ASTM G60-2001(2007) Standard Practice for Conducting Cyclic Humidity Exposures《进行循环湿度试验的标准实施规程》.pdf

1、Designation: G 60 01 (Reapproved 2007)Standard Practice forConducting Cyclic Humidity Exposures1This standard is issued under the fixed designation G 60; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A

2、number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for conducting cyclichumidity exposures with a corrosive dip.2It sets forth theconditions required in

3、cyclic humidity testing.1.2 This practice does not prescribe the type of exposurespecimen or exposure periods nor the interpretation to be givento the results.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standar

4、d 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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documen

5、ts2.1 ASTM Standards:3D 1193 Specification for Reagent WaterG1 Practice for Preparing, Cleaning, and Evaluating Cor-rosion Test Specimens3. Significance and Use3.1 The procedure described is used to observe the behaviorof steels under exposure conditions that retard the formation ofa protective type

6、 of rust. It is also used to evaluate seal coat oninsulation.3.2 This practice should not be used to rank steels that forma protective type of rust under atmospheric exposure condi-tions.4. Apparatus4.1 The apparatus required for cyclic humidity exposuresconsists of a test chamber, provisions for he

7、ating the chamber,a humidifying tower, a drying train, a dip mechanism, provi-sions for introducing and draining the solution, a supply ofcompressed air, specimen supports, and necessary means ofcontrol.4.2 The size and detailed construction of the apparatus areoptional, provided the conditions obta

8、ined meet the require-ments of this practice.4.3 Aschematic diagram of the apparatus is shown in Fig. 1.4.4 The apparatus should be capable of providing an 8-hhumidity cycle three times per day, as shown in Fig. 2, and adip cycle once a day.4.4.1 The cyclic variation of humidity can be obtained byva

9、riation of the temperature of the water in the humidifyingtower. The temperature of the water is cycled thermostaticallysuch that the relative humidity of air bubbling through thewater at a minimum rate of 1 L/min (0.04 ft3/min) will varybetween 100 and 50 % when the temperature of the air in thetes

10、t chamber is brought to 52 6 1C (125 6 2F).4.4.2 The range of relative humidity can be extended byadding a drying period to the humidity cycle described above.The minimum relative humidity shall be #20 % and themaximum relative humidity shall be $95 % for each cycle.4.4.3 Drops of solution which acc

11、umulate on the ceiling orcover of the chamber shall not be permitted to fall on thespecimens being exposed.NOTE 1Instruments to continuously record temperature and humidityare not mandatory, but these provide the most reliable and economicalway of recording such information. In the absence of such i

12、nstrumenta-tion, temperature and humidity measurement shall be made, at least twicea day, at the maximum and minimum humidity in a cycle.4.5 Materials of Construction:4.5.1 The test chamber should be made of inert materialssuch as plastics, glass, or metals lined with impervious plastics,rubber or e

13、poxy-type materials, or materials exhibiting equiva-lent corrosion resistance. Material of construction shall be suchthat it will not affect the corrosiveness of the exposureatmosphere.4.5.2 The dip solution container should not be affected by orcause contamination of the dip solution.4.6 Specimen S

14、upports:4.6.1 The specimen-supporting device should not be af-fected by or cause contamination of the dip solution. See Note2.1This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Curr

15、ent edition approved June 1, 2007. Published July 2007. Originally approvedin 1979. Last previous edition approved in 2001 as G 6001.2Opinsky, A. J., Thomson, R. F., and Boegehold, A. L., “A Cyclic HumidityAccelerated Corrosion Test for Sheet Steel,” ASTM Bulletin, January 1953.3For referenced ASTM

16、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 standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohock

17、en, PA 19428-2959, United States.4.6.2 The method of supporting specimens will vary withthe apparatus used for conducting the tests, but should bedesigned to insulate the specimens from each other physicallyand electrically and to insulate the specimens from any metalliccontainer or supporting devic

18、e used within the apparatus. Thespecimens shall not contact any material capable of acting as awick.NOTE 2Suitable materials for the construction or coating of racks andsupports are glass, rubber, plastic, or suitably coated wood. Bare metalshall not be used. Specimens shall preferably be supported

