ASTM A472 A472M-07(2017) Standard Specification for Heat Stability of Steam Turbine Shafts and Rotor Forgings.pdf

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1、Designation: A472/A472M 07 (Reapproved 2017)Standard Specification forHeat Stability of Steam Turbine Shafts and Rotor Forgings1This standard is issued under the fixed designation A472/A472M; the number immediately following the designation indicates the yearof original adoption or, in the case of r

2、evision, 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 the determination of heatstability of steam turbine shafts and rotor fo

3、rgings to ensurestability at operating temperature. This specification is notordinarily applicable to generator rotor forgings.1.2 This specification is expressed in both inch-pound unitsand in SI units; however, unless the purchase order or contractspecifies the applicable M specification designati

4、on (SI units),the inch-pound units shall apply. The values stated in eitherinch-pound units or SI units are to be regarded separately asstandard. Within the specification, the SI units are shown inbrackets. The values stated in each system may not be exactequivalents; therefore, each system shall be

5、 used independentlyof the other. Combining values from the two systems mayresult in nonconformance with the standard.1.3 Supplementary requirements of an optional nature areprovided for use at the option of the purchaser. The supple-mentary requirements shall apply only when specified indi-vidually

6、by the purchaser in the purchase order or contract.1.4 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

7、regulatory limitations prior to use.2. Ordering Information2.1 It shall be the responsibility of the purchaser to specifyall requirements necessary for testing under this specification.Requirements to be considered include, but are not limited to,the following:2.1.1 ASTM designation and year date,2.

8、1.2 The minimum test temperature,2.1.3 The portion of the forging to be subjected to the heatstability test temperature, and2.1.4 Supplementary or other special requirements.3. Procedure3.1 The heat stability test shall be conducted by the forgingsupplier after final heat treatment and after the for

9、ging has beencentered and machined with allowance to finish to the purchas-ers drawing. Material for mechanical tests may be removedbefore or after the stability test at the manufacturers option,unless check tests after the stability test are required by thepurchaser.3.2 With prior approval from the

10、 purchaser, the forgingsmay be stress-relieved as part of the heat stability test. Whenthis is done, the stress-relieving temperature shall be within 50to 100 F 30 to 55 C below final tempering temperature.Rotate the forgings at 2 to 4 r/min and hold at stress-relievingtemperature for at least 2 h/i

11、n. 2 h/25 mm of maximum radialthickness, after which the temperature may be decreased to thespecified heat stability test temperature and the test performed.4. Heat Stability Test Bands4.1 The supplier shall mark positionsA, B, C, and D, spaced90 apart circumferentially, preferably on an end of the

12、forging.Markings shall be retained throughout all subsequent opera-tions.4.2 Preferably, there shall be a minimum of 5 test bands,denoted as 1, 2, 3, 4, and 5, machined on the circumference ofthe forging. Numbering shall start at the left side of the forgingdrawing. Bands 1 and 5 shall be located as

13、 close to the end ofthe forging as practical. Band 3 shall be located as near tomidlength as practical. Bands 2 and 4 shall be locatedapproximately equidistant between 1 and 3, and 3 and 5,respectively.4.3 When the shipped length of the barrel portion of theforging is less than 8 ft 2.4 m, bands 2 a

14、nd 4 may be omitted.4.4 The purchasers drawing may show the desired numberand location of bands and shall indicate that portion of theforging that shall be located within the heating chamber. Bands1 and 5 are to be located outside of the heating chamber.Preferably, the gland areas/packing seal areas

15、 are inside theheating chamber.4.5 The test bands shall be machined with the forgingrunning on centers except in the cases of forgings weighingover 125 000 lb 56.7 metric tons the machining shall beperformed with the forgings running on steady rests. Readings1This specification is under the jurisdic

16、tion 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 15, 2017. Published March 2017. Originallyapproved in 1962. Last previous edition approved in 2012 as A472/A472M

17、07(2012). DOI: 10.1520/A0472_A0472M-07R17.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision

18、 on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1shall be taken with the forging running on centers except in thecases of forgings weighing over 125 000 lb 56.7 metric tonswher

19、e readings may be taken with the forgings running onsteady rests. Between readings, the forgings may be rotated onsteady rests.5. Surface Preparation5.1 Remove oil, grease, dirt, and other foreign material fromthe surface of the forging prior to the heat stability test. Asuitable coating may be appl

20、ied to provide uniform emissivity.6. Heating and Cooling6.1 Place the forging in the heating chamber and rotate theforging at a speed of 2 to 4 r/min.6.2 Place thermocouples in contact with the forging at eachtest band within the heating chamber. Shield the thermocouplesfrom the heat source.6.3 Appl

