ASTM E317-94
(Practice)Standard Practice for Evaluating Performance Characteristics of Ultrasonic Pulse- Echo Examination Instruments and Systems Without the Use of Electronic Measurement Instruments
Standard Practice for Evaluating Performance Characteristics of Ultrasonic Pulse- Echo Examination Instruments and Systems Without the Use of Electronic Measurement Instruments
SCOPE
1.1 This practice describes procedures for evaluating the following performance characteristics of ultrasonic pulse-echo examination instruments and systems: Horizontal Limit and Linearity; Vertical Limit and Linearity; Resolution - Entry Surface and Far Surface; Sensitivity and Noise; Accuracy of Calibrated Gain Controls. Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this practice are expressed in terms that relate to their potential usefulness for ultrasonic examinations. Instrument characteristics expressed in purely electronic terms may be measured as described in E1324.
1.2 Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be evaluated.
1.3 The procedures are applicable to shop or field conditions; additional electronic measurement instrumentation is not required.
1.4 This practice establishes no performance limits for examination systems; if such acceptance criteria are required, these must be specified by the using parties. Where acceptance criteria are implied herein they are for example only and are subject to more or less restrictive limits imposed by customer's and end user's controlling documents.
1.5 The specific parameters to be evaluated, conditions and frequency of test, and report data required, must also be determined by the user.
1.6 This practice may be used for the evaluation of a complete examination system, including search unit, instrument, interconnections, fixtures and connected alarm and auxiliary devices, primarily in cases where such a system is used repetitively without change or substitution. This practice is not intended to be used as a substitute for calibration or standardization of an instrument or system to inspect any given material. There are limitations to the use of standard reference blocks for that purpose.
1.7 Required test apparatus includes selected test blocks and a precision external attenuator (where specified) in addition to the instrument or system to be evaluated.
1.8 Precautions relating to the applicability of the procedures and interpretation of the results are included.
1.9 Alternate procedures, such as examples described in this document, or others, may only be used with customer approval.
1.10 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)
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Designation: E 317 – 94 An American National Standard
Standard Practice for
Evaluating Performance Characteristics of Ultrasonic Pulse-
Echo Testing Systems Without the Use of Electronic
Measurement Instruments
This standard is issued under the fixed designation E 317; 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 2. Referenced Documents
1.1 This practice describes procedures for evaluating the 2.1 ASTM Standards:
following performance characteristics of ultrasonic pulse-echo E 114 Practice for Ultrasonic Pulse-Echo Straight-Beam
testing systems: Horizontal Limit and Linearity; Vertical Limit Examination by the Contact Method
and Linearity; Resolution-Entry Surface and Far Surface; E 127 Practice for Fabricating and Checking Aluminum
Sensitivity and Noise; Accuracy of Calibrated Gain Controls. Alloy Ultrasonic Standard Reference Blocks
Relevant terminology can be found in Terminology E 1316 and E 214 Practice for Immersed Ultrasonic Examination by the
IEEE Standard 100. Reflection Method Using Pulsed Longitudinal Waves
1.2 Ultrasonic test systems using pulsed-wave trains and E 428 Practice for Fabrication and Control of Steel Refer-
A-scan presentation (rf or video) may be evaluated. ence Blocks Used in Ultrasonic Inspection
1.3 The procedures are applicable to shop or field condi- E 1316 Terminology for Nondestructive Examinations
tions; additional electronic measurement instrumentation is not 2.2 Other Standard:
required. IEEE Std 100, IEEE Standard Dictionary of Electrical and
1.4 This practice establishes no performance limits for test Electronic Terms
systems; if such acceptance criteria are required, these must be
3. Summary of Practice
specified by the using parties.
3.1 A testing system to be evaluated comprises an ultrasonic
1.5 The specific parameters to be evaluated, conditions and
frequency of test, and report data required, must also be pulse-echo instrument, search unit, interconnecting cables, and
couplant; for immersion testing systems suitable fixturing is
determined by the user.
1.6 This practice is intended primarily for the evaluation of required.
3.2 Test conditions are selected that are consistent with the
a complete testing system, including search unit, instrument,
interconnections, and fixtures. However, certain characteristics intended end-use of the inspection system, as determined by
the user.
of the instrument alone can be determined within the limita-
tions discussed. 3.3 The ultrasonic response from appropriate test blocks is
obtained, and presented in numerical or graphical form.
1.7 Required test apparatus includes selected test blocks and
3.4 The test data can be used to characterize the related
a precision external attenuator (where specified) in addition to
the system to be evaluated. system parameters in accordance with user requirements.
1.8 Precautions relating to the applicability of the proce-
4. Significance and Use
dures and interpretation of the results are included.