19、from thebottom or the side. Slotted wooden strips are suitable for the support of flatpanels. Suspension from glass hooks or waxed string may be used as longas the specified position of the specimens is obtained, if necessary, bymeans of secondary support at the bottom of the specimens.4.6.3 Shape a

20、nd form of the specimen support should assurefree contact of the specimen with the corrosive solution, theliquid line, or the vapor phase. In a stacked rack, the first andlast specimens should be dummy specimens so that theoutermost exposure specimens are shielded by their neighborsin the same manne

21、r as specimens in the middle of the stack.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemica

22、l Society,where such specifications are available.45.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean distilled or deionizedwater conforming to Type IV reagent water described inSpecification D 1193 except that for this test method the limitsfor chlorides an

23、d sodium may be ignored.5.3 Dip SolutionThe dip solution should be prepared bydissolving 1 % sodium chloride (NaCl), 1 % calcium chloride4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by th

24、e American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Main Parts of the Cyclic Humidity Corrosion Exposure Apparatus (Schemati

25、c)FIG. 2 Humidity Cycle (Schematic)G 60 01 (2007)2(CaCl2), and 0.1 % sulfuric acid (H2SO4) by solution weight inwater. The solution volume to specimen surface area ratioshould be a minimum of 250 mL/cm2.6. Air Supply6.1 The compressed air supply shall be free of oil and dirt.7. Exposure Specimens7.1

26、 The type and number of test specimens to be used, aswell as the criteria for the evaluation of the test results, shall bedefined in the specifications covering the material or productbeing exposed or shall be mutually agreed upon between thepurchaser and the seller.7.2 Strip coupons 75 by 38 by 2 m

27、m (3 by 112 by116 in.)may be preferred as corrosion specimens.7.3 Six to eight identical specimens should be exposed.7.4 Specimens should be prepared, cleaned, and evaluatedin accordance with Practice G1.8. Position of Specimens During Exposure8.1 The position of the specimens in the cyclic humidity

28、chamber during the exposure shall be such that the followingconditions are met:8.1.1 Unless otherwise specified, the specimens shall besupported or suspended between 15 and 30 from the vertical.8.1.2 Each specimen shall be so placed as to permit freesettling of the humidity atmosphere on all specime

29、ns.9. Procedure9.1 Place specimens in the test chamber when the humidityis 100 %.9.2 Keep the chamber shut for the remainder of the expo-sure. Start the first dip cycle immediately after placing thespecimens in the chamber.9.2.1 One dip cycle shall consist of three 5-min immersionperiods. Drain the

30、dip solution from the test chamber for a1-min period between each immersion period.9.2.2 Maintain the dip solution at 52 6 1C (125 6 2F).9.3 Cycle the humidity as shown in Fig. 2 during theexposure period.9.3.1 Maintain the temperature in the test chamber at 52 61C (1256 2F).9.3.2 Operate the dip cy

31、cle once a day at a point in thehumidity cycle when the relative humidity is close to 100 %.9.4 The duration of the exposure should be a minimum of20 days. Longer exposure times may be used depending uponthe purpose of the test. Use fresh dip solution for each test, andchange the dip solution at lea

32、st every 90 days during extendedexposure periods.10. Report10.1 Data for the exposed specimens should include physi-cal dimensions, chemical composition, metallurgical history,surface preparation, and after-exposure cleaning methods.10.2 The report should include the exposure period and themethod of

33、 supporting the specimens in the test chamber.10.3 The results of the exposure should be expressed ascorrosion rate (Practice G1) such as penetration per unit time(for example, millimetre per year), loss in thickness over theexposure period, or plotted as mass loss per unit area versustime.10.4 Any

34、disturbances that significantly alter the prescribedtest conditions invalidate the test. Do not report results fromsuch exposure.11. Keywords11.1 cyclic exposure; exposure cycles; humidity; steels; testequipmentASTM International takes no position respecting the validity of any patent rights asserte

35、d 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 of such rights, are entirely their own responsibility.This standard is subject to revision at any time by th

36、e 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 for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive

37、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 to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Internat

38、ional, 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).G 60 01 (2007)3