inspectas ut procedure

ULTRASONIC EXAMINATION

Procedure: IAS_ UTE Document No.: IASC- 002 Issued:

5 March 2008 of 25

Inspection Advanced Services Co. Ltd.

Head Office: P.O. Box 36400 Al Jubail Industrial City - 31361 – K.S.A Tel: +966 (3) 340 11 00 Fax:+966 (3) 340 71 82

E-mail: [email protected]

This document is property of Inspection Advanced Services Co. ltd. It must not be reproduced, copied or handed out to a third party without the written consent of Inspection Advanced Services Co. ltd.

TABLE OF CONTENTS PAGE

1.0 SCOPE 4 2.0 RERENCES 4 3.0 PERSONNEL 4 4.0 EQUIPMENT AND MATERIAL 4 4.1 UT Equipment 4 4.2 Probe 4 4.3 Calibration Blocks 4 4.4 Couplant 5 4.5 Accessories 5 5.0 CALIBRATION 5 5.1 Screen Height linearity 5 5.2 Amplitude Control Linearity 6 5.3 Range Calibration 6 5.3.1 Angle Beam 6

5.3.2 Straight Beam 6

5.4 Distance Amplitude Correction 7 5.4.1 Angle Beam 7

5.4.2 Calibration Correction 7

5.4.3 Straight Beam 8

6.0 TEST SEQUENCE 8 6.1 Selection of Probes and Calibration 8 6.1.1 Probes 8

6.1.2 Calibration Blocks 8

6.2 Calibration 9 6.3 Surface Conditions 9

6.4 Mark Reference Line 9



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6.5 Scanning 9 6.5.1 Straight Beam 9

6.5.2 Angle Beam 10

6.6 Recording 10 6.7 Calibration Confirmation 11 6.7.1 Sweep Range Correction 11

6.7.2 DAC Correction 11

6.8 Post Examination Cleaning 11 7.0 INTERPRETATION AND EVALUATION 11 7.1 Method for Discrimination Geometric From Flaw Indication 11 7.2 Acceptance Standards 11

8.0 SAFETY 12 9.0 TECHNIQUE SHEET WITH SET UP SKETCHES 13

9.1 Calibration Blocks 13 9.1.1 Basic Calibration Block 13 9.1.2 Calibration Block for Pipe Weld 14

9.2 Sweep Range Calibration 15 9.2.1 Angle Beam 15 9.2.2 Straight Beam 16 9.3 Testing Techniques (sketches) 17

9.3.1 Basic Techniques For Angle Beam Scanning 18 ff 10.0 DOCUMENTATION 24 10.1 Test Report Format 24 & 25



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1.0 SCOPE This procedure is applicable for the Ultrasonic Examination of butt welds using pulse echo, contact, manual technique based on the requirements of ASME Section VIII Division 1 and its references. This procedure is applicable for thicknesses from 6mm to 100mm.

2.0 REFERENCES ASME SECTION V 2004, Article 4 with 2006 addenda ASME SECTION VIII Division I 2004 with 2006 addenda ASTM STANDARD E-164 – 2003

3.0 UT PERSONNEL Personnel performing, interpreting and evaluating UT using this procedure must be a Certified Level II in UT in accordance with IASC-001. In the case of Saudi Aramco projects, personnel shall also have passed the Aramco Verification exam in UT.

4.0 EQUIPMENT AND MATERIAL

4.1 UT Flaw Detectors The following equipment may be used

manufacturer Device type Krautkramer (GE) USM 25, USM 35 Digital Panamertics (Olympus) EPOCH IV series digital

Sonatest SiteScan 140 digital Karl Deutsch Echograph 1090 digital

All equipment shall be from Aramco approved equipment list.

4.2 Probes Angle beam probes with refracted angle of 45°, 60°, and 70° in steel as well as normal beam probes must be used. It is preferable to use probes/cables from the same brand. The actual angle is determined by the test variables.

4.3 Calibration Blocks The following calibration blocks are to be used:

1. IIW or IIW type V1 and V2 blocks and 2. ASME basic calibrations block (Refer to Section 10.1). 3. Calibration Block for welds in ferritic pipes (Refer to Section 10.1)



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4.4 Couplant Cellulose glue or commercially available couplants e.g. ZG5, Ultragel or oil should be used. The same couplant must be used for calibration and actual scanning.