4.1 This practice describes procedures applicable to both
1.9 This standard does not purport to address all of the
shop and field conditions. More comprehensive or precise
safety concerns, if any, associated with its use. It is the
measurements of the characteristics of complete systems and
responsibility of the user of this standard to establish appro-
their components will generally require laboratory techniques
priate safety and health practices and determine the applica-
and electronic equipment such as oscilloscopes and signal
bility of regulatory limitations prior to use.
generators. Substitution of these methods is not precluded
where appropriate; however, their usage is not within the scope
of this practice.
This practice is under the jurisdiction of ASTM Committee E-7 on Nonde-
4.2 This document does not establish system acceptance
structive Testing and is the direct responsibility of Subcommittee E07.06 on
Ultrasonic Testing Procedures.
Current edition approved Sept. 15, 1994. Published November 1994. Originally
published as E 317 – 67 T. Last previous edition E 317 – 93. Annual Book of ASTM Standards, Vol 03.03.
Published by Wiley-Interscience, New York, NY.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 317
limits, nor is it intended as a comprehensive equipment which increase sensitivity with higher panel readings are
specification. designated “gain” and those which decrease sensitivity with
4.3 While several important characteristics are included, higher readings are designated “attenuation.” Fine (reference)
others of possible significance in some applications are not gain controls when available are usually not calibrated in
covered. decibels and increase sensitivity with clockwise rotation.
4.4 Since the parameters to be evaluated and the applicable
5.1.3 Although the procedures in this practice do not de-
test conditions must be specified, this practice should be
scribe the use of electronic distance-amplitude compensation,
prescribed only by those familiar with ultrasonic NDT tech-
its use is not precluded. If it is used to affect any one or
nology and the required tests should be performed either by
combination of characteristics, measured under this document,
such a qualified person or under his supervision.
then all characteristics should be evaluated with the same level
4.5 Implementation may require more detailed procedural
of compensation as was used on any one, and this level should
instructions in the format of the using facility.
be referenced in the report. If desired by the using parties, a
4.6 Selection of the specific tests to be made should be done
dual set of test data may be made both with and without
cautiously; if the related parameters are not critical in the
distance-amplitude compensation.
intended application, then their inclusion may be unjustified.
5.1.4 If the CRT display does not provide a suitable internal
For example, vertical linearity may be irrelevant for a go/no-go
graticule, and deflection measurements are being made, fix the
test with a flaw gate alarm, while horizontal linearity might be
eye relative to the external scale to minimize parallax. This
required only for accurate flaw-depth or thickness measure-
practice assumes reading precision of within 2 % of full scale.
ment from the CRT display.
If, for any reason, this is not feasible for the system under test,
4.7 No frequency of system evaluation or calibration is
estimate the probable accuracy and include this in the report.
recommended or implied. This is the prerogative of the using
Readability can sometimes be improved by the use of an
parties and is dependent on application, environment, and
external scale attached to the CRT face having 50 or 100
stability of equipment.
divisions for full scale.
4.8 Certain sections are applicable only to instruments
5.1.5 When tests are being done by the contact method,
having receiver gain controls calibrated in decibels (dB). While
position the search unit securely and make certain that couplant
these may sometimes be designated “gain,” “attenuator,” or
changes are not measurably affecting the results. Refer also to
“sensitivity” on various instruments, the term “gain controls”
Practice E 114.
will be used in this practice in referring to those which
5.1.6 When using the immersion method, allow adequate
specifically control instrument receiver gain but not including
time for thermal stabilization; remove bubbles and particles
reject, electronic distance-amplitude compensation, or auto-
from search unit and test surfaces; maintain the search-unit
matic gain control.
manipulator and test blocks in stable positions. Refer also to
4.9 These procedures can generally be applied to any
Practice E 214.
combination of instrument and search unit of the commonly
5.2 Horizontal Limit and Linearity :
used types and frequencies, and to most straight-beam testing,
5.2.1 Significance— Horizontal limit and linearity have
either contact or immersed. Certain sections are also compat-
significance when determination of depth of a discontinuity is
ible with angle-beam, wheel, delay-line, and dual-search unit
required. A specified minimum trace length is usually neces-
techniques. Their use, however, should be mutually agreed
sary to obtain the horizontal readability desired. Nonlinearity
upon and so identified in the test report.
of sweep trace may affect accuracy of flaw depth or thickness
4.10 The validity of the results obtained will depend on the
determination made directly from the CRT.
precision of the CRT readings. This is assumed to be 60.04 in.
(61 mm), yielding between 1 % and 2 % of full scale (fs) 5.2.2 Apparatus—A test block is required that will give
several (preferably eleven) noninterfering multiple back reflec-
readability for available instrumentation having suitable screen
graticules and display sharpness. tions for the sweep range and other test conditions of interest.
