1、Designation: A940/A940M 06 (Reapproved 2016)Standard Specification forVacuum Treated Steel Forgings, Alloy, Differentially HeatTreated, for Turbine Rotors1This standard is issued under the fixed designation A940/A940M; the number immediately following the designation indicates the yearof original ad
2、option 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.1. Scope1.1 This specification covers vacuum treated, alloy steelforgings, differe
3、ntially heat treated for turbine rotors.1.2 Differential heat treatment of a rotor forging involvessubjecting two portions of the forging concurrently to twodifferent austenitizing temperatures followed by two differentcooling rates for normalizing and quenching, and thentempering, to achieve creep
4、resistance in the high pressure(HP) portion and high toughness in the low pressure (LP)portion.21.3 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 ind
5、ependently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.2. Referenced Documents2.1 ASTM Standards:3A275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA418/
6、A418M Practice for Ultrasonic Examination of Tur-bine and Generator Steel Rotor ForgingsA470/A470M Specification for Vacuum-Treated Carbon andAlloy Steel Forgings for Turbine Rotors and ShaftsA472/A472M Specification for Heat Stability of Steam Tur-bine Shafts and Rotor ForgingsA788/A788M Specificat
7、ion for Steel Forgings, General Re-quirementsE139 Test Methods for Conducting Creep, Creep-Rupture,and Stress-Rupture Tests of Metallic Materials3. Ordering Information3.1 In addition to the ordering information required bySpecification A788/A788M, the purchaser shall include withthe inquiry and ord
8、er a detailed drawing, sketch, or writtendescription of the forging, including the mechanical testlocations, the portion of the forging to be included in theheating chamber during the stability test, and the minimumstability test temperature.3.2 The purchaser shall specify if check tests for mechani
9、calproperties are required after stress relief or heat stability tests.3.3 Supplementary RequirementsSupplementary require-ments are provided. These requirements shall apply only whenspecified in the purchase order.4. General Requirements4.1 Material supplied to this specification shall conform toth
10、e requirements of Specification A788/A788M, which out-lines additional ordering information, manufacturingrequirements, testing and retesting methods and procedures,marking, certification, product analysis variations, and addi-tional supplementary requirements.4.2 If the requirements of this specifi
11、cation are in conflictwith the requirements of Specification A788/A788M, therequirements of this specification shall prevail.5. Manufacture5.1 Melting processes of Specification A788/A788M shallbe applicable, except that the open hearth or basic oxygenmethods of primary melting shall not be used and
12、 the moltensteel shall be vacuum treated during processing. Except forvacuum stream degassed ingots, the hydrogen content shall bedetermined. The acceptable hydrogen limit as well as the stagein processing when sampling, the sample preparation proce-dure and the method of analysis shall be establish
13、ed betweenthe manufacturer and the purchaser.5.1.1 If the ESR process is used, the electrodes shall havebeen produced from vacuum treated primary heat(s).1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility o
14、f SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1, 2016. Published April 2016. Originallyapproved in 1995. Last previous edition approved in 2011 as A940/A940M 06(2011). DOI: 10.1520/A0940_A0940M-06R16.2Symposium on Steel Forgings, ASTM STP 903, ASTM International,
15、WestConshohocken, PA, 1984, pp. 5986.3For 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.Copyright ASTM Internati
16、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information15.2 In addition to the requirements of Specificati
17、on A788/A788M, it is important to maintain the axial center of theforging in common with the axial center of the original ingot.5.3 Differential Heat TreatmentThe heat treatment formechanical properties shall consist of normalizing and temper-ing of the creep resistant portion, HP portion, and quenc
18、hingand tempering of the high toughness portion, LP portion.5.3.1 The preliminary heat treatment shall consist of nor-malizing well above the transformation temperature range.5.3.2 The normalizing and quenching treatments shall befrom above the transformation range but below the normalizingtemperatu
19、re described in 5.3.1. This treatment shall be per-formed after preliminary machining.5.3.2.1 The heat treatment for the HP portion shall consistof normalizing, accelerated air cooling, and tempering.5.3.2.2 For the high toughness LP portion, the heat treat-ment shall consist of water quenching (or
