ASTM A842-85(2004)

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.
1.2 The values stated in SI units are to be considered as the standard.
1.3 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 ).

General Information

• Status: Historical
• Publication Date: 30-Apr-2004
• Technical Committee: A04 - Iron Castings
• Drafting Committee: A04.02 - Malleable and Ductile Iron Castings

Relations

• Replaces: ASTM A842-85(1997) - Standard Specification for Compacted Graphite Iron Castings
• Effective Date: 01-May-2004
• Replaced By: ASTM A842-85(2009) - Standard Specification for Compacted Graphite Iron Castings
• Effective Date: 01-May-2009
• Referred By: ASTM A1095-15(2019) - Standard Specification for High-Silicon Molybdenum Ferritic Iron Castings
• Effective Date: 01-May-2004
• Referred By: ASTM A834-95(2020) - Standard Specification for Common Requirements for Iron Castings for General Industrial Use
• Effective Date: 01-May-2004

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 842 – 85 (Reapproved 2004)
Standard Specification for
Compacted Graphite Iron Castings
This standard is issued under the fixed designation A 842; 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.
TABLE 1 Tensile Requirements
1. Scope
A B
Grade Grade Grade Grade Grade
1.1 This specification covers castings made of compacted
250 300 350 400 450
graphite iron, which is described as cast iron with the graphite
Tensile strength, min,
in compacted (vermiform) shapes and essentially free of flake 250 300 350 400 450
MPa
graphite.
Yield strength, min,
175 210 245 280 315
MPa
1.2 The values stated in SI units are to be considered as the
Elongation in 50 mm,
3.0 1.5 1.0 1.0 1.0
standard.
min, %
1.3 No precise quantitative relationship can be stated be-
A
The 250 grade is a ferritic grade. Heat treatment to attain required mechanical
tweenthepropertiesofironinthevariouslocationsofthesame
properties and microstructure shall be the option of the manufacturer.
B
The 450 grade is a pearlitic grade usually produced without heat treatment
casting and those of a test bar cast from the same iron (see
with addition of certain alloys to promote pearlite as a major part of the matrix.
Appendix X1).
2. Referenced Documents
3.1.5 Certification if so designated by the purchaser, and
2.1 ASTM Standards:
3.1.6 Special preparation for delivery if required.
A 247 Test Method for Evaluating the Microstructure of
Graphite in Iron Castings
4. Chemical Composition
E8M Test Methods for Tension Testing of Metallic Mate-
4.1 It is the intent of this specification to subordinate
rials (Metric)
chemical composition to mechanical properties; however, any
2.2 Federal Standard:
chemical requirement may be specified by agreement between
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
the manufacturer and the purchaser.
2.3 American National Standard:
MIL-STD-129 Marking for Shipment and Storage
5. Microstructure Requirements Microstructure Requirements
3. Ordering Information 5.1 Compacted graphite cast iron shall be examined metal-
lographically for the acceptable graphite formation.
3.1 Orders for material to this specification shall include the
5.2 Themetallographicexaminationshallbeperformedona
following information:
casting, a separately cast test coupon, as shown in Fig. 1 or on
3.1.1 ASTM designation and year of issue,
a test lug from a casting. The test coupon or casting lug shall
3.1.2 Grade of compacted graphite iron required as identi-
represent the last metal from the treated batch. The casting lug
fied in Table 1,
dimension and location will be agreed on by manufacturer and
3.1.3 Special properties if required, (see 4.1 and 10.1),
purchaser.
3.1.4 If samples other than those identified in Section 9 are
5.3 When castings are produced to this specification by
required,
treating the iron in the mold for graphite form control, the
manufacturer may use separately cast test coupons or cut test
specimens from castings to qualify conformance of the micro-
This specification is under the jurisdiction of ASTM Committee A04 on Iron
structure requirements. When separately cast test coupons are
Castings and is the direct responsibility of SubcommitteeA04.02 on Malleable and
used, the test coupons shall have a chemical composition
Ductile Iron Castings.
Current edition approved May 1, 2004. Published May 2004. Originally
representative of that in the castings, produced from that iron
approved in 1985. Last previous edition approved in 1997 as A 842 - 85 (1997).
poured, and having a cooling rate equivalent to that obtained
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
through use of test molds as shown in Figs. 1-4.The size of the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
cast coupon representing the castings shall be the option of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
purchaser. In case no option is expressed, the manufacturer
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
shall make the choice. When test specimens are to be taken
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
from a casting, the location shall be agreed on by the purchaser
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. and the manufacturer and documented on the casting drawing.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 842 – 85 (2004)
FIG. 1 Test Coupon for Microscopical Examination of Compacted Graphite Iron
NOTE—The length of the keel block shall be 6 in. (152 mm).
FIG. 2 Design and Dimensions for Mold for Separately Cast
Cylindrical Test Bars
It is the manufacturer’s required responsibility to maintain
adequate controls and documentation to assure the customer
Metric Equivalents
in. mm in. mm
that test specimen microstructures are representative of micro-
1 1
⁄2 12.7 1 ⁄2 38.1
structure in the castings shipped.
1 25.4 2 ⁄2 63.5
5.4 The acceptable graphite formation in the microstructure
FIG. 3 Keel Block
of the test coupon or casting lug shall contain 80 % minimum
Type IV graphite (see Plate 1, Graphite Form Types of Test
Method A 247). The percentage graphite can be arrived at by
Methods E8M. Other methods may be used by mutual
using the manual particle count, semiautomatic, or automatic
agreement between manufacturer and purchaser.
image analysis methods. Whichever method is used, the
procedure should be agreed on between the manufacturer and
7. Cast Test Bars
the purchaser.
7.1 Test bars shall be separate castings poured from the
5.5 Unless otherwise specified, the matrix microstructure of
same iron as the castings they represent. The 30-mm diameter
castingscoveredbythisspecificationshallbesubstantiallyfree
cylindrical test bar shall be used as described in Table 2 and
of primary cementite.
shown in Fig. 2.
6. Tensile Requirements
7.2 Test coupons may also be cast to the size and shape of
6.1 The iron as represented by the test specimens shall the keel block or modified keel block shown in Fig. 3 and Fig.
conform to the requirements for tensile properties, as identified 4, respectively.
in Table 1. 7.3 Test bars and test coupons shall be cast in dried, baked,
6.2 The yield strength presented in Table 1 shall be deter- or chemically bonded molds consisting of an aggregate of
mined at 0.2 % offset by the offset method as described in Test silica sand with the appropriate binders.All molds shall have a
A 842 – 85 (2004)
FIG. 4 Mold for Modified Keel Block
TABLE 2 Diameter and Length of Cast Test Bar
same lot. Only one bar need be tested if its results conform to
As Cast Diameter, mm Length, mm the property requirements of this specification.
Test Bar Nominal
Minimum Maximum Minimum Maximum
10.2 If after testing, a test specimen shows evidence of a
B 30 29 31 150 230 defect, the results of the test may be invalidated and another
made on a specimen from the same lot.
10.3 If the results of a valid test fail to conform to the
requirements of this specification, two retests shall be made. If
thickness of sand adjacent to the test piece equal to or greater
either retest fails to meet the specification requirements, the
than the thi
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