ASTM_B_330_-_15.pdf

Designation:B33015Standard Test Methods forEstimating Average Particle Size of Metal Powders andRelated Compounds Using Air Permeability1This standard is issued under the fixed designation B330;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 These test methods use air permeability to determine anenvelope-specific surface area and its associated averageequivalent spherical diameter(from 0.2 to 75m)of metalpowders and related compounds.The powders may be ana-lyzed in their“as-supplied”(shipped,received,or processed)condition or after they have been de-agglomerated or milled bya laboratory procedure(“lab milled”)such as that specified inPractice B859.The values obtained are not intended to beabsolute but are generally useful on a relative basis for controlpurposes.1.2 UnitsWith the exception of the values for density andthe mass used to determine density,for which the use of thegram per cubic centimetre(g/cm3)and gram(g)units is thelongstanding industry practice;and the units for pressure,cmH2O-also long-standing practice;the values in SI units are tobe regarded as standard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B243 Terminology of Powder MetallurgyB859 Practice for De-Agglomeration of Refractory MetalPowders and Their Compounds Prior to Particle SizeAnalysisE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO/DIS Document:3ISO/DIS 10070 Metallic Powders:Determinations ofEnvelope-Specific Surface Area from Measurements ofthe Permeability to Air of a Powder Bed Under Steady-State Flow Conditions3.Terminology3.1 Definitions Many terms used in this test method aredefined in Terminology B243.3.2 Definitions of Terms Specific to This Standard:3.2.1 MIC Sub-sieve AutoSizer(MIC SAS),na commer-cially available permeability instrument for measuring enve-lopespecific surface area and estimating average particle sizefrom 0.2 to 75m.3.2.2 Fisher Sub-Sieve Sizer(FSSS),na commerciallyavailable permeability instrument for measuring envelope-specific surface area and estimating average particle size(Fisher Number)from 0.5 to 50 m.3.2.3 envelope-specific surface area,n specific surfacearea of a powder as determined by gas permeametry inaccordance with ISO/DIS 10070.3.2.4 air permeability,nmeasurement of air pressure dropacross a packed bed of powder.3.2.5 de-agglomeration,nprocess used to break up ag-glomerates of particles.3.2.6 Fisher Number,ncalculated value equated to anaverage particle diameter,assuming all the particles are spheri-cal and of uniform size.3.2.7 Fisher calibrator tube,njewel with a precisionorifice mounted in a tube similar to a sample tube.Thecalibrator tube value is directly traceable to the master tubemaintained by ASTM International Subcommittee B09.03 onRefractory Metal Powders.1These test methods are under the jurisdiction of ASTM Committee B09 onMetal Powders and Metal Powder Products and are the direct responsibility ofSubcommittee B09.03 on Refractory Metal Powders.Current edition approved Oct.1,2015.Published October 2015.Originallyapproved in 1958.Last previous edition approved in 2012 as B330-12.DOI:10.1520/B0330-15.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*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 States1 3.2.8 porosity of a bed of powder,nratio of the volume ofthe void space in the powder bed to the that of the overallvolume of the powder bed.3.2.9 agglomerate,nseveral particles adhering together.3.2.10 average particle size,n(for the purposes of thesetest methods only)an estimate of the equivalent averagespherical particle diameter,calculated from the measuredenvelope-specific surface area,assuming that all the powderparticles are spherical and that all are exactly the same size.4.Significance and Use4.1 These test methods provide procedures for deter