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.

Designation: A48/A48M − 22

Standard Specification for

Gray Iron Castings1
This standard is issued under the fixed designation A48/A48M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
This specification replaces Federal Specification QQ-I-652.

1. Scope 2.2 Military Standard:3

1.1 This specification covers gray iron castings intended for MIL-STD-129 Marking for Shipment and Storage
general engineering use where tensile strength is a major 2.3 Federal Standard:3
consideration. Castings are classified on the basis of the tensile Federal Standard No. 123 Marking for Shipment (Civil
strength of the iron in separately cast test bars. Agencies)
1.1.1 This specification subordinates chemical composition 3. Terminology
to tensile strength.
3.1 Definitions:
1.2 Castings produced to this specification are graded on the 3.1.1 Definitions for many terms common to gray iron
basis of minimum tensile strength obtained in special test castings are found in Terminology A644.
coupons designed to standardize cooling rate. The tensile
strength developed in certain casting sections may vary from 4. Classification
test coupon values (see X1.2). 4.1 Castings ordered and produced in accordance with this
1.3 The values stated in either SI units or inch-pound units specification are classified into a number of grades based on the
are to be regarded separately as standard. The values stated in properties of separately cast test bars (Tables 1 and 2). Each
each system may not be exact equivalents; therefore, each class is designated by a number followed by a letter. The
system shall be used independently of the other. Combining number indicates the minimum tensile strength of the sepa-
values from the two systems may result in nonconformance rately cast test bar, and the letter indicates the size of the test
with the standard. bar. Examples of proper designations are as follows:
1.4 This international standard was developed in accor- 4.1.1 Gray Iron Castings, ASTM Specification A48, Class
dance with internationally recognized principles on standard- 30B.
ization established in the Decision on Principles for the 4.1.2 Gray Iron Castings, ASTM Specification A48, Class
Development of International Standards, Guides and Recom- 40C.
mendations issued by the World Trade Organization Technical
5. Ordering Information
Barriers to Trade (TBT) Committee.
5.1 Orders for material to this specification shall include the
2. Referenced Documents following information:
5.1.1 ASTM designation number and year of issue,
2.1 ASTM Standards:2 5.1.2 Class of iron required (see 4.1 and Tables 1 and 2),
A644 Terminology Relating to Iron Castings 5.1.3 The size of the separately cast test bar (letter
E8/E8M Test Methods for Tension Testing of Metallic Ma- classification—A, B, C, or S) that best represents the thickness
terials of the controlling section of the casting (see Table 3),
5.1.4 The tension test specimen (B or C) to be machined
from test bar C (see 13.3, Table 4, and Fig. 1),
1
This specification is under the jurisdiction of ASTM Committee A04 on Iron 5.1.5 The tension test specimen to be machined from test
Castings and is the direct responsibility of Subcommittee A04.01 on Grey and White bar S (see 13.4, Table 4, and Fig. 1),
Iron Castings.
Current edition approved May 1, 2022. Published May 2022. Originally 5.1.6 Lot size (see Section 10),
approved in 1905. Last previous edition approved in 2021 as A48/ 5.1.7 Special requirements (see Section 6),
A48M – 03 (2021). DOI: 10.1520/A0048_A0048M-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
Standards volume information, refer to the standard’s Document Summary page on Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
the ASTM website. www.dodssp.daps.mil.

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 A48/A48M − 22
TABLE 1 Requirements for Tensile Strength of Gray Cast Irons in TABLE 2 Requirements for Tensile Strength of Gray Cast Irons in
Separately Cast Test Bars (Inch-Pound) Separately Cast Test Bars (Metric)
Tensile Strength, Nominal Test Bar Tensile Strength, Nominal Test Bar
Class Class
min, ksi Diameter, in. min, MPa Diameter, mm
No. 20 A 20 0.8 No. 150A 150 20 to 22
No. 20 B 1.2 No. 150B 30
No. 20 C 2.0 No. 150C 50
No. 20 S Bars SA No. 150S Bars SA

No. 25 A 25 0.88 No. 175A 175 20 to 22

No. 25 B 1.2 No. 175B 30
No. 25 C 2.0 No. 175C 50
No. 25 S Bars SA No. 175S Bars SA

No. 30 A 30 0.88 No. 200A 200 20 to 22

No. 30 B 1.2 No. 200B 30
No. 30 C 2.0 No. 200C 50
No. 30 S Bars SA No. 200S Bars SA

No. 35 A 35 0.88 No. 225A 225 20 to 22

No. 35 B 1.2 No. 225B 30
No. 35 C 2.0 No. 225C 50
No. 35 S Bars SA No. 225S Bars SA

No. 40 A 40 0.88 No. 250A 250 20 to 22

No. 40 B 1.2 No. 250B 30
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No. 40 C 2.0 No. 250C 50

