ASTM A247-67(1998)e1

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e1
Designation:A 247–67(Reapproved1998)
Standard Test Method for
Evaluating the Microstructure of Graphite in Iron Castings
This standard is issued under the fixed designation A 247; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
e NOTE—Adjunct references were corrected editorially in April 2006.
1. Scope particles are designated by numerals and letters. Type, distri-
bution, and size of observed graphite are compared with the
1.1 This test method covers the classification of graphite in
idealized microstructures in the standard charts and rated
cast irons in terms of type, distribution, and size. This test
accordingly as closely as possible to the equal or similar
method is intended to be applicable for all iron-carbon alloys
microstructures in the charts.
containing graphite particles, and may be applied to gray irons,
malleable irons, and the ductile (nodular) irons.
4. Significance and Use
1.2 The reference standards included in this test method are
4.1 The comparison of observed graphite particles with the
in no way to be construed as specifications. In an appropriate
structures shown in the charts give only purely descriptive
specification for a specific material where graphite microstruc-
informationonthetype,distribution,andsizeofthegraphitein
ture is an important consideration this test method may be used
the sample being evaluated. It does not indicate except in a
as a reference to define concisely the graphite microstructure
very broad way the origin of the graphite, or the suitability of
required.
the iron-carbon alloy for a particular service.
1.3 These standards are offered primarily to permit accurate
reporting of microstructures of cast irons and to facilitate the
5. Test Specimens or Samples
comparisonofreportsbydifferentlaboratoriesorinvestigators.
5.1 The preferred sample is a section cut from an actual
1.4 This standard does not purport to address all of the
casting that is being evaluated. When this is impractical, a test
safety problems associated with its use. It is the responsibility
lug or projection often can be cast attached to the casting and
oftheuserofthisstandardtoconsultandestablishappropriate
sawedorbrokenofftobeusedasthesample.Ifneitherofthese
safety and health practices and determine the applicability of
methodsisconvenient,microscopicaltestcoupons,suchasthat
regulatory limitations prior to use.
recommended by the Ductile Iron Research Committee (12K)
2. Referenced Documents of the American Foundrymen’s Society should be cast from
2 metal representative of the castings poured.
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
6. Polishing
2.2 ASTM Adjuncts:
6.1 Grinding and polishing may follow the usual accepted
Graphite microstructure in gray iron (3 plates)
metallographic procedures as covered in MethodsE3, except
that care must be taken that the graphite is retained at the
3. Summary of Test Method
polished surface and not torn or dragged out. Use of diamond
3.1 The reference diagrams included in this standard form
powder polishing compound in one of the final stages of
the basis for classification. Characteristic features of graphite
polishing is very effective in retaining the graphite at the
polished surface.
This test method is under the jurisdiction of ASTM Committee A04 on Iron
Castings and is the direct responsibility of Subcommittee A04.21 on Testing.
Current edition effective Aug. 25, 1967. Originally issued 1941. Replaces
A 247 – 47.
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.
Plates I, II, and III may be obtained from ASTM Headquarters. Order
ADJA0247. Transactions, American Foundrymen’s Society, 1960, p. 655.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
A 247–67 (1998)
TABLE 1 Graphite Size
7. Classification of Graphite Form with Chart
A
Size Class Maximum Dimension at 3 100, mm
7.1 The graphite form type chart (Plate I) is used as a
1 128
reference standard by scanning the polished specimen under
the microscope and noting the graphite forms in the micro-
structure that more nearly correspond to type designations on
the chart.
7.2 Type I is the normal and usually desirable graphite
...