ASTM A Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings. ASTM A ISO R classification of graphite flake size and shape. ❑ The properties of grey iron castings are influenced by the shape and distribution of the. Designation: A – 67 (Reapproved ) Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings1.
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ASTM B r Copyright ASTM Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings1 This standard is issued under the xed designation A ; 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.
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.
In an appropriate specication for a specic material where graphite microstructure is an important consideration this test method may be used as a reference to dene concisely the graphite microstructure required. It is the responsibility of the user of this standard to consult and establish astn safety and health practices and determine the applicability of ashm limitations prior to use.
E 3 Methods of Preparation of Metallographic Specimens2 3. Summary of Test Method 3. Characteristic features of graphite particles are designated by numerals and letters. ast,
ASTM A247-10 Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings
Type, distribution, and size of observed graphite are compared with the idealized microstructures in the standard charts and rated accordingly as closely as possible to the equal or similar microstructures in the charts. Signicance and Use 4.
Current edition effective Aug.
Replaces A — Test Specimens or Samples 5. When this is impractical, a test lug or projection often can be cast attached to the casting and sawed or broken off to be used as the sample.
ASTM A – 17 Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings
24 of diamond powder polishing compound in one of the nal stages of polishing is very effective in retaining the graphite at the polished surface. Classication of Graphite Form with Chart 7. The percentages of each sstm type are estimated by observation, or better, by counting the particles of each type.
Types present in a sample are to be reported in percentages to total Any convenient magnication that clearly reveals the graphite form may be used.
Some malleable irons may contain Types I or II graphite particles also. Classication of Ast, Distribution with Chart 8. Occasionally, however, graphite in malleable or ductile iron may occur in a nonrandom distribution pattern which the distributions B to E may be used to describe. Classication of Graphite Size by Chart 9. At exactly diameters magnication the maximum dimension of the graphite particles for the various size classes are shown in Table 1.
Usually visual comparison with the chart is adequate to dene the size class. Where a mixture of one or more sizes occurs in the same sample, the sizes may be reported as percentages of the total graphite area represented by the sizes involved.
It is a common practice in malleable iron to use nodule count per unit area instead of a comparison chart as given here. Nodule count, with known free carbon content, is a measure of calculated average nodule area. Report of Graphite Microstructure Sample identication; graphite form type or types; graphite distribution; astj size class. Graphite distribution is designated by a capital letter A through E. Graphite size is designated by an Arabic numeral 1 through 8.
If eutectiform graphite asym present, the rating might be VII D7. The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ve years and if not revised, either reapproved or withdrawn.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.