ASTM B527-23

Standard Test Method for Tap Density of Metal Powders and Compounds

SIGNIFICANCE AND USE
4.1 This test method covers the evaluation of the tap density physical characteristic of metal powders and related compounds. The measured tap density bears a relationship to the mass of powder that will fill a fixed volume die cavity or other container in situations where the container is tapped, vibrated, or otherwise agitated. The degree of correlation between the results of this test method and the quality of powders in use will vary with each particular application and has not been fully determined.
SCOPE
1.1 This test method specifies a method for the determination of tap density (packed density) of metal powders and compounds, that is, the density of a powder that has been tapped, to settle contents, in a container under specified conditions.  
1.2 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic centimetre (g/cm3) and gram (g) units is the long-standing industry practice, the values in SI units are to be regarded as standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jan-2023
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.03 - Refractory Metal Powders

Relations

• Refers: ASTM B243-18 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Oct-2018
• Refers: ASTM B243-16 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Jul-2016
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM B243-13 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Nov-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM B243-12 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Jul-2012
• Refers: ASTM B243-11 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Nov-2011
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM B215-10 - Standard Practices for Sampling Metal Powders
• Effective Date: 01-Dec-2010
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM B243-10 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Jan-2010
• Refers: ASTM B243-09a - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Dec-2009
• Refers: ASTM B243-09 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Jan-2009
• Refers: ASTM B215-08 - Standard Practices for Sampling Metal Powders
• Effective Date: 01-Nov-2008

Overview

ASTM B527-23: Standard Test Method for Tap Density of Metal Powders and Compounds sets out the procedure for determining the tap density (packed density) of metal powders and related compounds. Tap density is the density measured after a known mass of powder is mechanically compacted or "tapped" within a graduated container under specified conditions. This physical property plays a vital role in powder metallurgy, additive manufacturing, and materials research, influencing how powders flow and pack in various industrial processes.

This internationally recognized standard is developed by ASTM International’s Committee B09 on Metal Powders and Metal Powder Products. ASTM B527-23 ensures consistency and repeatability in tap density measurements, making it essential for manufacturers, researchers, and quality assurance professionals working with metal powders and powder-based compounds.

Key Topics

• Scope and Applicability: The method is relevant for all types of metal powders and associated compounds, specifying the determination of tap density under defined agitation or tapping.
• Units of Measurement: Density results are reported in grams per cubic centimetre (g/cm³), the standard industry unit.
• Apparatus Requirements: Utilizes high-precision balances, calibrated graduated cylinders, and standardized tapping devices to ensure accuracy and repeatability.
• Test Procedure:
  • Powder samples, typically in three portions, are measured as-received (or sometimes dried under controlled conditions).
  • Measured in a graduated cylinder, the powder is mechanically tapped until the volume stabilizes.
  • The final tap density is calculated by dividing the mass of the powder by its tapped volume.
• Reporting and Precision: The method outlines detailed reporting requirements and provides repeatability and reproducibility limits, supporting credible and traceable results.

Applications

ASTM B527-23 is widely used in industries and research settings that require reliable characterization of metal powder flow and packing behavior:

• Powder Metallurgy: Optimizes die filling efficiency for compacted parts, ensuring component quality and consistent mechanical properties.
• Additive Manufacturing: Determines powder suitability for processes like selective laser sintering (SLS) or direct metal laser sintering (DMLS), which rely on predictable powder flow and packing density.
• Quality Control: Assesses and compares batches of metal powders, monitoring for variations that could impact downstream manufacturing processes.
• Materials Development: Provides critical data for developing new powder blends or evaluating the effects of particle size, shape, or surface coatings.
• Standardization in Procurement: Ensures buyers and suppliers have a common, objective basis for specifying and accepting powder materials.

Related Standards

Several other ASTM standards are referenced and complement ASTM B527-23 in the field of metal powder characterization:

• ASTM B215: Practices for Sampling Metal Powders
  Ensures representative sampling before tap density testing.
• ASTM B243: Terminology of Powder Metallurgy
  Standardizes terminology for clear communication within the industry.
• ASTM E177: Practice for Use of the Terms Precision and Bias in ASTM Test Methods
  Provides guidance for precision and bias statements in test reporting.
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
  Supports the establishment of precision data for laboratory testing procedures.

Conclusion

ASTM B527-23 is an essential standard for evaluating the tap density of metal powders and related compounds, guiding industry best practices and supporting high-quality, repeatable measurements. Adoption of this test method enhances process control, product quality, and supply chain confidence in sectors utilizing metal powders for advanced manufacturing technologies.

