ASTM A521/A521M-06

1.1 This specification covers untreated and heat-treated steel, closed-impression die forgings (Note 1) for general industrial use. Note 1—For the definition of a forging, refer General Requirements Specification A 788/A 788M.

1.2 The Grades of forgings are as follows, the choice depending on design and stress or service to be imposed:

1.2.1 Grade CA Untreated, carbon steel forgings,

1.2.2 Grades CC, CC1, and CE Annealed, normalized and tempered, carbon steel forgings,

1.2.3 Grade CF Normalized and tempered carbon steel forgings,

1.2.4 Grade CF1 Double normalized and tempered carbon steel forgings,

1.2.5 Grade CG Quenched and tempered, or normalized, quenched and tempered carbon steel forgings,

1.2.6 Grade AA Annealed, normalized, or normalized and tempered alloy steel forgings,

1.2.7 Grades AB and AC Normalized and tempered alloy steel forgings, and

1.2.8 Grades AD, AE, AF, AG, and AH Normalized, quenched, and tempered alloy steel forgings.

1.3 Unless the order specifies the applicable "M" specification designation, the forgings shall be furnished with the inch-pound units.

1.4 The values stated in either inch-pound units or SI (metric) units are to be regarded separately as 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 shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.