1、Designation: B331 10Standard 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
2、. 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
3、 by the extent to which a sample can bedensified under controlled conditions in a specified die.1.2 With the exception of density values, for which theg/cm3unit is the industry standard, the values stated ininch-pound units are to be regarded as the standard. The valuesshown in parenthesis are mathe
4、matical conversions to SI unitsthat are presented for information only and are not to beconsidered 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 safe
5、ty 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 Specime
6、nsB962 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 PMinform
7、ation 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 sample 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 c
8、ompressibility 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 deve
9、lopmentprojects, 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
10、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 o
11、r alter-natively, 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 com
12、pression testing ma-chine or powder compacting press, capable of applying anadequate load with an accuracy of at least 61.0 %.6.3 BalanceAlaboratory balance readable to 0.001 g witha minimum capacity of 100 g to be used to determine the masssuitable for weighing at least 100 g to the nearest 0.01 g.
13、1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base Metal Powders.Current edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1958. Last previous edition
14、 approved in 2002 as B331 - 95(2002).DOI:10.1520/B0331-10.2For 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.1*A
15、 Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 MicrometerStandard outside micrometers or othersuitable measuring instruments for determining the dimensionsof the gre
16、en 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 samples. It shall be taken from the lot of powder that is tobe tested in accordance wit
17、h Practice B215.8. Preparation8.1 This test method contains procedures to be followed foreither lubricated or unlubricated metal powders. Lubrication isgenerally necessary to assist in the compaction and ejection ofthe compressibility compact.8.1.1 An alternative way of testing powder not containing
18、 alubricant is to use an otherwise unlubricated die after thor-oughly mixing into the powder a sufficient amount of a suitablelubricant.8.2 Lubricated Powders:8.2.1 Powder mixtures containing a lubricant shall be testedin the as-received condition.8.3 Unlubricated Powders:8.3.1 The needed lubricatio
19、n may be supplied either bylubricating the walls of the die or by mixing a powderedlubricant into the metal powder to be tested.8.3.1.1 Die-wall lubrication consists of coating the walls ofthe die with a thin film of lubricant prior to each compactionstep following the die-wall lubrication procedure
20、 in PracticesB925.8.3.1.2 Admixed lubrication consists of thoroughly mixinga small percentage of a powdered lubricant into the grosssample.8.4 Compressibility test results may vary in accordance withthe method of lubrication, type, and amount of lubricant.8.5 Compressibility test results may vary de
21、pending on therate at which the compacting pressure is applied.8.6 The parties concerned shall agree on the method oflubrication and the details of the procedure.9. Procedure9.1 Testing Methods:9.1.1 The test for compressibility of metal powder may beconducted in any of three ways:9.1.1.1 Method 1Co
22、mpressibility defined as the greendensity obtained at a selected compacting pressure.9.1.1.2 Method 2Compressibility as a graph relating den-sity as a function of at least four compacting pressures.9.1.1.3 Method 3Compressibility defined as the compact-ing pressure required to attain a target green
23、density.9.2 Test Specimens for Powder Compressibility:9.2.1 Either of two compressibility test specimens may beselected to determine compressibility.9.2.1.1 Cylindrical Compressibility Test SpecimenA shortcylindrical compact 1.000 in. in diameter by 0.280 6 0.010 in.thick (25.4 in diameter by 7.11 6
24、 0.25 mm thick), as shown inPractice B925 as Cylindrical Powder Compressibility TestSpecimen.9.2.1.2 Rectangular Compressibility Test SpecimenAshort rectangular compact 1.250 in. long by 0.500 in. wide by0.250 6 0.010 in. thick. (31.8 by 12.7 by 6.35 6 0.25 mm),similar to that which is shown in Prac
25、tices B925 as TransverseRupture Strength Test SpecimenThin.9.2.2 Release the pressure as soon as the maximum pressureis attained, because pressure dwells of as little as 10 s canincrease iron powder compressibility by 0.3 %.9.3 Powder Test Sample:9.3.1 The thickness of the compressibility test speci
26、men iscritical as the area of die wall contact has a strong effect on thegreen density and the thicknesses specified have been deter-mined to give equivalent results between the two powdercompressibility test specimens.9.3.2 The powder test sample shall be a powder charge ofsufficient mass to produc
27、e either a cylindrical test specimen0.280 6 0.010 in. (7.11 6 0.25 mm) thick or a rectangular testspecimen 0.250 6 0.010 in. (6.35 6 0.25 mm) thick.9.3.3 For a powder whose compressibility is not known, itmay be necessary to adjust the mass of the powder chargebased upon the thickness obtained in an
28、 initial test.9.4 Compacting:9.4.1 Compact and identify three (3) duplicate compress-ibility test specimens of the shape that has been selectedfollowing the compacting procedure listed in Practice B925.9.4.2 Be careful to release the load as soon as the maximumpressure is reached as a pressure dwell
