ASTM A747/A747M-23

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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: A747/A747M − 18 A747/A747M − 23
Standard Specification for
Steel Castings, Stainless, Precipitation Hardening
This standard is issued under the fixed designation A747/A747M; 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.
1. Scope*
1.1 This specification covers iron-chromium-nickel-copper corrosion-resistant steel castings, capable of being strengthened by
precipitation hardening heat treatment.
1.2 These castings may be used in services requiring corrosion resistance and high strengths at temperatures up to 600 °F [315 °C].
They may be machined in the solution heat-treated condition and subsequently precipitation hardened to the desired high-strength
mechanical properties specified in Table S24.1S51.1 with little danger of cracking or distortion.
1.3 The material is not intended for use in the solution heat-treated condition.
NOTE 1—If the service environment in which the material is to be used is considered conducive to stress-corrosion cracking, precipitation hardening
should be performed at a temperature that will minimize the susceptibility of the material to this type of attack.
NOTE 1—If the service environment in which the material is to be used is considered conducive to stress-corrosion cracking, precipitation hardening
should be performed at a temperature that will minimize the susceptibility of the material to this type of attack.
1.4 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary
requirements shall apply only when specified individually by the purchaser in the purchase order or contract.
1.5 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract
specifies the applicable M-specification designation (SI units), the inch-pound units shall apply.
1.6 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. Within the text, the SI units are shown in brackets.
1.6.1 Within the text, the SI units are shown in brackets.
1.7 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.
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 Nov. 1, 2018Sept. 1, 2023. Published November 2018September 2023. Originally approved in 1977. Last previous edition approved in 20162018
as A747/A747M – 16a.A747/A747M – 18. DOI: 10.1520/A0747_A0747M-18.10.1520/A0747_A0747M-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A747/A747M − 23
2. Referenced Documents
2.1 ASTM Standards:
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
A1067/A1067M Specification for Test Coupons for Steel Castings
A1080 Practice for Hot Isostatic Pressing of Steel, Stainless Steel, and Related Alloy Castings
2.2 ASME Standard:
ASME Boiler and Pressure Vessel Code, Supplementary Requirements Section II, Part A
3. General Conditions for Delivery
3.1 Except for investment castings, castings furnished to this specification shall be in accordance with the requirements of
Specification A781/A781M, including any supplementary requirements that are indicated in 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.
3.2 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.
4. Ordering Information
4.1 Orders for material to this specification should include the following:
4.1.1 Quantity,Quantity.
4.1.2 Specification designation and date of issue, issue.
4.1.3 Grade designation (Table 1), and).
4.1.4 Description of casting by part, pattern, or drawing number. (Dimensional tolerances and machined surfaces should be
indicated on the casting drawing.)
A,B
TABLE 1 Precipitation Hardening Heat Treatment
C
Time in hours, Cooling
PH Temperature,
Condition
°F [°C]
minimum Treatment
SA Not precipitation hardened (see 5.2.3)
Solution heat Not precipitation hardened
treated
H900 900 [480] 1.5 air cool
H925 925 [495] 1.5 air cool
H1025 1025 [550] 4.0 air cool
H1075 1075 [580] 4.0 air cool
H1100 1100 [595] 4.0 air cool
H1150 1150 [620] 4.0 air cool
H1150M 1400 [760] 2.0 air cool
1150 [620] 4.0 air cool
H1150 DBL 1150 [620] 4.0 air cool
1150 [620] 4.0 air cool
A
The furnace and controls used shall be calibrated and capable of uniformity of
heating in order to ensure consistent results.
B
See Note 1.
C
±25 °F [15 °C].
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.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A747/A747M − 23
4.1.5 Heat-treatment condition (SA, H900, and so forth); see 5.2 and Table 1, .
4.1.6 Options in the specification, if any, in accordance with 5.2 and Section 7, and .
4.1.7 Supplementary requirements, if any, including the standards of acceptance.
4.1.8 For ASME Boiler & Pressure Vessel Code applications and equipment, if applicable, Supplementary Requirements S6, S14,
and S27S51, and S52 are mandatory and shall be specified in the purchase order.
5. Materials and Manufacture
5.1 The steel shall be made by the electric furnace process with or without separate refining such as argon-oxygen decarburization
(AOD).
5.2 Heat Treatment—Castings may be given a homogenization heat treatment in accordance with 5.2.1 at the supplier’s option or
when specified by the purchaser (see S56) prior to solution heat treatment. All castings, whether homogenized or not, shall be given
a solution heat treatment in accordance with 5.2.2 and, unless ordered in the solution heat-treated condition, shall be precipitation
hardened to the ordered condition (Table 1).
5.2.1 Homogenization heat treatment shall consist of heating the castings and test material to a minimum of 1900 °F [1040 °C],
holding for a minimum of 1 ⁄2 h, and cooling to below 90 °F [30 °C].
5.2.1.1 When agreed upon between purchaser and supplier, Supplementary Requirement S18, hot isostatic pressing (HIPing), in
accordance with Practice A1080may be used in place of the homogenization heat treatment.
5.2.2 Solution heat treatment shall consist of heating the castings and test material to 1925 °F 6 50 °F [1050 °C 6 30 °C], holding
thefor 30 min/in. [1.2 min/mm] of section thickness but not less than 30 min, and cooling to below 90 °F [30 °C].
5.2.3 Temperature The temperature used for precipitation hardening shall be maintained within the range of 625 °F [615 °C] of
that listed in Table 1 for the heat-treatment condition ordered. (See Note 1.)
5.2.4 When the order or contract specifies a minimum columbium (niobium) niobium content, the minimum precipitation
hardening temperature shall be 925 °F [495 °C].
6. Chemical Composition
6.1 The steel shall be in accordance with the requirements as to chemical composition prescribed in Table 2.
6.2 When the H900 condition is ordered, the minimum columbium (niobium) niobium content (Table 2) shall not apply. It is
recommended that columbium (niobium) niobium other than that in revert material not be added.
7. Repair by Welding
7.1 Repairs Unless agreed upon between purchaser and supplier, repairs shall be made only in one of the following conditions:
homogenized, solution heat treated, H1100, H1150, H1150M, H1150DBL, or stress relieved at 1150 °F 6 25 °F [620 °C 6 15 °C]
for a minimum of 4 h. See Note 2.
7.2 Castings welded in one of the aged conditions noted in 7.1 shall be post-weld heat treated by the same aging treatment used
prior to welding, or, where necessary to meet mechanical property requirements, shall be solution heat treated and aged after
welding. Castings welded in the stress-relieved condition shall receive the specified heat treatment after welding.
7.3 When agreed upon between purchaser and supplier, castings may be repaired in the as-cast condition. (See S58.)as-cast, H900,
H925, H1025, and H1075 condition.
NOTE 2—Weldability will be reduced in these precipitation-hardened conditions due to high hardness, low ductility.
A747/A747M − 23
A
TABLE 2 Chemical Requirements
Grade
UNS
Type
Element
Grade CB7Cu-1 CB7Cu-2
UNS J92180 J92110
Type 17-4 15-5
Carbon 0.07 0.07
Manganese 0.70 0.70
Phosphorus 0.035 0.035
Sulfu
...