ASTM D6675-2001(2011) 0625 Standard Practice for Salt-Accelerated Outdoor Cosmetic Corrosion Testing of Organic Coatings on Automotive Sheet Steel《机动车薄钢板上有机涂层的盐加速户外表面腐蚀试验的标准操作规程》.pdf

1、Designation: D6675 01 (Reapproved 2011)Standard Practice forSalt-Accelerated Outdoor Cosmetic Corrosion Testing ofOrganic Coatings on Automotive Sheet Steel1This standard is issued under the fixed designation D6675; the number immediately following the designation indicates the year oforiginal adopt

2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONCorrosion of painted sheet steel of auto bodies is classified according t

3、o the initial location anddirection of the corrosive attack. When the corrosion starts on the visible exterior surface, mostly atnicks and scratches in the paint, it is called “cosmetic” or “outside in” corrosion. Corrosion initiatedat an interior surface or within a closed or semi-closed part is ca

4、lled “perforation” or “inside out”corrosion.1. Scope1.1 This practice is designed to assist procedures to befollowed when conducting outdoor exposures to evaluatecosmetic corrosion that might occur in steel panels coveredwith an organic coating that has been damaged. The outdoorexposures described a

5、re based on Practice G7 and includeperiodic wetting of the test specimens with a salt solution.1.2 The methods of preparing test specimens and the par-ticular exposure requirements of materials are beyond thescope of this practice.1.3 The values stated in SI units are to be regarded as thestandard.

6、The values given in parentheses are for informationonly.1.4 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 health practices and determine the applica-bilit

7、y of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray (Fog) ApparatusD609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD610 Practice for Evaluating

8、Degree of Rusting on PaintedSteel SurfacesD823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD1014 Practice for Conducting Exterior Exposure Tests ofPaints and Coatings on Metal SubstratesD1654 Test Method for Evaluation of Painted or CoatedS

9、pecimens Subjected to Corrosive EnvironmentsD1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for PaintingD2201 Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and RelatedCoating ProductsD3170 Test Method for Chipping Resistance of Co

10、atingsG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic MaterialsG50 Practice for Conducting Atmospheric Corrosion Testson MetalsG117 Guide for Calculating and Reporting Measures ofPrecision Using Data from Interlaboratory Wear or Ero-sion Tests3. Significance and Use3.1 Tes

11、ts of the type described in this practice may be usedto evaluate the corrosion resistance of organic coatings onmetal products exposed to highly salty environments, such asareas subjected to deicing salts or coastal areas. Exposureconditions are complex and changeable. Important factorsinclude clima

12、te, time of year, presence of pollution, and so1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.27 on Accelerated Testing.Current edition approved Nov. 1, 2011. Published Novem

13、ber 2011. Originallyapproved in 2001. Last previous edition approved in 2006 as D6675 - 01 (2006).DOI: 10.1520/D6675-01R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re

14、fer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.forth. Generally it is difficult, if not impossible, to define ormeasure precisely all the factors that influence degradati

15、on.Repeated exposure testing during different seasons and over aperiod of at least two years is required to obtain resultsrepresentative of any given location.3.2 Control specimens must always be used because this isa comparative test.4. Test Site4.1 LocationThe preferred location for the racks is a

16、cleared, grass covered area. Other conditions can be agreedupon between the parties involved.4.2 Rack Position and Type45 open rack facing theequator, direct weathering unless other conditions are agreedupon between the buyer and seller.NOTE 1Information on location, rack construction, and position

17、aregiven in Practices D1014, G7, and G50.5. Test Specimens5.1 Methods for the preparation of test panels and substratesare given in Practices D609, D1730 and D2201. Practice D823covers techniques for producing uniformly coated test panels.6. Preparation of Test Specimens6.1 Prior to exposure, the or

18、ganic coating shall be subjectedto damage by scribing, chipping or by a method agreed uponbetween all interested parties. Applicable methods for scribingare given in Practice D1654 and for chipping in PracticeD3170.7. Procedure7.1 Attach specimens to an exposure rack facing the equa-tor. Unless othe

