ASTM B311-22

Standard Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than Two Percent Porosity

SIGNIFICANCE AND USE
5.1 For PM materials containing less than two percent porosity, a density measurement may be used to determine if the part has been densified, either overall or in a critical region, to the degree required for the intended application. Density alone cannot be used for evaluating the degree of densification because chemical composition and heat treatment affect the pore-free density.  
5.2 For cemented carbides, a density measurement is normally used to determine if there is any significant deviation in composition of the carbide grade. For straight tungsten carbide-cobalt grades, the relationship is straightforward. For complex carbide grades (for example, grades containing tantalum carbide or titanium carbide, or both, in addition to tungsten carbide-cobalt), the situation is more complicated. If the measured density is beyond the specified limits, the composition is outside of the specified limits. A measured density within the specified limits does not ensure correct composition; compensation between two or more constituents could result in the expected density with the wrong composition. Density alone cannot be used for evaluating a cemented carbide grade.
SCOPE
1.1 This test method covers the determination of density for powder metallurgy (PM) materials containing less than two percent porosity and for cemented carbides. This test method is based on the water displacement method.  
Note 1: A test specimen that gains mass when immersed in water indicates the specimen contains surface-connected porosity. Unsealed surface porosity will absorb water and result in calculated density values higher than the true value. This test method is not applicable if this problem occurs, and Test Methods B962 should be used instead.  
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. The values given in parentheses after SI units are provided for information only and are not considered 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-Aug-2022
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.11 - Near Full Density Powder Metallurgy Materials

Relations

• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM B243-18 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Oct-2018
• Refers: ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM B243-16 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Jul-2016
• Refers: ASTM B962-15 - Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
• Effective Date: 01-Apr-2015
• Refers: ASTM B962-14 - Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
• Effective Date: 01-Sep-2014
• Refers: ASTM E456-13a - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM E456-13ae2 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Nov-2013
• Refers: ASTM B243-13 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Nov-2013
• Refers: ASTM E456-13 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 15-Aug-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 B962-13 - Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
• Effective Date: 01-Apr-2013

Overview

ASTM B311-22: Standard Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than Two Percent Porosity provides a reliable procedure for measuring the density of PM materials and cemented carbides with very low porosity. This test method is based on the water displacement technique, utilizing Archimedes’ principle to calculate density with high precision. Accurate density measurement is essential for quality assurance, research, and production in powder metallurgy and hard metal applications.

ASTM B311-22 is recognized internationally and developed in alignment with globally accepted standardization principles. The standard is widely used in industries involved with metal powders, cemented carbides, and metal injection molded (MIM) parts.

Key Topics

• Applicability: Intended for PM materials with less than 2% porosity and cemented carbides. Density measurement helps assess the degree of densification required for an application.
• Methodology: Utilizes water displacement, with an analytical balance for weighing the specimen in air and water. Special preparation and cleaning of test specimens are necessary for accuracy.
• Precision and Limits: The method cannot be used for samples with significant surface-connected porosity, as water absorption can cause incorrect results. For affected samples, an alternative method such as ASTM B962 is recommended.
• Cemented Carbides: Density measurement is particularly useful to monitor compositional deviations in cemented carbides, such as tungsten carbide-cobalt grades. However, density alone cannot confirm correct composition for complex grades.
• Units: Density is typically reported in grams per cubic centimeter (g/cm³), following industry standards.
• Quality Assurance: The procedure includes recommendations for calibration and repeatability within and between laboratories, ensuring reliable and reproducible results.

Applications

ASTM B311-22 is vital across sectors that produce or utilize powder metallurgy components, including but not limited to:

• Quality Control: Ensures PM parts, cemented carbides, and MIM components meet densification criteria and specification requirements.
• Material Characterization: Helps determine if manufacturing and processing steps achieve the targeted densification, directly influencing part performance and service life.
• Compliance and Certification: Used by manufacturers and testing laboratories for product certification and regulatory compliance in global markets.
• Component Evaluation: Useful in the automotive, aerospace, tooling, and industrial machinery sectors where high-density PM parts are critical for strength, durability, and wear resistance.

Related Standards

To ensure comprehensive and accurate evaluation of powder metallurgy materials and products, the following related standards are often referenced alongside ASTM B311-22:

• ASTM B243: Terminology of Powder Metallurgy
• ASTM B962: Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle - for materials with higher porosity or surface-connected pores.
• ASTM E456: Terminology Relating to Quality and Statistics
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Conclusion

ASTM B311-22 offers a rigorous and accurate method for determining the density of low-porosity powder metallurgy materials and cemented carbides. Its use of water displacement under precisely controlled conditions supports quality assurance in manufacturing and research. The standard plays a critical role in ensuring the integrity and reliability of high-performance PM parts and hard metals in demanding industrial applications. For materials with greater porosity or surface absorption, ASTM B962 provides an appropriate alternative test method.