4.5 Accessories Cables, adapters etc....

5.0 CALIBRATION

5.1 Screen Height Linearity Position an angle beam transducer as shown in Figure C below such that

indications can be obtained from the 1/2 and 3/4 T holes in the basic calibration block.

Adjust the position of the search unit to give 2:1 ratio of amplitude between the two indications.

Set the larger of the two indications at 80% of Full Screen Height (FSH). Without moving the search unit adjust the gain in steps of 2 dB to

successively set the larger of the indications from 100% to 20% of FSH. Record the amplitude of both indications. Evaluate the results in terms of the following paragraph.

The lower amplitude must be 50% of the higher amplitude within 5% of FSH. This Calibration shall be performed every three months in the Company base; and at the beginning of each assignment on Site.

FIGURE C



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5.2 Amplitude Control Linearity

Position an angle beam transducer as shown in Figure C above; such that the indication obtained from the 1/2 T hole in the basic calibration block is peaked on the screen.

Increase/decrease the dB as shown in Table 2 below. Record the amplitude of the indication. Evaluate the results in terms of the following paragraph.

The amplitude must fall within the limits specified in Table 2 below.

Table 2

Serial Indication set at % of FSH

dB Control change

Indication limits % of FSH

1 80 -6 32 to 48 2 80 -12 16 to 24 3 40 6 64 to 96 4 20 12 64 to 96

This Calibration shall be performed at the beginning of each examination.

5.3 Range Calibration This Calibration must be performed at the beginning of each shift and verified at the end of the shift. This must be repeated if any part of the UT system is changed. Refer to figure/s in Section 10.2.

5.3.1 Angle Beam Set up the instrument for angle beam examination. Verify the beam exit point and beam angle using a V1 block. Mark the beam index on the probe if it has changed. Note down the actual refracted angle Enter the refracted angle into the instrument. Position the search unit for the maximum first indication from the 1/4 T side drilled hole.

Adjust the left edge of this indication to line 2 on the screen (i.e. to 20% of sweep) with the delay control.

Position the search unit for the maximum first indication from the 3/4 T side drilled hole.



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Adjust the left edge of this indication to line 6 on the screen (i.e. to 60% of sweep) with the range control.

Repeat the range and delay control adjustment until the 1/4 T and 3/4 T hole reflections start at 2 and 6 (i.e. 20% and 60%)

Position the search unit for a maximum response from the square notch on the opposite surface. The indication will appear on line 8 (i.e. 80%).

Now using the instrument menu enter the thickness of the test object. Now the instrument range is calibrated with 2 divisions on the sweep equal

to1/4 T.

5.3.2 Straight Beam Set up the instrument for straight beam examination. Position the search unit for the maximum first indication from the 1/4 T side drilled hole.

Adjust the left edge of this indication to line 2 on the screen (i.e. to 20% of sweep) with the delay control.

Position the search unit for the maximum first indication from the 3/4 T side drilled hole.

Adjust the left edge of this indication to line 6 on the screen (i.e. to 60% of sweep) with the range control.

Repeat the range and delay control adjustment until the 1/4 T and 3/4 T hole reflections start at 2 and 6 (i.e.20% and 60%).

Now using the instrument menu enter the thickness of the job. Position the search unit for a maximum response from the square notch on the opposite surface. The indication will appear on line 8 (i.e. 80%)

Now the instrument range is calibrated with 2 divisions on the sweep equal to 1/4 T. The digital depth readout is also activated.

5.4 Distance Amplitude Correction (DAC) This Calibration must be performed at the beginning of each shift and verified at the end of each shift. This calibration must be repeated if any part of the UT system is changed.

5.4.1 Angle Beam Position the search unit for maximum response from the hole which gives the highest amplitude

Adjust the sensitivity control (gain) to provide 80% FSH (+ or - 5% FSH). Enter this point into the instrument as one DAC point.



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Position the search unit for the maximum indication from the other holes and enter those points also as DAC points.

Position the search unit for maximum amplitude from 3/4 T hole after bouncing from opposite face. Enter this point also into the instrument.

5.4.2 Calibration Correction For planar reflectors perpendicular to examination surface at or near opposite surface the following must be considered:

Position the search unit for maximum response from the square notch on the opposite side. This should appear at sweep line 8.

