ASTM E1901-97(2003)

Standard Guide for Detection and Evaluation of Discontinuities by Contact Pulse-Echo Straight-Beam Ultrasonic Methods

SIGNIFICANCE AND USE
This guide provides procedures for the application of contact straight-beam examination for the detection and quantitative evaluation of discontinuities in materials.
Although not all requirements of this guide can be applied universally to all inspections, situations, and materials, it does provide basis for establishing contractual criteria between the users, and may be used as a general guide for preparing detailed specifications for a particular application.
This guide is directed towards the evaluation of discontinuities detectable with the beam normal to the entry surface. If discontinuities or other orientations are of concern, alternate scanning techniques are required.
SCOPE
1.1 This guide covers procedures for the contact ultrasonic examination of bulk materials or parts by transmitting pulsed ultrasonic waves into the material and observing the indications of reflected waves. This guide covers only examinations in which one search unit is used as both transmitter and receiver (pulse-echo). This guide includes general requirements and procedures that may be used for detecting discontinuities, locating depth and distance from a point of reference and for making a relative or approximate evaluation of the size of discontinuities as compared to a reference standard.
1.2 This guide complements Practice E 114 by providing more detailed procedures for the selection and calibration of the inspection system and for evaluation of the indications obtained.
1.3 The values stated in inch-pound units are to be regarded as the standard. The SI units given in brackets are for information only.
1.4 This guide 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 guide to establish the appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Jul-2003
• ICS: 19.100 - Non-destructive testing
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.06 - Ultrasonic Method

Relations

• Replaces: ASTM E1901-97 - Standard Guide for Detection and Evaluation of Discontinuities by Contact Pulse-Echo Straight-Beam Ultrasonic Methods
• Effective Date: 10-Jul-2003
• Replaced By: ASTM E1901-08 - Standard Guide for Detection and Evaluation of Discontinuities by Contact Pulse-Echo Straight-Beam Ultrasonic Methods
• Effective Date: 01-Jul-2008
• Referred By: ASTM E3166-20e1 - Standard Guide for Nondestructive Examination of Metal Additively Manufactured Aerospace Parts After Build
• Effective Date: 10-Jul-2003
• Referred By: ASTM E543-21 - Standard Specification for Agencies Performing Nondestructive Testing
• Effective Date: 10-Jul-2003
• Referred By: ASTM E2533-21 - Standard Guide for Nondestructive Examination of Polymer Matrix Composites Used in Aerospace Applications
• Effective Date: 10-Jul-2003
• Referred By: ASTM E3370-23 - Standard Practice for Matrix Array Ultrasonic Testing of Composites, Sandwich Core Constructions, and Metals
• Effective Date: 10-Jul-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1901–97 (Reapproved 2003)
Standard Guide for
Detection and Evaluation of Discontinuities by Contact
Pulse-Echo Straight-Beam Ultrasonic Methods
This standard is issued under the fixed designation E 1901; 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 E 543 Practice for Agencies Performing Nondestructive
Testing
1.1 This guide covers procedures for the contact ultrasonic
E 1158 Guide for Material Selection and Fabrication of
examination of bulk materials or parts by transmitting pulsed
Reference Blocks for the Pulsed Longitudinal Wave Ultra-
ultrasonic waves into the material and observing the indica-
sonic Examinations of Metal and Metal Alloy Production
tions of reflected waves. This guide covers only examinations
Materials
in which one search unit is used as both transmitter and
E 1316 Terminology for Nondestructive Examinations
receiver (pulse-echo). This guide includes general require-
2.2 ASNT Standard:
ments and procedures that may be used for detecting discon-
SNT-TC-1A Recommended Practice for Personnel Qualifi-
tinuities, locating depth and distance from a point of reference
cation and Certification in Nondestructive Testing Person-
and for making a relative or approximate evaluation of the size
nel
of discontinuities as compared to a reference standard.
2.3 ANSI/ASNT Standard:
1.2 This guide complements Practice E 114 by providing
CP-189 ASNT Standard for Qualification and Certification
more detailed procedures for the selection and calibration of
of Nondestructive Testing Personnel
the inspection system and for evaluation of the indications
2.4 Military Standard:
obtained.
MIL-STD-410 Nondestructive Testing Personnel Qualifica-
1.3 The values stated in inch-pound units are to be regarded
tion and Certification
as the standard. The SI units given in brackets are for
information only.
3. Terminology
1.4 This guide does not purport to address all of the safety
3.1 Definitions—For definitions of terms used in this guide,
concerns, if any, associated with its use. It is the responsibility
see Terminology E 1316.
of the user of this guide to establish the appropriate safety and
health practices and determine the applicability of regulatory
4. Basis for Application
limitations prior to use.
4.1 Contractual Agreement—The using parties shall agree
on the applicable procedural requirements, as listed herein,
2. Referenced Documents
prior to the examination of any material.
