ASTM_G_60_-_01_2013.pdf

Designation:G6001(Reapproved 2013)Standard Practice forConducting Cyclic Humidity Exposures1This standard is issued under the fixed designation G60;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()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 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 asstandard.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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion 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 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 heating 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 obtained 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 byvariation 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 thetest 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 accumulate on the ceiling orcover of the chamber shall not be permitted to fall on thespecimens being exposed.NOTE1Instruments to continuously record temperature and humidityare not mandatory,but these provide the most reliable and economicalwayofrecordingsuchinformation.Intheabsenceofsuchinstrumentation,temperature and humidity measurement shall be made,atleast twice a 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 epoxy-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.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.Current edition approved May 1,2013.Published July 2013.Originally approvedin 1979.Last previous edition approved in 2007 as G6001(2007).DOI:10.1520/G0060-01R13.2Opinsky,A.J.,Thomson,R.F.,and Boegehold,A.L.,“A Cyclic HumidityAccelerated Corrosion Test for Sheet Steel,”ASTM Bulletin,January 1953.3For referenced ASTM 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.6 Specimen Supports:4.6.1 The specimen-supporting device should not be af-fected by or cause contamination of the dip solution.See Note2.4.6.2 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 metalliccon