1、Designation: F2832 11Standard Guide forAccelerated Corrosion Testing for Mechanical Fasteners1This standard is issued under the fixed designation F2832; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers test procedures for performing accel-erated tests to evaluate relative corrosion resistance of variouscoatings applied
3、 to mechanical fasteners. Corrosion mecha-nisms such as general and crevice corrosion may be evaluatedwith this method. Test duration may be selected to achieve anydesired level of corrosion exposure and provides a frame ofreference to determine relative coating resistance to corrosion.Fasteners tig
4、htened to a desired tension and subjected to thistest procedure may be evaluated to simulate a variety of serviceconditions. Without large amounts of accumulated field results,it is difficult to relate test duration or the number of test cyclesto actual service life for a given application.1.2 This
5、standard is not intended to cover tests of drivenfasteners such as nails, staples, screws and lag bolts.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and
6、health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A480/A480M Specification for General Requirements forFlat-Rolled Stainless and Heat-Resisting Steel Plate,Sheet, and StripB117 Practice for Operating Salt Spray (Fog) A
7、pparatusB605 Specification for Electrodeposited Coatings of Tin-Nickel AlloyD1193 Specification for Reagent WaterF1470 Practice for Fastener Sampling for Specified Me-chanical Properties and Performance InspectionF1789 Terminology for F16 Mechanical FastenersG1 Practice for Preparing, Cleaning, and
8、Evaluating Corro-sion Test Specimens2.2 ASME Standard:3ASME B18.12 Glossary of Terms for Mechanical Fasten-ers2.3 IFI Standards4IFI-170 Accelerated Corrosion Test for Mechanical Fas-teners3. Terminology3.1 Definitions for many of the terms used in this standardare included in Terminology F1789 and A
9、SME B18.12.3.2 Definitions of Terms Specific to This Standard:3.2.1 cyclea series of events scheduled over a 24-hourperiod3.2.2 phasea test period which has elapsed for 8 cycles.3.2.3 test durationa series of cycles as defined inSection 4.4. Test Duration4.1 Test duration is specified as A, B, C, D
10、or E inaccordance with Table 1.4.2 A typical cycle is shown in Table 2.5. Apparatus and Materials5.1 Coupons 25.4 mm wide and 50.8 mm long having athickness selected from Table 3 shall be used. Dimensionaltolerances of Specification A480/A480M shall apply. Couponsshall have a plain finish and be man
11、ufactured from AISI1008steel grade. Coupons shall be included with fasteners to betested to verify that uniform amounts of corrosion have beenproduced by tests. Refer to Fig. 1, Fig. 1(a) and Fig. 1(b) andTable 3. Inclusion of a metal loss coupon assists in makingcomparisons from one test to another
12、 and allows one toquantify a repeatable test.5.2 A fog humidity cabinet shall be used in which salt mistapplications are coupled with high humidity and moderatelyhigh temperature. Water fog or visible water droplets on partsbeing tested shall be continuous after equilibrium is reached.Dry-off may be
13、 sequenced manually or automatically.1This guide is under the jurisdiction of ASTM Committee F16 on Fasteners andis the direct responsibility of Subcommittee F16.01 on Test Methods.Current edition approved Feb. 1, 2011. Published February 2011. DOI: 10.1520/F283211.2For referenced ASTM standards, vi
14、sit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters
15、, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.4Available from Industrial Fasteners Institute (IFI), 6363 Oak Tree Blvd.Independence, OH 44131 http:/www.indfast.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3
16、Racks suitable for supporting bolt or screw assembliesshall be agreed upon between supplier and purchaser. Testresults shall always state materials used for racks duringtesting. Nylon or other suitable nonmetallic washers shall beinstalled to prevent bolt or screw heads or test coupons fromcontact w
17、ith test racks. See Fig. 1 and 7.8.6. Salt Mist Application and Dry-off6.1 Salt solution shall conform to requirements of Table 4.Solutions shall be sprayed by nozzles to provide a mist suchthat test fasteners and coupons are thoroughly wet and drippingwhen examined visually. Solution collection rat
18、es shall con-form to Practice B117. Salt accumulations shall have beenrinsed away during the salt solution spray application.6.2 For the drying part of a cycle, a dry-off environmentarea shall be maintained with sufficient air circulation to assureuniform temperature and shall allow thorough drying
19、of testedfasteners and coupons. Temperature and humidity conditionsare defined in Table 4.7. Test Procedure7.1 Fasteners to be tested with salt spray, shall be sampledin accordance with Practice F1470, Sample Level B.7.2 Each fastener to be tested shall be installed through itscorresponding rack usi