Any block having good ultrasonic transmittivity, flat parallel
5. Procedures for Obtaining Ultrasonic Response Data
faces, and a thickness of about one tenth of the specified sweep
5.1 General:
range will usually be adequate. The aluminum blocks shown in
5.1.1 For each procedure determine from the requesting Fig. 1 will be satisfactory for mid-range frequencies and sweep
documents the instrument test range to be evaluated, select the
settings on most instruments when the beam is directed through
appropriate search unit, fixtures, and test blocks, and establish the thickness T. For other test frequencies or very large search
the required display conditions. Unless otherwise required for
units, different block dimensions or other block designs may be
the test, mid-range values are suggested for most panel required to eliminate interferences. The couplant system used,
controls; reject must be off unless specifically allowed. To
either contact or immersed, must provide stable indications
obtain the exact display conditions required for certain tests, it
during the measurements. A horizontal scale permitting reading
may be necessary to vary the instrument controls from these
accuracy as specified in 5.1.4 is required.
initial values. It is important to observe and report any
NOTE 1—An encapsulated transducer-targets assembly may be used for
anomalous effects on the parameters being evaluated when the
this purpose.
controls are varied over the full range of intended use.
5.1.2 When a procedure requires a change in receiver gain 5.2.3 Procedure—Couple the appropriate block to the
by the use of a calibrated control, it is assumed that those search unit so that the sound beam does not intercept any test
E 317
Material: 7075T6 aluminum
Plug drilled holes with water-insoluble plastic.
FIG. 1 Suggested Test Blocks for Evaluation of Horizontal and Vertical Linearity
Table of Dimensions
US Customary Block (in.) Metric Block (mm)
Dimension Tolerance Dimension Tolerance
A 1.25 0.05 32 1
B 1.00 0.05 25 1
C 0.75 0.05 19 1
D 1.00 0.05 25 1
E 0.75 0.05 19 1
H 3.00 0.05 75 1
T 1.00 0.01 25 0.2
W 2.00 0.05 50 1
d and d 0.047 dia. 0.005 1.2 dia. 0.1
1 2
All surfaces:
Flatness . 0.001 . 0.02
Parallelism . 0.001 . 0.02
Finish 63 μ in. or smoother 1.5 μm or smoother
holes. Adjust the instrument gain, sweep-delay, and sweep- linear units (inches or millimetres). Unless otherwise noted,
length controls to display eleven noninterfering back reflec- this is also assumed to represent 100 % fs. Failure to obtain
tions. Set the amplitude of each back reflection at 50 % fs full-scale deflection may indicate an equipment malfunction.
before measurement of its position. Further adjust the sweep
5.2.4.2 Linearity test results may be presented in tabular
controls (range, centering, or delay) to position the leading
form or, preferably, plotted in the manner shown in Fig. 2. The
edge of the third and ninth back reflections at the 20 % and
deviation is given by the displacement (in % full scale) from
80 % scale divisions respectively (with each set in turn at 50 %
the straight line through the set-up points representing ideal
fs). After the third and ninth back reflections are positioned
linearity. For the test point shown (sixth multiple at 55 % fs)
accurately on the 20 % and 80 % divisions as described, read
the error is 5 % fs. Maximum nonlinearity is given by the
and record the scale positions of each other multiple. Alterna-
“worst case” test point. Linear range is given by the set of
tively, if sweep-delay is not available, position the second and
contiguous points falling entirely within a specified tolerance.
eighth back reflections at the 20 % and 80 % scale divisions
5.3 Vertical Limit and Linearity:
respectively; read and record the scale positions of the initial
5.3.1 Significance— Vertical limit and linearity have signifi-
pulse start and of the remaining multiples.
cance when echo signal amplitudes are to be determined from
NOTE 2—Either more or fewer reflections can be used by suitably
the CRT or corresponding output signals, and are to be used for
modifying the procedure. For example, six back reflections may be used
evaluation of discontinuities or acceptance criteria. A specified
if interference echoes are obtained with eleven, in which case the second
minimum trace deflection and linearity limit may be required to
back reflection is positioned at the 20 % scale division and the fifth back
achieve the desired amplitude accuracy. For other situations
reflection at the 80 % scale division. Measurement of the horizontal
they may not be important, for example, go/no-go tests with
position of each multiple echo, should be made at the same amplitude on
the leading edge of the indication. Any specific value may be selected if
flaw alarms or evaluation by comparison with a reference level
it is used consistently. Typically used values are baseline break, half
using calibrated gain controls. This practice describes both the
amplitude, or signal peak.
two-signal ratio technique (Method A) and the input/output
5.2.4 Interpretation of Data: attenuator technique (Method B). Both methods assume that
5.2.4.1 Horizontal limit is given by the maximum available the test indications used for measurement are free of interfer-
trace length falling within the CRT graticule lines expressed in ences resulting from nearby signals such as the initial pulse,
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