ASTM E1961-98(2003)e1

Standard Practice for Mechanized Ultrasonic Examination of Girth Welds Using Zonal Discrimination with Focused Search Units

SCOPE
1.1 This practice covers the requirements for mechanized ultrasonic examination of girth welds. Evaluation is based upon the results of mechanized ultrasonic examination. Acceptance criteria are based upon flaw limits defined by an Engineering Critical Assessment (ECA) or other accept/reject criteria defined by the Contracting Agency.
1.2 This practice shall be applicable to the development of an examination procedure agreed upon between the users of this practice.
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in brackets are for information only.
1.4 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.

General Information

• Status: Historical
• Publication Date: 09-Jun-2003
• ICS: 25.160.40 - Welded joints and welds
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.06 - Ultrasonic Method

Relations

• Replaces: ASTM E1961-98 - Standard Practice for Mechanized Ultrasonic Examination of Girth Welds Using Zonal Discrimination with Focused Search Units
• Effective Date: 10-Jun-2003
• Replaced By: ASTM E1961-06 - Standard Practice for Mechanized Ultrasonic Testing of Girth Welds Using Zonal Discrimination with Focused Search Units
• Effective Date: 01-Dec-2006
• Referred By: ASTM E2373/E2373M-19 - Standard Practice for Use of the Ultrasonic Time of Flight Diffraction (TOFD) Technique
• Effective Date: 10-Jun-2003
• Referred By: ASTM E543-21 - Standard Specification for Agencies Performing Nondestructive Testing
• Effective Date: 10-Jun-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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
e1
Designation: E 1961 – 98 (Reapproved 2003)
Standard Practice for
Mechanized Ultrasonic Examination of Girth Welds Using
Zonal Discrimination with Focused Search Units
This standard is issued under the fixed designation E 1961; 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.
e NOTE—Footnote was added to paragraph 6.4.1 in June 2003.
1. Scope ANSI/ASNT-CP-189 Standard for Qualification and Certi-
fication of Nondestructive Testing Personnel
1.1 This practice covers the requirements for mechanized
2.4 Military Standard:
ultrasonic examination of girth welds. Evaluation is based
MIL-Std-410 Nondestructive Testing Personnel Qualifica-
upon the results of mechanized ultrasonic examination.Accep-
tion and Certification
tance criteria are based upon flaw limits defined by an
2.5 API Standard:
Engineering Critical Assessment (ECA) or other accept/reject
API STD–1104 Welding of Pipeline and Related Facilities
criteria defined by the Contracting Agency.
2.6 CSA Standard:
1.2 This practice shall be applicable to the development of
CSA Z-662 Oil and Gas Pipelines Systems
an examination procedure agreed upon between the users of
this practice.
3. Terminology
1.3 The values stated in SI units are to be regarded as the
3.1 Definitions:
standard. The inch-pound units given in brackets are for
3.1.1 Definitions relating to ultrasonic examination, that
information only.
appear in Terminology E 1316 shall apply to the terms used in
1.4 This standard does not purport to address all of the
this practice.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 acceptance criteria—definition of acceptable/
priate safety and health practices and determine the applica-
rejectable flaws as defined by an Engineering Critical Assess-
bility of regulatory limitations prior to use.
ment (ECA), such as defined in CSA-Z662 or API 1104, or
2. Referenced Documents workmanship criteria as defined by the contracting agency.
3.2.2 contract document—any document specified in the
2.1 The following documents form a part of this practice to
contractbetweenthecontractingagencyandcontractor,includ-
the extent specified herein:
ing the purchase order, specification, drawings or other written
2.2 ASTM Standards:
material.
E 164 PracticeforUltrasonicContactExaminationofWeld-
3.2.3 contracting agency—a government agency, prime
ments
contractor or subcontractor procuring ultrasonic examination
E 317 Practice for Evaluating Performance Characteristics
services.
of Pulse-Echo Examination Systems Without the Use of
2 3.2.4 contractor—the nondestructive examination contrac-
Electronic Measurement Instruments
tor engaged by the contracting agency in work covered by this
E 1316 Terminology for Nondestructive Examinations
practice.
2.3 ASNT Standard:
3.2.5 mapping type presentations—an ultrasonic image pre-
ASNT Practice SNT-TC-1A Personnel Qualification and
sentation whereby the digitizedA-scan signal is represented as
Certification in Nondestructive Testing
colors or grayscale for amplitude variation along one axis
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.06 on
Ultrasonic Method. AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Current edition approved June 10, 2003. Published August 2003. Originally Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS
approved in 1998. Last previous edition approved in 1998 as E 1961 - 98. Available from American Petroleum Institute, 1220 L Street, Northwest,
Annual Book of ASTM Standards, Vol 03.03. Washington, DC 20005.
3 6
Available fromTheAmerican Society for NondestructiveTesting (ASNT), P.O. Available from Canadian Standards Association, 178 Rexdale Boulevard,
Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518. Etobicoke, Ontario, Canada M9W 1R3.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E 1961 – 98 (2003)
representing time of flight and the other axis is the sampling 5.1.1 All bevels should be examined immediately after
position, or the distance along the weld. machining to ensure compliance with the applicable welding
3.2.6 operator(s)—the term “operator(s)” as used in this procedure.This examination should be combined with scribing
practice shall mean the operator(s) of ultrasonic equipment the reference line as described in 9.3.
who is (are) certified according to the requirements in 6.6 and
5.1.2 Any items of non-compliance shall be referred to the
at a level deemed acceptable to the contracting agency.
contracting agency representative for corrective action.
5.2 Ultrasonic Examination—All girth welds identified for
4. Significance and Use
mechanized ultrasonic examination should be examined for
4.1 This practice is intended primarily for the mechanized
100 % of their circumference and assessed in accordance with
ultrasonic examination of pipe girth welds used in the con-
the contracting agency’s acceptance criteria. Examination
struction of gas and oil pipelines. This practice, with appropri-
should be conducted in accordance with procedures approved
ate modifications due to changes in weld profile, may also be
by the contracting agency.
used to examine repaired welds. Manual techniques such as
described in Practice E 164 may also be used to examine
6. Ultrasonic Equipment
production or repaired welds. This practice, with appropriate
6.1 Ultrasonic System—The system shall provide an ad-
modifications, may also be used to examine other forms of butt
equate number of examination channels to ensure the complete
welds including long seams.
volumetric examination of the weld through thickness in one
4.2 Techniques used are to be based on zonal discrimination
circumferential scan. The instrument should provide a linear
whereby the weld is divided into approximately equal vertical
“A” scan presentation for each channel selected. The exami-
examination sections (zones) each being assessed by a pair of
nation channels will allow the volume of the weld scanned to
ultrasonic search units. See Fig. 1 for typical zones.
be assessed in accordance with the examination zones as
4.3 Thicknesses of material examined are normally 7 to 25
typically defined in Fig. 1. Instrument linearity should be
mm [0.28 to 1.00 in.] and pipe diameters 15 cm [6.0 in.] and
determined according to the procedures detailed in Practice
greater but this standard may apply to other thicknesses and
E 317, within six months of the intended end use date. The
diameters if the techniques can be proven to provide the
contractor shall retain a copy of the calibration certificate.
required zonal discrimination.
Instrument linearity should be such that the accuracy of any
4.4 Examination zones are typically 2 to 3 mm [0.08 to 0.12
indicated amplitude is within 5 % of the actual full scale
in.] in height. For most applications this will require the use of
amplitude. This should apply to both linear and logarithmic
contact focused search units to avoid interfering signals origi-
amplifiers. Each examination channel should be selective for:
nating from off-axis geometric reflectors and to avoid exces-
pulse-echo or through-transmission mode, gate position and
sive overlap with adjacent zones.
length for a minimum of two gates, and gain. Recording
5. Examination Methods
thresholds should be selectable to display signals between 0
5.1 Visual Examination—All welds should be visually ex- and 100 % of full screen height for simple amplitude and
amined after completion and assessed in accordance with the transit time recording and should be from 0 to 100 % for
requirements of surface conditions for ultrasonic examination. B-scan or “mapping” type recording of data. Two recordable
FIG. 1 Schematic Representation of Weld Zones and Discontinuities
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E 1961 – 98 (2003)
signal outputs per gate should be available, being either analog 6.5 Reference Standards—Reference standards shall be
or digital and representative of signal height and time of flight. usedtoestablishsensitivityandqualifytheexaminationsystem
These will be suitable for recording on a multi-channel for field examination and to monitor the system’s performance
recorder or computer data acquisition software display. on an ongoing basis. Reference standards shall be manufac-
6.2 Recording System: tured from a section of unflawed project-specific line pipe
6.2.1 A distance measuring circuit or device suitable for supplied by the contracting agency. The contracting agency
connection to the recorder or acquisition system shall provide will provide the contractor with details of project-specific weld
a means of electronically determining circumferential weld geometries and the reference reflectors required in specific
distance to an accuracy of typically 61 cm [0.4 in.] or better, areas. The contractor shall then provide a reference standard
as required by the contracting agency, over the circumference design that must be submitted to the contracting agency for
