Ob 8 1 . I 033871.I3 0003LL5 T W NATIONAL, AEROSPACE STANDARD i Published and distributed by: National Stand
34、ards Association, Inc. Copyright, 1972, Aerospace Industries Association of America, Inc. 1321 Fourteenth Street, N. W. Washington, D. C. 20005 4.6.2 Adhesion - Adhesion shall be determined by scraping the surface of the coated article to expose the basis metal and examining at four diameters magnif
35、ication for evidence of nonadhesion. Alternatively, the article may be clamped in a vise and the projecting portion bent back and forth until rupture occurs. If the edge of the ruptured coating can be peeled back or if separation between the coating and the basis metal can be seen at the portion of
36、the rupture when examined at four diameters magnification, adhesion is not satisfactory. 4.6.3 Heat Resistance - Heat the test articles at 375F *25OF for four hours in air, and air cool. The articles shall then be tested per 4.6.2 for adhesion. hydraulic fluid (Aerosafe 2300 or equivalent) at 150F f
37、 5OF for 30 days. Dry the samples and test for adhesion per 4.6.2. Pencil hardness of coatings containing organic components shall be determined by pushing pencils of increasing hardness across the surface at an angle of 45O until one is fomd which will cut or scratch the coating. The number of this
38、 pencil shall be used to express the pencil hardness. 4.6.4 Fluid Resistance - Immerse two coated parts or separate test specimens in phosphate ester . in or coated with MIL-R-81294 paint stripper for 24 hours at room temperature (75F * 5F). Rinse the stripper 4.6.5 Paint Stripper Resistance - Two c
39、oated parts or separate test specimens shall be immersed off with tap water, dry, and test for adhesion per 4.6.2. Pencil hardness determination shall be made as described in 4.6.4. 4.6.6 Embrittlement - Four coated countersink head fasteneYs shall be installed in a 7075-T6 aluminum block with an in
40、terference of .001-. 003 inch between the hole and fastener shank. The fasteners shall be torqued to 80% of their rated ultimate load, and exposed for 72 hours at 300F *lOF. After exposure, the fasteners shall be removed from the fixture, sectioned, mounted, polished, and metallurgically examined at
41、 approximately 2OOx for cracks in the fillet to shank radius and thread areas. The sectioned, mounted for polished fasteners should be examined both before and after etching. countersink head fasteners of the same size and alloy shall be installed in 3/8-1/2 inch 7075-T6 block with the recommended n
42、ut OP collar system. The block shall be anodized per MIL-A-8625 Type II prior to drilling and countersinking the holes. Hole size shall be such as to allow .001-. 005 inch clearance fit. Fasteners shall be spaced such that the edge of each head is at least 1/2 inch away from all edges and other fast
43、ener heads. After installation of fasteners, the assembly should be solvent cleaned with methy-ethyl-ketone, trichloroethylene, or similar solvent to remove all grease and fingerprints. 4.6.7 Corrosion Protective Properties - Six coated countersink head fasteners and six cadmium plated Acetic Acid-S
44、alt Spray Test per ASTM B-287 with the following modifications: 4.6.7.1 Accelerated exposure procedure - The assembled block shall be exposedfor 14 days to the (a) Adjust and maintain pH of the solution with acetic acid to a range of 3.0-3.1. (b) Angle of inclination of the specimen shall be 45O fro
45、m vertical and in such a manner that runoff from one fastener does not flow over any other fastener. (c) Modify the spray cabinet by a suitable by-pass system that allows the air flow to be periodically vented directly into the chamber, thus by-passing the saturator tower and aspirator and allowing
46、the following continuous cycle: Four 6 hour cycles per day, each consisting of: (1) 45 minutes spray period. (2) 2 hour direct air purge (drying cycle), . (3) 3 hour, 15 minute soak period at 45 to 90% relative humidity and 95F. of the fasteners in the hole. Remove loose corrosion and salt deposits
47、by light brushing in water, and dry with 4.6.7.2 Examination - After exposure, remove all fasteners in such a manner as to prevent forming compressed air or in an oven, Compare countersink areas and areas on the surface around fastener heads of coated and cadmium plated fasteners for conformance to 3.5.7. 5. PREPARATION FOR DELIVERY I 5.1 This section not applicable to this specification. -,-,-