ASTM_A_470_-_A_470M_-_05_2015.pdf

Designation:A470/A470M05(Reapproved 2015)Standard Specification forVacuum-Treated Carbon and Alloy Steel Forgings forTurbine Rotors and Shafts1This standard is issued under the fixed designation A470/A470M;the number immediately following the designation indicates the yearof 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()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers vacuum-treated carbon andalloy steel forgings for turbine rotors and shafts.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA293 Specification for Steel Forgings,Carbon andAlloy,forTurbine Generator Rotors and Shafts;Replaced by A 470(Withdrawn 1984)3A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA418/A418M Practice for Ultrasonic Examination of Tur-bine and Generator Steel Rotor ForgingsA472/A472M Specification for Heat Stability of Steam Tur-bine Shafts and Rotor ForgingsA788/A788M Specification for Steel Forgings,General Re-quirementsE139 Test Methods for Conducting Creep,Creep-Rupture,and Stress-Rupture Tests of Metallic Materials3.Ordering Information and General Requirements3.1 Material supplied to this specification shall conform tothe requirements of Specification A788/A788M,which out-lines additional ordering information,manufacturing methodsand procedures,marking,certification,production analysisvariations,and additional supplementary requirements.3.2 In addition to the ordering information required bySpecification A788/A788M,the purchaser shall include withthe inquiry and order,the grade and class of steel,alternativemaximum for silicon content(see Table 1),the choice of yieldstrength offset(0.2 or 0.02%),and any tests,supplementaryrequirements,and purchase options desired.3.3 Forging DrawingEach forging shall be manufacturedin accordance with a drawing furnished by the purchasershowing the dimensions of the forging and bore hole,if any,and the location of mechanical test specimens.3.4 Supplementary RequirementsSupplementary require-ments are provided.These requirements shall apply only whenspecified in the purchase order.3.5 If the requirements of this specification are in conflictwith the requirements of Specification A788/A788M,therequirements of this specification shall prevail.4.Manufacture4.1 Melting Process:4.1.1 The steel shall be made by the basic electric-furnaceprocess.4.1.2 Provisions for subsequent secondary melting of thesteel by the consumable electrode-electroslag or vacuum-arcremelting processes are included in Supplementary Require-ment S7.4.2 Vacuum TreatmentThe vacuum degassing require-ments of Specification A788/A788M are mandatory.4.3 DiscardSufficient discard shall be taken from eachingot to secure freedom from pipe and harmful segregation inthe finished forging.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1,2015.Published March 2015.Originallyapproved in 1962.Last previous edition approved in 2010 as A470/A470M 05(2010).DOI:10.1520/A0470_A0470M-05R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.4 Forging ProcessThe forging shall receive its hotmechanical work under a press of ample power to adequatelywork the metal throughout the maximum section of theforging.It is important to maintain the axial center of theforging in common with the axial center of the ingot.4.5 Heat Treatment:4.5.1 The heat treatment for mechanical properties shallconsist of double-normalizing and tempering for Grades A,B,D,and E and normalizing,quenching,and tempering for GradeC.In normalizing treatments,the forging may be cooled in stillair or in an air blast at the