ASTM A521-96(2001)

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 to Definition A 509.

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

1.2.1 Class CA - Untreated, carbon steel forgings,

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

1.2.3 Class CF - Normalized and tempered carbon steel forgings,

1.2.4 Class CF1 - Double normalized and tempered carbon steel forgings,

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

1.2.6 Class AA - Annealed, normalized, or normalized and tempered alloy steel forgings,

1.2.7 Classes AB and AC - Normalized and tempered alloy steel forgings, and

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

Note 2 - The appendix tables list recommended tolerances for a number of materials other than those covered by the above classes. The tables are for information only and the purchaser must define the condition in which he desires forgings made from materials not described above.

1.3 The values stated in inch-pound units are to be regarded as the standard.