This specification covers quenched and tempered carbon and alloy steel forgings for pressure vessel components. Heat and product analyses shall be performed to evaluate material conformance with chemical composition requirements. Tension and Charpy V-notch tests shall also be carried out to assess material conformance with mechanical property requirements such as, tensile strength, yield strength, elongation, reduction of area, and Charpy value. Sampling of test specimens for mechanical examination shall be done by either one of four methods specified by the purchaser. Repair welding may also be made at the option of the purchaser.

1.1 This specification2 covers requirements for quenched and tempered carbon and alloy steel forgings for pressure vessel components.

1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used.

Note 1: Grades 1 and 1A have different chemistries but the same mechanical requirements.

Note 2: Designations have been changed as follows:

Current

Formerly

Grade 1

Class 1

Grade 1A

Class 1A

Grade 1C

Class 4

Grade 2 Class 1

Class 2

Grade 2 Class 2

Class 2A

Grade 3 Class 1

Class 3

Grade 3 Class 2

Class 3A

Grade 4N Class 1

Class 7

Grade 4N Class 2

Class 7A

Grade 4N Class 3

Class 7B

Grade 5 Class 1

Class 8

Grade 5 Class 2

Class 8A

Grade 11 Class 4

Class 11C

Grade 22 Class 3

Class 22B

Grade 22 Class 4

Class 22C

Grade 22 Class 5

Class 22D

Grade 22V

Class 22V

Grade 3V

Class 3V

1.3 The values stated in either inch-pound units or SI (metric) units are to be regarded separately as the standard. Within the text and tables, 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.

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