1、Designation: A 471 08Standard Specification forVacuum-Treated Alloy Steel Forgings for Turbine RotorDisks and Wheels1This standard is issued under the fixed designation A 471; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers vacuum-treated alloy steelforgings intended for use as turbine rotor disks and wheels.
3、1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, asso
4、ciated 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:2A 275/A 275M Practice for Magnetic Particle Examinationof
5、 Steel ForgingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 388/A 388M Practice for Ultrasonic Examination ofHeavy Steel ForgingsA 788/A 788M Specification for Steel Forgings, GeneralRequirementsE30 Test Methods for Chemical Analysis of Steel, CastIron, Open-Hearth Iro
6、n, and Wrought Iron3E 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 order, the class of steel
7、, alternative maximumfor silicon content (see Table 1), the choice of yield strengthoffset (0.2 or 0.02 %), and any tests, supplementary require-ments, and purchase options desired.3.2 Forging DrawingEach forging shall be manufacturedin accordance with a purchaser-supplied drawing showing thefinishe
8、d dimensions and the locations of mechanical testspecimens.3.3 Supplementary requirements are provided and shallapply only when specified in the purchasers order.4. Materials and Manufacture4.1 Melting Process:4.1.1 The steel shall be made by the basic electric-furnaceprocess.4.1.2 Provisions for su
9、bsequent secondary melting of thesteel by the consumable electrode-electroslag or vacuum-arcremelting processes are included in Supplementary Require-ment S4.4.2 Vacuum TreatmentThe vacuum degassing require-ments of Specification A 788/A 788M are mandatory.4.2.1 The molten steel shall be vacuum trea
10、ted prior to orduring the pouring of the ingot in order to remove objection-able gases, particularly hydrogen.4.2.1.1 When the vacuum stream degassing process4isused, the vacuum system must be of sufficient capacity to effecta blank-off pressure low enough (usually less than 1000 m) tobreak up the n
11、ormal tight, rope-like stream of molten metalinto a wide-angled conical stream of relatively small droplets.The capacity of the system must also be sufficiently high toreduce the initial surge pressure at the start of the pour to a lowlevel within 2 min.4.2.1.2 When the vacuum-lift process4is utiliz
12、ed, the mol-ten metal shall be repeatedly drawn into the evacuated vessel togive a recirculation factor (Note 1) of at least 2.5 to ensurethorough degassing and mixing of the entire heat. The evacu-ation system shall be capable of reducing the pressure surges,which occur each time a new portion of s
13、teel is admitted to thevessel, to increasingly lower levels until a blank-off pressure(usually less than 1000 m) is achieved.NOTE 1The recirculation factor is obtained as follows:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is th
14、e direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Oct. 1, 2008. Published October 2008. Originallyapproved in 1962. Last previous edition approved in 2006 as A 471 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
15、TM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Details of the vacuum stream degassing process may be found in the Journalof the Iron and Steel Institute, Vol 191, January 1959; “
16、Vacuum Pouring of Ingotsfor Heavy Forgings” by J. H. Stoll.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.tons of steel lifted per cycle 3 number of cyclesheat weight
17、 in tons4.2.1.3 When the ladle degassing process is used, theevacuation system shall be capable of reducing the systemvacuum pressure to a low level (usually less than 1000 m).The molten metal shall be adequately stirred for a sufficientlength of time to maximize exposure to the evacuated atmo-spher
18、e. When this process is used, hydrogen testing perSupplemental Requirement S2 is mandatory.4.2.1.4 Other methods of degassing may be used if thesupplier can demonstrate their adequacy to the satisfaction ofthe purchaser. When other processes are used, hydrogen testingper the supplemental requirement
19、 S2 is mandatory.4.3 DiscardSufficient discard shall be taken from eachingot to secure freedom from pipe and undue segregation in thefinished forging.4.4 Forging ProcessThe forgings shall receive their hotmechanical work under a press, hammer, or mill of sufficientpower to work the metal throughout
20、its section. The forgingsshall be upset by forming from a block having an axial lengthbefore upsetting of at least two times the thickness of theforging after upsetting.4.4.1 The as-forged dimensions of each forging shall beplanned so the metal is shaped by forging as close as ispractical to the dim
