ASTM B330-20

Standard Test Methods for Estimating Average Particle Size of Metal Powders and Related Compounds Using Air Permeability

SIGNIFICANCE AND USE
4.1 These test methods provide procedures for determining the envelope-specific surface area of powders, from which is calculated an “average” particle diameter, assuming the particles are monosize, smooth surface, nonporous, spherical particles. For this reason, values obtained by these test methods will be reported as an average particle size or Fisher Number. The degree of correlation between the results of these test methods and the quality of powders in use will vary with each particular application and has not been fully determined.  
4.2 These test methods are generally applicable to all metal powders and related compounds, including carbides, nitrides, and oxides, for particles having diameters between 0.2 and 75 μm (MIC SAS) or between 0.5 and 50 μm (FSSS). They should not be used for powders composed of particles whose shape is too far from equiaxed - that is, flakes or fibers. In these cases, it is permissible to use the test methods described only by agreement between the parties concerned. These test methods shall not be used for mixtures of different powders, nor for powders containing binders or lubricants. When the powder contains agglomerates, the measured surface area may be affected by the degree of agglomeration. Methods of de-agglomeration such as that specified in Practice B859 may be used if agreed upon between the parties concerned.  
4.3 When an “average” particle size of powders is determined either the MIC SAS or the FSSS, it should be clearly kept in mind that this average size is derived from the determination of the specific surface area of the powder using a relationship that is true only for powders of uniform size and spherical shape. Thus, the results of these methods are only estimates of average particle size.
SCOPE
1.1 These test methods use air permeability to determine an envelope-specific surface area and its associated average equivalent spherical diameter (from 0.2 to 75μm) of metal powders and related compounds. The powders may be analyzed in their “as-supplied” (shipped, received, or processed) condition or after they have been de-agglomerated or milled by a laboratory procedure (“lab milled”) such as that specified in Practice B859. The values obtained are not intended to be absolute but are generally useful on a relative basis for control purposes.  
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 longstanding industry practice; and the units for pressure, cm H2O - also long-standing 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: 30-Sep-2020
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.03 - Refractory Metal Powders

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: B330 − 20
Standard Test Methods for
Estimating Average Particle Size of Metal Powders and
1
Related Compounds Using Air Permeability
This standard is issued under the fixed designation B330; 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* B859 Practice for De-Agglomeration of Refractory Metal
Powders and Their Compounds Prior to Particle Size
1.1 These test methods use air permeability to determine an
Analysis
envelope-specific surface area and its associated average
E29 Practice for Using Significant Digits in Test Data to
equivalent spherical diameter (from 0.2 to 75µm) of metal
Determine Conformance with Specifications
powders and related compounds. The powders may be ana-
E456 Terminology Relating to Quality and Statistics
lyzed in their “as-supplied” (shipped, received, or processed)
E691 Practice for Conducting an Interlaboratory Study to
conditionoraftertheyhavebeende-agglomeratedormilledby
Determine the Precision of a Test Method
a laboratory procedure (“lab milled”) such as that specified in
3
2.2 ISO/DIS Document:
Practice B859. The values obtained are not intended to be
ISO/DIS 10070 Metallic Powders: Determinations of
absolute but are generally useful on a relative basis for control
Envelope-Specific Surface Area from Measurements of
purposes.
the Permeability to Air of a Powder Bed Under Steady-
1.2 Units—With the exception of the values for density and
State Flow Conditions
the mass used to determine density, for which the use of the
3
gram per cubic centimetre (g/cm ) and gram (g) units is the
3. Terminology
longstanding industry practice; and the units for pressure, cm
3.1 Definitions—Many terms used in these test methods are
H O - also long-standing practice; the values in SI units are to
2
defined in Terminology B243.
be regarded as standard.
3.2 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.2.1 agglomerate, n—several particles adhering together.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2.2 air permeability, n—measurement of air pressure drop
priate safety, health, and environmental practices and deter-
across a packed bed of powder.
mine the applicability of regulatory limitations prior to use.
3.2.3 average particle size, n—(for the purposes of these
1.4 This international standard was developed in accor-
test methods only) – an estimate of the equivalent average
dance with internationally recognized principles on standard-
spherical particle diameter, calculated from the measured
ization established in the Decision on Principles for the
envelope-specific surface area, assuming that all the powder
Development of International Standards, Guides and Recom-
particles are spherical and that all are exactly the same size.
mendations issued by the World Trade Organization Technical
3.2.4 de-agglomeration, n—process used to break up ag-
Barriers to Trade (TBT) Committee.
glomerates of particles.
2. Referenced Documents
3.2.5 envelope-specific surface area, n—specific surface
2
2.1 ASTM Standards:
area of a powder as determined by gas permeametry in
B243 Terminology of Powder Metallurgy
accordance with ISO/DIS 10070.
3.2.6 Fisher calibrator tube, n—jewel with a precision
1
These test methods are under the jurisdiction of ASTM Committee B09 on
orifice mounted in a tube similar to a sample tube.
Metal Powders and Metal Powder Products and are the direct responsibility of
3.2.6.1 Discussion—The calibrator tube value is directly
Subcommittee B09.03 on Refractory Metal Powders.
Current edition approved Oct. 1, 2020. Published November 2020. Originally
traceable to the master tube maintained byASTM International
approved in 1958. Last previous edition approved in 2015 as B330 – 15. DOI:
Subcommittee B09.03 on Refractory Metal Powders.
10.1520/B0330-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © AS
...

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: B330 − 15 B330 − 20
Standard Test Methods for
Estimating Average Particle Size of Metal Powders and
1
Related Compounds Using Air Permeability
This standard is issued under the fixed designation B330; 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 These test methods use air permeability to determine an envelope-specific surface area and its associated average equivalent
spherical diameter (from 0.2 to 75μm) of metal powders and related compounds. The powders may be analyzed in their
“as-supplied” (shipped, received, or processed) condition or after they have been de-agglomerated or milled by a laboratory
procedure (“lab milled”) such as that specified in Practice B859. The values obtained are not intended to be absolute but are
generally useful on a relative basis for control purposes.
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
3
cubic centimetre (g/cm ) and gram (g) units is the longstanding industry practice; and the units for pressure, cm H O - also
2
long-standing 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 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
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B859 Practice for De-Agglomeration of Refractory Metal Powders and Their Compounds Prior to Particle Size Analysis
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 ISO/DIS Document:
ISO/DIS 10070 Metallic Powders: Determinations of Envelope-Specific Surface Area from Measurements of the Permeability
to Air of a Powder Bed Under Steady-State Flow Conditions
1
These test methods are under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and are the direct responsibility of Subcommittee
B09.03 on Refractory Metal Powders.
Current edition approved Oct. 1, 2015Oct. 1, 2020. Published October 2015November 2020. Originally approved in 1958. Last previous edition approved in 20122015
as B330B330 – 15. -12. DOI: 10.1520/B0330-15.10.1520/B0330-20.
2
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.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*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

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B330 − 20
3. Terminology
3.1 Definitions—Many terms used in thisthese test methodmethods are defined in Terminology B243.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 MIC Sub-sieve AutoSizer (MIC SAS), agglomerate, n—a commercially available permeability instrument for measuring
envelopespecific surface area and estimating average particle size from 0.2 to 75μm.several particles adhering together.
3.2.2 air permeability, n—measurement of air pressure drop across a packed bed of powder.
3.2.3 Fisher Sub-Sieve Sizer (FSSS), average particle size, n—a commercially available permeability instrument for measuring
envelope-specific surface area and estimating average particle size (Fisher Number) from 0.5 to 50 μm.(for t
...