20、water-spray quench-ing) and tempering.5.3.3 The final tempering temperature for all zones shall notbe below 1200F 650C.5.3.4 After heat treatment and subsequent rough machiningand boring, the forging shall be stress relieved at a temperaturenot more than 100F 55C below the final temperingtemperature
21、, but not below 1100F 595C.5.3.5 With the prior approval of the purchaser, the stressrelieving temperature may approach, equal, or slightly exceedthe final tempering temperature as a means of adjusting finalstrength or toughness. If the stress relieving temperature iswithin 25F 15C of the final temp
22、ering temperature, orhigher, acceptance tests shall be obtained after the stressrelieving operation.5.3.6 The method of cooling the HP and LP portions duringthe normalizing, quenching, tempering, and stress relievingheat treating cycles shall be reported.5.4 Machining:5.4.1 Preliminary Rough Machini
23、ngAll exterior surfacesof the forging shall be machined prior to heat treatment formechanical properties.5.4.2 Second Rough MachiningAfter heat treatment formechanical properties, all surfaces of the forging shall be roughmachined prior to stress relief and the stability test.5.4.3 Boring:5.4.3.1 Fo
24、rgings shall be bored to permissible bore size andtolerances when required by the purchasers drawing.5.4.3.2 Forgings may be bored to limits agreed to by thepurchaser or indicated on the purchasers drawing, to removeobjectionable center conditions revealed by ultrasonic inspec-tion.5.4.3.3 Unless ot
25、herwise specified by the purchaser, themanufacturer may bore the forging at any time after quenchingand prior to stress relief.5.4.4 Machining to Purchasers Requirements forShipmentThe forging, as shipped, shall conform to the finishand dimensions specified on the purchasers drawing or order.6. Chem
26、ical Composition6.1 Heat AnalysisAn analysis of each heat of steel shall bemade by the manufacturer. This analysis shall be made from atest sample taken preferably during the pouring of the heat. Thesteel shall conform to the requirements for chemical composi-tion prescribed in Table 1.6.2 Product A
27、nalysisThe manufacturer shall make a prod-uct analysis from each forging. The chemical composition thusdetermined shall not vary from the requirements specified inTable 1 by more than the amounts prescribed in SpecificationA788/A788M.7. Mechanical Properties7.1 Tension Test:7.1.1 The steel shall con
28、form to the tensile requirements ofTable 2.7.1.2 The number and location of tension test specimensshall be as specified on the forging drawings furnished by thepurchaser.7.1.3 Final acceptance tests shall be performed after heattreatment of the forging for mechanical properties prior tostress relief
29、. If the stress relief temperature is within 25F15C of the tempering temperature, or higher, check testsshall be made after the stress relief treatment and reported tothe purchaser. The purchaser may require check tests after thecompletion of all heating cycles, including stress relief and theheat s
30、tability tests.7.1.4 The yield strength prescribed in Table 2 shall bedetermined by the offset method of Test Methods and Defini-tions A370.7.2 Impact Test:7.2.1 The steel shall conform to the requirements for notchtoughness (both transition temperature and room temperatureimpact values) prescribed
31、in Table 3.7.2.2 The notch toughness specimens shall be machinedfrom radial bars taken from the main body of the forging, asshown in the forging drawing. The specimens shall be CharpyV-notch, Type A, as shown in Test Methods and DefinitionsA370. The notch direction of the Charpy bars shall be aspres
32、cribed in Specification A470/A470M.8. Nondestructive Tests8.1 General Requirements:8.1.1 The forgings shall be free of cracks, seams, laps,shrinkage, and other injurious imperfections.8.1.2 The purchaser may request ultrasonic, magneticparticle, dye penetrant, etch, or other nondestructive inspec-ti
33、ons necessary to evaluate imperfections and to ensure com-pliance with this requirement.TABLE 1 Chemical CompositionComposition, % Grade 1Carbon 0.230.31Manganese 0.501.00Phosphorus, max 0.012Sulfur, max 0.015Silicon, max 0.10Nickel 0.801.10Chromium 0.901.50Molybdenum 1.101.50Vanadium 0.200.30Columb
34、ium (Niobium) 0.010.05Aluminum 0.010 maxA940/A940M 06 (2016)28.2 Ultrasonic Inspection:8.2.1 An ultrasonic inspection shall be performed on themachined forging at the manufacturers plant. This inspectionshall be made in accordance with Practice A418/A418M todemonstrate freedom from detrimental inter
