1、Designation: A472/A472M 07 (Reapproved 2012)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 unitand in SI units; however, unless the purchase order or contractspecifies the applicable M specification designatio
4、n (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 b
6、y 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 r
7、egulatory 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,2.1
8、.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 forg
9、ing 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 100F 30 to 55C below final tempering temperature.Rotate the forgings at 2 to 4 r/min and hold at stress-relievingtemperature for at least 2 h/in.
11、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 for
12、ging.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 cl
13、ose 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 and
14、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 ar
15、e 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 jurisdictio
16、n 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 May 1, 2012. Published May 2012. Originallyapproved in 1962. Last previous edition approved in 2007 as A472/A472M 07.DOI:
17、10.1520/A0472_A0472M-07R12.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.shall be taken with the forging running on centers except in thecases of forgings weighing over 125 000 lb 56.7 metric tonswhere readings may be taken with th
18、e 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 applied to provide uniform emissivi
19、ty.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 Apply heat uniformly to avoid local
20、ized overheating.Heat the forging at a rate not exceeding 200F/h 110C/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 to exist when three consecutive
21、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 consecutivehourly readings at the test temperat
22、ure.6.4 After uniform test conditions as described in 6.3 havebeen reached, cool the forging, while rotating, to below 100F40C. The heating chamber may be opened during cooling,but the cover shall not be removed until the temperature of theforging is less than 500F 260C.After the forging has cooledt
23、o approximately room temperature, rotate it for at least 2 hbefore the second cold measurements (see 7.4) are recorded.7. Stability Measurements7.1 Use an indicator located outside the heating chamber tomeasure to the nearest 0.0005 in. 0.013 mm. Actuate theindicator by a rod with one end contacting
24、 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 tominima by subtraction.7.2 First Cold Measu
25、rementsTake 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 the runout does notexceed 0.002 in. 0.0
26、5 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 deflection measurements at the specifi
27、ed 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 until two consecutive deflection measur
28、ements 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-mined by the difference between the o
29、fficial 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 B, C, and D.8.1.3 For each of these f
30、our 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,suitable corrections may be made to resu
31、lts 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.9. Report9.1 The forging supplier sha
32、ll 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 measure-ments were obtained. The rep
33、ort shall include the calculatedchange in measurements as determined under 8.1.3.10. Keywords10.1 emissivity; heat stability; rotor forgings; steam turbinesA472/A472M 07 (2012)2SUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall only apply when specified individually by thepurch
34、aser 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 light coats applied by spraying arere
35、commended.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 including non-uniform emissivity (see Supplem
36、entaryRequirement 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 unstable and are normally subject to furthe
37、r 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 determination of the validity of any such patent
38、 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 withdrawn. Your comments are invited either
39、 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 comments have not received a fair hea
40、ring 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 or multiple copies) of this standard
41、 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 ASTM website (www.astm.org/COPYRIGHT/).A472/A472M 07 (2012)3
