ASTM_D_7194_-_12.pdf

Designation:D719412Standard 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 withknown or controlled crystallinity,high molecular weight,goodmolecular weight retention during processing,dimensionalstability in the finished part,and tightly controlled engineeringtolerances.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 71 C(160 F),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 12,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 and healthpractices and to determine the applicability of regulatorylimitations prior to use.NOTE1There is no known ISO equivalent to this standard.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 PlasticsD1430 Classification System for Polychlorotrifluoroethylene(PCTFE)PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD1708 Test Method for Tensile Properties of Plastics by Useof Microtensile SpecimensD2512 Test Method for Compatibility of Materials withLiquid Oxygen(Impact Sensitivity Threshold and Pass-Fail Techniques)1This specification is under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials.Current edition approved Oct.1,2012.Published November 2012.Originallyapproved in 2005.Last previous edition approved in 2005 as D5111-05.DOI:10.1520/D7194-12.2For 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 States1 D4591 Test Method for Determining Temperatures andHeats of Transitions of Fluoropolymers by DifferentialScanning CalorimetryD7211 Specification for Parts Machined from Polychlorotri-fluoroethylene(PCTFE)and Intended for General UseG86 Test Method for Determining Ignition Sensitivity ofMaterials to Mechanical Impact in Ambient Liquid Oxy-gen and Pressurized Liquid and Gaseous Oxygen Envi-ronments2.2 Federal Standards3NASA-STD-6001B Flammability,Offgassing,and Compat-ibility Requirements and Test ProceduresMecha