Mark the peak indication on the screen. This indication may be 2:1 above DAC for 45° probe and 1/2 DAC for 60°. This must be taken into account while evaluating reflectors located at or near the opposite surface

5.4.3 Straight Beam

Position the search unit for maximum response from the hole which gives the highest amplitude

Adjust the sensitivity control (gain) to provide 80% FSH (+ or - 5% FSH). Enter this point into the instrument as one DAC point. Position the search unit for the maximum indication from the other holes and enter those points also as DAC points.

Position the search unit for maximum amplitude from 3/4 T hole after bouncing from opposite face. Enter this point also into the instrument.

6.0 TEST SEQUENCE

6.1 Selection of Probes and Calibration Blocks

6.1.1 Probes

2.25 MHz nominal frequency probe are recommended. It is also allowed to choose other frequencies between 1.0 and 5 MHz. For flat surfaces use a ½”to 1” diameter probe. For curved surfaces below 18" diameter use a 10mm diameter probe.



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6.1.2 Calibration Blocks

For welds in Pressure Vessels above 20" in OD the ASME Basic calibration block must be used. For welds in pipes use the Calibration Block for pipe welds. For Vessel joints with Diameter less than 20" use a curved block. A single curved block may be used for calibration on surfaces in the range of curvature from 0.9 to 1.5 times the calibration block diameter. The thickness of the Calibration Block/s shall be in accordance with Figure x in Section 10.1. Where two or more base material thicknesses are involved the calibration Block thickness shall be based on the average thickness of the weld. The material for the Blocks shall be of the same product form and equivalent P Number grouping as one of the materials being fabricated. P Numbers 1,3,4,5 being considered equivalent.

Where the component material is clad the Calibration Block shall be cladded by the same procedure as the production part. The Calibration Block must have received the minimum Tempering Treatment required by the material specification for the type and grade. If the calibration block contains weld/s other than cladding, then the block shall receive a Post Weld Heat Treatment of at least 2 hours. The block shall be scanned by a Straight beam search unit and any areas that contain an indication exceeding the remaining back reflection shall be excluded from the beam path s required to reach the various reflectors.

6.2 Calibration

Verify Calibration of Instrument as per paragraph 5.1 for Screen Height Linearity and as per 5.2 for Amplitude Control Linearity.

Calibrate angle beam and straight beam probes for range as per paragraph 5.3.

Establish DAC as per paragraph 5.4.

For pipe welds the notches shall be used for establishing DAC using angle beam and basic Calibration Block shall be used for straight beam calibration (with the appropriate curvature).

For other welds the ASME Basic Calibration Block shall be used.



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6.3 Surface Condition When the surface of the weld or base metal interferes with the examination, it shall be prepared as needed to permit the examination. The temperature of the calibration block shall be within 25° F of the component being inspected.

6.4 Mark Reference Line Mark a reference line, by using scriber, parallel to the weld and at some distance away. Mark another reference line perpendicular to this reference line. Use these reference lines to identify and locate discontinuities.

6.5 Scanning

The scanning shall be carried out from one face of the plate or from outside if a pipe weld is being examined. The scanning speed shall be less than 6”per sec. The scanning shall be 100%, i.e. the entire examination volume shall be scanned by moving the search unit in parallel paths with 10% (of transducer size) overlap of the transducer in a direction perpendicular to the scanning direction. The scanning shall be done at a gain setting 6dB higher than the DAC reference; it is however recommended to increase the gain 14dB above DAC. This will bring 20% DAC to 100% DAC on the screen and ensure all indications 20% of DAC are clearly observed.

6.5.1 Straight Beam

Scan the adjacent base metal to detect reflectors that might interfere with angle beam reflectors. Record any such reflectors.

Scan the weld and adjoining base metal (one inch on either side) after establishing DAC.

Scanning shall be done at two time’s primary reference Level. Evaluation shall be done with reference to primary reference Level.

6.5.2 Angle Beam

Scanning for reflectors oriented parallel to the weld:

After establishing DAC the angle beam shall be directed at the weld at approximately right angles. This shall be done from two directions and if possible,



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the search unit shall be manipulated so that the required volume of weld metal is scanned. Scanning shall be carried out at two time’s primary reference level. Evaluation shall be with reference to primary reference level. Refer to Figure 2, 12 & 14 for the respective geometries.

