2010 SECTION V

ARTICLE 23, SE-273

STANDARD PRACTICE FOR ULTRASONIC

EXAMINATION OF THE WELD ZONE OF WELDED
PIPE AND TUBING
SE-273
[Identical with ASTM E 273-01 (R2005)]

1.

Scope
1.1 This practice describes general ultrasonic examination procedures for the detection of discontinuities in the
weld and adjacent heat affected zones of welded pipe and
tubing by scanning with relative motion between the search
unit and pipe or tube. When contact or unfocused immersion search units are employed, this practice is intended
for tubular products having specified outside diameters
2 in. (50 mm) and specified wall thicknesses of 18 in.
to 1116 in. (3 mm to 27 mm). When properly focused
immersion search units are employed, this practice may
also be applied to material of smaller diameter and thinner wall.

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.

NOTE 1: When contact or unfocused immersion search units are used,

precautions should be exercised when examining pipes or tubes near the
lower specified limits. Certain combinations of search unit size, frequency,
thinwall thicknesses, and small diameters could cause generation of
unwanted sound waves that may produce erroneous examination results.

Recommended Practice SNT-TC-1A Personnel Qualification and Certification in Nondestructive Testing

2.

Referenced Documents
2.1 ASTM Standards:

E 543 Practice for Agencies Performing Nondestructive

Testing
E 1316 Terminology for Nondestructive Examinations
2.2 ASNT Document

3.

Terminology
3.1 Definitions For definitions of terms used in this
practice, see Terminology E 1316.

1.2 All surfaces of material to be examined in accordance with this practice shall be clean from scale, dirt,
burrs, slag, spatter or other conditions that would interfere
with the examination results. The configuration of the weld
must be such that interfering signals are not generated by
reflections from it. Treatment of the inner surface and outer
surface weld beads such as trimming (scarfing) or rolling
is often required to remove protuberances that could result
in spurious reflections.

4.

Summary of Practices
4.1 A pulsed ultrasonic angle beam shall be propagated
in the wall of the pipe or tube by either the surface contact
or immersion method. Figure 1 illustrates the characteristic
oblique sound entry into the pipe wall for both contact and
immersion examination from one search unit.

1.3 This practice does not establish acceptance criteria,

they must be specified by the using parties.
1.4 The values stated in inch-pound units are to be
regarded as the standard. The SI equivalents are in parentheses and may be approximate.

NOTE 2: The immersion examination method may include tanks, wheel

search units, or bubbler systems.

4.2 The weld line shall be examined from both sides

to ensure detection of imperfections with a shape or orientation that produces a preferential direction of reflection.

1.5 This standard does not purport to address all of

the safety concerns, if any, associated with its use. It is
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2010 SECTION V

FIG. 1 ANGLE PROJECTION OF ULTRASONIC WAVE

5.

6.

Apparatus
5.1 The instruments and accessory equipment shall be
capable of producing, receiving, amplifying, and displaying electrical pulses at frequencies and pulse rates
deemed necessary by the using parties. They shall be capable of distinguishing the reference reflectors described in
Section 7 to the extent required in the standardization procedure outlined in Section 9.

Basis of Application
6.1 The following are items that require decision for
use of this practice:
6.1.1 Acceptance criteria,
6.1.2 Type, dimension, and number of reference
reflectors to be placed in the reference standard,
6.1.3 Standardization of examination sensitivity
intervals,

5.2 For pulse echo examination systems, the contact

or immersion search units should produce ultrasonic waves
that travel in the pipe or tube wall at a refracted angle of
from 35 deg to 70 deg and perpendicular to the weld
seam. For pitch/catch or through transmission examination
systems, orientation of the entry sound beam other than
perpendicular to the weld seam may be required.

6.1.4 Operator qualifications,

6.1.5 Qualification of NDT agency (as defined in
Practice E 543), if required. Practice E 543 may be used
for this agency qualification.
6.1.6 Examination frequency,
6.1.7 Pulse repetition rate,

5.3 Couplant A liquid such as water, oil, glycerin,

etc., capable of conducting ultrasonic vibrations from the
search unit to the pipe or tube shall be used. Rust inhibitors,
softeners, and wetting agents may be added to the couplant.
The couplant liquid with all additives should not be detrimental to the surface condition of the pipe or tubing and
should wet the surface. In examining electric-resistancewelded pipe, water-soluble oil used in cooling the pipe
serves as a satisfactory couplant.

6.1.8 Sound beam orientation and number of

beams used,
6.1.9 Procedure and use of distance amplitude compensation, and
6.1.10 Reporting of examination results.

