1.

0 SCOPE:
This procedure describes the requirements for ultrasonic examination of full penetration CS /
LAS (Longitudinal, circumferential and nozzle) of thickness range from 10 mm to 300 mm with
use of pulse echo Contact technique, and the scanning shall be done manual.
2.0 APPLICABLE CODES, STANDARDS AND SPECIFICATIONS:
ASME Sec. VIII Div 2
ASME
Section V
BSI BS EN 473
BSI BS EN 12668-2, 3
ASTM E 317

3.0

: Ed.2007
: Ed.2007

QUALIFICATION OF PERSONNEL FOR EXAMINATIONS:

Trained, qualified and certified as Level-II or Level-III personnel in accordance with L&T written
practice for qualifying and administration of NDT personnel shall only be eligible for performing
ultrasonic testing activities.
Non-destructive testing personnel shall also hold an appropriate certificate of competence
Certification in Non- destructive testing which is recognized by the inspection authority or level
II in accordance with EN 473 or ISO 9712 or ASNT Level III.

4.0.

TEST SURFACE PREPARATION:

4.1

Base metal:
The base metal on each side of weld shall be free of weld spatters, surface irregularities or
foreign matters that might interfere with the examination.

4.2

Weld Metal:
Where the weld surface interferes with the examination, the weld must be ground &
smooth to permit the examination.

5.1

EQUIPMENT:

5.1

Apparatus:
A pulse echo-type of ultrasonic instrument shall be used. The instrument shall be capable
of operating at frequencies over the range of 1 MHz to 5 MHz and shall be equipped with a
stepped gain control in units of 2.0 dB or less. If the instrument has a damping control, it
shall not be used. The reject control shall be OFF position for all the examination. If in any
case damping and reject setting has been used it shall be mentioned in the report. Only
calibrated pulse-echo type of ultrasonic flaw detector shall be used for testing.
Calibration shall be made as well as the methods, tolerances and periodicity shall comply
the below table.
CALIBRATION OF APPARATUSES
Calibration of equipments:
Demonstration on qualification & calibration block, prior and after the weld inspection will
take care of probe angle, sensitivity & resolution criteria. (Any change in Personnel, PCS,
Probe angle, software, cable or any other essential variable re qualification scans shall be
performed)
5.1.1 SCREEN HEIGHT LINEARITY:
Screen height linearity shall be checked as per ASME Sec.V, clause T-461.1
Couple a straight beam probe to the IIW-V1 block and get multiple echoes from 25mm
back wall. Select any two echoes whose amplitudes are in the ratio of 2:1 with larger
echo set at 80% of full screen height. Without moving the search unit, adjust the gain to
successively set the larger indication from 100% to 20% of full screen height, in 10%
increments (or 2dB steps if a fine control is not available), and read the smaller indication
at each setting. The reading must be 50% of the larger amplitude, within 5% of full
screen height. The setting and readings must be estimated to nearest 1% of full screen
height.

5.1.2 AMPLITUDE CONTROL LINEARITY:

Amplitude control linearity shall be checked as per ASME Sec.V, clause T-461.2
Couple an angle beam probe to IIW V1 block and get multiple echoes from 100mm
quadrant. Select any echo and note its amplitude, reduce the gain by 6 dB and read the
amplitude of same indication . it must be 50% of the initial amplitude within 20 % of the
nominal amplitude ratio. Perform this exercise for full range of the gain. The settings and
readings must be estimated to the nearest 1% of full screen and the readings shall be as
shown in the following table.
AMPLITUDE CONTROL LINEARITY
INDICATION SET AT %
OF FULL SCREEN
HEIGHT
80 %
80 %
40 %
20 %
6.0.

dB
CONTROL
CHANGE
- 6 dB
-12 dB
+ 6 dB
+12 dB

INDICATION LIMITS %
OF
FULL SCREEN HEIGHT
32 to 48 %
16 to 24 %
64 to 96 %
64 to 96 %

SEARCH UNITS:

Frequency and size of the probe shall be selected depending upon thickness and acoustic
properties of the material to be tested. Angle shall be selected in such way that it hits major
reflecting surfaces approximately in right angles. Probe having refracted beam angle of
45/60/70 with frequency ranging from 1Mhz to 5Mhz for welds and longitudinal wave
straight beam probes with frequency ranging from 1Mhz to 5Mhz shall be used. Specific
technique sheets are made reflecting the specific probes used based on the material and weld
joint preparation. (Annexure-I to Annexure V)
6.1

CABLE:
Krautkramer make limo to mini limo or limo to limo cables of 2 mtr length or equivalent
shall be used.

