ASTM B923-23
(Test Method)Standard Test Method for Metal Powder Skeletal Density by Helium or Nitrogen Pycnometry
Standard Test Method for Metal Powder Skeletal Density by Helium or Nitrogen Pycnometry
SIGNIFICANCE AND USE
5.1 Both suppliers and users of metals can benefit from knowledge of the skeletal density of these materials. Results of many intermediate and final processing steps are controlled by or related to skeletal density of the metal. In addition, the performance of many sintered or cast metal structures may be predicted from the skeletal density of the starting metal powder, for all or a portion of the finished piece.
SCOPE
1.1 This test method covers determination of skeletal density of metal powders. The test method specifies general procedures that are applicable to many commercial pycnometry instruments. The method provides specific sample outgassing procedures for listed materials. It includes additional general outgassing instructions for other metals. The ideal gas law forms the basis for all calculations.
1.2 This test method does not include all existing procedures appropriate for outgassing metal materials. The included procedures provided acceptable results for samples analyzed during an interlaboratory study. The investigator shall determine the appropriateness of listed procedures.
1.3 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 longstanding industry practice, the values in SI units are to be regarded as standard.
1.4 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.
1.5 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
Relations
Buy Standard
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: B923 − 23
Standard Test Method for
Metal Powder Skeletal Density by Helium or Nitrogen
1
Pycnometry
This standard is issued under the fixed designation B923; 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* B243 Terminology of Powder Metallurgy
E177 Practice for Use of the Terms Precision and Bias in
1.1 This test method covers determination of skeletal den-
ASTM Test Methods
sity of metal powders. The test method specifies general
E691 Practice for Conducting an Interlaboratory Study to
procedures that are applicable to many commercial pycnom-
Determine the Precision of a Test Method
etry instruments. The method provides specific sample outgas-
sing procedures for listed materials. It includes additional
3. Terminology
general outgassing instructions for other metals. The ideal gas
3.1 Definitions:
law forms the basis for all calculations.
3.1.1 Refer to Terminology B243 for additional definitions
1.2 This test method does not include all existing proce-
relating to metal powders.
dures appropriate for outgassing metal materials. The included
3.2 Definitions of Terms Specific to This Standard:
procedures provided acceptable results for samples analyzed
3.2.1 density, n—the mass per unit volume of a material.
during an interlaboratory study. The investigator shall deter-
3.2.2 density, skeletal, n—the ratio of mass of discrete
mine the appropriateness of listed procedures.
pieces of solid material to the sum of the volumes of the solid
1.3 Units—With the exception of the values for density and
material in the pieces and closed pores within the pieces.
the mass used to determine density, for which the use of the
3
3.2.3 outgassing, n—the evolution of gas from a material in
gram per cubic centimetre (g/cm ) and gram (g) units is the
a vacuum or inert gas flow, at or above ambient temperature.
longstanding industry practice, the values in SI units are to be
regarded as standard. 3.2.4 skeletal volume, n—the sum of the volumes of the
solid material in the pieces and closed pores within the pieces.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 An appropriately sized sample (to provide at least the
priate safety, health, and environmental practices and deter-
minimum skeletal volume required for reliable results for the
mine the applicability of regulatory limitations prior to use.
instrument or apparatus used) is outgassed under appropriate
1.5 This international standard was developed in accor-
conditions prior to analysis.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.2 The sample is weighed to nearest 0.0001 g. It is impor-
Development of International Standards, Guides and Recom-
tant to use an analytical balance to determine the sample mass.
mendations issued by the World Trade Organization Technical
The pycnometer measures the total displaced skeletal volume
Barriers to Trade (TBT) Committee.
of the sample under analysis. The sample mass is then used to
calculate the skeletal density of the metal. Any error in the
2. Referenced Documents
sample mass will affect the calculated density. Some cleaning
2
2.1 ASTM Standards:
of the sample surface may take place inside the pycnometer.
B215 Practices for Sampling Metal Powders
Therefore, it is best to reweigh the sample after analysis and
use the final mass when calculating skeletal density.
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal
4.3 Sample skeletal volume is determined a minimum of
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.03 on Refractory Metal Powders.
five times. Skeletal volume average and standard deviation are
Current edition approved Nov. 15, 2023. Published November 2023. Originally
calculated using standard statistical methods.
approved in 2002. Last previous edition approved in 2022 as B923 – 22. DOI:
10.1520/B0923-23.
4.4 Calculations are based on the ideal gas law, as required
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
by the instrument being used for the determination. The
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
assumption of ideal behavior is accepted as valid at analytical
Standards volum
...
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: B923 − 22 B923 − 23
Standard Test Method for
Metal Powder Skeletal Density by Helium or Nitrogen
1
Pycnometry
This standard is issued under the fixed designation B923; 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 covers determination of skeletal density of metal powders. The test method specifies general procedures that
are applicable to many commercial pycnometry instruments. The method provides specific sample outgassing procedures for listed
materials. It includes additional general outgassing instructions for other metals. The ideal gas law forms the basis for all
calculations.
1.2 This test method does not include all existing procedures appropriate for outgassing metal materials. The included procedures
provided acceptable results for samples analyzed during an interlaboratory study. The investigator shall determine the
appropriateness of listed procedures.
1.3 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per
3
cubic centimetre (g/cm ) and gram (g) units is the longstanding industry practice, the values in SI units are to be regarded as
standard.
1.4 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.
1.5 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
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:
1
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 April 1, 2022Nov. 15, 2023. Published April 2022November 2023. Originally approved in 2002. Last previous edition approved in 20212022
as B923 – 21.B923 – 22. DOI: 10.1520/B0923-22.10.1520/B0923-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. 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
1
---------------------- Page: 1 ----------------------
B923 − 23
3.1.1 Refer to Terminology B243 for additional definitions relating to metal powders.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 density, n—the mass per unit volume of a material.
3.2.2 density, skeletal, n—the ratio of mass of discrete pieces of solid material to the sum of the volumes of the solid material in
the pieces and closed pores within the pieces.
3.2.3 outgassing, n—the evolution of gas from a material in a vacuum or inert gas flow, at or above ambient temperature.
3.2.4 skeletal volume, n—the sum of the volumes of the solid material in the pieces and closed pores within the pieces.
4. Summary of Test Method
4.1 An appropriately sized sample (to provide at least the minimum skeletal volume required for reliable results for the instrument
or apparatus used) is outgassed under appropriate conditions prior to analysis.
4.2 The sample is weighed to nearest 0.0001 g. It is important to use an analytical balance to determine the sample mass. The
pycnometer measures the total displaced skeletal volume of the sample under analysis. The sample mass is then used to calculate
the skeletal density of the metal. Any error in the sample mass will affect the calculated density. Some cleaning of the sample
surface ma
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.