2.1 ASTM Standards:
4.1.1 Materials, sizes, and shapes examined,
E 114 Practice for Ultrasonic Pulse-Echo Straight-Beam
2 4.1.2 Stage of manufacture when examined (time of test),
Examination by the Contact Method
4.1.3 Surface finish requirements,
E 127 Practice for Fabricating and Checking Aluminum
2 4.1.4 Minimum equipment requirements, as in Table 1
Alloy Ultrasonic Standard Reference Blocks
herein,
E 317 Practice for Evaluating Performance Characteristics
4.1.5 Search unit size, frequency and type,
of Ultrasonic Pulse-Echo Examination Instruments and
4.1.6 Couplant,
Systems without the Use of Electronic Measurement In-
4.1.7 Automated turning, fixturing or scanning, or both, as
struments
applicable,
E 428 Practice for Fabrication and Control of Steel Refer-
4.1.8 Type of reference block standards including surface
ence Blocks Used in Ultrasonic Inspection
curvature,
4.1.9 Standardizationdetails,includingattenuationcompen-
sation and DAC techniques,
This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-
tive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic
Method. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved July 10, 2003. Published September 2003. Originally 4th Floor, New York, NY 10036.
approved in 1997. Last previous edition approved in 1997 as E 1901 - 97. AvailablefromStandardizationDocumentsOrderDeck,Bldg.4SectionD,700
Annual Book of ASTM Standards, Vol 03.03. Robbins Ave., Philadelphia, PA 19111–5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1901–97 (2003)
TABLE 1 Minimum Equipment Requirements (Longitudinal Wave)
7. Apparatus
Ultrasonic Test
7.1 Apparatus shall include the following:
Instrument Characteristics Frequency MHZ
7.1.1 Electronic Equipment—The electronic equipment
(Record)
shall be capable of producing and processing electronic signals
Vertical limit, in. [mm] or percent
at frequencies in the range of the search unit frequencies being
of full screen height
Upper vertical linearity limit in. [mm]
used. The equipment and its display shall provide characteris-
or percent of full screen height
tics as listed in Table 1, that are suitable for the specific
Lower vertical linearity limit in. [mm]
application at the specified frequency, as determined in accor-
or percent of full screen height
Ultrasonic sensitivity, hole size,
dance with the procedures and tolerances described in Practice
64 ths, distance, in [mm]
E 317. The equipment, including the search unit, shall be
Entry surface resolution, in. [mm]
capable of producing echo amplitudes of at least 60 % of full
Back surface resolution in. [mm]
Horizontal limit, in. [mm] or
screen height from the reference reflector required for the
percent of full screen width
examination, with the material noise level, from front to back
Horizontal linearity range, in. [mm]
or percent of full screen width surface not exceeding 20 % of full screen height.Alternatively,
if these conditions can be met at one half the part thickness, the
part may be inspected from both sides.
NOTE 1—The using parties should agree on the minimum instrument
4.1.10 The surfaces to be examined and the scanning path,
characteristics prior to conducting an examination.
4.1.11 Acceptance standards,
7.1.2 Voltage Regulator—If fluctuations in line voltage
4.1.12 Personnel certification level, and
cause indication amplitude variations exceeding 6 ⁄2 dB, a
4.1.13 Instrument characteristics.
voltage regulator shall be required on the power source. This
4.2 Written Procedure—Ultrasonic examinations performed
requirement is not applicable to battery-operated units.
in accordance with this guide shall be detailed in a written
7.1.3 Search Units—The search unit selected shall be ca-
procedure. Documentation of procedure qualification shall be
pable of transmitting and receiving ultrasound at the required
maintained by the preparer. Procedures shall be sufficiently
frequencies and energy levels necessary for discontinuity
detailed so that other qualified examiners may duplicate the
detection in the material being examined. The search units
examination and obtain equivalent results.
shall be of the contact type. Only longitudinal wave, straight
4.3 Personnel Qualifications—Personnel performing ultra-
beam, non-focused search units should be used. Dual element
sonic examinations in accordance with this guide shall be
search units may provide better near-surface resolution and
qualified in accordance with a nationally recognized NDT
detection of small discontinuities. Generally, round or rectan-
personnel qualification practice or standard; such as SNT-TC-
gular search units are used for examination whereas round
1A, ANSI/ASNT CP-189, MIL-STD-410, or a similar docu-
searchunitswithsymmetricalsoundbeampatternsareusedfor
ment. The practice or standard used and its applicable revision
evaluation.Typicalsearchunitsizesrangefrom ⁄8in.[3.2mm]
shall be specified in the contractual agreement between the
in diameter to 1- ⁄8 in. [28.6 mm] in diameter with other sizes
using parties.
and shapes available for special applications. Search units may
4.4 If specified in the contractual agreement, NDT agencies
be fitted with contoured shoes to enhance coupling with curved
shall be qualified and evaluated as described in Practice E 543.
surfaces.