Keywords: ASTM B527-23, tap density, metal powders, packed density, powder metallurgy, additive manufacturing, bulk density, quality control, standards, powder testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B527 − 23
Standard Test Method for
Tap Density of Metal Powders and Compounds
This standard is issued under the fixed designation B527; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 3. Terminology
1.1 This test method specifies a method for the determina- 3.1 Definitions—For definitions of terms used in this test
method, see Terminology B243. Additional descriptive PM
tion of tap density (packed density) of metal powders and
compounds, that is, the density of a powder that has been information is available in the Committee Documents section
of the B09 Committee web page.
tapped, to settle contents, in a container under specified
conditions.
4. Significance and Use
1.2 Units—With the exception of the values for density and
4.1 This test method covers the evaluation of the tap density
the mass used to determine density, for which the use of the
physical characteristic of metal powders and related com-
gram per cubic centimetre (g/cm ) and gram (g) units is the
pounds. The measured tap density bears a relationship to the
long-standing industry practice, the values in SI units are to be
mass of powder that will fill a fixed volume die cavity or other
regarded as standard.
container in situations where the container is tapped, vibrated,
1.3 This standard does not purport to address all of the
or otherwise agitated. The degree of correlation between the
safety concerns, if any, associated with its use. It is the
results of this test method and the quality of powders in use
responsibility of the user of this standard to establish appro-
will vary with each particular application and has not been
priate safety, health, and environmental practices and deter-
fully determined.
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor-
5. Apparatus
dance with internationally recognized principles on standard-
5.1 Balance, of appropriate capacity to satisfy the require-
ization established in the Decision on Principles for the
ments shown in Table 1 and accuracy of 6 0.05 g.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
5.2 Graduated Glass Cylinder, calibrated to contain
Barriers to Trade (TBT) Committee.
100 cm at 20 °C, the height of the graduated portion being
approximately 175 mm. The graduations shall be at 1 cm
2. Referenced Documents intervals, thus allowing a measuring accuracy of 60.5 cm . For
apparent densities equal to or greater than 4 g ⁄cm , do not use
2.1 ASTM Standards:
the 100 cm cylinder; see 5.2.1.1.
B215 Practices for Sampling Metal Powders
5.2.1 Alternatively, the following may be used:
B243 Terminology of Powder Metallurgy
5.2.1.1 Graduated Glass Cylinder, calibrated to contain
E177 Practice for Use of the Terms Precision and Bias in
25 cm at 20 °C, the height of the graduated portion being
ASTM Test Methods
approximately 135 mm. The graduations shall be at 0.2 cm
E691 Practice for Conducting an Interlaboratory Study to
intervals, thus allowing a measuring accuracy of 60.1 cm .
Determine the Precision of a Test Method
5.2.1.2 A 25 cm cylinder shall be used for powders of
apparent density equal to or greater than 4 g ⁄cm , in particular
for refractory metal powders.
This test method is under the jurisdiction of ASTM Committee B09 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
5.3 Tapping Apparatus, which permits the tapping of the
mittee B09.03 on Refractory Metal Powders.
graduated cylinder against a firm base. The tapping shall be
Current edition approved Feb. 1, 2023. Published February 2023. Originally
such that a densification of the powder can take place without
approved in 1970. Last previous edition approved in 2022 as B527 – 22. DOI:
10.1520/B0527-23.
any loosening of its surface layers. The stroke shall be 3 mm
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and the tapping frequency shall be between 100 and
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
300 taps ⁄min. An example of a tapping apparatus is shown in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Fig. 1.
*A 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
B527 − 23
TABLE 1 Capacity and Accuracy of the Test Portion Mass and
6.3 The test shall be carried out on three test portions, if
Graduated Cylinder
possible.
Apparent Mass of Test Cylinder Cylinder Measuring
Density Portion Capacity Graduations Accuracy 7. Procedure
3 3 3 3
g/cm g cm cm ±cm
7.1 Clean the inside wall of the graduated cylinder (see 5.2)
<1 50 ± 0.2 100 1 0.5
1 to <4 100 ± 0.5 100 1 0.5
with a suitable clean brush or, if necessary, by rinsing with a
$4 100 ± 0.5 25 0.2 0.1
solvent, such as acetone. If a solvent is used, thoroughly dry
the cylinder before reuse.
7.2 Weigh, to the nearest 0.1 g, the mass of the test portion
as indicated in Table 1, using a balance (see 5.1).
7.3 Pour the test portion into the graduated cylinder. Take
care that a level surface of the powder is formed. Place the
cylinder in the tapping apparatus (see 5.3). Tap the cylinder
until no further decrease in the volume of the powder takes
place (see Note 1).
NOTE 1—In practice, the minimum number of taps, N, such that no
further change in volume takes place would be determined. For all further
tests on the same type of powder, the cylinder would be subjected to 2N
taps, except where general experience and acceptance have established a
specific number of taps (no less than N taps) as being satisfactory. For fine
refractory metal powders, 3000 taps has been found to be satisfactory for
all sizes.
7.4 If the tapped surface is level, read the volume directly. If
the tapped surface is not level, determine the tap volume by