7.0.

COUPLANT:

Couplant shall be grease, oil, water, cellulose based water or any other similar material, which
permits satisfactory transmission of ultrasonic waves. Same Couplant shall be used for
calibration as well as for testing. The Couplant, including additives, shall not be determined to
the material being examined.
Couplants used on Nickel base alloys shall not contain more than 250 ppm of sulfur.
Couplants used on austenitic stainless steel or titanium shall not contain more than 250 ppm
of halides (chlorides plus fluorides).
8.0. BASIC CALIBRATION BLOCK:
The standard calibration blocks e.g. IIW V1 and V2 shall be used for sweep range calibration.
The sensitivity setting shall be done using ASME basic calibration block and the reference
reflectors as per fig no.T-434.2.1 of Article-4 of Sec-V. The block size and reflector locations
shall be adequate to perform calibrations for the beam angle used. The basic calibration block
shall be curved for materials with diameter 500 mm and less. Single curved calibration blocks
can be used for testing of materials having curvatures ranging from 0.9 to 1.5 times the basic
calibration block diameter.

Fig 1.

Weld Thickness (t)

1 or Less
Over 1 through 2
Over 2 through 4
Over 4 through 6

Basic Calibration
Block Thickness
(T) in mm
19 or t
38 or t
75 or t
125 or t

Hole Diameter in mm
2.5
3
5
6

Where t is weld Thickness

General Notes:
a. Holes shall be drilled and reamed a minimum of 38 mm deep, essentially parallel to the
examination surface.
b. The tolerance for hole diameter shall be + 0.8mm. The tolerance for hole location through
the calibration block thickness shall be + 3.2mm.
c. For blocks less than 19mm in thickness, only the T SDH and surface notches are
required.
d. All holes may be located on the same face (side) of the calibration block provided care is
exercised to locate the holes far enough apart to prevent one hole from the indication of
another hole during calibration.
e. Minimum notch depth shall be 1.6% T and maximum notch depth shall be 2.2% T Plus
the thickness of cladding, if present
f. Maximum notch width is not critical. Notches may be made by EDM or with end mills up to
6.4mm in diameter.
g. The finish on the scanning surfaces of the block shall be representative of the scanning
surface finishes on the component to be examined.
h. The material from which block is fabricated shall be of the same product form and material
specification or equivalent P - No groupings. (P Nos 1, 3, 4 and 5 materials are considered
equivalent).
i. Prior to fabrication the block material shall be completely examined with a straight beam
search unit. Areas that contain an indication exceeding the remaining back wall reflection
shall be excluded from the beam paths required to reach have various calibration
reflectors.
j. Where component material is clad, the block shall be clad by same welding procedure as a
production part.
k. The calibration block shall receive at least the minimum tempering treatment required by
the material specification for the type and grade. If the calibration block contains welds
other than cladding, and the component weld at the time of the examination has been heat
treated, the block shall receive the same heat treatment.
l. Where block thickness + 25 mm spans two of the weld thickness ranges, the blocks used
shall be acceptable in those portions of each thickness range covered by 25 mm of the
calibration block thickness.
m. Where two or more base material thickness are involved the calibration block thickness
shall be determined by the minimum thickness of the weld.

n. For calibration blocks for dissimilar metal welds, the block material shall be based material
from which the testing shall be carried out. If the testing is to be carried out from both
sides, the calibration reflector shall be provided in both materials.
o. Post cleaning of Couplant shall be ensured after completion of testing.
9.0

IDENTIFICATION OF WELD EXAMINATION AREAS:

Weld locations and their identification shall be recorded on a weld map. For identification of
welds low stress stamps and/or vibratooling which indicate seam number and Spot
numbers shall be used.

