ASTM B594-97
(Practice)Standard Practice for Ultrasonic Inspection of Aluminum-Alloy Wrought Products for Aerospace Applications
Standard Practice for Ultrasonic Inspection of Aluminum-Alloy Wrought Products for Aerospace Applications
SCOPE
1.1 This practice covers the requirements for pulse-echo ultrasonic inspection and includes criteria used to define applicable quality levels of aluminum-alloy wrought products for aerospace applications when performance of the ultrasonic test by the producer is specified, or when ultrasonic inspection is performed by the purchaser upon receipt.
1.2 This practice is not applicable if plastic deformation is introduced into the material after delivery.
1.3 The ultrasonic test described in this practice is employed to detect internal discontinuities oriented in a direction parallel to, or nearly parallel to, the surface of the product. The test is performed either by the immersion method or the contact method 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.
Note 1—Ultrasonic tests employing angle-beam techniques require special reference blocks, search units, and scanning procedures and are subject to negotiation between the purchaser and the seller when such tests are required by the contract or purchase order.
1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
1.5 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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: B 594 – 97
Standard Practice for
Ultrasonic Inspection of Aluminum-Alloy Wrought Products
for Aerospace Applications
This standard is issued under the fixed designation B 594; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope Examination by the Contact Method
E 127 Practice for Fabricating and Checking Aluminum
1.1 This practice covers the requirements for pulse-echo
Alloy Ultrasonic Standard Reference Blocks
ultrasonic inspection and includes criteria used to define
E 214 Practice for Immersed Ultrasonic Examination by the
applicable quality levels of aluminum-alloy wrought products
Reflection Method Using Pulsed Longitudinal Waves
for aerospace applications when performance of the ultrasonic
E 317 Practice for Evaluating Performance Characteristics
test by the producer is specified, or when ultrasonic inspection
of Ultrasonic Pulse-Echo Testing Systems Without the Use
is performed by the purchaser upon receipt.
of Electronic Measurement Instruments
1.2 This practice is not applicable if plastic deformation is
2.3 American Society for Nondestructive Testing Standard:
introduced into the material after delivery.
ASNT Recommended Practice for Nondestructive Testing
1.3 The ultrasonic test described in this practice is employed
Personnel Qualification and Certification—Ultrasonic
to detect internal discontinuities oriented in a direction parallel
Testing Method, SNT-TC-1A
to, or nearly parallel to, the surface of the product. The test is
2.4 Military Standard:
performed either by the immersion method or the contact
MIL-STD-410 Certification of Inspection Personnel
method using pulsed longitudinal waves which are transmitted
and received by a search unit containing either a single crystal
3. Terminology
or a combination of electrically interconnected multiple crys-
3.1 Definitions:
tals. Ultrasonic tests employing either the through-transmission
3.1.1 The following definitions of aluminum-alloy wrought
or the angle-beam techniques are not included.
products shall be used in conjunction with this practice:
NOTE 1—Ultrasonic tests employing angle-beam techniques require
3.1.2 plate—a rolled product, rectangular in cross section
special reference blocks, search units, and scanning procedures and are
and form, of thickness equal to or greater than 0.250 in. (6.35
subject to negotiation between the purchaser and the seller when such tests
mm) with sawed or sheared edges.
are required by the contract or purchase order.
3.1.3 bar—a solid product that is long in relation to its cross
1.4 The values stated in inch-pound units are the standard.
section which either is a square or rectangle (excluding plate
The SI units in parentheses are for information only.
and flattened wire) with sharp or rounded corners, or is a
1.5 This standard does not purport to address all of the
regular hexagon or octagon and in which at least one perpen-
safety concerns, if any, associated with its use. It is the
dicular distance between parallel faces is equal to or greater
responsibility of the user of this standard to establish appro-
than 0.375 in. (9.53 mm).
priate safety and health practices and determine the applica-
3.1.4 shape—a wrought product that is long in relation to
bility of regulatory limitations prior to use.
the dimensions of its cross section which is of a form other than
that of sheet, plate, rod, bar, tube, or wire.
2. Referenced Documents
3.1.5 die forging—a forging that is worked to the required
2.1 The following documents of the issue in effect on date
shape and size in impression dies.
of material purchase form a part of this practice to the extent
3.1.6 rolled ring—a cylindrical product of short length in
referenced herein:
relation to its diameter which is formed by rolling a hollow
2.2 ASTM Standards:
section in the circumferential direction.
