05 Ultrasonic Test Procedure 500405
05 Ultrasonic Test Procedure 500405
05 Ultrasonic Test Procedure 500405
PROCEDURE
CONTENS
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1. SCOPE
2. APPLICATION
3. APPLICABLE DOCUMENTS
4. RESPONSIBILITIES
5. TEST APPARATUS
6. CALIBRATION
8. TEST
10. EVALUATIONS
12. NONCONFORMANCE
1 SCOPE
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1.1 This procedure defines the procedures and techniques of the ultrasonic test to detect cracks and other
discontinuities, in weldments when allowed within the provisions of
EN 583-1/2/3
EN 12223- EN 27963
EN 1714 EN 1713 EN 1712
ASME I PW-11.2 and
ASME B31.1 Table 136.4 (Note 3).
1.2 This procedure shall be used in conjunction with the applicable technical and construction specifications,
drawings, codes and standards.
2 APPLICATIONS
2.1 This procedure shall be applied to all ultrasonic test of the weldments fabricated for the subject project.
3 APPLICABLE DOCUMENTS
3.1 ASME V
3.2 ASME Sec I/ASME B31.1
3.3 EN 583-1/2/3
3.4 EN 12223- EN 27963
3.5 EN 1714 EN 1713 EN 1712
4 RESPONSIBILITIES
4.1 The N.D.E Level I shall conduct the test under the supervision of certified level - II (SNT- TC-1A) or EN 473
and he shall prepare the Ultrasonic Test Report/Record in accordance with this procedure, drawing and
specifications.
4.2 The N.D.E. Level II shall interpret or evaluate the test results.
5 TEST APPARATUS
5.1 Instruments
5.1.1 The ultrasonic instrument shall be of the pulse - echo type suitable for use with
transducers oscillating at frequencies between 1 to 6 MHz. The display will be "A"-
scan presentation.
5.1.2 The horizontal linearity shall be qualified over the full sound path distance to be used in testing.
5.1.3 The test instrument shall include internal stabilization so that after warm up, no variation in response greater
than 1 dB occurs with supply voltage change of 15 % nominal or in the case of a battery, the charge operating life.
5.1.4 The test instrument shall have a calibrated gain control adjustable in discrete 1or 2 dB steps over a range
of at least 60 dB. The accuracy of the calibrated gain control settings shall be within 1 dB.
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1) The straight beam search unit transducers shall have an active area of not less than 9.6 mm dia., or 10x10
square, nor more than 25 mm dia., or 25x25 square.
1 ) The angle beam search units shall consist of a transducer and an angled wedge.
2 ) The transducer crystal size shall be 8x9 mm to 25x25 mm square or rectangular in shape.
4 ) Angle beam search units shall produce a sound beam in the material being tested within 2 degrees of the
stated angle, i.e.70 degree, 60 degree, or 45 degree
5.2.3 The search units both straight and angled beam shall be capable of resolving the three reflections on the V1
resolution block
5.2.4 Different size or frequency of search unit may be used for better results
1 ) The International Institute of Welding (IIW) ultrasonic standard block or V1 block shall be the standard
used for distance calibration, sensitivity calibration,check to exit point and actual fracted angle of angled beam
search units.
2 ) The miniature block (V2 block) shall be used for distance calibration instead of the IIW/V1 block in the
field.
3 ) Other suitable blocks can be used for the purposes of 5.3.1 (1) and (2)
The calibration block(s), shall be used to establish sensitivity and distance amplitude correction (DAC) curve.
5.4 Couplants
5.4.1 A couplant material shall be used between the search unit and the test material, such as light oil, grease,
glycerin or glue mixed with water to a suitable consistency.
6 CALIBRATION
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6.1.1 The horizontal linearity of the test instrument shall be calibrated after each 40 hours of instrument use. (EN
12668-1/2 )
6.1.2 The instrument gain control shall meet the requirements of 5.1.4 and shall be checked for correct calibration
at two month intervals.
