1、Designation: B527 14Standard Test Method forDetermination of Tap Density of Metal Powders andCompounds1This standard is issued under the fixed designation B527; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 test method specifies a method for the determina-tion of tap density (packed density) of metal powders andcompounds, that
3、is, the density of a powder that has beentapped, to settle contents, in a container under specifiedconditions.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 indu
4、stry 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 a
5、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE6
6、91 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions of Terms Specific to This Standard:Termsused in this test method are defined in B243.4. Significance and Use4.1 This test method covers the evaluation of the tap densityphysica
7、l characteristic of metal powders and related com-pounds. The degree of correlation between the results of thistest method and the quality of powders in use will vary witheach particular application and has not been fully determined.5. Apparatus5.1 Balance, of appropriate capacity to satisfy the req
8、uire-ments shown in Table 1 and accuracy of 6 0.05 g.5.2 Graduated Glass Cylinder, calibrated to contain 100cm3at 20 C, the height of the graduated portion beingapproximately 175 mm. The graduations shall be at 1 cm3intervals, thus allowing a measuring accuracy of 60.5 cm3. Forapparent densities ove
9、r 4 g/cm3, do not use the 100 cm3cylinder, see section 5.2.1.1.5.2.1 Alternatively, the following may be used:5.2.1.1 Graduated Glass Cylinder, calibrated to contain 25cm3at 20 C, the height of the graduated portion beingapproximately 135 mm. The graduations shall be at 0.2 cm3intervals, thus allowi
10、ng a measuring accuracy of 60.1 cm3.5.2.1.2 A 25 cm3cylinder shall be used for powders ofapparent density higher than 4 g/cm3, in particular for refrac-tory metal powders.5.3 Tapping Apparatus, which permits the tapping of thegraduated cylinder against a firm base. The tapping shall besuch that a de
11、nsification of the powder can take place withoutany loosening of its surface layers. The stroke shall be 3 mmand the tapping frequency shall be between 100 and 300taps/min. An example of a tapping apparatus is shown in Fig.1.6. Test Specimen6.1 For the quantities of powder required for each test, se
12、eTable 1. Obtain test portions according to Practices B215.6.2 In general, the powder should be tested in the as-received condition. In certain instances the powder may bedried. However, if the powder is susceptible to oxidation, thedrying shall take place in a vacuum or in inert gas. If thepowder c
13、ontains volatile substances, it shall not be dried.1This specification is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.03 on Refractory Metal Powders.Current edition approved April 1, 2014. Published Augu
14、st 2014. Originallyapproved in 1970. Last previous edition approved in 2006 as B527 2006. DOI:10.1520/B0527-14.2For 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 s
15、tandards 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 States16.3 The test shall be carried out on three test portions, ifpossible.7.
16、 Procedure7.1 Clean the inside wall of the graduated cylinder (see 5.2)with a suitable clean brush or, if necessary, by rinsing with asolvent, such as acetone. If a solvent is used, thoroughly drythe cylinder before reuse.7.2 Weigh, to the nearest 0.1 g, the mass of the test portionas indicated in T
17、able 1, using a balance (see 5.1).7.3 Pour the test portion into the graduated cylinder. Takecare that a level surface of the powder is formed. Place thecylinder in the tapping apparatus (see 5.3). Tap the cylinderuntil no further decrease in the volume of the powder takesplace (see Note 1).NOTE 1In
18、 practice, the minimum number of taps, N, such that nofurther change in volume takes place would be determined. For all furthertests on the same type of powder, the cylinder would be subjected to 2Ntaps, except where general experience and acceptance have established aspecific number of taps (no les
19、s than N taps) as being satisfactory. For finerefractory metal powders, 3000 taps has been found to be satisfactory forall sizes.7.4 If the tapped surface is level, read the volume directly. Ifthe tapped surface is not level, determine the tap volume bycalculating the mean value between the highest
20、and the lowestreading of the tapped surface. Read the final volume to thenearest 0.5 cm3when using a 100 cm3cylinder and to thenearest 0.2 cm3when using a 25 cm3cylinder.8. Calculation8.1 The tap density is given in the following equationTD 5MV(1)where:TD = tap density, g/cm3,M = mass of powder, g,
21、andV = volume of tapped powder, cm3.9. Report9.1 Report the following information:9.1.1 Reference to this test method,9.1.2 All details necessary for identification of the testsample,9.1.3 The drying procedure, if the powder has been dried,9.1.4 Cylinder capacity, mass of test portion and methodused
