ASTM_B_311_-_17.pdf

Designation:B31117Standard Test Method forDensity of Powder Metallurgy(PM)Materials ContainingLess Than Two Percent Porosity1This standard is issued under the fixed designation B311;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 This test method covers the determination of density forpowder metallurgy(PM)materials containing less than twopercent porosity and for cemented carbides.This test method isbased on the water displacement method.NOTE1A test specimen that gains mass when immersed in waterindicates the specimen contains surface-connected porosity.Unsealedsurface porosity will absorb water and cause density values higher than thetrue value.This test method is not applicable if this problem occurs.1.2 With the exception of the values for density and themass used to determine density,for which the use of the gramper cubic centimetre(g/cm3)and gram(g)units is the long-standing industry practice,the values in SI units are to beregarded 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.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:2B243 Terminology of Powder MetallurgyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE456 Terminology Relating to Quality and Statistics3.Terminology3.1 Definitions of powder metallurgy(PM)terms can befound in Terminology B243.Additional descriptive material isavailable in the Related Material section of Vol.02.05 of theAnnual Book of ASTM Standards.4.Summary of Test Method4.1 Using an analytical balance,the test specimen is firstweighed in air and then in water.The density is determined bycalculation using Archimedes principle.5.Significance and Use5.1 For PM materials containing less than two percentporosity,a density measurement may be used to determine ifthe part has been densified,either overall or in a critical region,to the degree required for the intended application.Densityalone cannot be used for evaluating the degree of densificationbecause chemical composition and heat treatment affect thepore-free density.5.2 For cemented carbides,a density measurement is nor-mally used to determine if there is any significant deviation incomposition of the carbide grade.For straight tungstencarbide-cobalt grades,the relationship is straightforward.Forcomplex carbide grades(for example,grades containing tan-talum carbide or titanium carbide,or both,in addition totungsten carbide-cobalt),the situation is more complicated.Ifthe measured density is beyond the specified limits,thecomposition is outside of the specified limits.A measureddensity within the specified limits does not ensure correctcomposition;compensation between two or more constituentscould result in the expected density with the wrong composi-tion.Density alone cannot be used for evaluating a cementedcarbide grade.6.Apparatus6.1 Analytical Balanceprecision single-pan analytical bal-ance that will permit readings within 0.01%of the testspecimen mass.The analytical balance shall be supported in a1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.11 on Near Full Density Powder Metallurgy Materials.Current edition approved April 1,2017.Published April 2017.Originallyapproved in 1956.Last previous edition approved in 2008 as B311 08.DOI:10.1520/B0311-17.2For 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 manner to eliminate mech