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 (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.
ASTM A844/A844M-21 Referenced Document
ASTM A20/A20M Standard Specification for General Requirements for Steel Plates for Pressure Vessels
ASTM A435/A435M Standard Specification for Straight-Beam Ultrasonic Examination of Steel Plates
ASTM A577/A577M Standard Specification for Ultrasonic Angle-Beam Examination of Steel Plates
ASTM A578/A578M Standard Specification for Straight-Beam Ultrasonic Examination of Plain and Clad Steel Plates for Special Applications
ASTM A841/A841M Standard Specification for Steel Plates for Pressure Vessels, Produced by Thermo-Mechanical Control Process (TMCP)
ASTM A844/A844M-21 history
2021ASTM A844/A844M-21 Standard Specification for Steel Plates, 9 % Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
2009ASTM A844/A844M-09(2015) Standard Specification for Steel Plates, 9&x2009;%&x2009; Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
2009ASTM A844/A844M-09 Standard Specification for Steel Plates, 9 % Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
2004ASTM A844/A844M-04 Standard Specification for Steel Plates, 9 % Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process
1993ASTM A844/A844M-93(1999) Standard Specification for Steel Plates, 9% Nickel Alloy, for Pressure Vessels, Produced by the Direct-Quenching Process