ASTM A891-98(2003)

1.1 This specification covers precipitation hardening iron base superalloy forgings which are primarily intended for use as turbine rotor disks and wheels.

1.2 Two heat treatments are covered. Selection will depend upon design, service conditions, mechanical properties, and elevated temperature characteristics.

1.3 All of the provisions of Specification A 788, apply, except as amended herein.

1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.