ASTM A418/A418M-09
(Test Method)Standard Practice for Ultrasonic Examination of Turbine and Generator Steel Rotor Forgings
Standard Practice for Ultrasonic Examination of Turbine and Generator Steel Rotor Forgings
SIGNIFICANCE AND USE
This practice shall be used when ultrasonic inspection is required by the order or specification for inspection purposes where the acceptance of the forging is based on limitations of the number, amplitude, or location of discontinuities, or a combination thereof, which give rise to ultrasonic indications.
The acceptance criteria shall be clearly stated as order requirements.
SCOPE
1.1 This practice for ultrasonic examination covers turbine and generator steel rotor forgings covered by Specifications A 469/A 469M, A 470/A 470M, A 768/A 768M, and A 940/A 940M. This standard shall be used for contact testing only.
1.2 This practice describes a basic procedure of ultrasonically inspecting turbine and generator rotor forgings. It does not restrict the use of other ultrasonic methods such as reference block calibrations when required by the applicable procurement documents nor is it intended to restrict the use of new and improved ultrasonic test equipment and methods as they are developed.
1.3 This practice is intended to provide a means of inspecting cylindrical forgings so that the inspection sensitivity at the forging center line or bore surface is constant, independent of the forging or bore diameter. To this end, inspection sensitivity multiplication factors have been computed from theoretical analysis, with experimental verification. These are plotted in Fig. 1 (bored rotors) and Fig. 2 (solid rotors), for a true inspection frequency of 2.25 MHz, and an acoustic velocity of 2.30 × 105 in./s [5.85 × 105 cm/s]. Means of converting to other sensitivity levels are provided in Fig. 3. (Sensitivity multiplication factors for other frequencies may be derived in accordance with X1.1 and X1.2 of Appendix X1.)
1.4 Considerable verification data for this method have been generated which indicate that even under controlled conditions very significant uncertainties may exist in estimating natural discontinuities in terms of minimum equivalent size flat-bottom holes. The possibility exists that the estimated minimum areas of natural discontinuities in terms of minimum areas of the comparison flat-bottom holes may differ by 20 dB (factor of 10) in terms of actual areas of natural discontinuities. This magnitude of inaccuracy does not apply to all results but should be recognized as a possibility. Rigid control of the actual frequency used, the coil bandpass width if tuned instruments are used, and so forth, tend to reduce the overall inaccuracy which is apt to develop.
1.5 This practice for inspection applies to solid cylindrical forgings having outer diameters of not less than 2.5 in. [64 mm] nor greater than 100 in. [2540 mm]. It also applies to cylindrical forgings with concentric cylindrical bores having wall thicknesses of 2.5 [64 mm] in. or greater, within the same outer diameter limits as for solid cylinders. For solid sections less than 15 in. [380 mm] in diameter and for bored cylinders of less than 7.5 in. [190 mm] wall thickness the transducer used for the inspection will be different than the transducer used for larger sections.
1.6 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract.
1.7 This practice is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the inch-pound units shall apply. The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the practice, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.8 This standard does not purport to...
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Designation: A418/A418M – 09
Standard Practice for
Ultrasonic Examination of Turbine and Generator Steel
1
Rotor Forgings
This standard is issued under the fixed designationA418/A418M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.5 This practice for inspection applies to solid cylindrical
forgings having outer diameters of not less than 2.5 in. [64
1.1 This practice for ultrasonic examination covers turbine
mm] nor greater than 100 in. [2540 mm]. It also applies to
and generator steel rotor forgings covered by Specifications
cylindrical forgings with concentric cylindrical bores having
A469/A469M, A470/A470M, A768/A768M, and A940/
wall thicknesses of 2.5 [64 mm] in. or greater, within the same
A940M. This standard shall be used for contact testing only.
outer diameter limits as for solid cylinders. For solid sections
1.2 This practice describes a basic procedure of ultrasoni-
less than 15 in. [380 mm] in diameter and for bored cylinders
cally inspecting turbine and generator rotor forgings. It does
oflessthan7.5in.[190mm]wallthicknessthetransducerused
not restrict the use of other ultrasonic methods such as
for the inspection will be different than the transducer used for
reference block calibrations when required by the applicable
larger sections.
procurement documents nor is it intended to restrict the use of
1.6 Supplementary requirements of an optional nature are
new and improved ultrasonic test equipment and methods as
provided for use at the option of the purchaser. The supple-
they are developed.
mentary requirements shall apply only when specified indi-
1.3 This practice is intended to provide a means of inspect-
vidually by the purchaser in the purchase order or contract.
ing cylindrical forgings so that the inspection sensitivity at the
1.7 This practice is expressed in both inch-pound units and
forging center line or bore surface is constant, independent of
in SI units; however, unless the purchase order or contract
the forging or bore diameter.To this end, inspection sensitivity
specifies the applicable M specification designation (SI units),
multiplication factors have been computed from theoretical
the inch-pound units shall apply. The values stated in either
analysis, with experimental verification. These are plotted in
inch-pound units or SI units are to be regarded separately as
Fig. 1 (bored rotors) and Fig. 2 (solid rotors), for a true
standard. Within the practice, the SI units are shown in
inspection frequency of 2.25 MHz, and an acoustic velocity of
5 5
brackets. The values stated in each system may not be exact
2.30 3 10 in./s [5.85 3 10 cm/s]. Means of converting to
equivalents;therefore,eachsystemshallbeusedindependently
other sensitivity levels are provided in Fig. 3. (Sensitivity
of the other. Combining values from the two systems may
multiplication factors for other frequencies may be derived in
result in nonconformance with the standard.
accordance with X1.1 and X1.2 of Appendix X1.)
