1.1 This specification2 covers high-strength quenched and tempered low-alloy steel forged parts for pressure vessels. The maximum thickness of forgings under this specification shall be 1¹/₂ in. [38 mm] for Grade A, and 4 in. [100 mm] for Grades E and F.

1.2 Although no provision is made for supplementary requirements in this standard, the supplementary requirements in Specification A788/A788M may be considered by the purchaser.

1.3 Welding technique is of fundamental importance and it is presupposed that welding procedures will be in accordance with approved methods for the class of material used.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.5 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.

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.