SPECIFICATION FOR GRAY IRON CASTINGS FOR
PRESSURE-CONTAINING PARTS FOR
TEMPERATURES UP TO 650°F
SA-278
(Identical with ASTM Specification A 278-93.)
1. Scope in ksi. Class 25 has a minimum specified tensile strength
of 25 ksi.
1.1 This specification covers gray iron for castings
suitable for pressure-containing parts for use at tempera-
tures up to 650°F.
5. Ordering Information
1.2 Castings of all classes are suitable for use up
to 450°F. For temperatures above 450°F and up to 5.1 Orders for material in this specification should
650°F, only Class 40, 45, 50, 55, and 60 castings are include the following information:
suitable. 5.1.1 ASTM designation and year date,
1.3 A complete SI companion to Specification A 5.1.2 Class of iron required and service temper-
278 has been developed — A 278M; therefore, no SI ature,
equivalents are presented in this specification.
5.1.3 Quantity,
5.1.4 Whether or not heat treatment is required
2. Referenced Documents for Class 40, 45, 50, 55, and 60 castings to be used
at temperatures at 450°F or less (see 6.2),
2.1 ASTM Standards:
A 278M Specification for Gray Iron Castings for Pres- 5.1.5 The size of separately cast test bar to be
sure-Containing Parts for Temperatures Up to 350°C poured (see Section 9 and Table 1),
[Metric]
5.1.6 The size of test specimen to be machined
A 644 Terminology Relating to Iron Castings
from test bars C or S, and
E 8 Test Methods for Tension Testing of Metallic Mate-
rials 5.1.7 Special requirements.
3. Terminology 6. Materials and Manufacture
3.1 Definitions of many terms common to gray iron 6.1 Castings intended for use above 450°F shall be
castings may be found in Terminology A 644. stress-relieved by placing them in a suitable furnace
at a temperature not exceeding 400°F and heating them
uniformly to the temperatures and for the times specified
in Table 2. The heating and cooling rates shall be
4. Classification
uniform and shall not be more than 400°F /h for castings
4.1 Castings ordered to this specification are classified of 1 in. maximum section. For heavier sections the
based upon the minimum tensile strength of the iron maximum heating and cooling rates in degrees Fahren-
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SA-278 2001 SECTION II
heit per hour shall be 400 divided by the maximum 9.5 For castings weighing in excess of 10 000 lb or
section thickness. having a controlling section greater than 2 in., test bars
may be removed from the casting or integral projections
6.2 Castings of Class Nos. 40, 45, 50, 55, and 60,
having a cross section no less than the controlling
which are to be used at temperatures below 450°F,
section. The minimum tensile strength requirement for
may be heat treated in accordance with 6.1 or they
tension tests performed on either of these test bars
shall be cooled in the mold to 500°F at an average
shall be 80% of the specified class.
rate of not more than 100°F /h for castings up to 1
in. in section. For heavier sections the maximum cooling
rate in degrees Fahrenheit per hour shall be 100 divided
by the maximum section thickness. 10. Molding and Pouring Test Bars
10.1 The test bars shall be cast in dried siliceous sand
molds maintained at approximately room temperature. A
7. Chemical Composition
suitable design for a mold is shown in Fig. 1.
7.1 Class 40, 45, 50, 55, and 60 castings intended
for service above 450°F shall have a maximum carbon
equivalent of 3.8% as calculated from the equation
11. Tension Test Specimens
CE p %C + 0.3 (%Si + %P). The maximum phosphorus
and sulfur contents shall be 0.25% and 0.12%, respec- 11.1 Tension test specimens A and B in Fig. 2 shall
tively. be machined from test bars A and B in Table 1,
respectively.
7.2 The chemical analysis for total carbon shall be
made on either chilled cast pencil-type specimens or 11.2 The purchaser shall specify whether test speci-
thin wafers approximately 1⁄32 in. thick cut from test men B or C is to be machined from test bar C. If
coupons. Drillings shall not be used because of attendant no choice is made, the manufacturer shall make the
loss of graphite. selection.
11.3 The size of the test specimen to be machined
8. Tensile Requirements from test bar S shall be as agreed upon between the
manufacturer and purchaser.
8.1 Iron used in supplying castings to this specifica-
tion shall conform to the tensile requirements prescribed
in Table 3.
12. Number of Tests and Retests
12.1 One tension test shall be performed on each
9. Test Bars lot in accordance with Test Method E 8 and conform
9.1 Separately cast test bars having the dimensions to the tensile requirements specified.
shown in Table 1 shall be poured from the same lot 12.2 If the results of a valid test fail to conform to
as the castings represented. The size of the test bar to the requirements of this specification, two retests shall
be poured shall be selected by the purchaser using be made. If either retest fails to meet the specification
Table 4. In the event no choice is made, the selection requirements, the castings represented by these test
will be made by the manufacturer. specimens shall be rejected.
