ASTM A278/A278M-01(2011)

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:A278/A278M–01 (Reapproved 2006) Designation: A278/A278M – 01
(Reapproved 2011)
Standard Specification for
Gray Iron Castings for Pressure-Containing Parts for
Temperatures Up to 650°F (350°C)
This standard is issued under the fixed designationA278/A278M; 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 Department of Defense.
1. Scope
1.1 This specification covers gray iron for castings suitable for pressure-containing parts for use at temperatures up to 650°F
(350°C).
1.2 Classes of Iron:
1.2.1 Castings of all classes are suitable for use up to 450°F (230°C). For temperatures above 450°F and up to 650°F, only Class
40, 45, 50, 55, and 60 castings are suitable.
1.2.2 Castings of all classes are suitable for use up to 230°C. For temperatures above 230°C and up to 350°C, only Class 275,
300, 325, 350, 380, and 415 castings are suitable.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
2. Referenced Documents
2.1 ASTM Standards:
A644 Terminology Relating to Iron Castings
E8 Test Methods for Tension Testing of Metallic Materials
3. Terminology
3.1 Definitions of many terms common to gray iron castings may be found in Terminology A644.
4. Classification
4.1 Classification by tensile strength.
4.1.1 Castings ordered to this specification are classified based upon the minimum tensile strength of the iron in ksi, in English
units. Class 25 has a minimum specified tensile strength of 25 ksi.
4.1.2 Castings ordered to this specification are classified based upon the minimum tensile strength of the iron in MPa, in Metric
units. Class 150 has a minimum specified tensile strength of 150 MPa.
5. Ordering Information
5.1 Orders for material in this specification should include the following information:
5.1.1 ASTM designation and year date,
5.1.2 Class of iron required and service temperature,
5.1.3 Quantity,
5.1.4 Heat Treatment:
5.1.4.1 Whether or not heat treatment is required for Class 40, 45, 50, 55, and 60 castings to be used at temperatures at 450°F
or less (see 6.2),
This specification is under the jurisdiction of ASTM Committee A04 on Iron Castings and is the direct responsibility of Subcommittee A04.01 on Grey and White Iron
Castings.
Current edition approved Oct.March 1, 2006.2011. Published October 2006.September 2011. Originally approved in 1944. Last previous edition approved in 20012006
as A278/A278M – 01(2006). DOI: 10.1520/A0278_A0278M-01R0611.
For ASME Boiler and Pressure Vessel Code applications see related Specification SA-278 in Section II of that Code.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book ofASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A278/A278M – 01 (2011)
5.1.4.2 Whether or not heat treatment is required for Class 275, 300, 325, 350, 380, and 415 castings to be used at temperatures
at 230°C or less (see 6.2),
5.1.5 The size of separately cast test bar to be poured (see Section 9 and Table 1),
5.1.6 The size of test specimen to be machined from test bars C or S, and
5.1.7 Special requirements.
6. Materials and Manufacture
6.1 Castingsintendedforuseabove450°F(230°C)shallbestress-relievedbyplacingtheminasuitablefurnaceatatemperature
not exceeding 400°F (200°C) and heating them uniformly to the temperatures and for the times specified in Table 2. The heating
and cooling rates shall be uniform and shall not be more than 400°F/h (250°C/h) for castings of 1-in. (25-mm) maximum section.
For heavier sections the maximum heating and cooling rates in degrees Fahrenheit per hour shall be 400 divided by the maximum
section thickness.
6.2 Heat Treatment and Cooling Rate:
6.2.1 Castings of Class Nos. 45, 50, 55, and 60, which are to be used at temperatures below 450°F, may be heat treated in
accordance with 6.1 or they shall be cooled in the mold to 500°F at an average 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.
6.2.2 Castings of Class Nos. 275, 300, 325, 350, 380, and 415, which are to be used at temperatures below 230°C, may be heat
treated in accordance with 6.1 or they shall be cooled in the mold to 250°C at an average rate of not more than 50°C/h for castings
up to 25-mm in section. For heavier sections the maximum cooling rate in degrees Celsius per hour shall be 1250 divided by the
maximum section thickness.
7. Chemical Composition
7.1 Carbon Equivalent:
7.1.1 Class 40, 45, 50, 55, and 60 castings intended for service above 450°F (230°C) shall have a maximum carbon equivalent
of 3.8 % as calculated from the equation CE = %C + 0.3 (%Si + %P). The maximum phosphorus and sulfur contents shall be
0.25 % and 0.12 %, respectively.
7.1.2 Class 275, 300, 325, 350, 380, and 415 castings intended for service above 230°C shall have a maximum carbon
equivalent of 3.8 % as calculated from the equation CE = %C + 0.3 (%Si + %P). The maximum phosphorus and sulfur contents
shall be 0.25 % and 0.12 %, respectively.
7.2 The chemical analysis for total carbon shall be made on either chilled cast pencil-type specimens or thin wafers
approximately ⁄32 in. thick cut from test coupons. Drillings shall not be used because of attendant loss of graphite.
8. Tensile Requirements
8.1 IronusedinsupplyingcastingstothisspecificationshallconformtothetensilerequirementsprescribedinTable3andTable
4.
9. Test Bars
9.1 Separately cast test bars having the dimensions shown in Table 1 shall be poured from the same lot as the castings
represented. The size of the test bar to be poured shall be selected by the purchaser using Table 5. In the event no choice is made,
the selection will be made by the manufacturer.
9.2 Separately cast test bars shall be heat treated in the same furnace together with the castings represented.
9.3 At the option of the manufacturer, test coupons 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 represented either by separately cast test bars (9.1) or by integrally cast test
bars having a cooling rate closely approximating that of the controlling section of the casting.
9.5 For castings weighing in excess of 10 000 lb or having a controlling section greater than 2 in., test bars may be removed
from the casting or integral projections having a cross section no less than the controlling section. The minimum tensile strength
requirement for tension tests performed on either of these test bars shall be 80 % of the specified class.
TABLE 1 Diameters and Lengths of Cast Test Bars
Test As-Cast Diameter, in. (mm) Length, in. (mm)
Bar
Minimum Maximum Minimum Maximum
(Bottom) (Top) (Specified) (Recommended)
A 0.88 (23) 0.85 (22) 0.96 (25) 5.0 (125) 6.0 (1.50)
B 1.20 (33) 1.14 (32) 1.32 (36) 7.0 (150) 9.0 (230)
C 2.00 (54) 1.90 (53) 2.10 (58) 6.0 (175) 10.0 (255)
A
S
A
AlldimensionsofTestBarSs
...