1、Designation: A 940/A 940M 06Standard Specification forVacuum Treated Steel Forgings, Alloy, Differentially HeatTreated, for Turbine Rotors1This standard is issued under the fixed designation A 940/A 940M; the number immediately following the designation indicates the yearof original adoption or, in
2、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.1. Scope1.1 This specification covers vacuum treated, alloy steelforgings, differentially heat
3、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 then temper-ing, to achieve creep resistance
4、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 independently
5、 of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.2. Referenced Documents2.1 ASTM Standards:3A 275/A 275M Test Method for Magnetic Particle Exami-nation of Steel ForgingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 418/A
6、 418M Test Method for Ultrasonic Examination ofTurbine and Generator Steel Rotor ForgingsA 470/A 470M Specification for Vacuum-Treated Carbonand Alloy Steel Forgings for Turbine Rotors and ShaftsA 472/A 472M Test Method for Heat Stability of SteamTurbine Shafts and Rotor ForgingsA 788/A 788M Specifi
7、cation for Steel Forgings, GeneralRequirementsE 139 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 A 788/A 788M, the purchaser shall include withthe inquiry and
8、 order 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 mec
9、hanicalproperties 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
10、tothe requirements of Specification A 788/A 788M, which out-lines additional ordering information, manufacturing require-ments, testing and retesting methods and procedures, marking,certification, product analysis variations, and additional supple-mentary requirements.4.2 If the requirements of this
11、 specification are in conflictwith the requirements of Specification A 788/A 788M, therequirements of this specification shall prevail.5. Manufacture5.1 Melting processes of Specification A 788/A 788M shallbe applicable, except that the open hearth or basic oxygenmethods of primary melting shall not
12、 be used and 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
13、be established 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 resp
14、onsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1, 2006. Published March 2006. Originallyapproved in 1995. Last previous edition approved in 2001 as A 940 96 (2001).2Symposium on Steel Forgings, ASTM STP 903, ASTM International, WestConshohocken, PA, 198
15、4, 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.1Copyright ASTM International, 100 Barr Harbor Dr
16、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 In addition to the requirements of Specification A 788/A 788M, 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 form
17、echanical properties shall consist of normalizing and temper-ing of the creep resistant portion, HP portion, and quenchingand 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 T
18、he normalizing and quenching treatments shall befrom above the transformation range but below the normalizingtemperature 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 cooli
19、ng, and tempering.5.3.2.2 For the high toughness LP portion, the heat treat-ment shall consist of water quenching (or 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 bo
20、ring, the forging shall be stress relieved at a temperaturenot more than 100F 55C below the final tempering tem-perature, 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
21、 a means of adjusting finalstrength or toughness. If the stress relieving temperature iswithin 25F 15C of the final tempering 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, quench
22、ing, tempering, and stress relievingheat treating cycles shall be reported.5.4 Machining:5.4.1 Preliminary Rough MachiningAll exterior surfacesof the forging shall be machined prior to heat treatment formechanical properties.5.4.2 Second Rough MachiningAfter heat treatment formechanical properties,
23、all surfaces of the forging shall be roughmachined prior to stress relief and the stability test.5.4.3 Boring:5.4.3.1 Forgings 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
24、on the purchasers drawing, to removeobjectionable center conditions revealed by ultrasonic inspec-tion.5.4.3.3 Unless otherwise 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 forShipmen
25、tThe forging, as shipped, shall conform to the finishand dimensions specified on the purchasers drawing or order.6. Chemical Composition6.1 Heat AnalysisAn analysis of each heat of steel shallbe made by the manufacturer. This analysis shall be made froma test sample taken preferably during the pouri
26、ng of the heat.The steel shall conform to the requirements for chemicalcomposition prescribed in Table 1.6.2 Product AnalysisThe 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 tha
27、n the amounts prescribed in SpecificationA 788/A 788M.7. Mechanical Properties7.1 Tension Test:7.1.1 The steel shall conform 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 Fina
28、l acceptance tests shall be performed after heattreatment of the forging for mechanical properties prior tostress relief. 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
