1.1 This specification2 covers double-normalized and tempered 9 % nickel steel plates intended particularly for welded pressure vessels for cryogenic service. 1.2 Plates produced under this specification are subject to impact testing at −320°F [−195°C] or at such other temperatures as are agreed upon. 1.3 The maximum thickness of plates is limited only by the capacity of the material to meet the specific mechanical property requirements. 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 units 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. 1.6 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.