ASTM B548-03(2009)
(Test Method)Standard Test Method for Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure Vessels
Standard Test Method for Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure Vessels
SIGNIFICANCE AND USE
A number of factors such as the condition of the entry and back surfaces of the plate, the inclination of the ultrasonic beam with respect to the entry surface, and the performance characteristics of the test system may cause either a reduction of isolated indications or a substantial loss of back reflection and thereby could seriously impair the reliability of the test procedure outlined in this standard.
Accurate evaluations of discontinuity size also may be limited significantly by variations in beam characteristics which exist in most search units. For this reason, discontinuity size as determined by the test procedure outlined in this method is regarded as “apparent” or “estimated” in recognition of the limited quantitative value of the measurement.
Because a large number of interacting variables in a test system can adversely influence the results of an ultrasonic test, the actual quantitative effects of detected discontinuities upon the mechanical properties of the inspected plate are difficult to establish. Consequently, this ultrasonic inspection method is not applicable as an exclusive indicator of the ultimate quality and performance of pressure vessels but provides a reliable control of plate quality to avoid failure during the forming process for fabrication of vessels.
SCOPE
1.1 This test method covers pulse-echo ultrasonic inspection of aluminum-alloy plate of thickness equal to or greater than 0.500 in. (12.7 mm) for use in the fabrication of pressure vessels. The ultrasonic test is employed to detect gross internal discontinuities oriented in a direction parallel to the rolled surface such as cracks, ruptures, and laminations, and to provide assurance that only plate that is free from rejectable discontinuities is accepted for delivery.
1.2 The inspection method and acceptance criteria included in this standard shall be limited to plate of the following aluminum alloys: 1060, 1100, 3003, Alclad 3003, 3004, Alclad 3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652, 6061, and Alclad 6061.
1.3 This test method applies only to ultrasonic tests using pulsed longitudinal waves which are transmitted and received by a search unit containing either a single crystal or a combination of electrically interconnected multiple crystals. Ultrasonic tests employing either the through-transmission or the angle-beam techniques are not included.
1.4 This test method shall be used when ultrasonic inspection as prescribed herein is required by the contract, purchase order, or referenced plate specification.
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: B548 − 03 (Reapproved 2009)
Standard Test Method for
Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure
Vessels
This standard is issued under the fixed designation B548; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, 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. Scope 2. Referenced Documents
2.1 The following documents of the issue in effect on date
1.1 Thistestmethodcoverspulse-echoultrasonicinspection
of material purchase form a part of this specification to the
of aluminum-alloy plate of thickness equal to or greater than
extent referenced herein:
0.500 in. (12.7 mm) for use in the fabrication of pressure
vessels. The ultrasonic test is employed to detect gross internal
2.2 ASTM Standards:
discontinuities oriented in a direction parallel to the rolled E114 Practice for Ultrasonic Pulse-Echo Straight-Beam
surface such as cracks, ruptures, and laminations, and to Contact Testing
provide assurance that only plate that is free from rejectable E214 Practice for Immersed Ultrasonic Testing by the Re-
discontinuities is accepted for delivery. flection Method Using Pulsed Longitudinal Waves (With-
drawn 2007)
1.2 The inspection method and acceptance criteria included
E317 Practice for Evaluating Performance Characteristics of
in this standard shall be limited to plate of the following
Ultrasonic Pulse-Echo Testing Instruments and Systems
aluminum alloys: 1060, 1100, 3003,Alclad 3003, 3004,Alclad
without the Use of Electronic Measurement Instruments
3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652,
2.3 Other Standards:
6061, and Alclad 6061.
ASNT Recommended Practice for Nondestructive Testing
1.3 This test method applies only to ultrasonic tests using Personnel Qualification and Certification—Ultrasonic
pulsed longitudinal waves which are transmitted and received Testing Method—SNT-TC-1A
by a search unit containing either a single crystal or a
3. Summary of Method
combination of electrically interconnected multiple crystals.
