ASTM B312-14
(Test Method)Standard Test Method for Green Strength of Specimens Compacted from Metal Powders
Standard Test Method for Green Strength of Specimens Compacted from Metal Powders
SIGNIFICANCE AND USE
5.1 The green strength value determined under the conditions specified by this test method is influenced by the characteristics of the powder, how it compacts under the specified conditions (i.e., the particle to particle bonding that exists following compacting), and the lubrication system used.
5.2 Knowledge of the green strength value is useful to the production, characterization and utilization of metal powders in the manufacture of PM structural parts and bearings.
5.3 The test for green strength of a compacted metal powder can be used to:
5.3.1 Relate the resistance of a pressed compact to breakage or damage due to handling.
5.3.2 Compare the quality of a metal powder or powder mixture from lot to lot.
5.3.3 Determine the effect of the addition of a lubricant or other powders to a base powder.
5.3.4 Evaluate powder mixing or blending variables.
5.4 Factors that are known to influence the green strength of a metal powder are particle shape, particle size distribution and compressibility of the metal powder.
5.5 The amount and type of lubricant or other additives and the mixing procedures have a strong effect on the green strength of specimens produced from metal powder mixtures.
SCOPE
1.1 This standard covers a test method that may be used to measure the transverse rupture strength of a compacted but unsintered (green) test specimen produced from lubricated or unlubricated metal powders or powder mixtures.
1.2 Green strength is measured by a quantitative laboratory procedure in which the fracture strength is calculated from the force required to break an unsintered test specimen supported as a simple beam while subjected to a uniformly increasing three-point transverse load under controlled conditions.
1.3 This test method is a companion standard to Test Method B528 that covers the measurement of the transverse rupture strength of sintered PM test specimens.
1.4 With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic centimeter (g/cm3) and gram (g) units is the longstanding industry practice, the values in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: B312 − 14
Standard Test Method for
Green Strength of Specimens Compacted from Metal
1
Powders
This standard is issued under the fixed designation B312; 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* der Metallurgy (PM) Specimens
B925 Practices for Production and Preparation of Powder
1.1 This standard covers a test method that may be used to
Metallurgy (PM) Test Specimens
measure the transverse rupture strength of a compacted but
B962 Test Methods for Density of Compacted or Sintered
unsintered (green) test specimen produced from lubricated or
Powder Metallurgy (PM) Products Using Archimedes’
unlubricated metal powders or powder mixtures.
Principle
1.2 Green strength is measured by a quantitative laboratory
E691 Practice for Conducting an Interlaboratory Study to
procedure in which the fracture strength is calculated from the
Determine the Precision of a Test Method
force required to break an unsintered test specimen supported
3. Terminology
as a simple beam while subjected to a uniformly increasing
three-point transverse load under controlled conditions.
3.1 Definitions—the definitions of powder metallurgy (PM)
terms used in this test method can be found in Terminology
1.3 This test method is a companion standard to Test
B243. Additional descriptive PM information is available in
Method B528 that covers the measurement of the transverse
the Related Material section of Vol 02.05 of the Annual Book
rupture strength of sintered PM test specimens.
of ASTM Standards.
1.4 With the exception of the values for density and the
mass used to determine density, for which the use of the gram 4. Summary of Test Method
3
per cubic centimeter (g/cm ) and gram (g) units is the long-
4.1 Three rectangular test specimens are compacted to a
standingindustrypractice,thevaluesininch-poundunitsareto
predetermined green density or at a specified compacting
be regarded as standard. The values given in parentheses are
pressure from test portions of the metal powder or powder
mathematical conversions to SI units that are provided for
mixture that is to be tested.
information only and are not considered standard.
4.2 Each unsintered bar is placed, in turn, in a test fixture
1.5 This standard does not purport to address all of the
and subjected to a uniformly increasing transverse load under
safety concerns, if any, associated with its use. It is the
controlled conditions until fracture occurs.
responsibility of the user of this standard to establish appro-
4.3 The green strength or maximum flexural stress of each
priate safety and health practices and determine the applica-
specimenisdeterminedbycalculationusingthestressequation
bility of regulatory limitations prior to use.
for a simply supported beam with a concentrated mid-point
load.
