ASTM A844/A844M-93(1999)
(Specification)Standard Specification for Steel Plates, 9% Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
Standard Specification for Steel Plates, 9% Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
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. (This 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 The maximum nominal thickness of plates furnished under this specification shall not exceed 2 in. [50 mm].
1.4 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.
1.5 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.
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Designation: A 844/A 844M – 93 (Reapproved 1999)
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 A 844/A 844M; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope A 578/A578M Specification for Straight-Beam Ultrasonic
Examination of Plain and Clad Steel Plates for Special
1.1 This specification covers 9 % nickel-alloy steel plates
Applications
produced by the direct-quenching process. The plates are
intended primarily for use in welded pressure vessels.
3. General Requirements and Ordering Information
1.2 The direct-quenching process consists of quenching the
3.1 Material supplied to this material specification shall
plates directly after rolling, without permitting the plates to
conform to Specification A 20/A 20M. These requirements
cool below the critical temperature prior to initiation of the
outline the testing and retesting methods and procedures,
quenching operation, and subsequently tempering the plates.
permissible variations in dimensions, quality and repair of
(This differs from the “conventional” process in which the
defects, marking, loading, etc.
plates are permitted to cool to a temperature significantly
3.2 Specification A 20/A 20M also establishes the rules for
below the critical temperature, usually to ambient temperature,
ordering information that should be complied with when
prior to reheating to a temperature above the upper critical
purchasing material to this specification.
temperature, then quenching, and subsequently tempering.)
3.3 In addition to the basic requirements of this specifica-
1.3 The maximum nominal thickness of plates furnished
tion, certain supplementary requirements are available when
under this specification shall not exceed 2 in. [50 mm].
additional control, testing, or examination is required to meet
1.4 This material is susceptible to magnetization. Use of
end use requirements. These include:
magnets in handling after heat treatment should be avoided if
3.3.1 Vacuum treatment,
residual magnetism would be detrimental to subsequent fabri-
3.3.2 Additional or special tension testing,
cation or service.
3.3.3 Additional or special impact testing, and
1.5 The values stated in either inch-pound or SI units are to
3.3.4 Nondestructive examination.
be regarded separately as standard. Within the text, the SI units
3.4 The purchaser is referred to the listed supplementary
are shown in brackets. The values stated in each system are not
requirements in this specification and to the detailed require-
exact equivalents; therefore each system must be used inde-
ments in Specification A 20/A 20M.
pendently of the other. Combining values from the two systems
3.5 If the requirements of this specification are in conflict
may result in nonconformance with the specification.
with the requirements of Specification A 20/A 20M, the re-
2. Referenced Documents quirements of this specification shall prevail.
2.1 ASTM Standards:
4. Manufacture
A 20/A20M Specification for General Requirements for
2 4.1 Steelmaking Practice—The steel shall be killed and
Steel Plates for Pressure Vessels
shall conform to the fine austenitic grain size requirement of
A 435/A435M Specification for Straight-Beam Ultrasonic
Specification A 20/A 20M.
Examination of Steel Plates
4.2 Heat Treatment:
A 577/A577M Specification for Ultrasonic Angle-Beam
4.2.1 The plates shall be quenched directly after rolling,
Examination of Steel Plates
without being allowed to cool below 1205°F [650°C]. The
quenching shall be initiated from a temperature within the
range from 1205 to 1670°F [650 to 910°C]. (The temperature
This specification is under the jurisdiction of ASTM Committee A-1 on Steel,
shall be reported in accordance with 19.2 of Specification
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
A01.11 on Steel Plates for Boilers and Pressure Vessels.
A 20/A 20M.)
Current edition approved June 15, 1993. Published August 1993. Originally
4.2.2 Subsequent to quenching, the plates shall be tempered
published as A 844/A 844M – 85. Last previous edition A 844/A 844M – 87b
within the range from 1050 to 1175°F [565 to 635°C], holding
(1991).
Annual Book of ASTM Standards, Vol 01.04. at that temperature for a minimum of 30 min/in. [1.2 min/mm]
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 844/A 844M – 93 (1999)
of thickness but for not less than 15 min., and then cooling at 7. Mechanical Requirements
a rate of not less than 300°F/h [165°C/h], either in air or by
7.1 Tension Test Requirements—The material as represented
quenching in water, to ambient temperature.
by the tension-test specimens shall conform to the require-
4.2.2.1 Prior to the tempering treatment, the plates may be
ments specified in Table 2.
subjected to an intermediate heat treatment consisting of
7.1.1 For nominal plate thicknesses of ⁄4 in. [20 mm] and
heating to a temperature in the range from 1165 to 1290°F [630 1
under, the 1 ⁄2-in. [40-mm] wide rectangular specimen may be
to 700°C], holding at that temperature for a minimum of 1 h/in.
used for the tension test and the elongation may be determined
(2.4 min/mm] of thickness, but in no case less than 15 min, and
in a 2-in. [50-mm] gage length that includes the fracture and
then water-quenching to below 300°F [150°C] in the case of
shows the great
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