10.0
10.1

CALIBRATION :

General calibration requirements:

a. Calibration shall include the complete ultrasonic system and shall be performed prior to
use of system in the thickness range under examination.
b. Calibration shall be performed from the surface (clad or unclad, convex or concave)
corresponding to the surface of the component from which the examination will be
performed.
c. The same couplant to be used during the examination shall be used for calibration.
d. The same contact wedges to be used during the examination shall be used for
calibration.
e. Any control which affects instrument linearity (e.g. filters, reject or clipping) shall be in
the same position for calibration, calibration checks, instrument linearity checks, and
examination.
f. The temperature differential between the calibration block and the examination surfaces
shall be within 25F (14C).
10.2 Straight beam calibration:
The standard calibration blocks e.g. IIW V1 and V2 shall be used for sweep range
calibration. Sensitivity calibration shall be done getting reflection from rear surface of the
material to be tested or by plotting Distance Amplitude correction curve using known
reference reflectors as follows:
a. Position the search unit for maximum response from the 1/4T SDH.
b.
Adjust the sensitivity control to provide an 80% ( + 5% ) FSH echo from the SDH. This is the
primary Ref level. Mark the peak on the screen.
c.
Position the search unit for maximum response from T SDH and mark the peak on the
screen without changing instrument setting.
d.
Position the search unit for maximum response from 3/4T SDH and mark the peak on the
screen.
e.
Connect the screen marks for SDHs and extend through the thickness to provide the
distance amplitude curve.
10.3.

Angle Beam Calibration:

The standard calibration blocks e.g. IIW V1 and V2 shall be used for sweep range
calibration. Sensitivity calibration shall be done by plotting Distance Amplitude Correction
curve using known reference reflectors as follows:
a.
Position the search unit for maximum response from the T SDH.
b.
Adjust the sensitivity control to provide an indication of 80% (+ 5%) of FSH echo from the
hole. Mark the peak of the indication on the screen.
c.
Position the search unit for maximum response from T SDH and mark the peak of the
indication on the screen without changing the instrument setting.
d.
Position the search unit for maximum response from the T SDH and mark the peak of
the indication on the screen.
e.
Connect the screen marks for the SDHs to provide a distance amplitude curve
10.4. Calibration correction for planar reflectors perpendicular to the examination
surface at or near the opposite surface:
The 45 deg. Angle beam shear wave reflects well from a corner reflector. However, mode
conversion and redirection of reflection occurs to part of the beam when a 60 deg. Angle
beam shear wave hits the same reflector. This problem also exists to a lesser degree
throughout the 50 deg. to 70 deg. Angle beam shear wave range. Therefore correction is
required in order to be equally critical of such an imperfection regardless of the
examination beam angle.

(a) Position the search unit for maximum amplitude from the square notch on the opposite
surface. Mark the peak of the indication with X on the screen near sweep line.
(b) The opposite surface square notch may give an indication 2 to 1 above DAC at 45 deg.
And DAC at 60 deg. Therefore, the indication from the square notch must be
considered when evaluating reflectors at the opposite surface.

11.0

CALIBRATION CONFIRMATION:

Calibration shall be verified on at least one of the reference reflectors in the basic calibration
block at the finish of each examination, every 4 hrs during the examination and when
examination personnel are changed, whichever occurs earlier.
If any distance range point has moved on the sweep line by more than 10% of the distance
reading or 5% of full sweep, whichever is greater, correct the distance range calibration and
note the correction in the examination record. All recorded indications since the last valid
calibration check shall be re-examined and their values shall be changed on the data sheets or
re-recorded.
If any sensitivity setting has changed by more than 20% or 2dB of its amplitude, correct the
sensitivity calibration and note the correction in the examination record, if the sensitivity
setting has decreased, all data sheets since the last valid calibration check shall be marked
void and the area covered by the voided data shall be re examined. If the sensitivity setting
has increased , all records since last valid calibration shall be re-examined and their values
shall be changed on the data sheets or re-recorded.
12.0

EXAMINATION:

Ultrasonic Examination shall be done using either by single or dual element search unit using
Contact Technique with manual scanning. Straight beam examination shall be done using
Longitudinal Wave and Angle beam examination shall use Shear Wave in the material. In case
of Bimetallic Joint Longitudinal Angle beam shall be used.
12.1

Area coverage:

Examination shall be conducted from one or both sides of weld surfaces or from combination of
surfaces so that 100% (full) volume of weld. In addition to the weld volume adjacent base
material of -inch or 1/2T, which ever is greater shall be examined. The angle beam search
unit or combination of angle beam search units that will be required to achieve full coverage.
(Refer annexure 1 to 5). Where geometry of the assembly does not allow examination from
both sides then any one of the alternatives as mentioned below shall be used.
a) Combination of angle beam and straight beam.
b) Straight beam in two directions at 90 deg. to each other.
c) Angle beam from one side of the weld using two different beam angles.
Special wedges, shoes or saddles may be used as and when needed depending on the
scanning surface/curvature of scanning surface and scanning techniques used. Post
examination cleaning of the test surface shall be carried out. The pulse repetition rate shall be
small enough to assure that a signal from a reflector located at the maximum distance in the
examination volume will arrive back at the search unit before the next pulse is placed on the
transducer.
12.2. Scanning Overlap and Speed:
Each pass of the search unit shall overlap a minimum of 10% of the active transducer
(piezoelectric element) dimension perpendicular to the direction of the scan. The rate of the
search unit movement (scanning speed) shall not exceed 6 inch per second (152 mm per
second). .
12.3

Straight Beam Examination:

The scanning of adjacent base material shall be performed to detect reflectors that might
affect interpretation of angle beam results. The result of this scanning is not to be used for
acceptance or rejection of the weld. Location and areas of such reflectors shall be recorded.
The weld and base metal shall be scanned, to the extent possible with the straight beam
search unit with backwall technique. The scanning shall be performed at a gain setting of at

least two times the primary reference level. Evaluation shall be performed with respect to the
primary reference level.

12.4

Angle Beam Examination:

12.4.1

Scanning For Reflectors Oriented Parallel To The Weld Seam:

The shear wave angle beam shall be directed approximately at right angles to the weld axis
from two directions wherever possible. The search unit shall be manipulated so that the
ultrasonic energy passes through the required volumes of the weld and adjacent base metal.
The scanning shall be performed at a gain setting of at least two times the primary reference
level. Evaluation shall be performed with respect to the primary reference level.
12.4.2Scanning For Reflectors Oriented Transverse To The Weld Seam:
The shear wave angle beam shall be directed essentially parallel to the weld axis. The search
unit shall be manipulated so that the angle beam passes through the required volumes of the
weld and the adjacent weld metal. The scanning shall be performed at a gain setting at least
two times the primary reference level. The search unit shall be rotated 180 and the
examination shall be repeated.

12.4.3 Scanning For Restricted Access Welds:

Welds that cannot be fully examined from two directions using the angle beam technique (e.g.
corner and tee joints) shall be also examined, if possible, with a straight beam technique.
These areas of restricted access shall be noted in the on the column NDT Remark in the
examination report refer Annexure VIII.
12.4.4 Inaccessible Welds:
Welds that cannot be examined from at least one side (edge) by using the angle beam
technique shall be noted in the examination report. For flange weld, the weld may be
examined with a straight beam or low angle longitudinal wave from the flange face, provided
the examination volume shall be covered.

13.0

EVALUATION:

All evaluation shall be carried out at primary reference level. Any imperfection that causes an
indication in excess of 20% of DAC shall be investigated to the extent that it can be evaluated.
For acceptance or rejection refer Cl.12.0.
It is recognized that not all ultrasonic reflectors indicate flaws, since certain metallurgical
discontinuities and geometric conditions may produce indications that are not relevant.
Included in this category are plate segregates in the heat-affected zone that become reflective
after fabrication. Under straight beam examination, these may appear as spot or line
indications. Under angle beam examination, indications that are determined to originate from
surface conditions (such as weld root geometry) or variations in metallurgical structure in
austenitic materials (such as the automatic-to-manual weld clad interface) may be classified as
geometric indications. The identity, maximum amplitude, location and extent of reflector
causing a geometric indication shall be recorded. The following steps shall be taken to classify
an indication as geometric:
a. Interpret the area containing the reflector in accordance with the applicable examination
procedure.
b. Plot and verify the reflector co-ordinates. Prepare a cross-sectional sketch showing the
reflector position and surface discontinuities such as root and counter bore.
c. Review fabrication or weld preparation drawings. Other ultrasonic techniques or
nondestructive examination methods may be helpful in determining a reflectors true
position, size, and orientation.
14.0

