ASTM A418/A418M-10 - 1.11.2010
 
Significance and Use

This practice shall be used when ultrasonic inspection is required by the order or specification for inspection purposes where the acceptance of the forging is based on limitations of the number, amplitude, or location of discontinuities, or a combination thereof, which give rise to ultrasonic indications.

The acceptance criteria shall be clearly stated as order requirements.

 
1. Scope

1.1 This practice for ultrasonic examination covers turbine and generator steel rotor forgings covered by Specifications A469/A469M, A470/A470M, A768/A768M, and A940/A940M. This standard shall be used for contact testing only.

1.2 This practice describes a basic procedure of ultrasonically inspecting turbine and generator rotor forgings. It does not restrict the use of other ultrasonic methods such as reference block calibrations when required by the applicable procurement documents nor is it intended to restrict the use of new and improved ultrasonic test equipment and methods as they are developed.

 
2. Referenced Documents

E1065/E1065M-20(2025)

Standard Practice for Evaluating Characteristics of Ultrasonic Search Units

Recommended Practice No. SNT-TC-1A

Personnel Qualification and Certification in Nondestructive Testing Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.

A788/A788M-26a

Standard Specification for Steel Forgings, General Requirements (Includes all amendments and changes 8/6/2026).

A940-A940M-06

Standard Specification for Vacuum Treated Steel Forgings, Alloy, Differentially Heat Treated, for Turbine Rotors

A768-A768M-05

Standard Specification for Vacuum-Treated 12 % Chromium Alloy Steel Forgings for Turbine Rotors and Shafts

E317-21

Standard Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the Use of Electronic Measurement Instruments

A469/A469M-07(2022)

Standard Specification for Vacuum-Treated Steel Forgings for Generator Rotors

A470/A470M-05(2025)

Standard Specification for Vacuum-Treated Carbon and Alloy Steel Forgings for Turbine Rotors and Shafts