6.1.3 Each angle beam search unit shall be checked after each eight hours of use to determine exit point and actual
refracted angle.
6.2.1 All calibrations and Tests shall be made with the reject (or suppression) control turn off.
6.2.2 Calibration for horizontal sweep, DAC construction and establishment of the sensitivity shall be made by the
ultrasonic operator just prior to and at the location of the testing of each location.
6.2.4 Construction of Distance Amplitude Correction (DAC) Curve for Angle Beam Testing.
The calibration block which will be use for DAC curve is determined acc. to EN 583-2 or ASME V Article-5, T-
542.2. and figure T-542.2.1
1 ) Position the search unit for maximum response from the 1/8, 2/8 and 3/8 vee path which gives the highest
amplitude.
2 ) Adjust the sensitivity control to provide 80 % of full screen height, and mark the peak on the screen.
3 ) Decrease 6dB of the above adjusted sensitivity control and mark the peak on the screen.
4 ) Position the search unit for maximum response from another vee path indication, and mark the peak on
the screen.
5 )Repeat the above step 3).
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The sensitivity shall be adjusted at a location free of indication so that the first back reflection from the base
material shall be 50 to 75 % of full screen height.
The sensitivity shall be adjusted at a location of primary reference sensitivity level (80 % of FSH) of the DAC
curve.
6.4 Re calibration
6.4.1 Re calibration shall be made after a change of operators at 30 minute maximum time intervals or when the
electrical circuitry is disturbed in any way including the following:
1 ) Transducer change
2 ) Battery change
6.4.2 Re calibration procedures are the same as para, 6.2 and 6.3.
7.2The volume of weld to be examined is the weld volume plus 0.5” (12.7 mm) on either side of the welds,
regarded as heat affected zone.
7.3The base metal on each side of the weldseam shall be scanned with a straight-beam search unit as required by
ASME V para. T-441.3.2.2.b.
7.4 The volume of weld to be examined shall be scanned for reflectors oriented parallel to the weld, with angle
beam probes, so that each point of the complete volume of weld to be examined shall be reached by two angle
beams, with a difference in angle of more than 10º. The surface breaking zone on the inside of vessel, shall in
addition be examined with another two angle beam probes, or in total with four different angles.
7.5 The volume of weld to be examined shall be scanned for reflectors oriented transverse to the weld, with angle
beam probes, oriented at ca.15° to the weld axes, from two opposite directions from either side of the
weldseam. The same series of search units used for the different scans for defects oriented parallel to the weld
shall at least be used.
The surface breaking zone shall also be examined with a beam orientation of 0º to the weld axes.
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7.6 Each scan of weld-volume and heat affected zone shall be divided into a top-half-scan (T), a bottom-half-scan
(B), a penetration (P) or root scan(R) and an inner surface breaking-scan (S).
8 TEST
8.1.1 All surfaces to which a search unit is applied shall be free of weld spatter, dirt, grease, oil (except couplant),
paint and loose scale and shall have a contour permitting adequate coupling.
8.1.2 The outside weld crown can be left on. 100 mm or the widht required for scanning adjacent to the weld, on
the shell and/or head, shall be smooth, with an andulation smaller than 0.3 mm over 25 mm. A roughness of 250
inch CLA or sand paper grain size of 80 is sufficent. The as painted conditions will normally satisfy these
requirements.
8.2.1 Scanning surfaces are the surfaces beside the weld from which the examination is performed.
8.2.2 The surface above the weld, when the direction is seen from left to right, is called face A, the other one side
face B.
8.2.3 This specification only applies to welds examined from the external surface of the vessel.
8.3.2 The Z- co-ordinates zero point is the inside surface of the vessel, with the positive direction into the weld.
The entire base metal through which ultrasound will travel to test the weld shall be tested for laminar reflectors using a
straight beam search unit conforming to the requirements of 5.2.1 and calibrated in accordance with 6.2.3 and 6.3.1.
