ASTM D6675-2001(2006) 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实施规程》.pdf

1、Designation: D 6675 01 (Reapproved 2006)Standard Practice forSalt-Accelerated Outdoor Cosmetic Corrosion Testing ofOrganic Coatings on Automotive Sheet Steel1This standard is issued under the fixed designation D 6675; the number immediately following the designation indicates the year oforiginal ado

2、ption 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.INTRODUCTIONCorrosion of painted sheet steel of auto bodies is classified accordin

3、g to 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

4、 called “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 describe

5、d are 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 thestandar

6、d. 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-bi

7、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray (Fog) ApparatusD 609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD 610 Test Method for Eva

8、luating Degree of Rusting onPainted Steel SurfacesD 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD 1014 Practice for Conducting Exterior Exposure Tests ofPaints and Coatings on Metal SubstratesD 1654 Test Method for Evaluation of Painted

9、 or CoatedSpecimens Subjected to Corrosive EnvironmentsD 1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for PaintingD 2201 Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and RelatedCoating ProductsD 3170 Test Method for Chipping Re

10、sistance of CoatingsG7 Practice for Atmospheric Environmental ExposureTesting of Nonmetallic MaterialsG50 Practice for Conducting Atmospheric Corrosion Testson MetalsG 117 Guide for Calculating and Reporting Measures ofPrecision Using Data from Interlaboratory Wear or Ero-sion Tests3. Significance a

11、nd Use3.1 Tests 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 factors

12、include climate, 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, 2006. Pu

13、blished November 2006. Originallyapproved in 2001. Last previous edition approved in 2001 as D 6675 - 01.2For 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 standar

14、ds 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 degradation.Repeated exposu

15、re 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 acleared, grass cov

16、ered 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 aregiven in Practi

17、ces D 1014, G7, and G50.5. Test Specimens5.1 Methods for the preparation of test panels and substratesare given in Practices D 609, D 1730 and D 2201. PracticeD 823 covers techniques for producing uniformly coated testpanels.6. Preparation of Test Specimens6.1 Prior to exposure, the organic coating

18、shall be subjectedto damage by scribing, chipping or by a method agreed uponbetween all interested parties. Applicable methods for scribingare given in Practice D 1654 and for chipping in PracticeD 3170.7. Procedure7.1 Attach specimens to an exposure rack facing the equa-tor. Unless otherwise specif

19、ied, 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 Unless othe

20、rwise 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. Make sure

21、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 test does not

22、 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 upon, sprayt

23、he 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 number of days, m

24、onths 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. Evaluation of Spe

25、cimens After Exposure9.1 Evaluate the specimens in accordance with Test MethodD 610 and Practice D 1654.9.2 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 tested and

26、 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 occurrence of natur

27、al 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., and Osterm

28、iller, 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, R. F., “

29、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 Cosmetic Corrosi

30、on 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 Cosmetic Corrosio

31、n Tests of Automotive Coated Steel Sheet,” PaperNo. 98553 presented at the Symposium on Automotive Corrosion, NACE Interna-tional, March, 1998.D 6675 01 (2006)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this stan

32、dard. 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 must be revie

33、wed 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 theresponsibl

34、e 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 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).D 6675 01 (2006)3