29、 of as little as 10 s mayincrease compressibility by as much as 0.3 %.9.4.3 Note the load used, then calculate and record thecompacting pressure based on the pressing area of the selectedcompressibility test specimen.9.4.4 The compressibility compacts may be lightly sandedon fine emery paper to remo
30、ve any flash.9.5 Measurements:9.5.1 Determine the mass of each green compressibility testspecimen to the nearest 0.01 g.9.5.2 Measure the dimensions of each green compressibilitytest specimen to the nearest 0.0002 in.10. Calculations10.1 Calculate the green density of each powder compress-ibility te
31、st specimen as follows:10.1.1 For the Cylindrical Test Specimen:Green Density, DG50.078 3 MD23 T(1)where:DG= green density of the cylindrical compressibility testspecimen, g/cm3.0.078 = combined conversion factor, in.3to cm3and p forthe area calculation.M = mass of the green compressibility test spe
32、cimen, g.D2= diameter of the compact, squared, in.2.T = thickness of the compact, in.10.1.2 For the Rectangular Test Specimens :Green Density, DG50.061 3 ML 3 W 3 T(2)B331 102where:DG= green density of the rectangular compressibilitytest specimen, g/cm3.0.061 = conversion factor, in.3,tocm3.M = mass
33、 of the green compressibility test specimen, g.L = length of the compact, in.W = width of the compact, in.T = thickness of the compact, in.10.2 The density of the green powder compressibility testspecimen may also be determined by the water displacementmethod of Test Method B962.11. Report11.1 Metho
34、d 1Report the compressibility in g/cm3as thearithmetic average of three density measurements, calculatedto the nearest 0.01 g/cm3, at a given compacting pressure. (forexample 6.00 g/cm3at 30 tsi (400 MPa).11.2 Method 2Display the compressibility as a graph ofgreen density as a function of compacting
35、 pressure using atleast four (4) determinations.11.3 Method 3Alternatively, report the compressibility intsi to the nearest 0.5 tsi (10 MPa), as the compacting pressurerequired to reach the specified green density. (for example,30.0 tsi (400 MPa) for a green density of 6.50 g/cm3)11.4 Report the com
36、pact type, thickness, and method oflubrication and the die material.11.4.1 For lubricated powder tested as-received, report thetype and percentage of lubricant, if known.11.4.2 For unlubricated powder tested using die-wall lubri-cation, report the type and amount of lubricant as the masspercent diss
37、olved in the solvent.11.4.3 For unlubricated powder tested after a powder lubri-cant has been admixed, report the type and percentage of thepowder lubricant as well as details of the mixing procedure.12. Precision and Bias312.1 The following precision values were developed fromdata contained in rese
38、arch report RR: B09-1002 collected usingMethod 1 of this test standard.12.1.1 Precision:12.1.1.1 The within-laboratory repeatability limit, r,asde-fined by Terminology E456, is estimated to be 0.025 g/cm3.Duplicate results from the same laboratory should not beconsidered different at the 95 % confid
39、ence level unless theydiffer by more than 0.025 g/cm3.12.1.1.2 The between-laboratories reproducibility limit, R,as defined by Terminology E456 is estimated to be 0.07 g/cm3.Duplicate results from different laboratories should not beconsidered different at the 95 % confidence level unless theydiffer
40、 by more than 0.07 g/cm3.12.1.2 Bias:12.1.2.1 No information can be presented on the bias of theprocedures in this test method for measuring metal powdercompressibility because no material having an accepted refer-ence value is available.12.1.3 Measurement Uncertainty:12.1.3.1 The precision of this
41、test method shall be consid-ered by those performing the test when reporting metal powdercompressibility results.13. Keywords13.1 compressibility; metal powderSUMMARY OF CHANGESCommittee B09 has identified the location of selected changes to this standard since the last issue(B331 - 95(2002) that ma
42、y impact the use of this standard. (October 1, 2010)(1) Subsection 1.2 rewritten.(2) Subection 2.1: Added B925 to illustrate tooling and com-pacts and SI reference; and Terminology E456.(3) Subsection 6: Deleted old references to tooling and madereferral to B925.(4) Subsection 6.3: Rewrote descripti
43、on of balance.(5) Subsection 8.5: Added reference to rate of pressure appli-cation.(6) Subsection 9.1: Made reference to compact in B925.(7) Section 9 has been completely rewritten and have used theterm “Powder Compressibility Test Specimen” to describe thecompact resulting from the test procedure.(
44、8) Subsections 10.1.1 and 10.1.2: Changed the symbol fordensity from Greek rho to D and corrected formula (2), whichlacked a division sign after the first M.(9) Subsection 11.1: Inserted Method 1.(10) Subsection 11.2: Inserted Method 2.(11) Subsection 11.3: Inserted Method 3 and added the word“mean”
45、 to the statistics.(12) Section 12: Reference to RR-B09-1022 added and thesection completely rewritten.(13) Fig. 1 was deleted and replaced by reference to B925.(14) Fig. 2 was deleted and replaced by reference to B925.(15) Changed die material to allow use of tool steel in additionto carbide.3Suppo
46、rting data are available from ASTM Headquarters. Request RR:B09-1002.B331 103ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validi
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49、t received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the