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: B311 − 22
Standard Test Method for
Density of Powder Metallurgy (PM) Materials Containing
Less Than Two Percent Porosity
This standard is issued under the fixed designation B311; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* B962 Test Methods for Density of Compacted or Sintered
Powder Metallurgy (PM) Products Using Archimedes’
1.1 This test method covers the determination of density for
Principle
powder metallurgy (PM) materials containing less than two
E456 Terminology Relating to Quality and Statistics
percent porosity and for cemented carbides.This test method is
E691 Practice for Conducting an Interlaboratory Study to
based on the water displacement method.
Determine the Precision of a Test Method
NOTE 1—A test specimen that gains mass when immersed in water
indicates the specimen contains surface-connected porosity. Unsealed
3. Terminology
surface porosity will absorb water and result in calculated density values
higher than the true value. This test method is not applicable if this
3.1 Definitions of powder metallurgy (PM) terms can be
problem occurs, and Test Methods B962 should be used instead.
found in Terminology B243.Additional descriptive material is
1.2 Units—With the exception of the values for density and available under “General Information on PM” on the ASTM
the mass used to determine density, for which the use of the
B09 web page.
gram per cubic centimetre (g/cm ) and gram (g) units is the
long-standing industry practice, the values in SI units are to be
4. Summary of Test Method
regarded as standard. The values given in parentheses after SI
4.1 Using an analytical balance, the test specimen is first
units are provided for information only and are not considered
weighed in air and then in water. The density is determined by
standard.
calculation using Archimedes’ principle.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 For PM materials containing less than two percent
priate safety, health, and environmental practices and deter-
porosity, a density measurement may be used to determine if
mine the applicability of regulatory limitations prior to use.
the part has been densified, either overall or in a critical region,
1.4 This international standard was developed in accor-
to the degree required for the intended application. Density
dance with internationally recognized principles on standard-
alone cannot be used for evaluating the degree of densification
ization established in the Decision on Principles for the
because chemical composition and heat treatment affect the
Development of International Standards, Guides and Recom-
pore-free density.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 5.2 For cemented carbides, a density measurement is nor-
mally used to determine if there is any significant deviation in
2. Referenced Documents
composition of the carbide grade. For straight tungsten
2.1 ASTM Standards:
carbide-cobalt grades, the relationship is straightforward. For
B243 Terminology of Powder Metallurgy
complex carbide grades (for example, grades containing tan-
talum carbide or titanium carbide, or both, in addition to
This test method is under the jurisdiction of ASTM Committee B09 on Metal
tungsten carbide-cobalt), the situation is more complicated. If
Powders and Metal Powder Products and is the direct responsibility of Subcom-
the measured density is beyond the specified limits, the
mittee B09.11 on Near Full Density Powder Metallurgy Materials.
composition is outside of the specified limits. A measured
Current edition approved Sept. 1, 2022. Published September 2022. Originally
density within the specified limits does not ensure correct
approved in 1956. Last previous edition approved in 2017 as B311 – 17. DOI:
