ASTM A744/A744M-21a

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Designation: A744/A744M − 21 A744/A744M − 21a
Standard Specification for
Castings, Iron-Chromium-Nickel, Corrosion Resistant, for
Severe Service
This standard is issued under the fixed designation A744/A744M; 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.
1. Scope*
1.1 This specification covers iron-chromium-nickel alloy stainless steel castings intended for particularly severe corrosive
applications.
1.2 This specification requires post-weld heat treatment of all weld repairs affecting surfaces intended to be wetted by the corrosive
medium. For applications for which post-weld heat treatment is not considered mandatory for retention of acceptable corrosion
resistance, refer to Specification A743/A743M.
NOTE 1—For general corrosion-resistant alloy castings, reference should be made to Specification A743/A743M. For general heat-resistant alloy castings,
reference should be made to Specification A297/A297M. For nickel-base alloy castings, refer to Specification A494/A494M.
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 nonconformance with the standard.
1.3.1 Within the text, the SI units are shown in brackets.
1.3.2 Inch-pound units are applicable for material ordered to Specification A744 and SI units for material ordered to Specification
A744M.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
A297/A297M Specification for Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, for General
Application
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.18
on Castings.
Current edition approved March 1, 2021Nov. 1, 2021. Published March 2021November 2021. Originally approved in 1977. Last previous edition approved in 20202021
as A744/A744M – 20a.A744/A744M – 21. DOI: 10.1520/A0744_A0744M-21.10.1520/A0744_A0744M-21A.
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 the ASTM website.
*A Summary of Changes section appears at the end of this standard
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A744/A744M − 21a
A494/A494M Specification for Castings, Nickel and Nickel Alloy
A743/A743M Specification for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application
A781/A781M Specification for Castings, Steel and Alloy, Common Requirements, for General Industrial Use
A957/A957M Specification for Investment Castings, Steel and Alloy, Common Requirements, for General Industrial Use
2.2 American Welding Society Standards:
AWS A5.11 Specification for Nickel and Nickel Alloy Covered Welding Electrodes
AWS A5.14 Specification for Nickel and Nickel Alloy Bare Welding Rods and Electrodes
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 wetted surface, n—one that contacts a corrosive environment.
4. General Conditions for Delivery
4.1 Except for investment castings, castings furnished to this specification shall conform to the requirements of Specification
A781/A781M, including any supplementary requirements that are indicated on the purchase order. Failure to comply with the
general requirements of Specification A781/A781M constitutes nonconformance with this specification. In case of conflict between
the requirements of this specification and Specification A781/A781M, this specification shall prevail.
4.2 Steel investment castings furnished to this specification shall conform to the requirements of Specification A957/A957M,
including any supplementary requirements that are indicated in the purchase order. Failure to comply with the general requirements
of Specification A957/A957M constitutes nonconformance with this specification. In case of conflict between the requirements of
this specification and Specification A957/A957M, Specification A957/A957M shall prevail.
5. Ordering Information
5.1 Orders for material to this specification should include the following, as required, to describe the material adequately:
5.1.1 Description of the casting by pattern number or drawing (dimensional tolerances shall be included on the casting drawing),
5.1.2 Grade,
5.1.3 Heat treatment,
5.1.4 Identify wetted surface(s),
5.1.5 Options in the specification,
5.1.6 Whether casting are to be produced using the investment casting process, and
5.1.7 Supplementary requirements desired, including the standards of acceptance.
6. Process
6.1 Alloys shall be melted by the electric furnace process with or without separate refining, such as argon-oxygen-decarburization
(AOD).
7. Heat Treatment
7.1 Castings shall be heat treated in accordance with the requirements in Table 1.
NOTE 2—Proper heat treatment of these alloys is usually necessary to enhance corrosion resistance and, in some cases, to meet mechanical properties.
Minimum heat-treat temperatures are specified; however, it is sometimes necessary to heat treat at higher temperatures, hold for some minimum time at
temperature, and then rapidly cool the castings in order to enhance the corrosion resistance and meet mechanical properties.
Available from The American Welding Society (AWS), 550 NW LeJeune Rd., Miami, FL 33126.