Scanning for reflectors oriented transverse to the weld:

The angle beam shall be directed essentially parallel to the weld axis. The search unit shall be manipulated such that the required volume of weld metal and adjacent base metal is scanned. Scanning shall be carried out at two time’s primary reference level. Evaluation shall be with reference to primary reference level. The search unit shall be rotated by 180 degrees and the scanning repeated. Refer to Figures 3,4,13 & 15. In case the weld is not ground flush, this scan shall be done from both sides of the weld cap in both weld axis directions.

6.6 Recording

Recording shall be done manually. Record all indications 20% of DAC and over as follows:

1. Position the search unit to give maximum amplitude from the reflector. Read

and record the maximum amplitude in percent of DAC. 2. Read and record the sweep reading (at the leading edge of the indication). 3. Read and record the position of the search unit with reference to the reference

line. 4. Read and record the discontinuity location echo amplitude along and

perpendicular to the weld. 5. Move the search unit towards and away from reflector until the amplitude falls to

20% DAC and record through thickness dimension of discontinuity.

The record of all indications shall be made in terms of the shape, location, depth and identity of the reflector. The record shall include a sketch of the job showing clearly the location of all recorded indications.

6.7 Calibration Conformation

Verify range and sensitivity calibration at the end of every shift or every 4 hours during examination or when any part of the equipment or personnel is changed or at the end of the examination if terminated earlier.



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6.7.1 Sweep Range Correction

If a point on the sweep range has moved more than 10% of the sweep or more than 5% of full sweep whichever is greater, correct the sweep range calibration and note the correction in the examination record. All recorded indications since the last valid calibration shall be re examined with the corrected calibration and their values shall be changed in the data sheets.

6.7.2 DAC Correction

If a point on the DAC has reduced by 20% or 2 dB of its amplitude, all data sheets since the last calibration or calibration check shall be marked void. A new calibration shall be made and recorded, and the area covered by the voided data shall be re-examined.

If a point on the DAC has increased more than 20% or 2 dB of its amplitude, all recorded indications since the last valid calibration or calibration check shall be re examined with the corrected calibration and their values changed on the data sheets.

6.8 Post Examination Cleaning

After conclusion of the examination clean the job of all couplant and any other material on the surface.

7.0 INTERPRETATION AND EVALUATION

7.1 Method for discriminating geometric from flaw indication

Indications from geometric conditions like clad interface, counter bore etc. shall be recorded with description, location and amplitude (as % of DAC). This should be verified against fabrication drawings.

7.2 Acceptance Standards Interpret and evaluate all recordable indications in accordance with the acceptance standards given below.

Imperfections that are characterised as lack of fusion, cracks or lack of penetration are unacceptable regardless of length.



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All other linear imperfections are unacceptable if the amplitude exceeds the reference level and the length of the imperfection exceeds the following:

(1) 1/4" for T up to 3/4"

(2) 1/3 T for T from 3/4" to 2-1/4" (3) 3/4" for T over 2-1/4"

where T is the thickness of the weld being examined. If the weld joins two members of different thicknesses at the weld, T is the thinner of the two thicknesses.

8.0 DOCUMENTATION

The results of the Examination shall be documented in the Report Format Enclosed (UT-1 and UT-2), and signed by the Level II performing the examination. The report shall include a sketch of the job showing clearly the location of all recorded indications.

9.0 SAFETY 9.1 Use Personnel Protective Equipments (PPE) at work site. 9.2 Wear Safety belt, working at elevated heights. 9.3 The inspector shall be responsible for compliance with applicable client’s safety

rules and regulations.



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10.0 TECHNIQUE SHEET WITH SET UP SKETCH 10.1 Calibration Blocks 10.1.1 Basic Calibration block



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10.1.2 Calibration Block for Pipe Welds



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10.2 SWEEP RANGE CALIBRATION

10.2.1 Angle Beam FIGURE - SWEEP RANGE



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10.2.2 Straight Beam Figure Sweep Range



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10.3 TECHNIQUE SKETCHES

10.3.1 Basic Techniques for Angle Beam Scanning

FIGURE 2

Angle Beam Scanning for defects oriented parallel to weld



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FIGURE 3

Technique 2

FIGURE 4

Technique 3



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FIGURE 5

Technique 12 for Circumferential welds



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FIGURE 13

Supplementary Technique 13 for Circumferential welds, for welds ground flush



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FIGURE 14

Technique 14 for Longitudinal welds



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FIGURE 15

Supplementary Technique 15 for longitudinal welds, for welds ground flush



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11.0 DOUCMENTATION

11.1 Test Report Format



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