10.1520/B0311-22.
composition; compensation between two or more constituents
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
could result in the expected density with the wrong composi-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
tion. Density alone cannot be used for evaluating a cemented
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. carbide grade.
*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
B311 − 22
A
TABLE 2 Density of Air-Free Water
6. Apparatus
Temperature ρ Temperature ρ
w w
6.1 AnalyticalBalance—Precisionsingle-pananalyticalbal- 3 3
°C g/cm °F g/cm *
ance that will permit readings within 0.01% of the test 15.0 0.9991 60 0.9990
15.5 0.9990 61 0.9989
specimen mass. See Table 1. The analytical balance shall be
16.0 0.9989 62 0.9988
supported in a manner to eliminate mechanical vibrations and
16.5 0.9988 63 0.9987
be shielded from air drafts. 17.0 0.9988 64 0.9986
17.5 0.9987 65 0.9985
6.2 Water—Distilled or deionized and preferably degassed
18.0 0.9986 66 0.9984
18.5 0.9985 67 0.9983
water to which 0.05 to 0.1 volume percent of a wetting agent
19.0 0.9984 68 0.9982
has been added to reduce the effects of surface tension. The
19.5 0.9983 69 0.9981
density of distilled water changes as a function of water
20.0 0.9982 70 0.9980
20.5 0.9981 71 0.9978
temperature and therefore should be accounted for when
21.0 0.9980 72 0.9977
calculating the density of the specimen; see Table 2.
21.5 0.9979 73 0.9975
22.0 0.9978 74 0.9974
NOTE 2—Degassing the water by evacuation, boiling, or ultrasonic
22.5 0.9976 75 0.9973
agitation helps to prevent air bubbles from collecting on the test specimen
23.0 0.9975 76 0.9972
and specimen support when immersed in water.
23.5 0.9974 77 0.9970
24.0 0.9973 78 0.9969
6.3 Water Container—A glass beaker or other suitable
24.5 0.9972 79 0.9967
transparent container should be used to contain the water.
25.0 0.9970 80 0.9966
25.5 0.9969 81 0.9964
NOTE 3—A transparent container makes it easier to see air bubbles
26.0 0.9968 82 0.9963
adhering to the test specimen and specimen support when immersed in
26.5 0.9966 83 0.9961
water.
27.0 0.9965 84 0.9959
NOTE 4—For the most precise density determination, the water con- 27.5 0.9964 85 0.9958
tainershouldbeofasizethatthelevelofthewaterdoesnotrisemorethan 28.0 0.9962 86 0.9956
28.5 0.9961
2.5 mm (0.10 in.) when the test specimen is lowered into the water.
29.0 0.9959 *Interpolated from
6.4 Test Specimen Support for Weighing in Water—Two
29.5 0.9958 °C Data
30.0 0.9956
typical arrangements are shown in Fig. 1. The suspension wire
A
may be twisted around the test specimen, or the test specimen Metrological Handbook 145, “Quality Assurance for Measurements,” National
Institute of Standards and Technology, 1990, p. 9.10.
may be supported in a wire basket that is attached to the
suspension wire. For either arrangement, a single corrosion
resistant wire—for example, austenitic stainless steel, copper,
nichrome—shall be used for the basket and suspension wire.
whichanairbubblemayadhere.A100-gritsandingorabrasive
For the maximum recommended diameter of suspension wire
grinding is recommended to remove all rough surfaces.
to be used for various mass ranges, see Table 3.
8. Procedure
NOTE 5—For the most precise density determinations, it is important
that the mass and volume of all supporting wires immersed in water be 8.1 The part or test specimen, the analytical balance and
minimized.
surrounding air shall be at a uniform temperature when
weighing is performed.
6.5 Thermometer—A thermometer to measure the tempera-
ture of the water to the nearest 0.5 °C (1 °F).
8.2 For the most precise density determinations, duplicate
weighings should be made for all mass measurements. A
...