21、y heat uniformly to avoid localized overheating.Heat the forging at a rate not exceeding 200 F h 110 C h tothe stability test temperature specified by the purchaser. Main-tain the specified testing temperature until the forging is heateduniformly. A uniform temperature condition shall be consid-ered

22、 to exist when three consecutive hourly deflection mea-surements taken at the test temperature are within 0.0005 in.0.013 mm. To consider a uniform test temperature conditionto exist, it is also necessary that the axial thermal expansion beconsistent within 0.010 in. 0.25 mm for three consecutivehou

23、rly readings at the test temperature.6.4 After uniform test conditions as described in 6.3 havebeen reached, cool the forging, while rotating, to below 100 F40 C. The heating chamber may be opened during cooling,but the cover shall not be removed until the temperature of theforging is less than 500

24、F 260 C. After the forging hascooled to approximately room temperature, rotate it for at least2 h before the second cold measurements (see 7.4) arerecorded.7. Stability Measurements7.1 Use an indicator located outside the heating chamber tomeasure to the nearest 0.0005 in. 0.013 mm. Actuate theindic

25、ator by a rod with one end contacting the forging at testbands described in 4.2 or 4.3. Take measurements at each testband at positions A, B, C, and D. For each band, the indicatormay be set to zero for the minimum deflection at one of thepositions A, B, C, or D or the figures may be reduced tominim

26、a by subtraction.7.2 First Cold MeasurementsTake measurements on eachband after rotation is started but prior to heating. If the runoutexceeds 0.002 in. 0.05 mm at any band, continue rotation for1 h. If runout continues to exceed 0.002 in. 0.05 mm, recenterthe forging or remachine the bands until th

27、e runout does notexceed 0.002 in. 0.05 mm in any band. Refer to the lastmeasurements as the official first cold measurements.7.3 Hot MeasurementsTake measurements on all bandshourly during the heating cycle until the forging has beenheated to the specified temperature. When three consecutivehourly d

28、eflection measurements at the specified temperaturecheck within 0.0005 in. 0.013 mm, cooling may commence.Refer to the last of these measurements as the official hotmeasurements.7.4 Second Cold MeasurementsAfter cooling in accor-dance with 6.4, take measurements on all bands at half-hourintervals un

29、til two consecutive deflection measurements checkwithin 0.0005 in. 0.013 mm. Refer to the last of thesemeasurements as the official second cold measurements.8. Interpretation of Results8.1 The forging shall be acceptable if the movement of itscenter is not greater than 0.001 in. 0.025 mm when deter-

30、mined by the difference between the official hot and the officialcold second measurements. This movement shall be deter-mined for each band as follows:8.1.1 From the official hot measurements at position Asubtract the official cold measurement for position A.8.1.2 Repeat the procedure for positions

31、B, C, and D.8.1.3 For each of these four results, numerically total thegreatest plus value and the greatest minus value without regardto sign. The maximum deflection in any band as indicated bythese totals shall not exceed 0.002 in. 0.05 mm.8.2 In case of changes in measurements in bands 1 and 5,sui

32、table corrections may be made to results obtained frombands 2, 3, and 4. The corrected figures shall be within therequirements of 8.1.3.8.3 If the forging does not meet the requirements of thestability test, it may be retested, stress relieved before retest orcompletely reheat treated before retest.

33、9. Report9.1 The forging supplier shall report to the purchaser theofficial first cold measurements, the hourly measurementsduring heating and holding at specified temperature, the officialhot measurements and the official second cold measurements,as well as the temperature of the forging when these

34、 measure-ments were obtained. The report shall include the calculatedchange in measurements as determined under 8.1.3.10. Keywords10.1 emissivity; heat stability; rotor forgings; steam turbinesA472/A472M 07 (2017)2SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall only apply wh

35、en specified individually by thepurchaser in the contract or purchase order.S1. Emissivity CoatingS1.1 Apply a surface coating that will provide a uniformthermal emissivity throughout the test. The coating shall beuniform and completely cover all surfaces within and adjacentto the ovens. Successive

36、light coats applied by spraying arerecommended.APPENDIX(Nonmandatory Information)X1. RESULTS DISCUSSIONX1.1 This specification determines whether a forging willbe stable at elevated temperatures and sets go/no go limits foracceptance. Instability is typically caused by one of severalfactors includin

37、g non-uniform emissivity (see SupplementaryRequirement S1) or relief of residual stresses (in both casesthese rotors will normally be stable during a subsequent test),non-uniform heat treatment, and machining off the forgingcenterline. Rotors that do not meet the go/no go limits areconsidered unstab

38、le and are normally subject to further review,retested, or even re-heat treated and retested.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determinati

39、on of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdr

40、awn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your

41、comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single

42、 or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 07 (2017)3