ASTM B548-90(1997)
(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
SCOPE
1.1 This 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 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 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 the standard. The SI values in parentheses are for information only.
1.6 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: B 548 – 90 (Reapproved 1997)
Standard Test Method for
Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure
Vessels
This standard is issued under the fixed designation B 548; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Examination by the Contact Method
E 214 Practice for Immersed Ultrasonic Examination by the
1.1 This test method covers pulse-echo ultrasonic inspection
Reflection Method Using Pulsed Longitudinal Waves
of aluminum-alloy plate of thickness equal to or greater than
E 317 Practice for Evaluating Performance Characteristics
0.500 in. (12.7 mm) for use in the fabrication of pressure
of Ultrasonic Pulse-Echo Testing Systems Without the Use
vessels. The ultrasonic test is employed to detect gross internal
of Electronic Measurement Instruments
discontinuities oriented in a direction parallel to the rolled
2.3 Other Standards:
surface such as cracks, ruptures, and laminations, and to
ASNT Recommended Practice for Nondestructive Testing
provide assurance that only plate that is free from rejectable
Personnel Qualification and Certification—Ultrasonic
discontinuities is accepted for delivery.
Testing Method—SNT-TC-1A
1.2 The inspection method and acceptance criteria included
in this standard shall be limited to plate of the following
3. Summary of Method
aluminum alloys: 1060, 1100, 3003, Alclad 3003, 3004, Alclad
3.1 The plate is inspected ultrasonically by scanning one
3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652,
rolled surface with a beam of pulsed longitudinal waves which
6061, and Alclad 6061.
is oriented in a direction perpendicular to the entry surface of
1.3 This test method applies only to ultrasonic tests using
the plate. The ultrasound is transmitted into the plate either by
pulsed longitudinal waves which are transmitted and received
the direct contact, immersion, or liquid-column coupling
by a search unit containing either a single crystal or a
method. During the scan, an indication representing the first
combination of electrically interconnected multiple crystals.
back reflection is observed on the A-scan screen of the test
Ultrasonic tests employing either the through-transmission or
instrument.
the angle-beam techniques are not included.
3.2 When the test system sensitivity level is appropriately
1.4 This test method shall be used when ultrasonic inspec-
adjusted, a discontinuity is detected during the scan by noting
tion as prescribed herein is required by the contract, purchase
an isolated indication associated with a loss of the first back
order, or referenced plate specification.
reflection indication. The apparent size of the discontinuity is
1.5 The values stated in inch-pound units are to be regarded
determined by measuring the total area in the scanned entry
as the standard. The values given in parentheses are for
surface of the plate where the isolated indication and the loss
information only.
of back reflection persist. The estimated discontinuity size and
1.6 This standard does not purport to address all of the
location are then compared with suitable acceptance criteria.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
NOTE 1—Additional information describing ultrasonic tests by the
priate safety and health practices and determine the applica- direct contact method and by the immersion method is available in
Practices E 114 and E 214.
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
4.1 A number of factors such as the condition of the entry
2.1 The following documents of the issue in effect on date
and back surfaces of the plate, the inclination of the ultrasonic
of material purchase form a part of this specification to the
beam with respect to the entry surface, and the performance
extent referenced herein:
characteristics of the test system may cause either a reduction
2.2 ASTM Standards:
of isolated indications or a substantial loss of back reflection
E 114 Practice for Ultrasonic Pulse-Echo Straight-Beam
and thereby could seriously impair the reliability of the test
procedure outlined in this standard.
This test method is under the jurisdiction of ASTM Committee B-7 on Light
Metals and Alloys and is under the jurisdiction of Subcommittee B07.03 on
Aluminum Alloy Wrought Products. Annual Book of ASTM Standards, Vol 03.03.
Current edition approved Feb. 23, 1990. Published April 1990. Originally American Society for Nondestructive Testing, 914 Chicago Ave., Evanston, Ill.
published as B 548 – 71. Last previous edition B 548 – 82. 60202.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
B 548
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-
size as determined by the test procedure outlined in this method 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 (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-
tion within 1° in two vertical planes that are perpendicular to
5.1 Test Instrument—Any electronic device that produces
each other.
pulsed longitudinal waves and displays ultrasonic reflections
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
amplification of received pulses at a selected test frequency and device are equivalent to those obtained by the immersion method.
shall be free from significant interface signal interference at the
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
5.5 Couplant—Clean, deaerated water at room temperature
containing both a transmitting and a receiving crystal in one
is the recommended couplant for tests either by the immersion
container may be used provided the test instrument will
method or by the liquid-column coupling technique. Inhibitors
accommodate two-crystal operation and the resulting pulse-
or wetting agents or both may be used. For tests by the contact
echo test is equivalent to that obtained with a search unit
method, the recommended couplant is clean, light-grade oil.
containing a single-crystal.