No. 40 S Bars SA No. 250S Bars SA

No. 45 A 45 0.88 No. 275A 275 20 to 22

No. 45 B 1.2 No. 275B 30
No. 45 C 2.0 No. 275C 50
No. 45 S Bars SA No. 275S Bars SA

No. 50 A 50 0.88 No. 300A 300 20 to 22

No. 50 B 1.2 No. 300B 30
No. 50 C 2.0 No. 300C 50
No. 50 S Bars SA No. 300S Bars SA

No. 55 A 55 0.88 No. 325A 325 20 to 22

No. 55 B 1.2 No. 325B 30
No. 55 C 2.0 No. 325C 50
No. 55 S Bars SA No. 325S Bars SA

No. 60 A 60 0.88 No. 350A 350 20 to 22

No. 60 B 1.2 No. 350B 30
No. 60 C 2.0 No. 350C 50
No. 60 S Bars SA No. 350S Bars SA
A
All dimensions of test bar S shall be as agreed upon between the manufacturer
No. 375A 375 20 to 22
and the purchaser.
No. 375B 30
No. 375C 50
No. 375S Bars SA

No. 400A 400 20 to 22

No. 400B 30
5.1.8 Saving tested specimens or unbroken test bars (see No. 400C 50
No. 400S Bars SA
15.1), and
A
All dimensions of test bar S shall be as agreed upon between the manufacturer
5.1.9 Special preparation for delivery (see Section 19). and the purchaser.

6. Special Requirements
6.1 When agreed upon in writing between the manufacturer 8. Dimensional Requirements
and the purchaser, it may be necessary for the castings to meet
8.1 The castings shall conform to the dimensions or draw-
special requirements as to hardness, chemical composition,
ings furnished by the purchaser or, if there are no drawings, to
microstructure, pressure tightness, radiographic soundness,
the dimensions predicted by the pattern equipment supplied by
dimensions, surface finish, and so forth.
the purchaser.
7. Tensile Requirements 9. Workmanship and Finish
7.1 Test bars representing castings conforming to this speci- 9.1 The surface of the casting shall be free of adhering sand,
fication shall meet the requirements for tensile strength as scale, cracks, and hot tears, as determined by visual examina-
described in Tables 1 and 2. tion.

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 A48/A48M − 22
TABLE 3 Separately Cast Test Bars for Use When a Specific 11.4 Test bars that are intended to represent castings that are
Correlation Has Not Been Established Between the Test Bar and hotter than 900 °F [480 °C], when shaken out of their molds,
the Casting
shall be cooled as described in 11.3 or (by agreement between
Thickness of the Wall of the Controlling
Section of the Casting, in. [mm]
Test Bar the manufacturer and the purchaser) may be shaken out of their
Under 0.25 [under 5] S
molds at approximately the same temperature as the castings
0.25 to 0.50 [5 to 14] A they represent.
0.51 to 1.00 [15 to 25] B
1.01 to 2 [26 to 50] C 11.5 When castings are stress-relieved, annealed, or other-
Over 2 [over 50] S wise heat-treated, test bars shall receive the same thermal
treatment and shall be treated adjacent to the castings they
represent.

