ASTM_D_5638_-_18.pdf

Designation:D563818Standard Test Method forChemical Resistance of Electrical Insulating Varnishes1This standard is issued under the fixed designation D5638;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.Scope*1.1 This test method covers the mechanical performance ofinsulating varnishes after exposure to various chemicals.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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.See 7.1.NOTE1There is no IEC/ISO equivalent.1.4 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:2D2519 Test Method for Bond Strength of Electrical Insulat-ing Varnishes by the Helical Coil Test3.Terminology3.1 See Test Method D2519.4.Summary of Test Method4.1 Flexural strength tests are made on varnish-treatedhelical coils to determine the force required to break the coilunder specified conditions both before and after exposure toliquid chemicals.5.Significance and Use5.1 This test method is useful for the evaluation of insulat-ing varnish performance in chemical exposure.6.Apparatus6.1 Tensile Testing MachineSee Test Method D2519.6.2 Test FixtureSee Test Method D2519.6.3 Chemical ContainersSealable 1000-mL containers ofsuitable material and design for containing the chemicals to beused.7.Safety Precautions7.1 It is unsafe to use varnish at temperatures above theflash point without adequate ventilation,especially if thepossibility exists that flames or sparks are present.Storevarnish in sealed containers.8.Test Specimen8.1 Prepare a minimum of five test specimens for eachchemical solution to be tested and a minimum of five todetermine unconditioned bond strength in accordance with TestMethod D2519 using a wire mutually agreed upon by supplierand user.9.Procedure9.1 Condition a minimum of five test specimens in eachchemical.Chemicals,test temperature,and conditioning timeare mutually agreed upon by supplier and user.9.2 Test specimens both conditioned and unconditioned asdescribed in Test Method D2519 at 23 6 2C and less than55%RH.Test conditioned specimens within 15 min ofremoval from container to minimize any change in bondstrength after exposure.Rinse conditioned specimens withwater and pat dry when water soluble chemicals were used forconditioning.Otherwise wipe specimens to remove excesschemical.10.Report10.1 Report the following information:10.1.1 Description of varnish,10.1.2 Identification of wire used,1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Products.Current edition approved Nov.1,2018.Published November 2018.Originallyapproved in 1994.Last previous edition approved in 2014 as D5638 14.DOI:10.1520/D5638-18.2For 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.*A Summary of Changes section appears at the end of this standardCopyright 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.1 10.1.3 Cure time and temperature and number of dips usedto prepare the coils,10.1.4 Average bond strength in newtons(pounds-force)ofunconditioned coils,10.1.5 Average bond strength in newtons(pounds-force)ofconditioned coils,10.1.6 Description of chemical,exposure temperature,andexposure time to which the specimens were subjected,and10.1.7 Percent retention of bond strength after conditioningper the formula below.%Retained Bond Strength5Average Bond StrengthfconditionedgAverage Bond Strengthfunconditionedg310011.Precision and Bias11.1 PrecisionNo information has been presented toASTM upon which to base a statement of precision.Noactivity has been planned to develo