19、rwise specified, the rack shall be oriented at anangle of 45 to the horizontal. The panels must be electricallyinsulated from each other and the exposure rack. The use ofinsulators or painting all sides of the specimens to protectagainst galvanic corrosion, are suitable methods for achievingthis.7.2

20、 Unless otherwise specified, twice weekly, at 3 to 4 dayintervals, apply the electrolyte solution to test specimens.Unless otherwise specified, use a 5 % aqueous sodium chloridesolution prepared in accordance with Practice B117. Use ahand pump atomizer or other means to spray the electrolytesolution

21、. Make sure that each specimen is completely wetted.Since the degree of atomization and volume of solution canaffect the corrosion rate, the details of the solution applicationmust be reported. Make sure to use the same applicationconditions each time the electrolyte solution is applied.NOTE 2This t

22、est does not necessarily agree with any other acceleratedtest, or any other natural exposure conducted in severe locations.3,4,5,67.3 The application of electrolyte solution should be per-formed on the scheduled day regardless of the weather condi-tions such as rain or snow. Unless otherwise agreed

23、upon, spraythe panels after the evaporation of the morning dew formation.Do not remove snow and ice from the specimens prior to theelectrolyte solution application.8. Periods of Exposure8.1 The duration of exposure should be specified on one ofthe following bases:8.1.1 Exposure for a specified numbe

24、r of days, months oryears. The report shall indicate exact dates of exposure.8.1.2 Exposure until a specified level of corrosion or deg-radation has occurred.8.1.3 Exposure until a specified amount of corrosion ordegradation has occurred in a standard specimen exposed withthe test specimens.9. Evalu

25、ation of Specimens After Exposure9.1 Evaluate the specimens in accordance with Test MethodD610 and Practice D1654.9.2 Other methods for evaluating test specimens may beused as agreed upon between the buyer and seller.10. Report10.1 Report all the following information, if available:10.1.1 Materials

26、tested and number of specimens obtained,10.1.2 Preparation of the test panel and description of thepaint damage before exposure; scribe, chip or otherwise,10.1.3 Exposure site location include ground cover, rackmaterials or construction and position (angle facing the equa-tor) and possible occurrenc

27、e of natural salt spray,10.1.4 Type of electrolyte solution, application method,sprayer type and interval,10.1.5 Duration of exposure,10.1.6 Exposure dates, and10.1.7 Results of the evaluation.11. Keywords11.1 atmospheric testing; corrosion; exposure tests-exterior3Townsend, H. E., Davidson, D. D.,

28、and Ostermiller, M. R., “Development ofLaboratory Corrosion Tests by the Automotive and Steel Industries of NorthAmerica,” Proceedings of the Fourth International Conference on Zinc andZinc-Alloy Coated Steel Sheet, Iron and Steel Institute of Japan, Tokyo, 1998, pp.659666.4Lutze, F. W., and Shaffer

29、, R. F., “AcceleratedAtmospheric Corrosion Testing ofAISI Panels,” Automotive Corrosion and Prevention Conference Proceedings,P-250, Society of Automotive Engineers, Warrendale, PA, 1991 , pp. 115127.5Davidson, D. D., and Sumacher, W. A., “An Evaluation and Analysis ofCommonly Used Accelerated Cosme

30、tic Corrosion Tests Using Direct Comparisonswith Actual Field Exposure,” Automotive Corrosion and Prevention ConferenceProceedings, P-250, Society of Automotive Engineers, Warrendale, PA, 1991 , pp.205-219.6Simpson, M. W., Van der Linde, W. B., McCune, D. C., and Townsend, H. E.,“License-Plate Cosme

31、tic Corrosion Tests of Automotive Coated Steel Sheet,” PaperNo. 98553 presented at the Symposium on Automotive Corrosion, NACE Interna-tional, March, 1998.D6675 01 (2011)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedi

32、n this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and mu

33、st be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of th

34、eresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views 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 C70

35、0, 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/).D6675 01 (2011)3