E 114 Practice for Ultrasonic Pulse-Echo Straight-Beam
1 2
This practice is under the jurisdiction of ASTM Committee B-7 on Light Metals Annual Book of ASTM Standards, Vol 03.03.
and Alloys and is the direct responsibility of Subcommittee B07.03 on Aluminum Available from American Society for Nondestructive Testing, 3200 Riverside
Alloy Wrought Products. Dr., P.O. Box 5642, Columbus, OH 43221.
Current edition approved Oct. 10, 1997. Published May 1998. Originally Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
published as B 594 – 74. Last previous edition B 594 – 95. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
B 594
3.1.7 hand forging—a forging that is worked to the required purchaser and the producer at the time of quotation or
shape and size between flat or simply shaped dies by repeated acceptance of purchase order or contract.
strokes or blows and manipulation of the piece.
6.1.2 Engineering Drawings—When ultrasonic inspection
is specified for alloys, section thicknesses, and weights outside
4. Summary of Practice
limits established in applicable product specifications, the
4.1 The product is inspected ultrasonically by scanning
special discontinuity class limits shall be as negotiated between
specified entry surfaces with a beam of pulsed longitudinal
the purchaser and the producer and shall be indicated on zoned
waves oriented in a direction perpendicular to the entry
engineering drawings describing the material to be inspected
surface. The ultrasound is transmitted into the product either by
on part machine drawings. The drawings shall also indicate
the direct contact or the immersion method. During the scan,
noncritical areas on the material and areas that will be removed
indications representing discontinuities are displayed on an
by machining.
A-scan screen of the test instrument and may be detected by
6.1.3 Special Testing Procedures—Cylindrical sections or
auxiliary electronic monitors, if used.
specified areas of parts containing fillets may require additional
4.2 When the test system sensitivity level is appropriately
inspections employing special ultrasonic testing procedures
adjusted, detected discontinuities and variations in back reflec-
(for example, angle-beam, shear-wave technique) not covered
tion patterns are evaluated by comparing amplitudes of indi-
by this practice. Such special testing procedures and accep-
cations with the ultrasonic responses from selected ultrasonic
tance limits shall be established by negotiation and agreement
standard reference blocks. The evaluated ultrasonic disconti-
between the purchaser and producer.
nuity responses are then classified and compared with appli-
cable acceptance criteria.
7. Apparatus
NOTE 2—Additional information describing ultrasonic tests by the
7.1 The required ultrasonic test system shall consist of the
direct contact method and by the immersion method is available in
following:
Practices E 114 and E 214.
7.1.1 Basic Test Instrument—Any electronic device that
produces electrical pulses to activate a search unit and displays
5. Significance and Use
pulses representing ultrasonic reflections on an A-scan screen
5.1 A number of factors such as the condition of the entry
is satisfactory if the minimum performance characteristics
and back surfaces of the inspected part, the inclination of the
specified in 7.1.3 are met. The instrument shall provide stable
ultrasonic beam with respect to the entry surface, and varia-
linear amplification of received pulses at a selected test
tions in the performance characteristics of the test system may
frequency and required sensitivity levels within the specified
cause significant differences in amplitudes of discontinuity
minimum performance limits.
indications and back reflections. These factors can seriously
7.1.2 Search Unit—The recommended search unit is the flat
impair the reliability and the quantitative value of the ultra-
nonfocusing type and contains a piezoelectric crystal which
sonic test outlined in this practice.
generates and receives longitudinal waves at the rated fre-
5.2 Accurate evaluations of discontinuity size are also
quency when connected to the test instrument through a
significantly affected by variations in search unit characteristics
suitable coaxial cable. A dual-crystal search unit containing
and by irregularities in discontinuity surfaces which can
both a transmitting and a receiving crystal in one container may
influence reflectivity. For these reasons, the discontinuity sizes
be used provided the test instrument will accommodate two-
that may be implied by the ultrasonic comparisons outlined in
crystal operation. Special tests employing focusing search units
this practice must be regarded as “apparent” or “estimated” in
may be used provided such tests are established by negotiation
recognition of the limited quantitative value of the measure-
and agreement between purchaser and producer.
ment.