Ultrasonic tests employing either the through-transmission or
3.1 The plate is inspected ultrasonically by scanning one
the angle-beam techniques are not included.
rolled surface with a beam of pulsed longitudinal waves which
is oriented in a direction perpendicular to the entry surface of
1.4 This test method shall be used when ultrasonic inspec-
the plate. The ultrasound is transmitted into the plate either by
tion as prescribed herein is required by the contract, purchase
the direct contact, immersion, or liquid-column coupling
order, or referenced plate specification.
method. During the scan, an indication representing the first
1.5 The values stated in inch-pound units are to be regarded
back reflection is observed on the A-scan screen of the test
as standard. The values given in parentheses are mathematical instrument.
conversions to SI units that are provided for information only
3.2 When the test system sensitivity level is appropriately
and are not considered standard.
adjusted, a discontinuity is detected during the scan by noting
an isolated indication associated with a loss of the first back
1.6 This standard does not purport to address all of the
reflection indication. The apparent size of the discontinuity is
safety concerns, if any, associated with its use. It is the
determined by measuring the total area in the scanned entry
responsibility of the user of this standard to establish appro-
surface of the plate where the isolated indication and the loss
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This test method is under the jurisdiction of ASTM Committee B07 on Light Standards volume information, refer to the standard’s Document Summary page on
Metals and Alloys and is the direct responsibility of Subcommittee B07.03 on the ASTM website.
Aluminum Alloy Wrought Products. The last approved version of this historical standard is referenced on
Current edition approved Dec. 1, 2009. Published January 2010. Originally www.astm.org.
approved in 1971. Last previous edition approved in 2003 as B548 – 03. DOI: AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
10.1520/B0548-03R09. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B548 − 03 (2009)
of back reflection persist. The estimated discontinuity size and 5.3 Tank—Fortestsbytheimmersionmethod,anycontainer
location are then compared with suitable acceptance criteria. is satisfactory that will facilitate the accurate, stable position-
ing of both the search unit and the plate to be inspected.
NOTE 1—Additional information describing ultrasonic tests by the
direct contact method and by the immersion method is available in
5.4 Scanning Apparatus—During the inspection procedure,
Practices E114 and E214.
the search unit is supported by any one of the following
devices. The scanning apparatus shall permit measurement of
4. Significance and Use
both the scan distance and the index distance within 60.1 in.
4.1 A number of factors such as the condition of the entry
(62 mm).
and back surfaces of the plate, the inclination of the ultrasonic
5.4.1 ManipulatorandBridge—When a manipulator is used
beam with respect to the entry surface, and the performance
in tests by the immersion method, the manipulator shall
characteristics of the test system may cause either a reduction
adequately support a search tube containing a search unit and
of isolated indications or a substantial loss of back reflection
shall provide fine adjustment of angle within 1° in two vertical
and thereby could seriously impair the reliability of the test
planes that are perpendicular to each other. The bridge shall be
procedure outlined in this standard.
of sufficient strength to provide rigid support for the manipu-
4.2 Accurate evaluations of discontinuity size also may be
lator and shall allow smooth, accurate positioning of the search
limited significantly by variations in beam characteristics
unit. Special search unit supporting fixtures may be used
which exist in most search units. For this reason, discontinuity
provided they meet the requirements prescribed for a manipu-
sizeasdeterminedbythetestprocedureoutlinedinthismethod
lator and bridge.
is regarded as “apparent” or “estimated” in recognition of the
5.4.2 Liquid Coupling Nozzle—For tests by the liquid-
limited quantitative value of the measurement.
column coupling method, the nozzle is usually positioned
4.3 Because a large number of interacting variables in a test
manually and shall be capable of containing the couplant while
system can adversely influence the results of an ultrasonic test,
rigidly supporting the search unit with its active surface
the actual quantitative effects of detected discontinuities upon
immersed in the couplant. The couplant distance shall be
the mechanical properties of the inspected plate are difficult to
maintained so that the second couplant reflection is to the right
establish. Consequently, this ultrasonic inspection method is
of the first back reflection on the instrument cathode ray tube
not applicable as an exclusive indicator of the ultimate quality 1
(CRT).The couplant path shall not vary more than 6 ⁄4 in. (6.4
and performance of pressure vessels but provides a reliable
mm) during calibration, initial scanning, and discontinuity
control of plate quality to avoid failure during the forming
evaluation. The recommended minimum inside dimension of
process for fabrication of vessels.
the nozzle is 1.0 in. (25 mm) greater than the maximum
dimension of the crystal surface in the search unit. Provisions
5. Apparatus
also should be included for adjustment of search unit inclina-
5.1 Test Instrument—Any electronic device that produces tion within 1° in two vertical planes that are perpendicular to
pulsed longitudinal waves and displays ultrasonic reflections each other.
