This specification deals with ferritic alloy steel forgings for high-pressure and high-temperature parts, such as boilers, pressure vessels, and associated equipment. The steel grades covered here include the following: Grade F1; Grade F11, Classes 1, 2, and 3; Grade F12; Grade F5; Grade F5A; Grade F9; Grade F6; Grades F21 and F22, Classes 1 and 3; Grade F91, Grade F3V; and Grade F22V. Other steel grades may also be treated under this specification. Alloy steels shall be melted, forged, and rough machined at stipulated conditions. Except as permitted for Grade F22V, steel forgings shall be annealed or normalized and tempered, but may alternatively be liquid quenched and tempered as well. Impact and Charpy V-notch tests shall be performed wherein specimens shall conform to specified mechanical requirements such as notch toughness, tensile strength, yield strength, elongation, and reduction of area. Materials shall also undergo heat and product analyses and conform to specified chemical requirements.

1.1 This specification covers ferritic steel forgings for boilers, pressure vessels, high-temperature parts, and associated equipment.

1.2 Forgings made of steel grades listed in Specification A 335/A 335M, may also be ordered under this specification. The chemical, tensile, heat treatment, and marking requirements of Specification A 335/A 335M shall apply, except the forging shall conform to the chemical requirements of Tables 1 and 2 of Specification A 335/A 335M only with respect to heat analysis. On check analysis they may deviate from these limits to the extent permitted in Table 1 of this specification.

1.3 Supplementary Requirements S1 to S9 are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.

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

1.5 Specification A 336/A 336M formerly included austenitic steel forgings, which are now found in Specification A 965/A 965M.

1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.