21、ensions shown on the purchasers drawingso as to keep subsequent machining to a minimum.4.4.2 The axial center of the forging shall be maintained incommon with the axial center of the ingot.4.5 Heat Treatment:4.5.1 Cooling Prior to Heat TreatmentAfter forging andbefore reheating for heat treatment, t
22、he forging shall beallowed to cool in a manner to prevent damage and toaccomplish transformation.4.5.2 Preliminary Heat TreatmentThe forgings shall begiven such preliminary heat treatment as is proper for thedesign and composition. The forgings shall be heated to asuitable temperature for a sufficie
23、nt length of time for completeaustenitization and shall be suitably cooled to bring aboutcomplete transformation.4.5.3 Heat Treatment for Mechanical PropertiesThe forg-ings shall be reheated to a temperature above the upper criticaltemperature, held a sufficient length of time for completeaustenitiz
24、ation, and liquid quenched.4.5.4 Tempering TemperatureThe forgings shall be tem-pered to develop the specified properties. The final temperingtemperature for Class 1 to 6 and 11 through 14 shall be not lessthan 1100F (593C), and for Class 10 not less than 1200F(649C). The forgings shall be cooled un
25、der suitable conditionsfrom the tempering temperature.4.5.5 Stress ReliefUnless otherwise specified by the pur-chaser, the forgings shall be stress relieved after machining(see 4.6.2) by heating slowly to a temperature within 100F(56C) below the final tempering temperature but in no casebelow 1025F
26、(552C) for Classes 1 to 6 and 11 through 14 and1150F (621C) for Class 10. They shall be held for a sufficientlength of time and then cooled under suitable conditions. Thisstress-relief temperature may be omitted provided the metalremoved in accordance with 4.6.2, excluding test metal, doesnot exceed
27、316 in. (4.8 mm) on any surface.4.6 Machining:4.6.1 Preliminary MachiningThe forgings shall be pre-liminarily machined on all surfaces prior to heat treatment formechanical properties (see 4.5.3).4.6.2 Machining to Purchasers Requirements forShipmentAfter heat treatment for mechanical properties (se
28、e4.5.3), the forgings shall be machined to the dimensions of thepurchasers forging drawing or instructions on his order.5. Chemical Composition5.1 The steel shall conform to the requirements for chemicalcomposition prescribed in Table 1.5.2 Chemical Analysis:5.2.1 Heat AnalysisAn analysis of each he
29、at of steel shallbe made by the manufacturer to determine the percentages ofthose elements specified in Table 1. This analysis shall be madefrom a test ingot taken during the pouring of the heat.5.2.1.1 If the test sample taken for the ladle analysis is lostor declared inadequate for chemical determ
30、inations, the manu-facturer may take alternative samples from appropriate loca-tions near the surface of the ingot or forging as necessary toestablish the analysis of the heat in question.TABLE 1 Chemical RequirementsComposition, %Classes 1 to 6,inclClass 10 Classes 11 to 13,inclClass 14Carbon 0.28
31、maxA0.270.37 0.380.43 0.45 maxManganese 0.70 max 0.701.00 0.601.00 0.601.00Phosphorus 0.012 max 0.012 max 0.012 max 0.012 maxSulfur 0.015 max 0.015 max 0.015 max 0.015 maxSiliconBBBBBNickel 2.004.00 0.50 max 0.50 max 1.653.50Chromium 0.752.00 0.851.25 0.801.10 0.501.25Molybdenum 0.200.70 1.001.50 0.
32、15 min 0.20 minVanadium 0.05 min 0.200.30 0.06 max optionalAntimonyCCCCAluminumD0.015 max 0.015 max 0.015 max 0.015 maxA0.35 % C max for Classes 4 and 5; 0.40 % C, max, for Class 6.B0.10% max unless an alternative value, not in excess of 0.35%, is specified in the purchase order.CTo be reported for
33、information only.DTotal of soluble and insoluble.A4710825.2.2 Product AnalysisA product analysis may be madeby the purchaser on each forging. Sample for an analysis maybe taken from the forging at any point from the mid-radius tothe outside diameter or from a full-size prolongation, orturnings may b
34、e taken from a test specimen. The chemicalcomposition thus determined shall not vary from the require-ments specified in Table 1 more than the amounts prescribed inTable 2.5.3 Test Methods of AnalysisTest Methods E30shall beused for referee purposes.6. Mechanical Properties6.1 Tension TestThe materi
35、al shall conform to the require-ment for tensile properties prescribed in Table 3 when tested inaccordance with Test Methods and Definitions A 370. Tensiontest specimens shall be the standard round,12-in. (12.7-mm)diameter, 2-in. (50.8-mm) gauge length as shown in TestMethods and Definitions A 370.