on an A-scan indicator when used with an appropriate search
NOTE 3—Nozzles containing either sealed or unsealed openings may be
unit is satisfactory. The instrument shall provide stable, linear
used for inspecting plate provided the test results obtained with either
amplificationofreceivedpulsesataselectedtestfrequencyand
device are equivalent to those obtained by the immersion method.
shallbefreefromsignificantinterfacesignalinterferenceatthe
5.4.3 Contact Scanning Unit—During tests by the contact
required sensitivity level.
method, the search unit usually is supported and positioned
5.2 Search Unit—The search unit recommended for this
manually on the entry surface of the inspected plate. However,
standard is the flat nonfocusing type, and contains a piezoelec-
special fixtures for contact scanning may be employed pro-
tric crystal which generates and receives longitudinal waves at
vided their use ensures conformance to the requirements in this
the rated frequency when connected to the test instrument
specification.
through a suitable coaxial cable. A dual-crystal search unit
containing both a transmitting and a receiving crystal in one 5.5 Couplant—Clean, deaerated water at room temperature
container may be used provided the test instrument will
is the recommended couplant for tests either by the immersion
accommodate two-crystal operation and the resulting pulse-
method or by the liquid-column coupling technique. Inhibitors
echo test is equivalent to that obtained with a search unit
or wetting agents or both may be used. For tests by the contact
containing a single-crystal.
method, the recommended couplant is clean, light-grade oil.
5.2.1 The total effective area of the crystal or combination
NOTE 4—Other coupling liquids may be employed for inspecting plate
of crystals in the search unit used for initial scanning shall not
provided their use does not adversely affect test results.
2 2 2
be less than 0.4 in. (2.6 cm ) nor greater than 3.0 in. (19.4
cm ).
6. Personnel Requirements
5.2.2 The effective diameter of the round search unit used to
evaluate discontinuity size shall not exceed 0.75 in. (19 mm). 6.1 The testing operator performing the ultrasonic examina-
tion prescribed in this standard shall be qualified and certified
NOTE 2—For control purposes, the performance characteristics of the
to at least a Level I—UltrasonicTesting in accordance with the
test instrument and search unit may be established in accordance with
procedures outlined in Practice E317. ASNT Recommended Practice SNT-TC-1A.
B548 − 03 (2009)
system to enhance detection reliability during the scan.
6.2 The required documentation supporting qualification
and certification of ultrasonic testing operators shall be estab-
8.5 Scan Index—When the initial scan is completed, move
lished by the certifying agency and shall be available upon
the search unit over a predetermined scan index distance in a
request by the purchaser.
direction parallel to the predominant rolling direction of the
plateandproceedwithasecondscanalongalineparalleltothe
7. Condition of Plate
initialscanningdirectionwhileobservingthetestpatternonthe
7.1 The entry and back surfaces of the inspected plate shall
A-scan indicator screen. Calculate the scan index distance as
be sufficiently clean, smooth, and flat to maintain a first back
follows:
reflection amplitude greater than 50 % of the initial standard-
Scan index distance in. , S 5 0.810.7D (1)
~ !
i s
ization amplitude while scanning an area in the plate that does
not contain significant isolated ultrasonic discontinuities. Scan index distance mm , S 5 2010.7D (2)
~ !
i s
7.2 The inspected plate shall be at room temperature during
where:
the test.
D = actual crystal diameter.
s
8. Procedure
8.5.1 Continue the inspection by constantly observing the
test pattern on the A-scan indicator while successively scan-
8.1 Preferred Method—The ultrasonic test may be per-
ning the plate at a constant scanning rate in a direction
formedbyeithertheliquidcolumncoupling,thedirectcontact,
perpendicular to the predominant rolling direction of the plate
or the immersion methods. However, the immersion method is
and indexing the search unit through the index distance
preferred.
calculated in 8.5.