1.8 This standard does not purport to address all of the
1.4 Considerableverificationdataforthismethodhavebeen
safety concerns, if any, associated with its use. It is the
generated which indicate that even under controlled conditions
responsibility of the user of this standard to establish appro-
very significant uncertainties may exist in estimating natural
priate safety and health practices and determine the applica-
discontinuities in terms of minimum equivalent size flat-
bility of regulatory limitations prior to use.
bottom holes. The possibility exists that the estimated mini-
mum areas of natural discontinuities in terms of minimum
2. Referenced Documents
areas of the comparison flat-bottom holes may differ by 20 dB
2.1 The reference is to the latest issue of these designations
(factorof10)intermsofactualareasofnaturaldiscontinuities.
that appear in the Annual Book of ASTM Standards or are
This magnitude of inaccuracy does not apply to all results but
available as separate reprints. It shall also apply to product
should be recognized as a possibility. Rigid control of the
specifications, which may be issued when specifically refer-
actual frequency used, the coil bandpass width if tuned
enced therein.
instruments are used, and so forth, tend to reduce the overall
2
2.2 ASTM Standards:
inaccuracy which is apt to develop.
A469/A469M SpecificationforVacuum-TreatedSteelForg-
ings for Generator Rotors
1
This practice is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee
A01.06 on Steel Forgings and Bil
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:A 418/A418M–07 Designation: A 418/A 418M – 09
Standard Practice for
Ultrasonic Examination of Turbine and Generator Steel
1
Rotor Forgings
ThisstandardisissuedunderthefixeddesignationA418/A418M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice for ultrasonic examination covers turbine and generator steel rotor forgings covered by Specifications A
293A469/A469M, A470/A470M, A469/A469MA768/A768M, and A470/A470MA940/A940M. This standard shall be used
for contact testing only.
1.2This practice describes a basic procedure of ultrasonically inspecting turbine and generator rotor forgings. It shall in no way
restrict the use of other ultrasonic methods such as reference block calibrations when required by the applicable procurement
documents nor is it intended to restrict the use of new and improved ultrasonic test equipment and methods as they are developed.
The procedure utilizes different calibration techniques than had been used in previous issues. The frequency or amplitudes of
recordable indications should not be interpreted necessarily as a change in quality of the product being examined.
1.2 Thispracticedescribesabasicprocedureofultrasonicallyinspectingturbineandgeneratorrotorforgings.Itdoesnotrestrict
the use of other ultrasonic methods such as reference block calibrations when required by the applicable procurement documents
nor is it intended to restrict the use of new and improved ultrasonic test equipment and methods as they are developed.
1.3 Thispracticeisintendedtoprovideameansofinspectingcylindricalforgingssothattheinspectionsensitivityattheforging
centerlineorboresurfaceisconstant,independentoftheforgingorborediameter.Tothisend,inspectionsensitivitymultiplication
factorshavebeencomputedfromtheoreticalanalysis,withexperimentalverification.TheseareplottedinFig.1(boredrotors)and
5 5
Fig. 2 (solid rotors), for a true inspection frequency of 2.25 MHz, and an acoustic velocity of 2.30 3 10 in./s [5.85 3 10 cm/s].
Means of converting to other sensitivity levels are provided in Fig. 3. (Sensitivity multiplication factors for other frequencies may
be derived in accordance with X1.1 and X1.2 of Appendix X1.)
1.4 Considerable verification data for this method have been generated which indicate that even under controlled conditions
verysignificantuncertaintiesmayexistinestimatingnaturaldiscontinuitiesintermsofminimumequivalentsizeflat-bottomholes.
The possibility exists that the estimated minimum areas of natural discontinuities in terms of minimum areas of the comparison
flat-bottomholesmaydifferby20dB(factorof10)intermsofactualareasofnaturaldiscontinuities.Thismagnitudeofinaccuracy
doesnotapplytoallresultsbutshouldberecognizedasapossibility.Rigidcontroloftheactualfrequencyused,thecoilbandpass
width if tuned instruments are used, and so forth, tend to reduce the overall inaccuracy which is apt to develop.
1.5 This practice for inspection applies to solid cylindrical forgings having outer diameters of not less than 2.5 in. [64 mm] nor
greater than 100 in. [2540 mm]. It also applies to cylindrical forgings with concentric cylindrical bores having wall thicknesses
of 2.5 [64 mm] in. or greater, within the same outer diameter limits as for solid cylinders. For solid sections less than 15 in. [380
mm] in diameter and for bored cylinders of less than 7.5 in. [190 mm] wall thickness the transducer used for the inspection will
be different than the transducer used for larger sections.
1.6 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary
requirements shall apply only when specified individually by the purchaser in the purchase order or contract.
1.7 This practice is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies
theapplicableMspecificationdesignation(SIunits),theinch-poundunitsshallapply.Thevaluesstatedineitherinch-poundunits
or SI units are to be regarded separately as standard. Within the practice, the SI units are shown in brackets. The values stated in
eachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfrom
the two systems may result in nonconformance with the standard.
1.8 This standard does not purport to address all of the saf
...
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