7.1.2.1 Search Unit Size—Any search unit of either circular
5.3 Because numerous interacting variables in a test system
or rectangular configuration may be used for initial scanning.
can adversely influence the results of an ultrasonic inspection,
For a circular configuration that provides an effective crystal
the actual quantitative effects of detected discontinuities upon
2 2
area greater than 1.00 in. (6.45 cm ) and for all rectangular
the mechanical properties of the inspected product are difficult
search units a documented method of providing a uniform
to establish. Although this practice provides a reliable control
entry surface for the full extent of the sound beam shall be
of product quality during manufacture, it is not applicable as an
agreed upon between the purchaser and producer. A search unit
exclusive indicator of the ultimate quality and performance of
containing a circular crystal of an effective diameter no greater
components fabricated from the inspected products covered by
than 0.75 in. (19.0 mm) is required to evaluate the ultrasonic
this practice.
response from detected discontinuities. When connected to the
6. Special Requirements
test instrument and used for initial scanning and evaluating
6.1 When ultrasonic inspection of the finished product is responses from discontinuities, the search unit shall meet or
required of the producer, purchase orders or contracts shall exceed the required minimum performance characteristics at
include the following information: the selected test frequency. Search units used only for initial
6.1.1 Special Acceptance Limits—Discontinuity class lim- scanning of a part prior to evaluation of suspect discontinuities
its, if other than those defined in Section 11, shall be subject to shall, as a minimum, have adequate performance of sensitivity
negotiation between the purchaser and the producer and shall and signal to noise ratio appropriate to the class of inspection
be in accordance with an agreement established between the described in Section 11.
B 594
NOTE 3—The same search unit used for initial scanning may also be
reevaluated and the test system shall be restandardized to
used for evaluating discontinuities provided its effective crystal diameter
ensure proper conformance to the requirements in this practice,
is no greater than 0.75 in. (19.0 mm) and minimum test system
and all metal tested since the previous standardization shall be
performance requirements are satisfied. Rectangular search units may be
retested.
used for evaluation if the method of use is established in writing by the
producer and approved by the purchaser.
NOTE 4—The distance amplitude curve may be established on one or
7.1.2.2 Effective Beam Width—The effective beam width of more sets of ultrasonic standard reference blocks, containing other than
No. 5 flat bottomed holes, when justified by the inspection class of Section
the search unit shall be established by determining the total
11.
traverse distance over which response is maintained within
NOTE 5—This section is not applicable when using the alternative
limits specified below. The hole size in the standard Practice
procedure allowed by 10.5.2.
E 127 reference block to be used for determining effective
beam width shall be in accordance with those listed in Table 1 7.1.2.4 Uniformity of Response for Rectangular Search
for the applicable class of inspection. The metal distance of the
Units—Rectangular search units shall exhibit beam uniformity
reference block shall be that which produces the smallest within 610 % of the mean amplitude of indication from the
clearly resolved hole indication. The same water distance to be
flat-bottomed hole during a traverse along the longitudinal axis
used for scanning shall be used to determine effective beam of the search unit at the scanning sensitivity established with
width.
reference blocks for the applicable class (exclusive of end lobe
(a) For round search units, a maximum indication shall be responses).
obtained from the hole and then the instrument gain control
7.1.3 Test System Performance—When used with appropri-
shall be adjusted to obtain a hole indication that is equal to
ate auxiliary equipment described in subsequent paragraphs,
80 % of the vertical limit. The effective beam width shall be the
the test system shall be capable of meeting or exceeding the
traverse distance in the index direction over which the indica-
minimum performance characteristics listed in Table 2 as
tion from the flat-bottom hole equals or exceeds 40 % of the
determined by procedures outlined in Practice E 317. If instru-
vertical limit.
ment A-scan display dimensions exceed the 2.5-in. (63.5-mm)
(b) For rectangular search units, an indication shall be
vertical limit and the 3.5-in. (88.9-mm) horizontal limit, the
obtained from the hole at any point along the longitudinal axis
instrument shall be considered usable throughout the entire
of the search unit and then the instrument gain control shall be
A-scan screen height or width found to be linear with the
adjusted to obtain a hole indication that is equal to 80 % of the
procedures prescribed in Practice E 317. All other minimum
vertical limit. The effective beam width shall be the traverse
characteristics listed in Table 2 remain applicable.
distance in the index direction over which the indication from
7.2 Auxiliary Equipment—In addition to the ultrasonic test
the flat-bottom hole equals or exceeds 40 % of the vertical
system previously described, the following equ
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