A744/A744M − 21a
TABLE 1 Heat Treatment Requirements
Grade Heat Treatment
CF8 (J92600), CG8M (J93000), CF8M (J92900), CF8C (J92710), Heat to 1900 °F [1040 °C] minimum, hold for sufficient time to heat casting to
A
CF3 (J92500), CF3M (J92800), CG3M (J92999) temperature, quench in water or rapid cool by other means.
CN7M (N08007), CN3MCu (J80020) Heat to 2050 °F [1120 °C] minimum, hold for sufficient time to heat casting to
temperature, quench in water or rapid cool by other means.
CN7MS (J94650) Heat to 2100 °F [1150 °C] minimum, 2150 °F [1180 °C] maximum, hold for sufficient time
(2 h min) to heat casting to temperature, and quench in water.
CK3MCuN (J93254), CN3MN (J94651) Heat to 2200 °F [1200 °C] minimum, hold for a minimum of 4 h, quench in water or cool
rapidly by other means.
A
For optimum tensile strength, ductility, and corrosion resistance, the solution heat treatment temperatures for Grades CF8M, CG8M, and CF3M should be in excess of
1900 °F [1040 °C].
8. Chemical Composition Requirements
8.1 The materials shall conform with the chemical composition requirements prescribed in Table 2.
9. Workmanship, Finish, and Appearance
9.1 Machined welding ends shall be suitably protected against damage during shipping.
10. Repair by Welding
10.1 The composition of the deposited weld metal composition shall be similar to that of the casting except in grade CK3MCuN.
In the case of Grade CK3MCuN, the composition of the deposited metal shall be similar to that of AWS A5.14 ER NiCrMo-3 (UNS
NO6625) or AWS A5.11 E NiCrMo-3 (UNS W 86112) when post-weld heat treatment is not required, and the composition of the
deposited metal shall be either similar to that of the base metal or similar to that of AWS A5.14 ER NiCrMo-3 or AWS A5.11 E
NiCrMo-3 when post-weld heat treatment is required.for grades CK3MCuN and CN3MN.
10.1.1 The composition of the deposited weld metal For CK3MCuN, when post-weld heat treatment is required, the weld metal
composition shall be similar to that of the casting except in grade CN3MN. In the case of grade CN3MN, the composition of the
deposited weld metal or AWS A5.14 ER NiCrMo-3 (UNS N06625) or AWS A5.11 E NiCrMo-3 (UNS W86112). When post-weld
heat treatment is not required, the weld metal composition shall be similar to that of AWS A5.14 ER NiCrMo-3 or ER NiCrMo-4
or ER NiCrMo-10, or the composition of the deposited weld metal shall be similar to that of (UNS N06625) or AWS A5.11 E
NiCrMo-3 or E NiCrMo-4 or E NiCrMo-10 when post-weld heat treatment is or is not required. (UNS W86112).
10.1.2 For CN3MN, when post-weld heat treatment is or is not required, the weld metal composition shall be similar to that of
AWS A5.14 ER NiCrMo-3 (UNS N06625), ER NiCrMo-4 (UNS N10276), ER NiCrMo-10 (UNS N06022), or ER NiCrMo-14
(UNS N06686); or AWS A5.11 E NiCrMo-3 (UNS W86112), E NiCrMo-4 (UNS W80276), E NiCrMo-10 (UNS W86022), or E
NiCrMo-14 (UNS W86686).
10.2 Weld repairs shall be considered major in the case of a casting that has leaked on hydrostatic test or when the depth of the
cavity after preparation for repair exceeds 20 % of the actual wall thickness, or 1 in. [25 mm], whichever is smaller, or when the
2 2
extent of the cavity exceeds approximately 10 in. [65 cm ]. All other weld repairs shall be considered minor. Major and minor
weld repairs shall be subject to the same quality standards as are used to inspect the castings. When methods involving high
temperatures are used in the removal of discontinuities, castings shall be preheated to 50 °F [10 °C] min.
10.3 Except for grades CK3MCuN and CN3MN, castings shall be post-weld heat treated in accordance with Table 1 after all major
weld repairs and after those mi
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