8.1.1 Maintain the couplant distance so that the second
couplant reflection is to the right of the first back reflection on 8.5.2 Duringtheinspectionprocedure,checkthetestsystem
the instrument’s A-scan display. The couplant path shall not sensitivity standardization periodically by noting the amplitude
vary more than 6 ⁄4 in. (6.4 mm) during calibration, initial of the first back reflection when the search unit is repositioned
scanning, and discontinuity evaluation. over the reference area of the plate and by adjusting the
instrument gain control as required to maintain the sensitivity
8.2 Test Frequency—When using any of the three methods
standardization specified previously in 8.3.
listed in 8.1, the recommended test frequency is 5.0 MHz.
Other test frequencies between 2.0 MHz and 10.0 MHz may be
8.6 Scanning Rate—When the screen pattern on the A-scan
employed when necessary to minimize possible adverse effects
indicator is monitored visually by the test operator during the
of plate thickness, microstructure, and test system characteris-
inspection, the scanning rate shall not be greater than 12 in./s
tics upon test results and thereby maintain a clean, easily
(305 mm/s).
interpreted A-scan screen pattern throughout the inspection.
NOTE 6—Scanning rates greater than 12 in./s (305 mm/s) may be
8.3 Sensitivity Standardization—Standardize the sensitivity
employed if auxiliary monitoring apparatus is used to maintain adequate
level of the test system operating at the selected frequency by
detection reliability.
adjusting the instrument gain control to obtain a first back
8.7 Detection of Discontinuities—When an isolated ultra-
reflection amplitude of 75 6 5 % of the vertical limit exhibited
sonic indication of amplitude greater than 30 % of the A-scan
by theA-scan indicator when the search unit is positioned over
vertical limit is encountered or when the first back reflection
an area free from significant discontinuities in the plate to be
indication decreases to an amplitude less than 5 % of the
inspected. During tests by either the immersion method or the
vertical limit at any time during the inspection procedur
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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:B548–03 Designation: B548 – 03 (Reapproved 2009)
Standard Test Method for
Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure
Vessels
This standard is issued under the fixed designation B548; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, 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. Scope
1.1 This test method covers pulse-echo ultrasonic inspection of aluminum-alloy plate of thickness equal to or greater than 0.500
in. (12.7 mm) for use in the fabrication of pressure vessels. The ultrasonic test is employed to detect gross internal discontinuities
oriented in a direction parallel to the rolled surface such as cracks, ruptures, and laminations, and to provide assurance that only
plate that is free from rejectable discontinuities is accepted for delivery.
1.2 The inspection method and acceptance criteria included in this standard shall be limited to plate of the following aluminum
alloys: 1060, 1100, 3003, Alclad 3003, 3004, Alclad 3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652, 6061, and
Alclad 6061.
1.3 This test method applies only to ultrasonic tests using pulsed longitudinal waves which are transmitted and received by a
search unit containing either a single crystal or a combination of electrically interconnected multiple crystals. Ultrasonic tests
employing either the through-transmission or the angle-beam techniques are not included.
1.4 This test method shall be used when ultrasonic inspection as prescribed herein is required by the contract, purchase order,
or referenced plate specification.
1.5The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information
only.
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 The following documents of the issue in effect on date of material purchase form a part of this specification to the extent
referenced herein:
2.2 ASTM Standards:
E114 Practice for Ultrasonic Pulse-Echo Straight-Beam Contact Testing
E214 Practice for Immersed Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves
E317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without
the Use of Electronic Measurement Instruments
2.3 Other Standards:
ASNT Recommended Practice for Nondestructive Testing Personnel Qualification and Certification—Ultrasonic Testing
Method—SNT-TC-1A
3. Summary of Method
3.1 The plate is inspected ultrasonically by scanning one rolled surface with a beam of pulsed longitudinal waves which is
orientedinadirectionperpendiculartotheentrysurfaceoftheplate.Theultrasoundistransmittedintotheplateeitherbythedirect
contact, immersion, or liquid-column coupling method. During the scan, an indication representing the first back reflection is
observed on the A-scan screen of the test instrument.
ThistestmethodisunderthejurisdictionofASTMCommitteeB07onLightMetalsandAlloysandisunderthejurisdictiondirectresponsibilityofSubcommitteeB07.03
on Aluminum Alloy Wrought Products.
Current edition approved Nov.Dec. 1, 2003.2009. Published November 2003.January 2010. Originally approved in 1971. Last previous edition approved in 19972003 as
B548–90 (1997). B548 – 03. DOI: 10.1520/B0548-03R09.