NOTE 4—Other coupling liquids may be employed for inspecting plate
5.2.1 The total effective area of the crystal or combination
provided their use does not adversely affect test results.
of crystals in the search unit used for initial scanning shall not
2 2 2
be less than 0.4 in. (2.6 cm ) nor greater than 3.0 in. (19.4
6. Personnel Requirements
cm ).
6.1 The testing operator performing the ultrasonic examina-
5.2.2 The effective diameter of the round search unit used to
tion prescribed in this standard shall be qualified and certified
evaluate discontinuity size shall not exceed 0.75 in. (19 mm).
to Level I—Ultrasonic Testing in accordance with the ASNT
NOTE 2—For control purposes, the performance characteristics of the
Recommended Practice SNT-TC-1A.
test instrument and search unit may be established in accordance with
6.2 The required documentation supporting qualification
procedures outlined in Practice E 317.
and certification of ultrasonic testing operators shall be estab-
lished by the certifying agency and shall be available upon
5.3 Tank—For tests by the immersion method, any con-
request by the purchaser.
tainer is satisfactory that will facilitate the accurate, stable
positioning of both the search unit and the plate to be
7. Condition of Plate
inspected.
7.1 The entry and back surfaces of the inspected plate shall
5.4 Scanning Apparatus—During the inspection procedure,
the search unit is supported by any one of the following be sufficiently clean, smooth, and flat to maintain a first back
reflection amplitude greater than 50 % of the initial standard-
devices. The scanning apparatus shall permit measurement of
ization amplitude while scanning an area in the plate that does
both the scan distance and the index distance within 60.1 in.
not contain significant isolated ultrasonic discontinuities.
(62 mm).
7.2 The inspected plate shall be at room temperature during
5.4.1 Manipulator and Bridge—When a manipulator is
the test.
used in tests by the immersion method, the manipulator shall
adequately support a search tube containing a search unit and
8. Procedure
shall provide fine adjustment of angle within 1° in two vertical
planes that are perpendicular to each other. The bridge shall be 8.1 Preferred Method—The ultrasonic test may be per-
of sufficient strength to provide rigid support for the manipu- formed by either the liquid column coupling, the direct contact,
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
B 548
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 8.5.2 During the inspection procedure, check the test system
sensitivity standardization periodically by noting the amplitude
couplant reflection is to the right of the first back reflection on
the instrument cathode ray tube (CRT). The couplant path shall of the first back reflection when the search unit is repositioned
over the reference area of the plate and by adjusting the
not vary more than 6 ⁄4 in. (6.4 mm) during calibration, initial
scanning, and discontinuity evaluation. instrument gain control as required to maintain the sensitivity
standardization specified previously in 8.3.
8.2 Test Frequency—When using any of the three methods
8.6 Scanning Rate—When the screen pattern on the A-scan
listed in 8.1, the recommended test frequency is 5.0 MHz.
indicator is monitored visually by the test operator during the
Other test frequencies between 2.0 MHz and 10.0 MHz may be
employed when necessary to minimize possible adverse effects inspection, the scanning rate shall not be greater than 12 in./s.
of plate thickness, microstructure, and test system characteris-
NOTE 6—Scanning rates greater than 12 in./s may be employed if
tics upon test results and thereby maintain a clean, easily
auxiliary monitoring apparatus is used to maintain adequate detection
interpreted A-scan screen pattern throughout the inspection.
reliability.
8.3 Sensitivity Standardization—Standardize the sensitivity
8.7 Detection of Discontinuities—When an isolated ultra-
level of the test system operating at the selected frequency by
sonic indication of amplitude greater than 30 % of the A-scan
adjusting the instrument gain control to obtain a first back
vertical limit is encountered or when the first back reflection
reflection amplitude of 75 6 5 % of the vertical limit exhibited
indication decreases to an amplitude less than 5 % of the
by the A-scan indicator when the search unit is positioned over
vertical limit at any time during the inspection procedure, stop
an area free from significant discontinuities in the plate to be
the scan and angulate the search unit to obtain a maximum
inspected. During tests by either the immersion method or the
isolated indication and to determine that the loss of back
liquid column coupling method, adjust the angular alignment
reflection is not caused by misalignment of the search unit with
of the search unit to obtain a maximum number of back
respect to the plate.
reflections before the final sensitivity level is established.
8.7.1 To ensure that the loss of back reflection is not caused
8.4 Scanning—With no further adjustments of the instru-
by surface interference, check the condition of both the entry
ment gain controls, locate the search unit over one corner of the
and back surfaces of the plate at the location where a
plate to be inspected so that the edge of the crystal in the search
substantial (95 % or greater) loss of back reflection occurs.
unit is about 1 in. (25 mm) from either edge of the plate.
8.7.2 Either a maximized isolated ultraso
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