9.2 No repairing by plugging or welding of any kind shall 12. Number of Tests and Retests
be permitted unless written permission is granted by the 12.1 The tension test shall be conducted in accordance with
purchaser. Test Methods E8/E8M.
10. Sampling 12.2 One tension test shall be performed on each lot and
shall conform to the tensile requirements specified.
10.1 A lot shall consist of one of the following:
10.1.1 All the metal poured from a single heating in a 12.3 If the results of a valid test fail to conform to the
batch-type melting furnace. requirements of this specification, two retests shall be made. If
10.1.2 All the metal from two or more batch-type melting either retest fails to meet the specification requirements, the
furnaces poured into a single ladle or a single casting. castings represented by these test specimens shall be rejected.
10.1.3 All the metal poured from a continuous melting A valid test is one wherein the specimen has been properly
furnace for a given period of time between changes in charge, prepared and appears to be sound and on which the approved
processing conditions, or aim-for chemistry or 4 h, whichever test procedure has been followed.
is the shorter period. 12.4 If sufficient separately cast test pieces are not available,
10.1.3.1 The purchaser may agree to extend the 4-h time the manufacturer shall have the option of removing a test
period to 8 h if the manufacturer can demonstrate sufficient specimen from a location of representative casting, as agreed
process control to warrant such an extension. upon between the manufacturer and purchaser.
11. Cast Test Bars 12.5 If the first test results indicate that a heat treatment is
needed to meet the test requirements, the entire lot of castings
11.1 Test bars shall be separate castings poured from the and the representative test specimens shall be heat treated
same lot as the castings they represent and shall have dimen- together. Testing shall proceed in accordance with 12.1 – 12.3.
sions as shown in Table 4. Allowance may be made for
reasonable pattern draft within the tolerances shown in Table 4. 12.6 If, after testing, a test specimen shows evidence of a
Test bars A, B, and C are all standard test bars in the form of defect, the results of the test may be invalidated and another
simple cylinders. Test bar S is special and is intended for use made on a specimen from the same lot.
where the standard bars are not satisfactory.
13. Tension Test Specimens
11.2 The test bars shall be cast in dried, baked, or chemi-
13.1 For test bar A, the tension test specimen A, as shown in
cally bonded molds made mainly of an aggregate of siliceous
Fig. 1, shall be machined concentric with the axis of the test
sand with appropriate binders. The average grain size of the
bar.
sand shall approximate that of the sand in which the castings
are poured. Molds for the test bars shall be approximately at 13.2 For test bar B, the tension test specimen B, as shown in
room temperature when poured. More than one test bar may be Fig. 1, shall be machined concentric with the axis of the test
cast in a single mold, but each bar in the mold shall be bar.
surrounded by a thickness of sand which is not less than the 13.3 For test bar C, tension test specimens B or C, as shown
diameter of the bar. A suitable design for a mold is shown in in Fig. 1, shall be machined concentric with the axis of the test
Fig. 2. bar. Unless the size of the tension test specimen to be machined
NOTE 1—The intent of these provisions is as follows: to prohibit the from test bar C is specified in writing by the purchaser, the
casting of test bars in molds of metal, graphite, zircon, light-weight decision whether to use tension test specimen B or C shall be
aggregates, or other materials which would significantly affect the tensile made by the manufacturer of the castings.
strength of the iron; to prohibit control of tensile strength of the test bars
by manipulation of the grain size of the sand; and to prohibit the casting 13.4 For test bar S, the nature and dimensions of the tension
of test bars in molds preheated substantially above room temperature. test specimen shall be determined by agreement between the
11.3 Test bars that are intended to represent castings that are manufacturer and purchaser.
cooled in the mold to less than 900 °F [480 °C], before
shakeout, shall be cooled in their molds to a temperature less 14. Tension Test
than 900 °F [480 °C]. They then may be cooled in still air to 14.1 Tension test specimens shall fit the holders of the
room temperature. testing machine in such a way that the load shall be axial.
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 A48/A48M − 22
TABLE 4 Diameters and Lengths of Cast Test Bars
As-Cast Diameter, in. [mm] Length, in. [mm]
Test Bar Nominal Minimum Maximum
Minimum (Bottom) Maximum (Top)
(Mid-Length) (Specified) (Recommended)
A 0.88 [22.4] 0.85 [21.6] 0.96 [24.4] 5.0 [125] 6.0 [150]
B 1.20 [30.5] 1.14 [29.0] 1.32 [33.5] 6.0 [150] 9.0 [230]
C 2.00 [50.8] 1.90 [48.3] 2.10 [53.3] 7.0 [175] 10.0 [255]
SA ... ... ... ... ...
A
All dimensions of test bar S shall be as agreed upon by the manufacturer and the purchaser.

Tension Test Tension Test Tension Test

Dimensions, in. [mm]
Specimen A Specimen B Specimen C
G—Length of parallel, min 0.50 [13] 0.75 [19] 1.25 [32]
D—Diameter 0.500 ± 0.010 0.750 ± 0.015 1.25 ± 0.025
[13 ± 0.25] [20 ± 0.4] [30 ± 0.6]
R—Radius of fillet, min 1 [25] 1 [25] 2 [50]
A—Length of reduced section, min 1 ⁄4 [32]
1 1 ⁄2 [38]
1 2 ⁄4 [57]
1

L—Over-all length, min 33⁄4 [95] 4 [100] 63⁄8 [160]

C—Diameter of end section, approx 7⁄8 [20] 11⁄4 [20] 17⁄8 [47]
E—Length of shoulder, min 1⁄4 [6] 1⁄4 [6] 5⁄16 [8]

F—Diameter of shoulder 5⁄8 ± 1⁄64 15⁄16 ± 1⁄64 17⁄16 ± 1⁄64

[16 ± 0.4] [24 ± 0.4] [36 ± 0.4]
A A A
B—Length of end section
A
Optional to fit holders on testing machine. If threaded, root diameter shall not be less than dimension F.