Welds shall be tested using an angle beam search unit conforming to the requirements of 5.2.2 with the
calibration in accordance with 6.2.3, 6.2.4 and 6.3.2
8.5 Scanning
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1) Scanning shall be performed at a gain setting of at least two times (6dB) the reference level.
2 ) During scanning only the gain controls may be adjusted. Any adjustments to the other controls shall
require re calibration.
Scanning Pattern
1) Longitudinal discontinuities
Movement A : Rotating angle A = 10 deg.
Movement B : Scanning distance B shall be such that the section of the weld being tested will be
covered.
Movement C : Progression distance C shall be approximately 1/2 the width of the transducer being used.
Movements A,B and C are combined in one scanning pattern.
2 ) Transverse discontinuities
Scanning pattern D :(When welds are ground flush.)
Scanning pattern E :(When welds are not ground flush.)
Scanning angle E = 15 deg. maximum.
The scanning pattern is to be such that the full weld section is covered.
9.1 Any one of the known sizing methods can be used within their typical restriction;
9.1.1 20dBPB-(plotted beam) or 10dBPB-drop systems can be used for sizing in the VERTICAL PLANE and
LENGHT DETERMINATION for ALL INDICATIONS.
9.1.2 DGS/AVG: shall only be used for VERY SMALL PORE-LIKE INDICATIONS.
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9.1.3 MA: maximum amplitude sizing can be used for LENGHT DETERMINATION of LONGER
INDICATIONS.
9.1.4 6dBCB: 6dB-drop with the central beam (a good system for large lamination sizing) is NOT ACCEPTED for
sizing in this specification seen the small dimensions of the possible indications.
9.1.5 6dBPB: 6dB-drop with a plotted beam can be used for sizing in the VERTICAL AND HORIZONTAL
PLANE for SHORT INDICATIONS.
For each scan, attenuation shall be measured and compared with the one of the calibration block.
Attenuation shall be measured with two equal probes in the T-R mode, comparing the signals at skip distance
with DAC – curves.
The difference between the calibration block surface and the vessel surface shall be compensated by the surface
transfer losses.
This measurement shall be done at skip distance on the calibration block and the surface under test, at the same
moment as the attenuation measurement for each scan.
10 EVALUATION
1 ) Indications that are equal to or greater than the original back reflection.
The indications greater than 20 % of the primary reference sensitivity level shall be investigated to the
extent.
10.2 Acceptance Criteria: EN 1712 / ASME Sec I (PW-52)/ASME B31.1 Chapter VI clause 136.4.6
11 ACCEPTANCE CRITERIA
(a)Technique and standards for ultrasonic examination shall follow Section V, Article 5.
(b)The Manufacturer’s report, as required by T-590 of Section V, shall be retained by the Manufacturer for a
minimum of 5 years.
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(c)Acceptance-rejection standards. imperfections that cause an indication greater than 20% of the reference level
shall be investigated to the extent that the ultrasonic examination personnel can determine their shape, and
location, and evaluate them in terms of (a) and (b).
(e)Other imperfections are unacceptable if the indication exceeds the reference level and their length exceeds the
following:
where t is the thickness of the weld being examined. If the weld joins two members having different thicknesses
at the weld, t is the thickness.
(a)Acceptance Standards. Welds that are shown by ultrasonic examination to have discontinuities which produce an
indication greater than 20% of the reference level shall be investigated to the extent that ultrasonic examination
personnel can determine their shape, identity, and location so that they may evaluate each discontinuity for
acceptance in accordance with (1) and (2) below.
(1)Discontinuity evaluated as being cracks, lack of fusion, or incomplete penetration are unacceptable regardless of
length.
(2)Other discontinuities are unacceptable if the indication exceeds the reference level and their length exceeds the
following;
12 NON CONFORMANCE
12.1 Nonconformances identified by the ultrasonic test shall be reported in accordance with the project
documentation and this procedure.
12.2 Nacceptable defects shall be repaired, and re examined by the same ultrasonic technique and procedure used
originally.
13 REPORTS / RECORDS
All indications shall be recorded to the ultrasonic test report/record by the examiner who carried out the Test.
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