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: B311 − 17 B311 − 22
Standard Test Method for
Density of Powder Metallurgy (PM) Materials Containing
Less Than Two Percent Porosity
This standard is issued under the fixed designation B311; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method covers the determination of density for powder metallurgy (PM) materials containing less than two percent
porosity and for cemented carbides. This test method is based on the water displacement method.
NOTE 1—A test specimen that gains mass when immersed in water indicates the specimen contains surface-connected porosity. Unsealed surface porosity
will absorb water and cause result in calculated density values higher than the true value. This test method is not applicable if this problem occurs.occurs,
and Test Methods B962 should be used instead.
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. The values given in parentheses after SI units are provided for information only and are not considered 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 safety, health, and healthenvironmental 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:
B243 Terminology of Powder Metallurgy
B962 Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E456 Terminology Relating to Quality and Statistics
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 B09.11
on Near Full Density Powder Metallurgy Materials.
Current edition approved April 1, 2017Sept. 1, 2022. Published April 2017September 2022. Originally approved in 1956. Last previous edition approved in 20082017 as
B311 – 08.B311 – 17. DOI: 10.1520/B0311-17.10.1520/B0311-22.
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
B311 − 22
3. Terminology
3.1 Definitions of powder metallurgy (PM) terms can be found in Terminology B243. Additional descriptive material is available
in the Related Material section of Vol. 02.05 of the under “General Information on PM” on the Annual Book of ASTM
Standards.ASTM B09 web page.
4. Summary of Test Method
4.1 Using an analytical balance, the test specimen is first weighed in air and then in water. The density is determined by calculation
using Archimedes’ principle.
5. Significance and Use
5.1 For PM materials containing less than two percent porosity, a density measurement may be used to determine if the part has
been densified, either overall or in a critical region, to the degree required for the intended application. Density alone cannot be
used for evaluating the degree of densification because chemical composition and heat treatment affect the pore-free density.
5.2 For cemented carbides, a density measurement is normally used to determine if there is any significant deviation in
composition of the carbide grade. For straight tungsten carbide-cobalt grades, the relationship is straightforward. For complex
carbide grades (for example, grades containing tantalum carbide or titanium carbide, or both, in addition to tungsten
carbide-cobalt), the situation is more complicated. If the measured density is beyond the specified limits, the composition is outside
of the specified limits. A measured density within the specified limits does not ensure correct composition; compensation between
two or more constituents could result in the expected density with the wrong composition. Density alone cannot be used for
evaluating a cemented carbide grade.
6. Apparatus
6.1 Analytical Balance—precisionPrecision single-pan analytical balance that will permit readings within 0.01% of the test
specimen mass. See Table 1. The analytical balance shall be supported in a manner to eliminate mechanical vibrations and be
shielded from air drafts. See Table 1.
6.2 Weighing Liquid—Water—Distilled or deionized and preferably degassed water to which 0.05 to 0.1 volume percent of a
wetting agent has been added to reduce the effects of surface tension. The density of distilled water changes as a function of water
temperature and therefore should be accounted for when calculating the density of the specimen; see Table 2.
NOTE 2—Degassing the water by evacuation, boiling, or ultrasonic agitation helps to prevent air bubbles from collecting on the test specimen and
specimen support when immersed in water.
6.3 Water Container—A glass beaker or other suitable transparent container should be used to contain the water.
NOTE 3—A transparent container makes it easier to see air bubbles adhering to the test specimen and specimen support when immersed in water.
NOTE 4—For the most precise density determination, the water container should be of a size that the level of the water does not rise more than 2.5 mm
(0.10 in.) when the test specimen is lowered into the water.
6.4 Test Specimen Support for Weighing in Water—Two typical arrangements are shown in Fig. 1. The suspension wire may be
twisted around the test specimen, or the test specimen may be supported in a wire basket that is attached to the suspension wire.
TABLE 1 Balance Readability
Mass, g Balance Readable to, g
less than 10 0.0001
10 to less than 100 0.001
100 to less than 1000 0.01
1000 to less than 10 000 0.1
B311 − 22
A
TABLE 32 Density of Air-Free Water
Temperature (°C) Density (g/cm )
Temperature ρ Temperature ρ
w w
3 3
°C g/cm °F g/cm *
15.0 0.9991 60 0.9990
15.5 0.9990 61 0.9989
16.0 0.9989 62 0.9988
16.5 0.9988 63 0.9987
17.0 0.9988 64 0.9986
17.5 0.9987 65 0.9985
18.0 0.9986 66 0.9984
18.5 0.9985 67 0.9983
19.0 0.9984 68 0.9982
19.5 0.9983 69 0.9981
20.0 0.9982 70 0.9980
20.5 0.9981 71 0.9978
21.0 0.9980 72 0.9977
21.5 0.9979 73 0.9975
22.0 0.9978 74 0.9974
22.5 0.9976 75 0.9973
23.0 0.9975 76 0.9972
23.5 0.9974 77 0.9970
24.0 0.9973 78 0.9969
24.5 0.9972 79 0.9967
25.0 0.9970 80 0.9966
25.5 0.9969 81 0.9964
26.0 0.9968 82 0.9963
26.5 0.9966 83 0.9961
27.0 0.9965 84 0.9959
27.5 0.9964 85 0.9958
28.0 0.9962 86 0.9956
28.5 0.9961
29.0 0.9959 *Interpolated from
29.5 0.9958 °C Data
30.0 0.9956
A
Metrological Handbook 145, “Quality Assurance for Measurements,” National
Institute of Standards and Technology, 1990, p. 9.10.
For either arrangement, a single corrosion resistant wire—for example, austenitic stainless steel, copper, nichrome—shall be used
for the basket and suspension wire. For the maximum recommended diameter of suspension wire to be used for various mass
ranges, see Table 23.
NOTE 5—For the most precise density determinations, it is important that the mass and volume of all supporting wires immersed in water be minimized.
6.5 Thermometer—A thermometer with an accuracy of
0.2 °C to measure the temperature of the water.water to the nearest 0.5 °C (1 °F).
7. Preparation of Test Specimens
7.1 A complete part or a section of a part may be used for the test specimen. For the highest precision, the test specimen shall
have a minimum mass of 5.0 g. If less precision can be tolerated, several test specimens may be used to reach the minimum mass,
provided each test specimen has a mass of not less than 1.0 g.
NOTE 6—For metal injection molded (MIM) parts of less than 1.0 g, several parts may be used to reach the minimum mass.
7.2 All test specimen surfaces shall be thoroughly cleaned of all adhering foreign mat
...