35、nal defects.8.2.2 The ultrasonic inspection shall be conducted from allavailable surfaces prior to removal of the test specimens thatwould interfere with complete testing of the forging.8.2.3 Forgings with reportable ultrasonic indications shallbe referred to the purchaser for evaluation based on th
36、e nature,frequency, and location of the indications, both stationary andtraveling. It shall be determined by conventional or mutuallyacceptable inspection procedures whether the forging will berejected if the ultrasonic indications are considered objection-able.8.3 Internal Inspection:8.3.1 When spe
37、cified for internal borescope inspection,boring shall be in accordance with the drawings furnished bythe purchaser. The drawings shall specify the nominal dimen-sions of the bore hole.8.3.2 If objectionable conditions are encountered duringinternal inspection of the bore hole, the manufacturer shall
38、notify the purchaser of the location and nature of the condition.Further action shall be taken only after mutual agreementbetween the manufacturer and the purchaser.9. Stability Test9.1 Each forging shall be subjected to a heat stability test atthe manufacturers plant in accordance with the latest i
39、ssue ofSpecification A472/A472M to determine the stability or free-dom from a tendency to distort during high-temperatureoperating conditions.9.2 The stability test shall be conducted after the forging hasbeen stress relieved.9.2.1 The stress relief may be performed as part of thestability test if a
40、greed to by the purchaser.9.3 Stability Test Requirements:9.3.1 The purchasers drawings shall indicate the portion ofthe forging to be included within the heating chamber duringthe stability test.9.3.2 The purchasers drawings or order shall indicate theminimum stability test temperature.10. Retreatm
41、ent10.1 If the results of the mechanical tests of any forging donot conform to the requirements specified, the manufacturermay retreat the entire forging one or more times, but not morethan three additional times, without the approval of thepurchaser.10.2 If the bore core properties are specified un
42、der Supple-mentary Requirement S1 and retemper is necessary afterboring, the remaining portions of the core shall be replaced inthe bore during retemper. If the stress relief temperature iswithin 25F 15C of the tempering temperature, the core barshall be reinserted for the stress relief.10.3 If comp
43、lete retreatment, including differential heattreatment by normalizing and quenching, is necessary afterboring, the feasibility of retreating portions of the bore core inthe bore of the forging shall be discussed between the manu-facturer and the purchaser and a procedure agreed upon beforetreatment.
44、11. Dimensions, Tolerances, and Finish11.1 Each forging shall conform to the dimensions andtolerances specified on the purchasers drawing or order.11.2 The finish on each forging shall conform to the finishspecified on the purchasers drawing or order.12. Certification and Reports12.1 In addition to
45、the certification requirements of Speci-fication A788/A788M, the following shall be reported:12.1.1 Hydrogen determination method and results12.1.2 Product analysis results, and12.1.3 Location of the heat treatment transition point on theforging.13. Package Marking, Packing, and Loading13.1 Each for
46、ging shall be stamped legibly by the manufac-turer with the manufacturers name or symbol, the manufac-turers identification number, the ASTM designation, the ap-propriate grade number, and identification numbers specifiedby the purchaser on his drawing of the order.13.2 The location of such identifi
47、cation marks may bespecified by the purchaser on his drawing or order.13.3 Test specimens shall be identified with numbers corre-sponding to the test location and type, if specified on thepurchasers drawings or order.13.4 The axial bores of bored forgings shall be protectedand plugged suitably to pr
48、event damage or corrosion duringshipment or storage.14. Keywords14.1 differential heat treatment; steel forgings; turbine rotor;vacuum treated steelTABLE 2 Tensile RequirementsGrade 1Tensile strength, ksi MPa 105125 725860Yield strength, min, ksi MPa, 0.2 % offset 85 585Elongation in 2 in. or 50 mm,
49、 min, % 17 longitudinal14 radialReduction of area, min, % 43 longitudinal38 radialTABLE 3 Notch Toughness RequirementsTest Location Grade 1ftlb J, minTransition Temperature,FATT50F C, maxHP 6 8.2 250 120LP 25 34 36 2A940/A940M 06 (2016)3SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall apply only when specified by the purchaser in theinquiry, contract, or order. Details of these supplementary requirements shall be agreed upon by themanufacturer and the purchaser.S1. B