FIG. 1 Tension Test Specimens

14.2 The elapsed time from the beginning of loading in the 16. Rejection and Resubmission
tension test to the instant of fracture shall be not less than 15 s
16.1 Any castings or lot of castings failing to comply with
for test specimen A and not less than 20 s for specimens B and
the requirements of this specification may, where possible, be
C.
reprocessed, retested, and reinspected. If the tests and inspec-
15. Inspection tions on the reprocessed casting(s) show compliance with this
specification, the castings shall be acceptable; if they do not,
15.1 Unless otherwise specified in the contract or purchase they shall be rejected.
order, the manufacturer shall be responsible for carrying out all
the tests and inspections required by this specification, using 16.2 If the purchaser should find that a casting or lot of
his own or other reliable facilities, and he shall maintain castings fails to comply with this specification subsequent to
complete records of all such tests and inspections. Such records receipt at his facility, he shall so notify the manufacturer
shall be available for review by the purchaser. promptly and in no case later than six weeks after receipt of the
15.1.1 When agreed upon between the manufacturer and shipment, stating clearly the basis for rejection.
purchaser, tested specimens or unbroken test bars from the
same lot shall be saved for a period of three months after the 17. Certification
date of the test report. 17.1 When specified by the purchaser’s order or contract, a
15.2 The purchaser reserves the right to perform any of the manufacturer’s certification or compliance statement that the
inspections set forth in the specification where such inspections casting or lot of castings was made, sampled, tested, and
are deemed necessary to ensure that supplies and services inspected in accordance with this specification, including a
conform to the prescribed requirements. report of test results, shall be furnished at the time of shipment,
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 A48/A48M − 22

Required Features: Optional Features:

1. Material—Aggregate of dry siliceous sand. 1. Number of test bars in a single mold—Two suggested.
2. Position—Bars vertical. 2. Design of pouring cup.
3. L—See Table 4. 3. P—2 in. [50 mm], suggested.
4. D—See Table 4. 4. N—5⁄16 in. [8 mm] in diameter, suggested.

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5. W—Not less than diameter D. f5. M = 1.5 N, suggested.

FIG. 2 Suitable Design and Dimensions for Mold for Separately Cast Cylindrical Test Bars for Gray Iron

and such certification or compliance statement shall be the 19. Preparation for Delivery
basis for acceptance of the casting or lot of castings.
19.1 Unless otherwise stated in the contract or order, the
17.2 A signature is not required on the certification or test cleaning, preservation, and packing of castings for shipment
report. However, the document shall clearly identify the shall be in accordance with the manufacturer’s commercial
organization submitting the certification and the authorized practice. Packaging and marking shall also be adequate to
agent of the manufacturer who certified the test results. identify the contents and to ensure acceptance and safe delivery
Notwithstanding the absence of a signature, the organization by the carrier for the mode of transportation employed.
submitting the certification is responsible for its content.
19.2 U.S. Government Procurement—When specified in the
18. Product Marking contract or purchase order, marking for shipment shall be in
18.1 When the size of the casting permits, each casting shall accordance with the requirements of Fed. Std. No. 123 for civil
bear the identifying mark of the manufacturer and the part or agencies and MIL-STD-129 for military activities.
pattern number at a location shown on the covering drawing or,
if not shown on the drawing, at a location at the discretion of 20. Keywords
the producer. 20.1 gray iron castings

APPENDIX

(Nonmandatory Information)

X1. MECHANICAL PROPERTIES OF CASTINGS

X1.1 The mechanical properties of iron castings are influ- thickness; and the existence of bosses, projections, and
enced by the cooling rate during and after solidification, by intersections, such as junctions of ribs and bosses. Because of
chemical composition (particularly carbon equivalent), by the the complexity of the interactions of these factors, no precise
design of the casting, by the design and nature of the mold, by quantitative relationship can be stated between the properties
the location and effectiveness of gates and risers, and by certain of the iron in various locations of the same casting or between
other factors. the properties of a casting and those of a test specimen cast
from the same iron. When such a relationship is important and
X1.2 The cooling rate in the mold and hence, the properties
developed in any particular section, are influenced by the must be known for a specification application, it may be
presence of cores; chills and chaplets; changes in section determined by appropriate experimentation.

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 A48/A48M − 22
X1.3 Gray iron castings in Classes 20, 25, 30, and 35 are separately cast test specimen, and where experimentation
characterized by excellent machinability, high damping would be unfeasible, the size of the test casting should be so
capacity, low modulus of elasticity, and comparative ease of selected as to approximate the thickness of the main or
manufacture. controlling section of the casting.
X1.3.1 Castings in Classes 40, 45, 50, 55, and 60 are usually
more difficult to machine, have lower damping capacity and a X1.5 If iron castings are welded (see 9.2), the microstruc-
higher modulus of elasticity, and are more difficult to manu- ture of the iron is usually altered, particularly in the vicinity of
facture. the weldment. Therefore, the properties of the casting may be
adversely affected by welding. Where practical, appropriate
X1.4 When reliable information is unavailable on the rela- post-weld heat treatment may reduce this effect of welding.
tionship between properties in a casting and those in a

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