This specification covers precipitation hardened iron base superalloy forgings which are primarily intended for use as turbine rotor disks and wheels. Two heat treatments are covered and selection will depend upon design, service conditions, mechanical properties, and elevated temperature characteristics. The material shall be made by vacuum melting followed by consumable electrode vacuum arc or electroslag remelting. The forgings shall undergo the following tests: tension test, hardness test, stress rupture test, and creep test. Also, the forgings shall be subjected to non-destructive examinations like ultrasonic examination and liquid penetrant examination. The forgings shall be uniform in quality and condition, clean, sound, and free of cracks, seams, laps, shrinkage, and other injurious imperfections.

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 A788/A788M, apply, except as amended herein.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.