9.2 Separately cast test bars shall be heat treated in 12.3 If, after testing, a test specimen shows evidence
the same furnace together with the castings represented. of a defect, the results of the test may be invalidated
9.3 At the option of the manufacturer, test coupons and another made on a specimen from the same lot.
may be removed from the casting at a location agreed
upon between the manufacturer and purchaser.
9.4 Castings weighing in excess of 2000 lb may be 13. Sampling
represented either by separately cast test bars (9.1) or 13.1 A lot shall consist of one of the following:
by integrally cast test bars having a cooling rate closely
approximating that of the controlling section of the 13.1.1 All the metal poured from a single heating
casting. in a batch type melting furnace,
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13.1.2 All the metal from two or more batch type the year date. The certification shall also include the
melting furnaces poured into a single ladle or single results of all tests performed.
casting, or 16.2 A signature is not required on the certification.
13.1.3 All the metal poured from a continuous However, the document shall clearly identify the organi-
melting furnace for a given period of time between zation submitting the certification and the authorized
changes in charge, processing conditions, or aim-for agent of the manufacturer who certified the test results.
chemistry or 4 h, whichever is the shorter period. Notwithstanding the absence of a signature, the organi-
zation submitting the certification is responsible for its
13.1.3.1 The purchaser may agree to extend the content.
4-h time period to 8 h if the manufacturer can demon-
strate sufficient process control to warrant such an
extension. 17. Inspection
17.1 All tests and inspections required by this specifi-
cation shall be performed by the manufacturer or other
14. Workmanship, Finish, and Appearance reliable sources whose services have been contracted
for by the manufacturer. Complete records of all tests
14.1 All castings shall be made in a workmanlike and inspections shall be maintained by the manufacturer
manner and shall conform to the dimensions on drawings and shall be available for review by the purchaser.
furnished by the purchaser. If the pattern is supplied
by the purchaser without drawings, the dimensions of
the casting shall be as predicted by the pattern. 18. Rejection and Rehearing
14.2 The surface of the casting shall be free of 18.1 Castings which fail to conform to the require-
adhering sand, scale, cracks, and hot tears as determined ments specified when inspected or tested by the pur-
by visual examination. Other surface discontinuities chaser or his agent may be rejected. Rejection shall
shall meet the visual acceptance standards specified in be reported to the manufacturer or supplier promptly
the order. and in writing. In case of dissatisfaction with the test
results, the manufacturer or supplier may make claim
for a rehearing.
15. Repair
19. Product Marking
15.1 Any repairs performed on castings produced to
this specification shall be agreed upon between the 19.1 Castings shall have the name of the manufac-
manufacturer and purchaser. turer, or his recognized trademark, and the class of
iron to which it conforms, cast or indelibly stamped
on a surface indicated by the purchaser or in such a
position as not to injure the usefulness of the casting.
16. Certification
16.1 When requested by the purchaser, the manufac-
20. Keywords
turer shall furnish his certification stating that the
material was manufactured, sampled, tested, and in- 20.1 elevated temperature service; gray iron castings;
spected in accordance with this specification including pressure containing parts
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SA-278 2001 SECTION II
FIG. 1 SUITABLE DESIGN AND DIMENSIONS FOR MOLD FOR SEPARATELY CAST
CYLINDRICAL TEST BARS FOR GRAY IRON
FIG. 2 TENSION-TEST SPECIMENS
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PART A — FERROUS MATERIAL SPECIFICATIONS SA-278
TABLE 1
DIAMETERS AND LENGTHS OF CAST TEST BARS
As-Cast Diameter, in. Length, in.
Test Nominal Minimum Maximum Minimum Maximum
Bar (Mid-Length) (Bottom) (Top) (Specified) (Recommended)
A 0.88 0.85 0.96 5.0 6.0
B 1.20 1.14 1.32 7.0 9.0
C 2.00 1.90 2.10 6.0 10.0
SA
A
All dimensions of Test Bar S shall be as agreed upon by the
manufacturer and the purchaser.
TABLE 2
STRESS RELIEVING REQUIREMENTS
Holding Time, h A
Class Metal Temperature, °F Minimum Maximum
40, 45, 50, 55, 60 1050 to 1200 2 12
A
In no case shall the holding time be less than 1 h/in. of maximum
metal section, or in excess of 12 h maximum, dependent upon which
governs.
TABLE 3
TENSILE REQUIREMENTS
Tensile Strength,
Class min, ksi
No. 20 20
No. 25 25
No. 30 30
No. 35 35
No. 40 40
No. 45 45
No. 50 50
No. 55 55
No. 60 60
TABLE 4
SEPARATELY CAST TEST BARS FOR USE WHEN A
SPECIFIC CORRELATION HAS NOT BEEN
ESTABLISHED BETWEEN THE TEST BAR AND THE
CASTING
Thickness of the Wall of the Controlling
Section of the Casting, in. Test Bar
Under 0.25 S
0.25 to 0.50 A
0.51 to 1.00 B
1.01 to 2 C
Over 2 S
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