ASTM_D_6944_-_15_2020.pdf

Designation:D694415(Reapproved 2020)Standard Practice forDetermining the Resistance of Cured Coatings to ThermalCycling1This standard is issued under the fixed designation D6944;the number immediately following the designation indicates the year oforiginal adoption 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.1.Scope1.1 This practice determines the resistance of cured coatingsor coating systems to repeated thermal cycles and is designedto assess the effect of thermal cycling on the properties of acoating or coating system.These properties may includeadhesion,resistance to checking,cracking,blistering,or others.This procedure is not intended to provide a quantitativemeasure of the service life that can be expected from a specificcoating system on a given substrate.1.2 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D660 Test Method for Evaluating Degree of Checking ofExterior PaintsD661 Test Method for Evaluating Degree of Cracking ofExterior PaintsD714 Test Method for Evaluating Degree of Blistering ofPaintsD3359 Test Methods for Rating Adhesion by Tape TestD4541 Test Method for Pull-Off Strength of Coatings UsingPortable Adhesion TestersD6132 Test Method for Nondestructive Measurement of DryFilm Thickness of Applied Organic Coatings Using anUltrasonic Coating Thickness GageD6677 Test Method for Evaluating Adhesion by KnifeD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic,Nonconductive Coat-ings Applied to Non-Ferrous MetalsD7234 Test Method for Pull-Off Adhesion Strength of Coat-ings on Concrete Using Portable Pull-Off Adhesion Tes-tersG147 Practice for Conditioning and Handling of Nonmetal-lic Materials for Natural and Artificial Weathering Tests3.Summary of Test Methods3.1 Test Method ACured test specimens are subjected to30 thermal cycles of immersion,freezing and heating.3.2 Test Method BCured test specimens are subjected to30 thermal cycles of freezing and heating.4.Significance and Use4.1 The purpose of this test is to obtain information on theability of a coating system to adhere to substrates underthermal stress.It is assumed that the coating systems tested areapplied and cured according to the coating manufacturersinstructions.TEST METHOD AFREEZE/THAW/IMMERSION5.Apparatus5.1 Thermal Cycling Apparatus:5.1.1 The thermal cycling apparatus shall consist of asuitable chamber or chambers in which the test specimens mayundergo the specified cycle.Ideally,a chamber which containsheating and refrigeration equipment and immersion capabilitiesin the same unit should be used.This chamber shall have theability to maintain continuous reproducible cycles within thespecified temperature requirements.In the event that an appa-ratus having freezing,heating,and immersion capabilities isnot available,separate equipment for freezing,heating andimmersion may be used.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Feb.1,2020.Published February 2020.Originallyapproved in 2003.Last previous edition approved in 2015 as D6944 15.DOI:10.1520/D6944-15R20.2For 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 standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.5.1.2 The chamber or chambers shall have the ability tomaintain a constant temperature during each of the respectivetemperature intervals as specified by the procedure.5.1.3 The samples shall be arranged to minimize contactwith the chamber surfaces or any mounting racks,and tomaximize air flow.5.1.4 The temperature of t