Active Standard ASTM A470 / A470M | Developed by Subcommittee: A01.06
Book of Standards Volume: 01.05
Historical (view previous versions of standard)
This specification covers vacuum-treated carbon and alloy steel forgings for turbine rotors and shafts. Materials shall be manufactured and treated by: melting process via basic electric-furnace; secondary melting process via electrode-electroslag or vacuum-arc remelting; vacuum degassing; forging process via hot mechanical working; heat treatment via double-normalizing and tempering, or normalizing, quenching and tempering; and rough machining and axial boring. Tension and impact tests shall be done to evaluate the conformance of steel forgings with the following mechanical properties: tensile strength and toughness, notch toughness, yield strength, elongation, and reduction of area. Chemical composition conformances shall also be assessed by heat and product analyses. Nondestructive tests, such as ultrasonic and internal examination, and stability tests shall also be performed. Retreatments may be executed one or more times, but not more than three additional times, if results of the mechanical tests do not conform to specified requirements.
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1.1 This specification covers vacuum-treated carbon and alloy steel forgings for turbine rotors and shafts.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each 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 safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A275/A275M Practice for Magnetic Particle Examination of Steel Forgings
A293 Specification for Steel Forgings, Carbon and Alloy, for Turbine Generator Rotors and Shafts; Replaced by A 470
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A418/A418M Practice for Ultrasonic Examination of Turbine and Generator Steel Rotor Forgings
A472/A472M Specification for Heat Stability of Steam Turbine Shafts and Rotor Forgings
A788/A788M Specification for Steel Forgings, General Requirements
E139 Test Methods for Conducting Creep, Creep-Rupture, and Stress-Rupture Tests of Metallic Materials
ICS Number Code 77.140.85 (Iron and steel forgings)