ASTM A768.pdf

Designation: A 768/A 768M – 05

Standard Specification for

Vacuum-Treated 12 % Chromium Alloy Steel Forgings for

Turbine Rotors and Shafts

1

This standard is issued under the fixed designation A 768/A 768M; the number immediately following the designation indicates the year

of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.

A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

system shall be used independently of the other. Combining

values from the two systems may result in non-conformance

with the standard.

1.3 This standard does not purport to address all of the

2. Referenced Documents

2.1 ASTM Standards:

and Generator Steel Rotor Forgings

A 472 Test Method for Heat Stability of Steam Turbine

Shafts and Rotor Forgings

A 788 Specification for Steel Forgings, General Require-

ments

3. Ordering Information

3.1 In addition to the ordering information required by

Specification

A 788, the purchaser shall include with the

inquiry and order a detailed drawing, sketch, or written

tional ordering information, manufacturing requirements, test-

ing and retesting methods and procedures, marking, certifica-

tion, product analysis variations, and additional supplementary

requirements.

with the requirements of Specification

of this specification shall prevail.

5. Manufacture

is important to maintain the axial center of the forging in

common with the axial center of the original ingot.

consist of quenching and tempering.

normalizing well above the transformation temperature range.

This operation may be performed before preliminary machin-

preliminary machining (see

5.4.1). Austenitizing temperatures

shall be in accordance with Table 1.

dance with

Table 1.

This specification is under the jurisdiction of ASTM Committee A01 on Steel,

Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee

A01.06 on Steel Forgings and Billets.

the ASTM website.