ASTM A844/A844M-21

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Designation: A844/A844M − 09 (Reapproved 2015) A844/A844M − 21
Standard Specification for
Steel Plates, 9 % Nickel Alloy, for Pressure Vessels,
Produced by the Direct-Quenching Process
This standard is issued under the fixed designation A844/A844M; 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 Scope*
1.1 This specification covers 9 % nickel-alloy steel plates produced by the direct-quenching process. The plates are intended
primarily for use in welded pressure vessels.
1.2 The direct-quenching process consists of quenching the plates directly after rolling, without permitting the plates to cool below
the critical temperature prior to initiation of the quenching operation, and subsequently tempering the plates. (Thisplates (see
Appendix X1). (Note: The direct-quenching process differs from the “conventional” process in which the plates are permitted to
cool to a temperature significantly below the critical temperature, usually to ambient temperature, prior to reheating to a
temperature above the upper critical temperature, then quenching, and subsequently tempering.)
1.3 If the plates are subjected to warm forming, the temperature shall not exceed 950°F [510°C].
1.4 The maximum nominal thickness of plates furnished under this specification shall not exceed 2 in. [50 mm].
1.5 This material is susceptible to magnetization. Use of magnets in handling after heat treatment should be avoided if residual
magnetism would be detrimental to subsequent fabrication or service.
1.6 The values stated in either inch-pound or SI units are to be regarded separately as standard. Within the text, the SI units are
shown in brackets. The values stated in each system are not exact equivalents; therefore each system must be used independently
of the other. Combining values from the two systems may result in nonconformance with the specification.
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.
2. Referenced Documents
2.1 ASTM Standards:
A20/A20M Specification for General Requirements for Steel Plates for Pressure Vessels
A435/A435M Specification for Straight-Beam Ultrasonic Examination of Steel Plates
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.11
on Steel Plates for Boilers and Pressure Vessels.
Current edition approved Sept. 1, 2015Nov. 1, 2021. Published September 2015November 2021. Originally approved in 1985. Last previous edition approved in 20092015
as A844/A844M – 09.A844/A844M – 09 (2015). DOI: 10.1520/A0844_A0844M-09R15.10.1520/A0844_A0844M-21.
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
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A844/A844M − 21
A577/A577M Specification for Ultrasonic Angle-Beam Examination of Steel Plates
A578/A578M Specification for Straight-Beam Ultrasonic Examination of Rolled Steel Plates for Special Applications
A841/A841M Specification for Steel Plates for Pressure Vessels, Produced by Thermo-Mechanical Control Process (TMCP)
3. General Requirements and Ordering Information
3.1 Material supplied to this material specification shall conform to Specification A20/A20M. These requirements outline the
testing and retesting methods and procedures, permitted variations in dimensions, quality and repair of defects, marking, loading,
and ordering information.
3.2 In addition to the basic requirements of this specification, certain supplementary requirements are available when additional
control, testing, or examination is required to meet end use requirements. The purchaser is referred to the listed supplementary
requirements in this specification and to the detailed requirements in Specification A20/A20M.
3.3 If the requirements of this specification are in conflict with the requirements of Specification A20/A20M, the requirements of
this specification shall prevail.
4. Manufacture
4.1 Steelmaking Practice—The steel shall be killed and shall conform to the fine austenitic grain size requirement of Specification
A20/A20M.
A844/A844M − 21
TABLE 1 Chemical Requirements
Element Composition, %
A
Carbon, max 0.13
Manganese, max:
Heat analysis 0.90
Product analysis 0.98
A
Phosphorus, max 0.015
A
Sulfur, max 0.015
Silicon:
B
Heat analysis 0.15–0.40
B
Product analysis 0.13–0.45
Nickel:
Heat analysis 8.50–9.50
Product analysis 8.40–9.60
A
Applies to both heat and product analyses.
B
The specified minimum limit does not apply if the total aluminum content is
0.030 % or more, or provided that acid soluble aluminum is 0.025 % or more.
4.2 Heat Treatment:
4.2.1 The plates Plates shall be quenched directly after rolling, without being allowed to cool below 1205°F [650°C].rolling and
before cooling below 985°F [530°C]. The quenching shall be initiated from a temperature within the range from 1205 985 to
1670°F [650 to 910°C]. (The temperature [530 to 910°C] and shall be reported in accordance with 19.2 of Specification
A20/A20M.) if requested by the purchaser.
4.2.2 Subsequent to quenching, the plates shall be tempered within the range from 1050 to 1175°F [565 to 635°C], holding at that
temperature for a minimum of 30 min/in. [1.2 min/mm] of thickness but for not less than 15 min., and then cooling at a rate of
not less than 300°F/h [165°C/h], either in air or by quenching in water, to ambient temperature.
4.2.2.1 Prior to the tempering treatment, the plates may be subjected to an intermediate heat treatment consisting of heating to a
temperature in the range from 1165 to 1290°F [630 to 700°C], holding at that temperature for a minimum of 1 h/in. (2.4 min/mm]
of thickness, but in no case less than 15 min, and then water-quenching to below 300°F [150°C] in the case of plate thicknesses
5 5
of more than ⁄8 in. [16 mm] or cooling in air or water-quenching to below 300°F [150°C] in the case of plate thicknesses of ⁄8
in. [16 mm] and under.
NOTE 1—The intermediate heat treatment is for the purpose of enhancing elongation and notch-toughness and for red
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