7.1.4 Alarm(s)—For the examination of parts with regular
5. Summary of Guide
shapeandparallelsurfacessuchasmachinedcylinders,rounds,
5.1 This guide describes a means for obtaining an evalua-
bars, forgings, etc. an audible/visual alarm may be used in
tion of discontinuities in materials by contact examination
conjunction with visual monitoring of the display for the
using longitudinal waves. Equipment, reference standards,
detection of discontinuities or for the monitoring and detection
examination and evaluation procedures, and documentation of
of loss of back surface reflection, or both. The alarm should be
results are described in detail.
adjustable to allow triggering at commonly required indication
amplitudes, back-echo heights, and depths. During examina-
6. Significance and Use
tion the audible visual alarm shall be easily detectable by the
6.1 This guide provides procedures for the application of operator.
contact straight-beam examination for the detection and quan- 7.1.4.1 When reduction in the amplitude of back-surface
titative evaluation of discontinuities in materials. reflection is monitored simultaneously with the detection of
6.2 Although not all requirements of this guide can be lower amplitude signals from small, discrete discontinuities,
applied universally to all inspections, situations, and materials, two separate gate/alarm systems are required. The negative
it does provide basis for establishing contractual criteria slaved alarm system may also provide for a significantly lower
between the users, and may be used as a general guide for receiver gain at the gated depth to avoid back-echo saturation.
preparing detailed specifications for a particular application. See 10.1 and 10.4.
6.3 This guide is directed towards the evaluation of discon- 7.1.4.2 For some applications it may be advantageous to
tinuities detectable with the beam normal to the entry surface. utilize a flaw gate system in which the echo-amplitude alarm
If discontinuities or other orientations are of concern, alternate level can be varied as a function of target depth. Refer to
scanning techniques are required. distance/amplitude gate (DAG) in 9.3.2.1.
E1901–97 (2003)
7.2 Couplant—A couplant, usually a liquid or semi-liquid, correct angle to a stationary axle about which rotates a
is required between the face of the search unit and the liquid-filled flexible tire. A minimum amount of couplant
examinationsurfacetopermittransmittanceofultrasoundfrom provides for ultrasonic transmission into the examination
the search unit into the material under examination. Typical surface since the elastic tire material is in rolling contact and
couplants include water, cellulose gel, oil and grease. Corro- conforms closely to the surface.
sion inhibitors or wetting agents or both may be used. 7.3 Reference Standards—The production item itself may
Couplants selected must not be detrimental to the product or be an adequate standard using the height of the back-wall echo
the process. The same couplant used for standardization shall forreference.Formorequantitativeinformation,chartssuchas
be used for the examination. During the performance of a (AVG-DGS) representing distance-amplitude relationships of
contact ultrasonic examination, the couplant layer between known reflector sizes for a particular search unit, frequency
search unit and examination material must be maintained such and material may be used for standardization and evaluation of
that the contact area is held constant while maintaining discontinuities.
adequate couplant thickness. Lack of couplant that will reduce 7.3.1 Reference Blocks—Ultrasonic reference blocks, often
the effective contact area, or excess couplant, will reduce the called test blocks, are used to standardize the ultrasonic
amount of energy transferred between the search unit and the equipment and to evaluate the indications received from
examination surface. These couplant variations, in turn, result discontinuities within the part.The ultrasonic characteristics of
in examination sensitivity variations. the reference blocks such as attenuation, noise level, surface
7.2.1 The couplant should be selected such that its viscosity condition, and sound velocity, should be similar to the material
is appropriate for the surface finish of the material to be to be examined. Standardization verifies that the instrument
examined. The examination of rough surfaces generally re- search unit is performing as required and establishes a detec-
quires a high-viscosity couplant and will result in some tion level for discontinuities.
deterioration of near-surface discontinuity detection. The tem- 7.3.2 Flat Blocks—The three most commonly used sets of
perature of the material surface can change the couplant’s reference block are area-amplitude set, containing blocks with
viscosity as in the case of oil and grease. See Table 2 for the thesamematerialpathandvarioussizesofreferencereflectors;
suggested viscosity of oil couplants for given surface rough- distance-amplitude set, containing blocks with one size refer-
nesses. ence reflector at various material distances; and a combination
7.2.2 At elevated temperatures as conditions warrant, heat- including both area-amplitude and distance-amplitude blocks
resistant coupling materials such as silicone oils, gels, or in one set. These sets are described in Practices E 127 and
greases should be used. Further, intermittent contact of the E 428.
search unit with the part surface or auxiliary cooling of the 7.3.3 Curved Surfaces—Reference blocks with flat surfaces
searchunitmaybenecessarytoavoidtemperaturechangesthat may be used for establishing gain settings for examinations on
affect the ultrasonic characteristics of the search unit.At higher concave test surfaces and convex surfaces with radii of
temperatures, certain couplants based on inorganic salts or curvature4in.[101.6mm]orgreater.Forconvexsurfaceswith
thermoplastic organic materials, high-temperature delay mate- radii of curvature less than 4 in. [101.6 mm] it is recommended
rials (shoes) and search units that are not affected by high that reference blocks with approximately the same nominal
temperatures may be required. radius of curvature shall be used. Guide E 1158 illustrates
7.2.3 Where constant coupling over large areas is required, typical curved entry surface blocks.
as in automated examination, or where severe changes in 7.4 Reference Reflectors—Flat-bottomed holes, (FBH), or
surfaceroughnessarefound,othermethodsofcouplingsuchas other artificial discontinuities, located directly in the
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