22、,9.1.5 All results obtained. Report tap density to the nearest0.1 g/cm3for powders with apparent densities up to andincluding 4 g/cm3. For powders with apparent densities higherthan 4 g/cm3, report to the nearest 0.2 g/cm3;9.1.6 All operations not specified in this test method orregarded as optional
23、, and9.1.7 Details of any occurrence that may have affected theresult.10. Precision and Bias10.1 PrecisionThe precision of this test method is basedon an intralaboratory study of Test Method B527, conducted in20112012. A single laboratory with two operators analyzedthree different powders for tap de
24、nsity. Either 10 or 20replicates were reported for each material in this study. Exceptfor testing in just one lab, Practice E691 was followed for thestudy design; the details are given in ASTM Research ReportNo. RR:B09-1020.3The precision statement was determined3Supporting data have been filed at A
25、STM International Headquarters and maybe obtained by requesting Research Report RR:B09-1020. ContactASTM CustomerService at serviceastm.org.TABLE 1 Capacity and Accuracy of the Test Portion Mass andGraduated CylinderApparentDensityg/cm3Mass of TestPortiongCylinderCapacitycm3CylinderAccuracycm34 100
26、0.5 25 0.2FIG. 1 Example of Tapping ApparatusB527 142through statistical examination of 50 results, from a singlelaboratory, testing three materials. The materials were desig-nated in the study as:1. Cermet (TiC based), apparent density 1.02 g/cm32. Iron (Ancorsteel 1000), apparent density 2.92 g/cm
27、33. Tungsten carbide (WC), apparent density 6.91 g/cm310.1.1 Test ResultsThe precision information presentedherein has been calculated for the comparison of threematerials, each of which is the mathematical average of ten ortwenty individual test determinations.10.1.1.1 95 % Repeatability Limit (r)T
28、wo test resultsobtained within one laboratory shall be judged not equivalentif they differ by more than the r value for that material; r is theinterval representing the critical difference between two testresults for the same material, using the same mass andappropriate volumetric cylinder capacity
29、according to Table 1.Repeatability limits are listed in Table 2. The within-laboratoryrepeatability limit, r, as defined by Terminology E456,isdependent on the apparent density of the tested material (seeTable 2). At the 95 % confidence level, duplicate tap densityresults from the same laboratory sh
30、ould not be considered to bedifferent unless they differ by more than r.10.1.1.2 Reproducibility Limit (R)The reproducibilitylimit of this test method is being determined and will beavailable in December, 2019. Reproducibility results cannot bedetermined from a single laboratory study.10.2 BiasNo in
31、formation can be presented on the bias ofthe procedure in Test Method B527 for measuring tap densitybecause no material having an accepted reference value isavailable.10.3 The above terms (“repeatability limit” and “reliabilitylimit”) are used as specified in Practice E177.10.4 Any judgment in accor
32、dance with statement 10.1.1would normally have an approximate 95 % probability ofbeing correct, however because of the limited number ofparticipants in this study, consider the precision noted as anestimate.11. Keywords11.1 apparent density; bulk density; density; density ratio;metal powders; packed
33、 density; powder metallurgy; tap densitySUMMARY OF CHANGESCommittee B09 has identified the location of selected changes to this standard since the last issue (B527 06)that may impact the use of this standard. (Approved April 1, 2014.)(1) Changed “metallic” to “metal” in the title.(2) Section 3 on Te
34、rminology was added and subsequentsections were renumbered.(3) Units statement added to the Scope, Section 1, indicatingthat the standard uses SI, and removed inch-pound units.(4) Minor editorial changes were made throughout.(5) Clarifications in some sections regarding accuracy.(6) In 5.2.1.2, dele
35、te phrase allowing the use of 25 cm3cylinder for lower density powders. A larger volume cylindermust be used for powders with density less than 4 g/cm3.(7) Replacement of Table 1. Mass of sample used and capacityof the graduated cylinder was modified to be consistent withother international standard
36、s following the analysis of pub-lished data.(8) Addition of data in Section 10.(9) Changes made to acronyms to conform with newly ac-cepted B09 Policy Guide, e.g., Ptfor tap density is now TD.ASTM International takes no position respecting the validity of any patent rights asserted in connection wit
37、h any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible techn
38、ical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful considerati
39、on at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not 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 Har
40、bor 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
41、.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 2 Tap Density (g/cm3)Material(100 gm per run)CylinderCapacitycm3AverageAxRepeatabilityStandardDeviationsrRepeatabilityLimitrCermet 20replicates100 1.6 0.02 0.06Iron 20 replicates 100 3.7 0.10 0.29Tungsten Carbide(WC) 10 replicates25 8.2 0.07 0.20AThe average of the laboratories calculated averages.B527 143