7.

Personnel Qualification
7.1 Personnel performing the ultrasonic examination
shall be qualified and certified in accordance with ASNT
Recommended Practice SNT-TC-1A or an equivalent document, to establish their ability to conduct ultrasonic weld
examinations.

5.4 Distance Amplitude Compensation The use of

electronic methods to compensate for attenuation losses
as a function of ultrasonic metal travel distance may be
employed.
5.5 Search Units The search unit must be appropriately sized with respect to width and beam included angle
to achieve full wall thickness coverage. Where this can
not be achieved with a single search unit propagating in a
given direction, two or more search units may be used to
scan in each direction. The effective beam length of the
search units shall be such that reliable detection of all
reference reflectors is accomplished without exceeding the
noise limits of 9.2. The focal length of focused search
units shall be at least equal to the radius of the material
plus a suitable water path so that initial focus may be on
the tube or pipe central axis.

8.

Reference Standards
8.1 A reference standard, of sufficient length to allow
verification of system standardization, shall be prepared
from a length of pipe or tubing of the same nominal diameter and wall thickness, material, surface finish, and nominal
heat treatment as the material to be examined. The pipe
or tube selected for this purpose shall be free of discontinuities or other abnormal conditions that can cause interference with the detection of the reference reflectors. The
reference reflectors shall be selected to ensure uniform

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2010 SECTION V

FIG. 2 TYPICAL NOTCH LOCATIONS FOR

FUSION WELDED PIPE

ARTICLE 23, SE-273

FIG. 3. COMMON REFERENCE REFLECTORS

shall be placed in the weld-bead crown on both the outside

and inside surfaces.
8.1.2.1 When drilled holes are employed, they
shall be drilled radially from both the outside and inside
surfaces through 50% of the wall thickness at the weldbead crown or such other depth as agreed upon by the user
or contracting agency and separated by some distance that
guarantees a distinct and separate response from each one
[see Fig. 2(c) and Fig. 2(d)]. By agreement between the
purchaser and manufacturer, a hole drilled radially 100%
through the pipe wall may be used instead of the 50%
drilled hole [see Fig. 2(e)].

coverage of the weld at the sensitivity levels prescribed.

The reference reflectors most commonly used will consist
of machined notches and drilled holes as described in paragraph 8.2. All upset metal, burrs, etc., adjacent to the
reference reflectors, shall be removed.
8.1.1 Electric Resistance-Welded, Laser-Welded or
Butt-Welded Pipe Reference reflectors shall be placed
in the center of weld seam and in a line parallel to it unless
permission is obtained from the contracting or using agency
to place the reference reflectors elsewhere in the reference
standard. When longitudinal notches are used as reference
reflectors, they shall be placed on the outer and inner
surfaces of the reference standard and be separated by a
sufficient distance to ensure that the response from one
reflector does not interfere with that from the other.

NOTE 4: Fill 50% deep or through-holes with a waterproof filler such

as bees wax to prevent couplant entry. Otherwise, such entry could
produce erratic and/or spurious reflections.

8.1.2.2 Additional reflectors may be used to produce signals at reflection times that define weld-zone
extremities for the purpose of establishing alarm gate timing or other means of controlling the examination area.
Holes may be drilled radially 100% through the pipe wall
at the weld-zone edges.

NOTE 3: If reference reflectors are placed in a location other than the

centerline of the weld seam there is no assurance that the beam is penetrating the weld unless adequate signal response is obtained from the search
units scanning the reflector from both sides of the weld. The lower
amplitude of response from the two directions must be used in determining
the rejection threshold level. Positioning of automatic alarm gates must
be such as to respond to the signal from the reference reflector, but also
the signals originating from the reflections from discontinuities anywhere
in the weld seam itself.

8.2 The notch dimensions of length, depth, width, and

for Fig. 3(a) and Fig. 3(b) the included angle shall be
decided upon by the using party or parties. Figure 3 illustrates the commonly accepted notch configurations and the
dimensions to be measured.
8.2.1 The notch depth (h) shall be measured from the
adjacent surface to its maximum and minimum penetration.
Measurements may be made by optical, replicating or
mechanical, or other techniques. Notch depth is commonly
specified as a percent of nominal wall thickness with typical
values being 10%, 1212%, or 20%. A +0/-10% tolerance
is allowable on notch depths.

