ASTM A247-67(1998)
(Test Method)Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings
Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings
SCOPE
1.1 This test method covers the classification of graphite in cast irons in terms of type, distribution, and size. This test method is intended to be applicable for all iron-carbon alloys containing graphite particles, and may be applied to gray irons, malleable irons, and the ductile (nodular) irons.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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.
1. Scope informationonthetype,distribution,andsizeofthegraphitein
the sample being evaluated. It does not indicate except in a
1.1 This test method covers the classification of graphite in
very broad way the origin of the graphite, or the suitability of
cast irons in terms of type, distribution, and size. This test
the iron-carbon alloy for a particular service.
method is intended to be applicable for all iron-carbon alloys
containing graphite particles, and may be applied to gray irons,
5. Test Specimens or Samples
malleable irons, and the ductile (nodular) irons.
5.1 The preferred sample is a section cut from an actual
1.2 The reference standards included in this test method are
casting that is being evaluated. When this is impractical, a test
in no way to be construed as specifications. In an appropriate
lug or projection often can be cast attached to the casting and
specification for a specific material where graphite microstruc-
sawedorbrokenofftobeusedasthesample.Ifneitherofthese
ture is an important consideration this test method may be used
methodsisconvenient,microscopicaltestcoupons,suchasthat
as a reference to define concisely the graphite microstructure
recommended by the Ductile Iron Research Committee (12K)
required.
of the American Foundrymen’s Society should be cast from
1.3 These standards are offered primarily to permit accurate
metal representative of the castings poured.
reporting of microstructures of cast irons and to facilitate the
comparisonofreportsbydifferentlaboratoriesorinvestigators.
6. Polishing
1.4 This standard does not purport to address all of the
6.1 Grinding and polishing may follow the usual accepted
safety problems associated with its use. It is the responsibility
metallographic procedures as covered in Methods E 3, except
oftheuserofthisstandardtoconsultandestablishappropriate
that care must be taken that the graphite is retained at the
safety and health practices and determine the applicability of
polished surface and not torn or dragged out. Use of diamond
regulatory limitations prior to use.
powder polishing compound in one of the final stages of
2. Referenced Documents polishing is very effective in retaining the graphite at the
polished surface.
2.1 ASTM Standards:
E 3 Methods of Preparation of Metallographic Specimens
7. Classification of Graphite Form with Chart
7.1 The graphite form type chart (Plate I) is used as a
3. Summary of Test Method
reference standard by scanning the polished specimen under
3.1 The reference diagrams included in this standard form
the microscope and noting the graphite forms in the micro-
the basis for classification. Characteristic features of graphite
structure that more nearly correspond to type designations on
particles are designated by numerals and letters. Type, distri-
the chart.
bution, and size of observed graphite are compared with the
7.2 Type I is the normal and usually desirable graphite form
idealized microstructures in the standard charts and rated
in ductile iron, although the presence of Type II graphite forms
accordingly as closely as possible to the equal or similar
has little or no adverse effect on properties. Graphite forms
microstructures in the charts.
represented by Types IV through VI often occur in ductile iron
4. Significance and Use in conjunction with Types I and II. The percentages of each
graphite type are estimated by observation, or better, by
4.1 The comparison of observed graphite particles with the
counting the particles of each type. Types present in a sample
structures shown in the charts give only purely descriptive
This test method is under the jurisdiction of ASTM Committee A-4 on Iron
Castings and is the direct responsibility of Subcommittee A04.21 on Testing.
Current edition effective Aug. 25, 1967. Originally issued 1941. Replaces Transactions, American Foundrymen’s Society, 1960, p. 655.
A 247 – 47. Plates I, II, and III may be obtained from ASTM Headquarters. Order
Annual Book of ASTM Standards, Vol 03.01. ADJA0247.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.