1、Designation: F 1428 92 (Reapproved 2005)Standard Specification forAluminum Particle-Filled Basecoat/Organic or InorganicTopcoat, Corrosion Protective Coatings for Fasteners1This standard is issued under the fixed designation F 1428; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the basic requirements for ac
3、orrosion-resistant coating consisting of an inorganic alumi-num particle-filled basecoat and an organic or inorganictopcoat, depending on the specific requirements.1.2 The coating may be specified with basecoat only, or withthe top coated with compatible organic polymer or inorganictopcoats, dependi
4、ng on the specific requirements.1.3 The basecoat is a water-dilutable slurry containingaluminum particles dispersed in a liquid binder of chromate/phosphate compounds.1.4 The organic topcoats consist of polymer resins anddispersed pigments and are for service where temperatures donot exceed 230C (45
5、0F).1.5 The inorganic topcoats consist of ceramic oxide pig-ments dispersed in a liquid binder of chromate/phosphatecompounds and are for service where temperatures do notexceed 645C (1200F).1.6 These coatings are applied by conventional dip/spin,dip/drain, or spray methods.1.7 The coating process d
6、oes not normally induce hydrogenembrittlement, provided that the parts to be coated have notbeen subjected to an acid cleaner or pretreatment (see Note 1).NOTE 1Although this coating material contains water, it has arelatively low susceptibility to inducing hydrogen embrittlement in steelparts of te
7、nsile strengths equal to or greater than 1000 MPa (approxi-mately RC31). Normal precautions for preparing, descaling, and cleaningsteels of these tensile strengths must be observed. An initial stress relieftreatment should be considered prior to any chemical treatment orcleaning operation. Acids or
8、other treatments that evolve hydrogen shouldbe avoided. Mechanical cleaning methods may be considered. Some steelsare more susceptible to hydrogen embrittlement than others and may alsorequire hydrogen embrittlement relief baking after cleaning but beforecoating. Since no process can completely guar
9、antee freedom fromembrittlement, careful consideration must be given to the entire coatingprocess and the specific steel alloy employed.1.8 The coating systems defined by this specification can beapplied to ferrous alloy steels, aluminum, and ferritic andaustenitic stainless steels.1.9 The values st
10、ated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.10 The following safety hazards caveat pertains only tothe test methods portion, Section 6, of this specification: Thisstandard does not purport to address all of the safety concerns,if any,
11、 associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray (Fog) Apparatus
12、B 487 Test Method for Measurement of Metal and OxideCoating Thicknesses by Microscopical Examination of aCross SectionB 568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryD 1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa
13、 Ferrous BaseD 2247 Practice for Testing Water Resistance of Coatings in100 % Relative HumidityD 3359 Test Methods for Measuring Adhesion by Tape TestE 122 Practice for Choice of Sample Size to Estimate, Witha Specified Tolerable Error, the Average for a Characteris-tic of a Lot or ProcessE 376 Prac
14、tice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) TestMethods1This specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.03 on Coatings onFasteners.Current edition approved May 1, 2005. Pub
15、lished May 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as F 1428 92 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standard
16、s Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3. Classification3.1 The inorganic aluminum particle-filled basecoat and thesubsequent topcoats are classified into three groups, withsubseque
17、nt subgroups formed according to the requirementsgiven in Table 1. The coating bath requirements and curetemperatures recommended by the chemical manufacturershould be followed.3.2 Regardless of the processes or materials used, theinorganic and organic coatings shall conform to all of theapplicable
18、requirements of this specification.4. Ordering Information4.1 Orders for material in accordance with this specificationshall include the following information:4.1.1 Quantity of parts,4.1.2 Grade of coating (see Table 1),4.1.3 Color of coating,4.1.4 Any additions to specifications as agreed upon by t
19、hepurchaser and the supplier, and4.1.5 Certification and test report requirements.5. Requirements5.1 AppearanceThe coatings shall have a smooth, uni-form appearance and shall be free of lacerations and otherdiscontinuities that may affect the appearance or performanceof the coatings.All topcoat colo
20、rs shall be agreed upon by boththe purchaser and the supplier.5.2 AdhesionThe coating shall show no evidence ofblistering or other appearance changes after exposure tohumidity testing for 96 h, it shall show no more than 3.0-mmpeel-back from the intersection of scribed lines that aretape-tested imme
21、diately after a 10-min recovery period fromthe humidity test, and there shall be no other peeling under thetape.5.3 CorrosionThese coatings shall be capable of with-standing neutral salt spray testing for the minimum timespecified in Table 1. Unless otherwise defined, acceptablecorrosion resistance
22、shall be considered to be met where thereis no base metal corrosion on significant surfaces.5.3.1 Significant surfaces on threaded fasteners are definedas the surfaces exposed when the fasteners are installed in anormal manner (bolt head, nut drive, face, and so forth). Onother surfaces on which coa