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from The American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B548 – 03 (2009)
3.2 When the test system sensitivity level is appropriately adjusted, a discontinuity is detected during the scan by noting an
isolated indication associated with a loss of the first back reflection indication.The apparent size of the discontinuity is determined
by measuring the total area in the scanned entry surface of the plate where the isolated indication and the loss of back reflection
persist. The estimated discontinuity size and location are then compared with suitable acceptance criteria.
NOTE 1—Additional information describing ultrasonic tests by the direct contact method and by the immersion method is available in Practices E114
and E214E114E214and E214.
4. Significance and Use
4.1 Anumber of factors such as the condition of the entry and back surfaces of the plate, the inclination of the ultrasonic beam
with respect to the entry surface, and the performance characteristics of the test system may cause either a reduction of isolated
indications or a substantial loss of back reflection and thereby could seriously impair the reliability of the test procedure outlined
in this standard.
4.2 Accurateevaluationsofdiscontinuitysizealsomaybelimitedsignificantlybyvariationsinbeamcharacteristicswhichexist
in most search units. For this reason, discontinuity size as determined by the test procedure outlined in this method is regarded
as “apparent” or “estimated” in recognition of the limited quantitative value of the measurement.
4.3 Because a large number of interacting variables in a test system can adversely influence the results of an ultrasonic test, the
actual quantitative effects of detected discontinuities upon the mechanical properties of the inspected plate are difficult to establish.
Consequently, this ultrasonic inspection method is not applicable as an exclusive indicator of the ultimate quality and performance
of pressure vessels but provides a reliable control of plate quality to avoid failure during the forming process for fabrication of
vessels.
5. Apparatus
5.1 Test Instrument—Any electronic device that produces pulsed longitudinal waves and displays ultrasonic reflections on an
A-scan indicator when used with an appropriate search unit is satisfactory.The instrument shall provide stable, linear amplification
of received pulses at a selected test frequency and shall be free from significant interface signal interference at the required
sensitivity level.
5.2 Search Unit—The search unit recommended for this standard is the flat nonfocusing type, and contains a piezoelectric
crystal which generates and receives longitudinal waves at the rated frequency when connected to the test instrument through a
suitable coaxial cable. A dual-crystal search unit containing both a transmitting and a receiving crystal in one container may be
used provided the test instrument will accommodate two-crystal operation and the resulting pulse-echo test is equivalent to that
obtained with a search unit containing a single-crystal.
5.2.1 The total effective area of the crystal or combination of crystals in the search unit used for initial scanning shall not be
2 2 2 2
less than 0.4 in. (2.6 cm ) nor greater than 3.0 in. (19.4 cm ).
5.2.2 The effective diameter of the round search unit used to evaluate discontinuity size shall not exceed 0.75 in. (19 mm).
NOTE 2—For control purposes, the performance characteristics of the test instrument and search unit may be established in accordance with procedures
outlined in Practice E317.
5.3 Tank—For tests by the immersion method, any container is satisfactory that will facilitate the accurate, stable positioning
of both the search unit and the plate to be inspected.
5.4 Scanning Apparatus—During the inspection procedure, the search unit is supported by any one of the following devices.
The scanning apparatus shall permit measurement of both the scan distance and the index distance within 60.1 in. (62 mm).
5.4.1 ManipulatorandBridge—Whenamanipulatorisusedintestsbytheimmersionmethod,themanipulatorshalladequately
support a search tube containing a search unit and shall provide fine adjustment of angle within 1° in two vertical planes that are
perpendicular to each other. The bridge shall be of sufficient strength to provide rigid support for the manipulator and shall allow
smooth, accurate positioning of the search unit. Special search unit supporting fixtures may be used provided they meet the
requirements prescribed for a manipulator and bridge.
5.4.2 Liquid Coupling Nozzle—For tests by the liquid-column coupling method, the nozzle is usually positioned manually and
shallbecapableofcontainingthecouplantwhilerigidlysupportingthesearchunitwithitsactivesurfaceimmersedinthecouplant.
