ASTM A247-16a

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Designation: A247 − 16a
Standard Test Method for
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Evaluating the Microstructure of Graphite in Iron Castings
This standard is issued under the fixed designation A247; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 2.2 ASTM Adjuncts:
Iron Casting Graphite Microstructure Rating Chart (Wall
1.1 This test method covers the classification of graphite in
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Chart)
cast irons in terms of type, distribution, and size by visual
comparisontoreferencephotomicrographs.Thistestmethodis
3. Summary of Test Method
intended to be applicable for all iron-carbon alloys containing
3.1 The reference micrographs included in this standard
graphite particles, and may be applied to gray irons, malleable
form the basis for classification. Characteristic features of
irons, compacted graphite irons, and the ductile (nodular)
graphite particle shape and distribution are designated by
irons.
numerals and letters. Type, distribution, and size of observed
1.2 The reference photomicrographs included in this test
graphitearecomparedwiththeidealizedmicrostructuresinthe
method are in no way to be construed as specifications. In an
standard charts and rated accordingly as closely as possible to
appropriate specification for a specific material where graphite
the equal or similar microstructures in the charts.
microstructure is an important consideration, this test method
may be used as a reference to define concisely the graphite
4. Significance and Use
microstructure required.
4.1 The comparison of observed graphite particles with the
structures shown in the charts give only purely descriptive
1.3 These reference photomicrographs are offered primarily
informationonthetype,distribution,andsizeofthegraphitein
to permit accurate reporting of microstructures of cast irons
the sample being evaluated. It does not indicate, except in a
and to facilitate the comparison of reports by different labora-
very broad way, the origin of the graphite or the suitability of
tories or investigators.
the iron-carbon alloy for a particular service.
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
5. Test Specimens or Samples
standard.
5.1 The preferred sample is a section cut from an actual
1.5 This standard does not purport to address all of the
casting that is being evaluated at a location agreed upon
safety concerns, if any, associated with its use. It is the
between the manufacturer and purchaser. When this is
responsibility of the user of this standard to establish appro-
impractical, a test lug or projection often can be appended to
priate safety and health practices and determine the applica-
the casting and sawed or broken off to be used as the test
bility of regulatory limitations prior to use.
sample. If neither of these methods is convenient, microstruc-
tural test coupons, such as that recommended by the Cast Iron
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2. Referenced Documents
Research Committee (5R) of the American Foundry Society
shall be cast from metal representative of the castings poured.
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2.1 ASTM Standards:
E3Guide for Preparation of Metallographic Specimens
6. Polishing
6.1 Grinding and polishing may follow the usual accepted
metallographic procedures as covered in Guide E3, except that
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This test method is under the jurisdiction of ASTM Committee A04 on Iron
care must be taken that the graphite is retained at the polished
Castings and is the direct responsibility of Subcommittee A04.21 on Testing.
Current edition approved April 1, 2016. Published April 2016. Originally surface and not torn or dragged out. Use of diamond powder
approved in 1941. Last previous edition approved in 2016 as A247–16. DOI:
10.1520/A0247-16A.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from ASTM International Headquarters. Order Adjunct No.
Standards volume information, refer to the standard’s Document Summary page on ADJA0247A. Original adjunct produced in 2010.
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the ASTM website. Transactions, American Foundrymen’s Society, 1960, p. 655.
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A247 − 16a
polishing compound in one of the final stages of polishing is 8. Classification of Graphite Distribution Using Chart
very effective in retaining the graphite at the polished surface.
8.1 The graphite distrib
...