36、The yield strength prescribedin Table 3 shall be determined by the 0.2 % offset method ofTest Methods and Definitions A 370. The offset shall be 0.2 %unless 0.02 % is specified in the ordering information.6.2 Impact TestThe material shall conform to the require-ments for impact (both transition-temp
37、erature and room-temperature impact value) as prescribed in Table 3. The impacttests shall be performed in accordance with Test Methods andDefinitions A 370 using standard full-size specimens.6.3 HardnessForgings made from Classes 11 to 14 andsubjected to group testing in accordance with 6.4.1 shall
38、conform to the Brinell hardness requirements prescribed inTable 3 when tested in accordance with Test Methods andDefinitions A 370.6.4 Location and Number of TestsClasses 1 through 10tension and impact test specimen shall be identified and takenfrom the locations as specified by the purchaser and ag
39、reed toby the producer. One tension test and a transition-temperaturedetermination, including room-temperature impact strengthshall be considered a minimum number of tests conducted onforgings made to this specification.6.4.1 For Classes 11 through 14 unless otherwise specifiedby the purchaser, test
40、s shall be made as follows:6.4.1.1 Forgings 30 in. (762 mm) and under in diameter maybe group tested. One tension test and one Charpy V-notch testshall be considered representative of each lot of forgingsmanufactured from the same heat of material and heat treatedtogether. When group tested two Brin
41、ell tests, 180 apart, shallbe made on the same face of each forging near the rim.6.4.1.2 For forgings over 30 in. in diameter, at least one rimtension test and one Charpy V-notch test shall be made fromeach forging.6.4.1.3 LocationUnless otherwise specified, tension andCharpy V-notch specimens shall
42、 be taken on full thicknessprolongations on the forging periphery. The test specimen shallbe taken as close as possible to the quarter thickness of theforging, with the axis of the specimen tangential.6.5 Removal of Test SpecimensRemoval of mechanicaltest specimens shall be done after all heat treat
43、ment, includingthe stress relief when required, has been completed. Testmaterial shall not be separated from the forging until after thequench and temper cycles. If separated prior to a requiredstress relief cycle, test material sufficient to satisfy 6.4 and ofthe proper orientation shall be include
44、d with the stress reliefcycle of the forgings and subsequently tested.TABLE 2 Permissible Variations in Product AnalysisNOTEProduct cross-sectional area is defined as either:(1) maximum cross-sectional area of rough machined forging (excluding boring),(2) maximum cross-sectional area of the unmachin
45、ed forging, or(3) maximum cross-sectional area of the billet, bloom, or slab.Area taken at right angles to the axis of the original ingot or billetElementUnit or Maximum SpecifiedRange, %Permissible Variation Over the Specified Maximum Limit orUnder the Specified Minimum Limit, %Up to andincluding10
46、0 in.2(645 cm2)Over 100to 200 in.2(645 to1290 cm2),inclOver 200to 400 in.2(1290 to2580 cm2),inclOver 400to 800 in.2(2580 to5160 cm2),inclOver 800to 1600in.2(5160to 10 320cm2), inclOver 1600in.2(10 320cm2)Carbon . . . 0.03 0.04 0.04 0.05 0.06 0.06Manganese up to and including 0.90 0.03 0.04 0.05 0.06
47、 0.07 0.080.91 and over 0.06 0.06 0.07 0.08 0.08 0.09Phosphorus . . . 0.008 0.008 0.010 0.010 0.015 0.015Sulfur . . . 0.005 0.005 0.005 0.005 0.006 0.006Silicon . . . 0.02 0.03 0.04 0.04 0.05 0.06Nickel up to and including 1.00 0.03 0.03 0.03 0.03 0.03 0.031.01 to 2.00, incl 0.05 0.05 0.05 0.05 0.05
48、 0.052.01 and over 0.07 0.07 0.07 0.07 0.07 0.07Chromium up to and including 0.90 0.03 0.04 0.04 0.05 0.05 0.060.91 and over 0.05 0.06 0.06 0.07 0.07 0.08Molybdenum up to and including 0.20 0.01 0.02 0.02 0.02 0.03 0.030.21 to 0.40, incl 0.02 0.03 0.03 0.03 0.04 0.040.41 to 1.15, incl 0.03 0.04 0.05
49、 0.06 0.07 0.081.16 and over 0.05 0.06 0.08 0.10 0.12 0.12Vanadium up to and including 0.10 0.01 0.01 0.01 0.01 0.01 0.010.11 to 0.25, incl 0.02 0.02 0.02 0.02 0.02 0.020.26 and over 0.03 0.03 0.03 0.03 0.03 0.03A4710837. Nondestructive Test Requirements7.1 General RequirementsThe forgings shall be free fromcracks, seams, laps, shrinkage, and other similar imperfections.7.2 Ultrasonic InspectionAn ultrasonic inspection of theforgings shall be made on all available surfaces to demonstratefreedom from detrimental internal indic