The couplant distance shall be maintained so that the second couplant reflection is to the right of the first back reflection on the
instrument cathode ray tube (CRT). The couplant path shall not vary more than 6 ⁄4 in. (6.4 mm) during calibration, initial
scanning, and discontinuity evaluation.The recommended minimum inside dimension of the nozzle is 1.0 in. (25 mm) greater than
the maximum dimension of the crystal surface in the search unit. Provisions also should be included for adjustment of search unit
inclination within 1° in two vertical planes that are perpendicular to each other.
NOTE 3—Nozzles containing either sealed or unsealed openings may be used for inspecting plate provided the test results obtained with either device
are equivalent to those obtained by the immersion method.
5.4.3 ContactScanningUnit—During tests by the contact method, the search unit usually is supported and positioned manually
on the entry surface of the inspected plate. However, special fixtures for contact scanning may be employed provided their use
ensures conformance to the requirements in this specification.
5.5 Couplant—Clean, deaerated water at room temperature is the recommended couplant for tests either by the immersion
B548 – 03 (2009)
method or by the liquid-column coupling technique. Inhibitors or wetting agents or both may be used. For tests by the contact
method, the recommended couplant is clean, light-grade oil.
NOTE 4—Other coupling liquids may be employed for inspecting plate provided their use does not adversely affect test results.
6. Personnel Requirements
6.1 The testing operator performing the ultrasonic examination prescribed in this standard shall be qualified and certified to at
least a Level I—Ultrasonic Testing in accordance with the ASNT Recommended Practice SNT-TC-1A.
6.2 The required documentation supporting qualification and certification of ultrasonic testing operators shall be established by
the certifying agency and shall be available upon request by the purchaser.
7. Condition of Plate
7.1 The entry and back surfaces of the inspected plate shall be sufficiently clean, smooth, and flat to maintain a first back
reflection amplitude greater than 50 % of the initial standardization amplitude while scanning an area in the plate that does not
contain significant isolated ultrasonic discontinuities.
7.2 The inspected plate shall be at room temperature during the test.
8. Procedure
8.1 Preferred Method—The ultrasonic test may be performed by either the liquid column coupling, the direct contact, or the
immersion methods. However, the immersion method is preferred.
8.1.1 Maintain the couplant distance so that the second couplant reflection is to the right of the first back reflection on the
instrument’sA-scan display. The couplant path shall not vary more than 6 ⁄4 in. (6.4 mm) during calibration, initial scanning, and
discontinuity evaluation.
8.2 TestFrequency—When using any of the three methods listed in 8.1, the recommended test frequency is 5.0 MHz. Other test
frequencies between 2.0 MHz and 10.0 MHz may be employed when necessary to minimize possible adverse effects of plate
thickness, microstructure, and test system characteristics upon test results and thereby maintain a clean, easily interpreted A-scan
screen pattern throughout the inspection.
8.3 Sensitivity Standardization—Standardize the sensitivity level of the test system operating at the selected frequency by
adjusting the instrument gain control to obtain a first back reflection amplitude of 75 6 5 % of the vertical limit exhibited by the
A-scan indicator when the search unit is positioned over an area free from significant discontinuities in the plate to be inspected.
During tests by either the immersion method or the liquid column coupling method, adjust the angular alignment of the search unit
to obtain a maximum number of back reflections before the final sensitivity level is established.
8.4 Scanning—With no further adjustments of the instrument gain controls, locate the search unit over one corner of the plate
to be inspected so that the edge of the crystal in the search unit is about 1 in. (25 mm) from either edge of the plate.
8.4.1 Subsequent to checking the angular alignment of the search unit with respect to the rolled entry surface to ensure a
maximum first back reflection, proceed to scan the plate continuously by moving the search unit at a constant scanning rate (see
8.6) from the initial starting position to the opposite edge in a direction perpendicular to the predominant rolling direction of the
plate.
8.4.2 During the scan, note the occurrence of isolated discontinuity indications and monitor the amplitude of the first back
reflection by continuously observing the A-scan indicator screen.
NOTE 5—Auxiliary monitoring devices may be employed in the test system to enhance detection reliability during the scan.
8.5 Scan Index—When the initial scan is completed, move the search unit over a predetermined scan index distance in a
direction parallel to the predominant rolling direction of the plate and proceed with a second scan along a line parallel to the initial
scanning direction while observing the test pattern on the A-scan indicator screen. Calculate the scan index distance as follows:
Scan index distance ~in.!,S 5 0.8 1 0.7D (1)
i s
Sca
...
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