calculating the mean value between the highest and the lowest
reading of the tapped surface. Read the final volume to the
3 3
nearest 0.5 cm when using a 100 cm cylinder and to the
3 3
nearest 0.1 cm when using a 25 cm cylinder.
8. Calculation
8.1 The tap density is given in the following equation
M
TD 5 (1)
V
where:
TD = tap density, g/cm ,
M = mass of powder, g, and
V = volume of tapped powder, cm .
9. Report
9.1 Report the following information:
9.1.1 Reference to this test method;
9.1.2 All details necessary for identification of the test
sample;
9.1.3 The drying
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B527 − 22 B527 − 23
Standard Test Method for
Tap Density of Metal Powders and Compounds
This standard is issued under the fixed designation B527; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method specifies a method for the determination of tap density (packed density) of metal powders and compounds,
that is, the density of a powder that has been tapped, to settle contents, in a container under specified conditions.
1.2 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per
cubic centimetre (g/cm ) and gram (g) units is the long-standing industry practice, the values in SI units are to be regarded as
standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B215 Practices for Sampling Metal Powders
B243 Terminology of Powder Metallurgy
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, see Terminology B243. Additional descriptive PM information
is available in the Committee Documents section of the B09 Committee web page.
4. Significance and Use
4.1 This test method covers the evaluation of the tap density physical characteristic of metal powders and related compounds. The
measured tap density bears a relationship to the mass of powder that will fill a fixed volume die cavity or other container in
This test method is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.03
on Refractory Metal Powders.
Current edition approved March 1, 2022Feb. 1, 2023. Published March 2022February 2023. Originally approved in 1970. Last previous edition approved in 20202022
as B527 – 20.B527 – 22. DOI: 10.1520/B0527-22.10.1520/B0527-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A 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
B527 − 23
situations where the container is tapped, vibrated, or otherwise agitated. The degree of correlation between the results of this test
method and the quality of powders in use will vary with each particular application and has not been fully determined.
5. Apparatus
5.1 Balance, of appropriate capacity to satisfy the requirements shown in Table 1 and accuracy of 6 0.05 g.
5.2 Graduated Glass Cylinder, calibrated to contain 100 cm at 20 °C, the height of the graduated portion being approximately
3 3
175 mm. The graduations shall be at 1 cm intervals, thus allowing a measuring accuracy of 60.5 cm . For apparent densities equal
3 3
to or greater than 4 g ⁄cm , do not use the 100 cm cylinder; see 5.2.1.1.
5.2.1 Alternatively, the following may be used:
5.2.1.1 Graduated Glass Cylinder, calibrated to contain 25 cm at 20 °C, the height of the graduated portion being approximately
3 3
135 mm. The graduations shall be at 0.2 cm intervals, thus allowing a measuring accuracy of 60.1 cm .
3 3
5.2.1.2 A 25 cm cylinder shall be used for powders of apparent density equal to or greater than 4 g ⁄cm , in particular for
refractory metal powders.
5.3 Tapping Apparatus, which permits the tapping of the graduated cylinder against a firm base. The tapping shall be such that
a densification of the powder can take place without any loosening of its surface layers. The stroke shall be 3 mm and the tapping
frequency shall be between 100 and 300 taps ⁄min. An example of a tapping apparatus is shown in Fig. 1.
6. Test Specimen
6.1 For the quantities of powder required for each test, see Table 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 be dried. However,
if the powder is susceptible to oxidation, the drying shall take place in a vacuum or in inert gas. If the powder contains volatile
substances, substances other than water, it shall not be dried.
6.3 The test shall be carried out on three test portions, if possible.
7. Procedure
7.1 Clean the inside wall of the graduated cylinder (see 5.2) with a suitable clean brush or, if necessary, by rinsing with a solvent,
such as acetone. If a solvent is used, thoroughly dry the cylinder before reuse.
7.2 Weigh, to the nearest 0.1 g, the mass of the test portion as indicated in Table 1, using a balance (see 5.1).
7.3 Pour the test portion into the graduated cylinder. Take care that a level surface of the powder is formed. Place the cylinder in
the tapping apparatus (see 5.3). Tap the cylinder until no further decrease in the volume of the powder takes place (see Note 1).
NOTE 1—In practice, the minimum number of taps, N, such that no further change in volume takes place would be determined. For all further tests on
the same type of powder, the cylinder would be subjected to 2N taps, except where general experience and acceptance have established a specific number
of taps (no less than N taps) as being satisfactory. For fine refractory metal powders, 3000 taps has been found to be satisfactory for all sizes.
TABLE 1 Capacity and Accuracy of the Test Portion Mass and
Graduated Cylinder
Apparent Mass of Test Cylinder Cylinder Measuring
Density Portion Capacity Graduations Accuracy
3 3 3 3
g/cm g cm cm ±cm
<1 50 ± 0.2 100 1 0.5
1 to <4 100 ± 0.5 100 1 0.5
$4 100 ± 0.5 25 0.2 0.1
B527 − 23
FIG. 1 Example of Tapping Apparatus
7.4 If the tapped surface is level, read the volume directly. If the tapped surface is not level, determine the tap volume by
calculat
...