SIZING OF DISCONTINUITY:
Sizing of discontinuity shall be done as follows:

a. Maximize the response echo and centered on this portion, search unit shall be moved in
all directions, till the response of indication is reduced to 50% of its original echo height.
b. Mark to points on either side, and evaluate the maximum length of separation between
two such points.
c. This maximum distance shall be considered as defect size.
15.0

ACCEPTANCE / REJECTION STANDARDS:

The acceptance and rejection criteria shall as follows

Imperfections that are interpreted to be cracks, lack of fusion or incomplete penetration are
unacceptable regardless of length.
All other linear type imperfection is unacceptable if the amplitude exceeds the reference level
and the length of the imperfection exceeds the following:
inch (6 mm) for t up to inch (19 mm)
1/3 t for t from inch (19 mm) to 2 inch (57 mm)
inch (19 mm) for t over 2 inch (57mm)
Where t is the thickness of the weld excluding any allowable reinforcement. For a butt weld
joining two members having different thickness at the weld t is the thinner of the two
thicknesses. If a full penetration weld includes a fillet weld, the thickness of the throat of the
fillet shall be included in t.

16.0

EXAMINATION OF REPAIRS:

All repaired areas shall be re-examined by the same procedure as used for the original
detection of the discontinuity.
17.0

REPORT OF EXAMINATION:

A report of the examination shall be made as per L&T standard format( Refer Annexure 6A)
and shall contain procedure No, & revision, Instrument make and model, probe details,
couplant, cables, calibration details, surface, weld details; technique followed, settings used.
Non-Rejectable indications:
All reflections from uncorrected areas having responses, which exceeds 50% of the primary
reference level. This record shall locate each area, the response level, the dimensions, the
depth below the surface, and the classification.
Rejectable indication:
Rejectable indications shall be recorded, as a minimum the type of indication (Crack, LOF, LOP,
slag etc.), location and extent shall be recorded. Refer Annexure 6B
In addition, a record of repaired areas shall be noted as well as the results of the reexamination of the repaired areas.

ANNEXURE 1

TYPE

1.1.
MAKE

SEARCH UNIT DETAILS

CRYSTAL
DOUBLE /
ANGLE
SIZE
SINGLE

FREQ.

MODE

WB 45 2E

KRAUTKRAMER

20 X 22 MM

SINGLE

450

2 MHz

TRANS

WB 60 2E

KRAUTKRAMER

20 X 22 MM

SINGLE

600

2 MHz

TRANS

2 MHz

TRANS

WB 70 2E

KRAUTKRAMER

20 X 22 MM

SINGLE

70

B2SN

KRAUTKRAMER

24 MM DIA.

SINGLE

00

2 MHz

LONG

4 MHz

LONG

SEB4E

KRAUTKRAMER

24 MM DIA.

DOUBLE

EQUIPMENT

PULSE ECHO ULTRASONIC EQUIPMENT WITH CALIBRATED GAIN CONTROL.

REFERENCE
AS PER FIGURE 1 OF PAGE NO. 5
BLOCK
REMARKS
Equivalent probes of other make may be used in place of above probes.
For partial penetration weld joint wherever accessible longitudinal scanning shall be
carried out from both surfaces.
Due to curvature where 700 probes is not covering the full weld 600 probes shall be
used in addition to 700

Annexure 2

SEARCH UNIT DETAILS

TYPE

1.2.
MAKE

CRYSTAL
SIZE

DOUBLE /
SINGLE

ANGLE

FREQ.

MODE

MSEB 4E

KRAUTKRAMER

10 MM DIA

DOUBLE

00

4 MHz

LONG

MWB 45 4E

KRAUTKRAMER

8 X 9 MM

SINGLE

450

4 MHz

TRANS

SINGLE

4 MHz

TRANS

MWB 60 4E

KRAUTKRAMER

8 X 9 MM

60

MWB 70 4E

KRAUTKRAMER

8 X 9 MM

SINGLE

70

4 MHz

TRANS

MB4F

KRAUTKRAMER

10 MM DIA

SINGLE

00

4 MHz

LONG

EQUIPMENT

PULSE ECHO ULTRASONIC EQUIPMENT WITH CALIBRATED GAIN CONTROL.