2. Referenced Documents
2
4.4 The green strength of the material being tested is
2.1 ASTM Standards:
reported as the arithmetic mean of the results of three indi-
B215 Practices for Sampling Metal Powders
vidual tests at the measured green density or at the specified
B243 Terminology of Powder Metallurgy
compacting pressure rounded to the nearest 100 psi (0.5 MPa).
B528 Test Method for Transverse Rupture Strength of Pow-
5. Significance and Use
5.1 The green strength value determined under the condi-
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 Subcom- tions specified by this test method is influenced by the
mittee B09.02 on Base Metal Powders.
characteristics of the powder, how it compacts under the
CurrenteditionapprovedJune1,2014.PublishedJuly2014.Originallyapproved
specified conditions (i.e., the particle to particle bonding that
in 1956. Last previous edition approved in 2009 as B312 – 09. DOI: 10.1520/
exists following compacting), and the lubrication system used.
B0312-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2 Knowledge of the green strength value is useful to the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
production, characterization and utilization of metal powders
Standards volumeinformation,refertothestandard’sDocumentSummarypageon
the ASTM website. in the manufacture of PM structural parts and bearings.
*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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B312 − 14
5.3 Thetestforgreenstrengthofacompactedmetalpo
...
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: B312 − 09 B312 − 14
Standard Test Method for
Green Strength of Specimens Compacted from Metal
1
Powders
This standard is issued under the fixed designation B312; 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 standard covers a test method that may be used to measure the transverse rupture strength of a compacted but
unsintered (green) test specimen produced from lubricated or unlubricated metal powders or powder mixtures.
1.2 Green strength is measured by a quantitative laboratory procedure in which the fracture strength is calculated from the force
required to break an unsintered test specimen supported as a simple beam while subjected to a uniformly increasing three-point
transverse load under controlled conditions.
1.3 This test method is a companion standard to Test Method B528 that covers the measurement of the transverse rupture
strength of sintered PM test specimens.
1.4 With the exception of density values, the values for density and the mass used to determine density, for which the g/cmuse
3
of the gram per cubic centimeter (g/cm unit ) and gram (g) units is the industry standard, and mass measurements used to calculate
density, the values stated longstanding industry practice, the values in inch-pound units are to be regarded as the standard. The SI
equivalents shown in parentheses have been converted in accordance withvalues given in parentheses are mathematical
conversions to SI units IEEE/ASTM SI 10, may be approximate and are only included for information. that are provided for
information only and are not considered standard.
1.5 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
B215 Practices for Sampling Metal Powders
B243 Terminology of Powder Metallurgy
B528 Test Method for Transverse Rupture Strength of Powder Metallurgy (PM) Specimens
B925 Practices for Production and Preparation of Powder Metallurgy (PM) Test Specimens
B962 Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
IEEE/ASTM SI 10 American National Standard for Metric Practice
3. Terminology
3.1 Definitions—the definitions of powder metallurgy (PM) terms used in this test method can be found in Terminology B243.
Additional descriptive PM information is available in the Related Material section of Vol 02.05 of the Annual Book of ASTM
Standards.
4. Summary of Test Method
4.1 Three rectangular test specimens are compacted to a predetermined green density or at a specified compacting pressure from
test portions of the metal powder or powder mixture that is to be tested.
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 B09.02
on Base Metal Powders.
Current edition approved May 1, 2009June 1, 2014. Published July 2009July 2014. Originally approved in 1956. Last previous edition approved in 20022009 as
B312 – 96B312 – 09. (2002). DOI: 10.1520/B0312-09.10.1520/B0312-14.
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 ----------------------
B312 − 14
4.2 Each unsintered bar is placed, in turn, in a test fixture and subjected to a uniformly increasing transverse load under
controlled conditions until fracture occurs.
4.3 The green strength or maximum flexural stress of each specimen is determined by calculation using the stress equation for
a simply supported beam with a concentrated mid-point load.
4.4 The green strength of the material being tested is reported as the arithmetic mea
...
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