23、ting control cannot be obtainedunder normal processing, such as holes, recesses, threads, andso forth, the above requirements do not apply.5.4 Thread-FitThe coating shall not have an adverseeffect on normal installation and removal practices, as deter-mined by the proper “GO” thread gage or the fit
24、and functioninspection method (see 8.2).5.4.1 SizingThe thickness of the coating is limited by thebasic thread size. Where greater thickness is necessary, threadsmay be produced undersize or oversize (before coating) toaccommodate the coating thickness, providing that the finishedfastener (after coa
25、ting) meets all specified mechanical proper-ties, as agreed upon by the supplier and the purchaser.5.5 WeatheringThe coatings shall show no blistering,peeling, cracking, loss of adhesion, discoloration, or red rust onsignificant surfaces after exposure to the weathering test for atleast as many hour
26、s as specified for salt spray resistance for thevarious codes.6. Test Methods6.1 CorrosionCorrosion resistance shall be tested in ac-cordance with Practice B117.6.2 Coating ThicknessCoating thickness shall be tested inaccordance with Test Methods D 1186, magnetic-permeability;Practice E 376, eddy-cu
27、rrent; or Test Method B 568, X-rayspectrometry. For referee purposes, micro-examination in ac-cordance with Test Method B 487 shall be used.6.3 Humidity TestThe humidity test shall be conducted inaccordance with Practice D 2247.6.4 AdhesionAfter exposure to the humidity test, adhe-sion shall be test
28、ed in accordance with Test Methods D 3359.7. Application7.1 Any conventional cleaning procedure that does notinduce hydrogen embrittlement or intergranular attack of thebasis metal can be used, followed by grit blasting or micro-zincphosphating (see Note 2).NOTE 2If not properly controlled, zinc pho
29、sphate coatings and certainacid descaling processes may produce hydrogen embrittlement or severeetching of the basis metal.7.2 The coatings are applied by conventional dip/spin,dip/drain, or spray methods.7.3 The coatings shall be applied under suitable controlconditions and in the stages necessary
30、to meet the requirementsof the specification. Unless otherwise specified, these coatingsshall be applied after all machining, forming, and heat treat-ments have been completed, but prior to final inspection.7.4 The contractor (applicator) shall maintain control overfactors that affect the quality of
31、 the treatment, including, butnot limited to, dip/spin parameters, coating viscosities, andTABLE 1 Classification of CoatingsNOTE 1 Grades 4A, 4B, and 2C require basecoat burnishing.NOTE 2The torque tension relationship of coated fasteners may bedifferent from those of uncoated fasteners. A wax lubr
32、icant may bespecified to improve the torque-tension characteristics of coated fasteners.NOTE 3When spray application methods are employed, the thicknessrequirements of the two individual coats may be achieved in one singlespray application.GradeNo.Coats ofBasecoatCoats ofTopcoatsAverageThickness,mSa
33、lt SprayLife Hours1AA1 1 1015 1682A 2 1 1525 2403A 2 2 2030 7204A 2 2 2030 10001BB1 1 1015 1682B 2 1 1525 2403B 2 2 2030 5004B 2 2 2030 10001CC2C220010201020168400AGrades with Suffix A are organic topcoated for a maximum service tempera-ture of 230C (450F).BGrades with Suffix B are inorganic topcoat
34、ed for a maximum service tempera-ture of 645C (1200F).CGrades with Suffix C are basecoated only for a maximum service temperatureof 645C (1200F).F 1428 92 (2005)2temperature. Chemical analyses, coating replenishment, visualinspection, and other process control devices shall be con-ducted with the fr
35、equency required to maintain good quality ofthe treatment and to meet the requirements of this specification.Visual inspection is intended to include appearance factorssuch as (1) streaking, (2) dulling, (3) uncoated areas, and (4)loss of color where color is specified.8. Inspection8.1 Samples may b
36、e taken in accordance with PracticeE 122 or as agreed upon by the purchaser and the supplier.8.1.1 Alot shall consist of all items having the same coatingspecification and processed at the same time.8.2 Fit and Function InspectionThe following fit andfunction thread inspection procedure may be used
37、if thespecified “GO” gage binds on the threads.8.2.1 Bolt or ScrewAssemble a phosphate-plated test nutwith a 2B or 6H class thread fit down the full length of thethread.8.2.2 NutAssemble a phosphate-plated test screw with a2A or 6g class thread for a minimum of one diameter throughthe nut.8.2.3 The
38、test nut or screw must run freely for the totallength without binding.9. Rejection and Rehearing9.1 Unless otherwise specified, any rejection based on thetests specified herein and made by the purchaser shall bereported to the manufacturer as soon as practical after receiptof the fasteners by the pu
39、rchaser.10. Certification Requirement10.1 Product designations used in the coating system are tobe reported to the purchasing organization, along with certifi-cation that the parts meet the requirements of this specification.10.2 When applicable, test reports affirming acceptance areto be attached t
40、o the certification.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement
41、 of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or fo
42、r additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known
43、 to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 1428 92 (2005)3
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