This specification covers 8 and 9% nickel alloy steel plates for use in the water quenched and tempered condition intended for the fabrication of welded pressure vessels. The materials shall be available in two types, namely Type I and II, having different chemical compositions. The maximum thickness of plates is limited only by the capacity of the material to meet the specified mechanical property requirements. The material is susceptible to magnetization and the use of magnets in handling after heat treatment should be avoided if residual magnetism would be detrimental to subsequent fabrication or service. The steels shall be killed and shall conform to the fine austenitic grain size requirement specified. The plates shall be tempered and hardened by heat treatment. The specimens shall be subjected to tension and Charpy V-notch impact tests.

1.1 This specification2 covers 7, 8, and 9 % nickel alloy steel plates for use in the water quenched and tempered condition intended for the fabrication of welded pressure vessels.

1.2 Material under this specification is available in three types having different chemical composition as follows:

Type

Nominal Nickel Content, %

I

9

II

8

III

7

1.3 Plates produced under this specification are subject to impact testing at −320°F [−195°C] for Type I or Type III, and −275°F [−170°C] for Type II; or at such other temperatures as are agreed upon.

1.4 The maximum thickness of plates is limited only by the capacity of the material to meet the specified mechanical property requirements; however, current mill practice normally limits this material to 2 in. [50 mm] max.

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 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.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 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.