20、ng nonmetallic washers as to maintain aminimum of 5 mm spacing between underside of the head andsurface of the rack. The washers for any testing protocol shallbe identical. Fig. 1(a) and Fig. 1(b) provide an illustrativerepresentation. Holes in test racks shall be offset to avoiddripping from one te
21、st fastener onto another. Fastener loadshall be achieved through finger tightening (Fig. 1 illustratesthe assembly). If higher loads or proof load tightening isrequired then the load level and method of tightening shall beby agreement between supplier and purchaser.7.3 Coupons to be tested shall be
22、permanently identified bynumbers stamped onto the surface.7.4 Coupons to be used shall be cleaned with a methanol oracetone solution and weighed prior to use. A coupons weightin 6 0.5-mg shall be recorded for comparison with its weightafter testing in accordance with Table 2.7.5 Coupons as shown in
23、Fig. 1(a) shall be installed bydrilling a hole to accept a nonmetallic hex fastener. Couponsshall be raised above coupon racks by two nonmetallic washersto expose both sides of coupons to the test environment. Aminimum of 5 mm shall be provided for spacing betweencoupons and test rack surfaces. Fixt
24、ures shall be modified asnecessary to maintain isolation from rack materials whilecreating and maintaining the required fastener tensions.7.6 Dry off shall consist of exposure to high temperature,low humidity air in accordance with Table 4 for three hours.7.7 Test coupon(s) shall be removed and anal
25、yzed afterdry-off in each phase. Each coupon shall be cleaned inaccordance with the procedures described in Practice G1.7.8 For corrosion products that are tightly adhered to thefastener specimen, cleaning by mechanically abrading thesurface before chemical cleaning will help remove the adherentcorr
26、osion products. Vigorous mechanical cleaning may resultin the removal of some coating or base metal; therefore, careshould be exercised when using mechanical cleaning tech-niques. Mechanical cleaning should be used only when othermethods have failed to provide adequate removal of corrosionproducts o
27、n the coupons. After a final phase, coupon mass lossshall be evaluated based on Table 3. Prior to completion of afinal testing phase, mass loss may be linearly extrapolatedbased on percent of the overall test completed.8. Report8.1 Reported test results shall include:8.1.1 Name of testing agency,8.1
28、.2 Date(s) and place of testing,8.1.3 Testing schedule as to number of cycles,8.1.4 Identification, all materials for coupons,8.1.5 Materials of construction for racks,8.1.6 Identification, materials and coatings of fasteners,8.1.7 Installation torques or tensions involved,8.1.8 Condition of coupons
29、,8.1.9 Mass loss of coupons, net and percent, and8.1.10 Condition of the fasteners, including section loss,estimated percent surface corrosion, timing of on-set, orphotographs as agreed with purchaser.9. Keywords9.1 corrosion; crevice; testingTABLE 1 Test DurationTest Duration Number of CyclesA8B16C
30、40D8E (# of cycles)A80AFor special applications as agreed between supplier and purchaser.F2832 112TABLE 2 Typical ScheduleTimeADurationHrsEvent6 a.m. 8 Salt mist application (in ambient environment.)2:00 p.m. 8 8 hour humidity cabinet exposure including 1 hour progression to wet conditions.10:00 p.m
31、. 8 8 hour environmental exposure including 3 hours progression to dry conditions.Weekends Ambient environmentATimes shown are illustrative. A test cycle may be started at any time and follow the order shown in the table. The events for a 24 h period complete one cycle. Ambientis specified in Table
32、4. Duration times are 6 5 minutes.TABLE 3 Coupon Mass Loss Target RangeInitialCouponThicknessmmTest Durationmg of Mass LossABCDE0.79 8281228 14961896 32103810 60386638SeeA1.59 8741274 15741974 33783978 63456945AThe corrosion rate (mass loss) is in linear relation with the number of test cycles. This
33、 linear relation can be used to calculate the mass loss for the number of cyclesdifferent than the test cycles corresponding to test durations shown in Table 3. Values in Table 3 are only applicable to Standard Test Procedure. Mass loss for test durationE(# of Cycles) is a function of the number of
34、the cycles agreed upon.F2832 113FIG. 1TABLE 4 Test Environment and SolutionsSalt Mist 25C35CSalt SolutionSodium Chloride 0.90%ACalcium ChlorideSodium BicarbonateSalt Solution pH0.10%0.25%A6.57.5Dry offTemperatureHumidity58C-64C10 years (See Note X1.1).Very severe, severe, moderate, and mild service
35、are defined inASTM B605. Test duration selection A, B, C, D or E(# ofCycles) should be based on the expected service condition. Aweight loss exceeding 2% is considered very severe service.NOTE X1.1Extended life service reflects special service applicationswhere design life exceeds a 10-year period a
36、nd testing exceeds 80 cycles.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 inf
37、ringement 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 stand
38、ard or for 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 vi
39、ews known 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F2832 115
