ASTM_B_331_-_16.pdf

Designation:B33116Standard Test Method forCompressibility of Metal Powders in Uniaxial Compaction1This standard is issued under the fixed designation B331;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 laboratory test method covers the determination ofthe compressibility of metal powders and metal powder mix-tures as measured by the extent to which a test portion can bedensified under controlled conditions in a specified die.1.2 With the exception of the values for density and mass,for which the use of gram per cubic centermetre(g/cm3)andgram(g)units is the longstanding industry practice,the valuesstated in inch-pound units are to be regarded as standard.Thevalues given in parentheses are mathematical conversions to SIunits that are provided for information only and are notconsidered 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:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyB925 Practices for Production and Preparation of PowderMetallurgy(PM)Test SpecimensB962 Test Methods for Density of Compacted or SinteredPowder Metallurgy(PM)Products Using ArchimedesPrincipleE456 Terminology Relating to Quality and Statistics3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod refer to Terminology B243.Additional descriptive PMinformation is available in the Related Material section of Vol02.05 of the Annual Book of ASTM Standards.4.Summary of Test Method4.1 A test portion of metal powder is uniaxially compressedin a specific die under controlled conditions.4.2 The green density of the resulting compact is deter-mined.4.3 The compressibility of the powder is defined as thegreen density of the test compact at the compacting pressurethat was used.5.Significance and Use5.1 The compressibility value obtained by this test is ameasure of a material characteristic of the powder.5.2 The test method is useful in research and developmentprojects,as a quality control test in the evaluation andmanufacturing control of metal powder production,and as anacceptance test for shipment of metal powder lots.5.3 In PM production operations,the test is helpful indetermining pressing and tooling requirements for high densityparts.5.4 Results may be affected by test conditions such as thetype,amount,and method of lubrication,dwell time duringcompaction,and die material.The compressibility values maynot necessarily agree with results obtained under productionconditions.6.Apparatus6.1 Compacting ToolingA cemented carbide die oralternatively,hardened tool steel die and two hardened steelpunches capable of producing the compressibility test speci-men.The designs shown in Practice B925 for a cylindrical testspecimen and a transverse rupture test specimen are examplesof acceptable tooling.6.2 Powder Compacting PressA compression testing ma-chine or powder compacting press,capable of applying anadequate load with an accuracy of at least 61.0%at a rate ofapproximately 30 tsi/min(400 MPa/min).6.3 BalanceA laboratory balance readable to 0.001 g witha minimum capacity of 100 g to be used to determine the massof the compacted test specimen to the nearest 0.01 g.1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Productsand is the direct responsibility of Subcommit-tee B09.02 on Base Metal Powders.Current edition approved April 1,2016.Published April 2016.Originallyapproved in 1958.Last previous edition approved in 2010 as B331 10.DOI:10.1520/B0331-16.2For 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 States1 6.4 MicrometerStandard outside micrometers or othersuitable measuring instruments for determining the dimensionsof the green compressibility compacts to the nearest 0.0002 in.(0.005 mm).7.Gross Metal Powder Sample7.1 The gross powder sample is a quantity of powder ofsufficient mass to be split into the required number of powdertest portions.It shall be taken from the lot of powder that is tobe tested in accordance with Practices B215.8.Preparation8.1 This test method contains procedures to be followed foreither lubricated or unlubricated metal powders.Lubrication isg