ASTM A842-11A(2022)e1
(Specification)Standard Specification for Compacted Graphite Iron Castings
Standard Specification for Compacted Graphite Iron Castings
ABSTRACT
This specification deals with compacted graphite iron castings. These materials shall be examined metallographically for the acceptance graphite formation. The acceptable graphite formation in the microstructure of the test coupon or casting lug shall contain 80% minimum Type IV graphite. The iron shall conform to the requirements for tensile properties: tensile strength, yield strength, and elongation. Test bars and test coupons shall be cast in dried, baked, or chemically bonded molds consisting of an aggregate of silica sand with appropriate bonders and shall be subjected to the same thermal treatment as the castings they represent.
SCOPE
1.1 This specification covers castings made of compacted graphite iron, which is described as cast iron with the graphite in compacted (vermiform) shapes and essentially free of flake graphite in the bulk of the casting.
1.2 No precise quantitative relationship can be stated between the properties of iron in the various locations of the same casting and those of a test bar cast from the same iron (see Appendix X1).
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3.1 Exception—The inch-pound units in Figs. 1-3 are standard. SI units are added for information only.
Note 1: The length of the keel block shall be 6 in. (152 mm).
FIG. 3 Mold for Modified Keel Block
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation:A842 −11a (Reapproved 2022)
Standard Specification for
Compacted Graphite Iron Castings
This standard is issued under the fixed designation A842; 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.
ε NOTE—Footnote 3 and 2.3 were updated editorially in October 2022.
1. Scope 2.2 Federal Standard:
Federal Standard No. 123 Marking for Shipment (Civil
1.1 This specification covers castings made of compacted
Agencies)
graphite iron, which is described as cast iron with the graphite
2.3 Military Standard:
in compacted (vermiform) shapes and essentially free of flake
MIL-STD-129 Marking for Shipment and Storage
graphite in the bulk of the casting.
1.2 No precise quantitative relationship can be stated be-
3. Ordering Information
tweenthepropertiesofironinthevariouslocationsofthesame
3.1 Orders for material to this specification shall include the
casting and those of a test bar cast from the same iron (see
following information:
Appendix X1).
3.1.1 ASTM designation and year of issue,
1.3 The values stated in SI units are to be regarded as
3.1.2 Grade of compacted graphite iron required as identi-
standard. No other units of measurement are included in this
fied in Table 1,
standard.
3.1.3 Special properties, if required (see 4.1 and 10.1),
1.3.1 Exception—The inch-pound units in Figs. 1-3 are
3.1.4 If samples other than those identified in Section 9 are
standard. SI units are added for information only.
required,
1.4 This standard does not purport to address all of the 3.1.5 Certification if so designated by the purchaser, and
safety concerns, if any, associated with its use. It is the 3.1.6 Special preparation for delivery, if required.
responsibility of the user of this standard to establish appro-
4. Chemical Composition
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4.1 It is the intent of this specification to subordinate
1.5 This international standard was developed in accor-
chemical composition to mechanical properties; however, any
dance with internationally recognized principles on standard-
chemical requirement may be specified by agreement between
ization established in the Decision on Principles for the
the manufacturer and the purchaser.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 5. Requirements
Barriers to Trade (TBT) Committee.
5.1 Compacted graphite cast iron shall be examined metal-
lographically for the acceptable graphite formation. Nonde-
2. Referenced Documents
structive testing such as ultrasonic velocity or resonance
2.1 ASTM Standards:
frequency may also be used to determine the graphite nodu-
A247 Test Method for Evaluating the Microstructure of
larity. However, in cases of dispute, the metallographic exami-
Graphite in Iron Castings
nation shall prevail.
E8/E8M Test Methods for Tension Testing of Metallic Ma-
5.2 Themetallographicexaminationshallbeperformedona
terials
sample sectioned from the casting, on a separately cast test
coupon as shown in Fig. 1, or on a test lug from a casting. The
This specification is under the jurisdiction of ASTM Committee A04 on Iron
location on the casting from which the metallographic speci-
Castings and is the direct responsibility of Subcommittee A04.02 on Malleable and
men is sectioned shall be agreed by the manufacturer and the
Ductile Iron Castings.
Current edition approved Oct. 1, 2022. Published October 2022. Originally
purchaser. In the case of a test coupon or test lug, the specimen
ɛ1
approved in 1985. Last previous edition approved in 2018 as A842 – 11a (2018) .
shall represent the last metal from the treated batch. The
DOI: 10.1520/A0842-11AR22E01.