29、. The purchaser may require check tests after thecompletion of all heating cycles, including stress relief and theheat stability tests.7.1.4 The yield strength prescribed in Table 2 shall bedetermined by the offset method of Test Methods and Defini-tions A 370.7.2 Impact Test:7.2.1 The steel shall c
30、onform to the requirements for notchtoughness (both transition temperature and room temperatureimpact values) prescribed 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 Ch
31、arpyV-notch, Type A, as shown in Test Methods and DefinitionsA 370. The notch direction of the Charpy bars shall be asprescribed in Specification A 470/A 470M.8. Nondestructive Tests8.1 General Requirements:8.1.1 The forgings shall be free of cracks, seams, laps,shrinkage, and other injurious imperf
32、ections.8.1.2 The purchaser may request ultrasonic, magnetic par-ticle, dye penetrant, etch, or other nondestructive inspectionsnecessary to evaluate imperfections and to ensure compliancewith this requirement.TABLE 1 Chemical CompositionComposition, % Grade 1Carbon 0.230.31Manganese 0.501.00Phospho
33、rus, max 0.012Sulfur, max 0.015Silicon, max 0.10Nickel 0.801.10Chromium 0.901.50Molybdenum 1.101.50Vanadium 0.200.30Columbium (Niobium) 0.010.05Aluminum 0.010 maxA 940/A 940M 0628.2 Ultrasonic Inspection:8.2.1 An ultrasonic inspection shall be performed on themachined forging at the manufacturers pl
34、ant. This inspectionshall be made in accordance with Test Method A 418/A 418Mto demonstrate freedom from detrimental internal 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
35、forging.8.2.3 Forgings with reportable ultrasonic indications shallbe referred to the purchaser for evaluation based on the nature,frequency, and location of the indications, both stationary andtraveling. It shall be determined by conventional or mutuallyacceptable inspection procedures whether the
36、forging will berejected if the ultrasonic indications are considered objection-able.8.3 Internal Inspection:8.3.1 When specified 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
37、 hole.8.3.2 If objectionable conditions are encountered duringinternal inspection of the bore hole, the manufacturer shallnotify 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
38、Test9.1 Each forging shall be subjected to a heat stability test atthe manufacturers plant in accordance with the latest issue ofTest Method A 472/A 472M to determine the stability orfreedom from a tendency to distort during high-temperatureoperating conditions.9.2 The stability test shall be conduc
39、ted after the forging hasbeen stress relieved.9.2.1 The stress relief may be performed as part of thestability test if agreed 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
40、 stability test.9.3.2 The purchasers drawings or order shall indicate theminimum stability test temperature.10. Retreatment10.1 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
41、 morethan three additional times, without the approval of thepurchaser.10.2 If the bore core properties are specified under 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 tempe
42、rature iswithin 25F 15C of the tempering temperature, the core barshall be reinserted for the stress relief.10.3 If complete retreatment, including differential heattreatment by normalizing and quenching, is necessary afterboring, the feasibility of retreating portions of the bore core inthe bore of
43、 the forging shall be discussed between the manu-facturer and the purchaser and a procedure agreed upon beforetreatment.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 s
44、hall conform to the finishspecified on the purchasers drawing or order.12. Certification and Reports12.1 In addition to the certification requirements of Speci-fication A 788/A 788M, the following shall be reported:12.1.1 Hydrogen determination method and results12.1.2 Product analysis results, and1
45、2.1.3 Location of the heat treatment transition point on theforging.13. Package Marking, Packing, and Loading13.1 Each forging 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 n
46、umber, and identification numbers specifiedby the purchaser on his drawing of the order.13.2 The location of such identification 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 specif
47、ied on thepurchasers drawings or order.13.4 The axial bores of bored forgings shall be protectedand plugged suitably to prevent damage or corrosion duringshipment or storage.14. Keywords14.1 differential heat treatment; steel forgings; turbine rotor;vacuum treated steelTABLE 2 Tensile RequirementsGr
48、ade 1Tensile strength, ksi MPa 105125 725860Yield strength, min, ksi MPa, 85 5850.2 % offsetElongation in 2 in. 17 longitudinalor 50 mm, min, % 14 radialReduction of area, 43 longitudinalmin, % 38 radialTABLE 3 Notch Toughness RequirementsTest Location Grade 1ftlb J, minTransition Temperature,FATT50
49、F C, maxHP 6 8.2 250 120LP 25 34 36 2A 940/A 940M 063SUPPLEMENTARY 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. Bore Core PropertiesS1.1 The purchaser may require the removal of a longitu-dinal bore core from the forging after heat treatment formechanical properties and subsequent approval of the usualsurface me