REFERENCE
BLOCK

AS PER FIGURE 1 OF PAGE NO. 5

REMARKS
Equivalent probes of other make may be used in place of above probes.
For partial penetration weld joint wherever accessible longitudinal scanning shall be
carried out from both surfaces.

Annexure - 3
SEARCH UNIT DETAILS
TYPE

1.3.
MAKE

CRYSTAL
SIZE

DOUBLE /
SINGLE

ANGLE

FREQ.

MODE

MB 4E

KRAUTKRAMER

10 MM DIA

SINGLE

00

4 MHz

LONG

WB 45 4E

KRAUTKRAMER

20 X 22 MM

SINGLE

450

4 MHz

TRANS

SINGLE

60

4MHz

TRANS

4 MHz

TRANS

2 MHz

LONG

WB 60 4E

KRAUTKRAMER

20 X 22 MM

WB 70 4E

KRAUTKRAMER

20 X 22 MM

SINGLE

70

B2SE

KRAUTKRAMER

24 MM DIA

SINGLE

00

MWB 45 2E
EQUIPMENT

KRAUTKRAMER
8 X 9 MM
SINGLE
45
4 MHz
TRANS
PULSE ECHO ULTRASONIC EQUIPMENT WITH CALIBRATED GAIN CONTROL.

REFERENCE
AS PER FIGURE 1 OF PAGE NO. 5
BLOCK
REMARKS
Equivalent probes of other make may be used in place of above probes.
For partial penetration weld joint wherever accessible longitudinal scanning shall be
carried out from both surfaces.

Annexure - 4

SEARCH UNIT DETAILS

TYPE

1.4.
MAKE

CRYSTAL
SIZE

DOUBLE /
SINGLE

ANGLE

FREQ.

MODE

MB 4E

KRAUTKRAMER

10 MM DIA

DOUBLE

00

4 MHz

LONG

MWB 45 4E

KRAUTKRAMER

8 X 9 MM

SINGLE

450

4 MHz

TRANS

MWB 60 4E

KRAUTKRAMER

8 X 9 MM

SINGLE

60

4 MHz

TRANS

MWB 70 4E

KRAUTKRAMER

8 X 9 MM

SINGLE

700

4 MHz

TRANS

EQUIPMENT

PULSE ECHO ULTRASONIC EQUIPMENT WITH CALIBRATED GAIN

CONTROL.

REFERENCE
AS PER AS FIGURE - 1 OF PAGE NO. 5
BLOCK
REMARKS
Equivalent probes of other make may be used in place of above probes.
For partial penetration weld joint wherever accessible longitudinal scanning shall be
carried out from both surfaces.

ANNE
XURE - 5
SEARCH UNIT DETAILS
TYPE
MB 4E
MWB 45 4E
MWB 70 4E
WB 45 2E
MSW-QC-5**
WB 70 2E
EQUIPMENT

1.5.
MAK
E

CRYSTAL
SIZE

DOUBLE /
SINGLE

ANGLE

FREQ.

MODE

4
LONG
MHz
4
KRAUTKRAMER
8 X 9 MM
SINGLE
450
TRANS
MHz
4
KRAUTKRAMER
8 X 9 MM
SINGLE
700
TRANS
MHz
2
KRAUTKRAMER
20 X 22 MM
SINGLE
TRANS
MHz
5
KRAUTKRAMER
6 MM DIA
SINGLE 450, 600, 700
TRANS
MHz
2
KRAUTKRAMER
20 X 22 MM
SINGLE
700
TRANS
MHz
PULSE ECHO ULTRASONIC EQUIPMENT WITH CALIBRATED GAIN
CONTROL.
KRAUTKRAMER

10 MM DIA

SINGLE

00

REFERENCE
AS PER FIGURE 1 0F PAGE NO. 5
BLOCK
REMARKS
Equivalent probes of other make may be used in place of above probes.
MSW-QC-5 probes shall be used on very small dia. noz welds where MWB probes can
not be used.
For partial penetration weld joint wherever accessible longitudinal scanning shall be
carried out from both surfaces.