8.1.2 Fusion-Welded Pipe The reference reflectors shall be placed in the weld. When longitudinal notches
are used as reference reflectors, they shall be placed in the
crown of the fusion-weld bead as shown in Fig. 2(a). In
fusion-welded pipe containing both inside and outside surface weld beads, a longitudinal notch reference reflector
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8.2.2 The notch length (l) is considered to be the

dimension over which the specified depth is maintained.

line skew with respect to the search units) that can be

tolerated without exceeding the stability limits of 9.2 shall
be determined and provisions made in the scanning system
to ensure that the positions of the search units relative to
the weld line are maintained within that limit.

8.2.3 The width (w) of the notch has negligible effect

on standardization and is not a critical dimension.

9.

Standardization of Examination Sensitivity

10.

9.1 Using the reference standard specified in 8.1, the

equipment shall be adjusted to produce readily distinguished and clearly identifiable indications from both the
inner and outer reference reflectors. The relative response
to the inner and outer reflectors shall be as near equal as
possible. The lesser of the two responses shall be used as
the acceptance level.

Examination Procedure

10.1 Move the pipe or tubing past the search unit with
the weld in a fixed position with respect to the search unit.
Movement of the search unit with respect to a stationary
pipe is satisfactory. During examination, maintain distance
(d) and angle in Fig. 1 and the water path for immersion
examination as determined during adjustment of the examination sensitivity. Depending upon the degree of crookedness of the material to be examined, maintenance of
these parameters may require the use of followers or
other devices to enable a stable scan pattern to be maintained.

NOTE 5: Adjustment of water path, adjustment of distance (d) in Fig.

1 and angulation of the beam are used to achieve equality. It should be
noted however, that detection, or balancing of signals from both outer
surface and inner surface notches does not guarantee that examination
for radical defects is being achieved throughout the full wall thickness.
To effect such examination, especially in pipes and tubes with thicker
walls, it is necessary that the beam refraction angle and search unit size
(beam included angle for focused units) be selected to be compatible
with the ration of diameter-to-wall-thickness of the material as stated
in 5.5.

10.2 Certain examination systems using multiple search

units or multiple beam transducers compensate for distance
(d) changes and do not require strict adherence to the
maintenance of this dimension during examination. With
whatever arrangement is used, the allowable amount of
weld line skew shall be determined as in 9.4 and scanning
provisions made to prevent that limit from being exceeded.

9.2 Instrument sensitivity and scanning system parameters, such as search unit positioning and scanning speed,
shall be adjusted to produce signal levels that are repeatable
from all reference indicators within the limits described
below. If a strip chart or similar recorder is used, the
amplitude stability of all target indications shall be within
10% of full scale height (FSH) for several successive scans
of the reference standard under conditions simulating those
that will be used for the actual material examination. Peak
noise signal amplitudes observed during scanning over
a length of the reference standard equal to at least twice
the distance between outer surface and inner surface
notches, shall not exceed 40% of the minimum amplitude
of the signals from the reference indicators. If only an
audible or other alarm device is used to indicate the presence of rejectable indications, such devices shall be actuated reliably by all reference indicators for several
successive scans of the reference standard under conditions
simulating those that will be used for the actual material
examination.

10.3 Periodically check the examination sensitivity of

the equipment by running the reference standard through
the examination system. Make these checks prior to any
pipe or tubing examination, prior to equipment shutdown
after examination and at least every four hours during
continuous equipment operation. Anytime the equipment
does not present a clearly defined signal within 10% of that
obtained when the examination sensitivity was established,
restandardize the equipment in accordance with Section 8.
10.4 In the event that the equipment presents a signal
more than 10% below the standardization level, reexamine,
when standardization has been accomplished, all pipe and
tubing examined subsequent to the last preceding acceptable standardization.

9.3 When weld edge reflectors are used, the equipment

shall be adjusted to produce clearly identifiable responses
from them that are distinguishable from the reference
reflectors used to set rejection limits when the reference
standard is scanned in a manner simulating the production
examination of the pipe or tubing.

11.

Interpretation of Results

11.1 All indications that are equal to or greater than

the reference signals established during standardization as
described in Section 9, or as specified in Section 6, shall
be considered as representing defects that may be cause
for rejection of the pipe or tube.

9.4 During the standardization procedure, the extent of

variation in the dimension (d) (that is, the amount of weld
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11.2 If upon examination of the pipe or tube, no

rejectable indications are detected, the material shall be
considered as having passed the ultrasonic examination,
except as noted in 10.4.

12. Keywords
12.1 angle beam; longitudinal welded pipe; longitudinal welded tubing; nondestructive examination; ultrasonic
examination.

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ARTICLE 23, SE-273