of the weld (an optical encoder is typically used for such approval before manufacturing. No design changes to the
distance measurement). Programmed scan lengths shall be reference standard shall be made without prior approval of the
sufficient to ensure all probes will travel the maximum circum- contracting agency.AnnexA3 provides an example of a typical
ferentialdistancerequiredforapipehavingadiameterwiththe reference standard.
maximum tolerance allowed by the contracting agency’s speci-
6.6 Personnel Qualification—If specified in the contractual
fication. For equipment with encoders traveling on a track or
agreement, personnel performing examinations to this practice
welding guide-band a correction factor will be incorporated to
shall be qualified in accordance with a nationally recognized
ensure the circumferential distance recorded on the chart
NDT personnel qualification practice or standard such as
corresponds to the search unit position on the pipe outer
ANSI/ASNT-CP-189, SNT-TC-1A, MIL-STD-410, or a simi-
surface.The recording or marking system shall clearly indicate
lar document and certified by the employer or certifying
the location of discontinuities relative to the marked starting
agency as applicable. The practice or standard used and its
position of the scan, with a 61 cm [0.4 in.] accuracy. There
applicable version shall be identified in the contractual agree-
shall be recordings from each search unit for weld discontinui- ment between the using parties.
ties and confirmation of the acoustic coupling arranged on the
6.7 Ultrasonic Examination Procedure—The contractor
chart or display in a manner acceptable to the contracting
should provide a procedure that will provide examination
agency.
criteria for the ultrasonic examination of the weld in a single
6.2.2 B-scan or other form of “mapping” displays will be
pass. It must allow for characteristic Hi/Lo fit-ups (edge
used for volumetric flaw detection and characterizations and
misalignment), weld shrinkage and be pipe-size specific. Pro-
Time of Flight Diffraction (TOFD) techniques may be added to
cedures submitted will allow zonal flaw characterization that
improve characterization and sizing. TOFD techniques may
permits use of the contracting agency’s engineering critical
augment pulse-echo techniques but shall not replace pulse-
assessment acceptance criteria. It should include but not be
echo techniques.
limited to describing the following requirements:
6.2.3 Where TOFD techniques are employed the recording
6.7.1 The mechanized variable speed scanner mountable on
system should be capable of a 256-level grayscale display and
mechanical welding bands or other tracking mechanism,
be capable of recording full R-F wave forms for the TOFD
6.7.2 The encoder capable of accurately indicating any flaw
search unit pairs.
location about the girth weld,
6.3 Coupling—The coupling shall be obtained by using a
6.7.3 Independently loaded ultrasonic search units mounted
medium suitable for the purpose. An environmentally safe
in an array that provides independent examination of the weld
wetting agent may be required to enhance acoustic coupling.
from both sides,
No residue should remain on the pipe surface after the liquid
6.7.4 Provisions for adjusting and maintaining the align-
has evaporated. For examination where ambient temperatures
ment of these search units,
arebelow0°C[32°F]amethylalcoholwasherfluidorasimilar
6.7.5 Provisions for recording the continuity of the cou-
medium may be used. This liquid medium may be recovered
pling,
and filtered for re-use. For examination where pipe cool-down
6.7.6 Provisions for ensuring the mechanical reliability of
mayberequiredafterwelding,watersprayorotheragentsmay
the equipment,
be used with contracting agency approval.
6.7.7 A technique summary stating beam angles, wave
6.4 Search Units:
types, search unit frequencies, beam sizes and profiles with
6.4.1 Each search unit shall be marked with a method to
sketches for each geometry to be examined,
identify the manufacturer’s name, search unit type, exit point,
6.7.8 Record analog or digital signals from the multi-
incident beam angle or refracted beam angle for a specific
7 channels to a common distance of rotation,
wedge/steel velocity ratio, frequency, and crystal size.
6.7.9 Provide permanent copy of the scans in an easily
6.4.2 The search unit array design shall be specific to the
interpretable format to meet archival and audit needs,
project where the examination is to be performed.
6.7.10 Provide construction and accuracy details of the
6.4.3 All search units shall be contoured to match the
reference standard,
curvature of the pipe surface.
6.7.11 Provide the standardization procedures to be used in
the field, and
6.7.12 Standardization checks should be established and
For phased array and EMAT probes, not all of the listed items may be
applicable. verified on a time or weld cycle defined by the contracting
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E 1961 – 98 (2003)
agency. System performance between standardization checks amplitude will be evaluated in accordance with the contracting
should be continually monitored for degradation. agency’s acceptance criteria. Porosity detection channels may
use a threshold for evaluation or patterns in mapping type
7. Ultrasonic Examination S
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