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 Available from General Services Administration – Vendor Support Center,
the ASTM website. https://vsc.gsa.gov.
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A842−11a (2022)
FIG. 1 Test Coupon for Microscopical Examination of Compacted Graphite Iron
from a casting, the location shall be agreed on by the purchaser
and the manufacturer and documented on the casting drawing.
It is the manufacturer’s required responsibility to maintain
adequate controls and documentation to assure the customer
that test specimen microstructures are representative of micro-
structure in the castings shipped.
5.4 The acceptable graphite formation in the microstructure
of the test coupon or casting lug shall contain 80 % minimum
Type IV graphite (see Plate 1, Graphite Form Types of Test
Method A247). The remainder of the graphite should be Type
I, II, or III, with no free flake graphite (Type VII) in the bulk
of the casting. The presence of up to 20 % of Types I, II, and
III graphite gives rise to the definition of a maximum of 20 %
nodularity in compacted graphite cast iron. The nodularity
percentage can be arrived at by using the manual particle
count, semiautomatic, or automatic image analysis methods.
Whichever method is used, the procedure should be agreed on
Metric Equivalents
in. mm in. mm
between the manufacturer and the purchaser.
1 1
⁄2 12.7 1 ⁄2 38.1
1 25.4 2 ⁄2 63.5
5.5 Unless otherwise specified, the matrix microstructure of
castingscoveredbythisspecificationshallbesubstantiallyfree
NOTE 1—The length of the keel block shall be 6 in. (152 mm).
of primary cementite.
FIG. 2 Keel Block 5.6 Flake graphite is not permitted except within the surface
rim zone of the casting. The amount of flake graphite at the
surface shall be agreed by the manufacturer and the purchaser.
casting lug dimension and location shall be agreed by manu-
NOTE 1—Flake graphite in the casting surface reduces fatigue life,
facturer and purchaser.
which should be taken into account during casting design. Machining
removes this flake graphite and shot blasting generally minimizes its
5.3 When castings are produced to this specification by
effect.
treating the iron in the mold for graphite form control, the
6. Tensile Requirements
manufacturer may use separately cast test coupons or cut test
specimens from castings to qualify conformance of the micro-
6.1 The iron as represented by the test specimens shall
structure requirements. When separately cast test coupons are
conform to the requirements for tensile properties, as identified
used, the test coupons shall have a chemical composition
in Table 1.
representative of that in the castings, produced from that iron
6.2 Tensile properties shall be determined using the test bar
poured, and having a cooling rate equivalent to that obtained
described in 7.1 or one of the test coupons described in 7.2,
through use of test molds as shown in Figs. 1-4.The size of the
except as provided in 10.4.
cast coupon representing the castings shall be the option of the
purchaser. In case no option is expressed, the manufacturer 6.3 The yield strength presented in Table 1 shall be deter-
shall make the choice. When test specimens are to be taken mined at 0.2 % offset by the offset method as described in Test
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A842−11a (2022)
FIG. 3 Mold for Modified Keel Block
TABLE 1 Tensile Requirements
A B
Grade Grade Grade
Grade Grade
250 450
300 350 400
Tensile strength, min, MPa 250 300 350 400 450
Yield strength, min, MPa 175 210 245 280 315
Elongation in 50 mm, min, % 3.0 1.5 1.0 1.0 1.0
A
The 250 grade is a ferritic grade. Heat treatment to attain required mechanical
properties and microstructure shall be the option of the manufacturer.
B
The 450 grade is a pearlitic grade usually produced without heat treatment with
addition of certain alloys to promote pearlite as a major part of the matrix.
TABLE 2 Diameter and Length of Cast Test Bar
As-Cast Diameter, mm Length, mm
Test Bar Nominal
Minimum Maximum Minimum Maximum
B 30 29 31 150 230
FIG. 4 Design and Dimensions for Mold for Separately Cast
Cylindrical Test Bars
Methods E8/E8M. Other methods may be used by mutual
agreement between manufacturer and purchaser.
thickness of sand adjacent to the test piece equal to or greater
than the thickness of the piece.
7. Cast Test Bars
7.4 Testbarsandtestcouponsshallbesubjectedtothesame
7.1 Test bars shall be separate castings poured from the
thermal treatment as the castings they represent.
same iron as the casti
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