ASTM_D_7194_-_19.pdf

Designation:D719419Standard Specification forAerospace Parts Machined from Polychlorotrifluoroethylene(PCTFE)1This standard is issued under the fixed designation D7194;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 specification is intended to be a means of callingout finished machined parts ready for aerospace use.Such partsmay also find use in selected commercial applications wherethere are clear benefits derived from the use of parts with highmolecular weight,good molecular weight retention duringprocessing,dimensional stability,controlled crystallinity,andtightly controlled engineering tolerances.1.2 This specification establishes requirements for partsmachined from virgin,unplasticized,100%polychlorotrifluo-roethylene(PCTFE)homopolymers.1.3 This specification does not cover parts machined fromPCTFE copolymers,PCTFE film or tape less than 0.25-mm(0.010-in.)thick,or modified PCTFE(containing pigments orplasticizers).1.4 This specification does not allow parts containing re-cycled material.1.5 The specification does not cover PCTFE parts intendedfor general use applications,in which control of dimensionalstability,molecular weight,and crystallinity are not as impor-tant.For machined PCTFE parts intended for general use,useSpecification D7211.1.6 This specification classifies parts into three classesbased upon intended uses and exposures:oxygen-containingmedia,reactive media,and inert media.1.7 ApplicationPCTFE components covered by this speci-fication are virgin,100%PCTFE resin,free of plasticizers andother additives.The components are combustion resistant inoxygen,dimensionally stable,and meet other specific physicalcharacteristics appropriate for their end use.They are used invalves,regulators,and other devices in oxygen,air,helium,nitrogen,hydrogen,ammonia,and other aerospace mediasystems.The components typically are used as valve seats,o-rings,seals,and gaskets.They are removed and replacedduring normal maintenance procedures.The components pro-vide reliable sealing surfaces resulting in proper closure ofvalves and related devices and no leakage from the system intothe environment.They will experience static mechanicalloading,cyclic mechanical loading,temperatures ranging fromcryogenic to 71C(160F),and pressures up to 68.9 MPa(10,000,psig)for oxygen and air media,and 103.4 MPa(15,000 psig)for inert media.1.8 The values stated in SI units are to be regarded asstandard.The values in parentheses are for information only.1.9 The following precautionary caveat pertains only to thetest methods portion,Section 13,of this specification:Thisstandard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety,health,andenvironmental practices and determine the applicability ofregulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.1.10 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:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD883 Terminology Relating to PlasticsD1204 Test Method for Linear Dimensional Changes ofNonrigid Thermoplastic Sheeting or Film at ElevatedTemperatureD1430 Classification System for Polychlorotrifluoroethylene(PCTFE)Plastics1This specification is under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials.Current edition approved Aug.1,2019.Published August 2019.Originallyapproved in 2005.Last previous edition approved in 2012 as D5111-12.DOI:10.1520/D7194-19.2For 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.1 D1600 Terminology forAbbreviated Terms Relating to Pla