UT Examination of Welds - BS Standard [PDF]

Zitiervorschau

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 1 of 16

Company Name

GLOBAL INSPECTION SERVICES W.L.L.

Mailing Address

P. O. Box 22410 DOHA – QATAR

Telephone

+ (974) 4460 4550

Fax

+ (974) 4460 4054

Email

[email protected]

Document Title

ULTRASONIC EXAMINATION OF WELDS

Document Ref. #

OPS-PR-BSUT-029A10 Rev - 00

Client Contract # Project Description

01

12-May-12

Revised to comply with BS EN ISO 17640

00

20-Nov-11

Initial Issue

Revision

Date

Revision Details

Shammy S. N. Technical Support Anup Nair Technical Support Asst.

Prepared By

GLOBAL INSPECTION SERVICES

M.R. Sarath Babu ASNT NDT Level III (184206) M.R. Sarath Babu ASNT NDT Level III (184206) Reviewed and Approved By

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

: : : :

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 2 of 16

CONTENTS 1.

SCOPE

2.

REFERENCE

3.

PERSONNEL QUALIFICATION

4.

DEFINITIONS AND SYMBOLS

5.

SURFACE CONDITION

6.

COUPLANT

7.

BASIC CALIBRATION BLOCK(S): GENERAL EXAMINATION REQUIREMENTS

8.

CALIBRATION CONFIRMATION

9.

EXAMINATION OF PARENT MATERIAL

10.

EXAMINATION OF WELDS

11.

ACCEPTANCE STANDARDS

12.

DOCUMENTATION

ATTACHMENT ATTACHMENT - I

REPORT FORMAT

ATTACHMENT - II

GENERAL TECHNIQUES FOR ANGLE BEAM CALIBRATIONS

ATTACHMENT - III

TECHNIQUE SHEET – EXAMINATION LEVEL B

ATTACHMENT - IV

ACCEPTANCE CRITERIA QCS 2007 SECTION 16 TABLE 5.2

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 3 of 16

1. SCOPE: 1.1. This procedure describes the method, technique and acceptance standards to be employed for the Manual Ultrasonic Examination of full penetration butt weld, structural welds and tubular intersection welds in wrought (rolled, forged, extruded or drawn) materials to detect weld discontinuities by contact method at temperatures from 0 °C to 60 °C

01

1.2. This procedure utilizes angle beam or straight beam, or both, depending upon the specific configuration. This procedure is intended to be used on thicknesses of 8 mm and above. 1.3. The testing shall be carried out using reference level to technique 1 of BS EN ISO 17640 (evaluation based primarily on length and echo amplitude of the signal indication), evaluation level -14 db from reference level and testing level B (ATTACHMENT –III).

01

1.4. The procedure accepts personnel’s qualified in accordance with SNT-TC-1A to do testing instead of EN 473 or ISO 9712 as required by BS EN ISO 17640.

01

2. 01

REFERENCE: 2.1. BS EN ISO 17640

Non- destructive testing of welded joints – Ultrasonic testing

2.2. BS EN ISO 17635

Non-destructive testing of welds. General rules for metallic materials

2.3. SNT-TC-1A

3.

Recommended practice for Personnel Qualification

PERSONNEL QUALIFICATION: 3.1. All personnel performing and evaluating Ultrasonic Examination shall be qualified and certified Level II in accordance with GLOBAL INSPECTION SERVICES (hereinafter called GIS) Written Practice OPS-PR-WP-014, prepared in accordance with SNT – TC – 1A, of ASNT.

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

4.

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 4 of 16

DEFINITIONS AND SYMBOLS; 4.1.

Indications shall be considered to be either longitudinal or transverse, depending on the direction of their major dimension with respect to the weld axis. Symbol t

5.

: : : :

Quantity Thickness of parent material (thinnest part)

Unit mm

DDSR

Diameter of a disc shaped reflector

mm

DSDH

Diameter of a side-drilled hole

mm

L

Length of the indication

mm

h

Extension of the indication in depth direction

mm

x

Position of the indication in the longitudinal direction

mm

y

Position of the indication in the transverse direction

mm

z

Position of the indication in depth

mm

lz

Projected length of the indication in depth

mm

lx

Projected length of the indication in the x-direction

mm

ly

Projected length of the indication in the y-direction

mm

p

Full skip distance

mm

SURFACE CONDITION: 5.1. All surfaces from which the weld is scanned shall be clean and free of loose scale, dirt, grease, paint or other foreign material that could interfere with interpretation of test results. 5.2. The waviness of the test surface shall not result in a gap between the probe and test surface greater than 0.5mm.

6.

COUPLANT: 6.1. Couplants having good wetting characteristics such as motor oil, glycerin, pine oil, Ultragel II, cellulose gum or water shall be used. Rust inhibitors, softeners and wetting agents may be added to the couplant. 6.2. Couplants may not be comparable to one another. Same couplant shall be used for calibration and examination.

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

7.

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 5 of 16

EQUIPMENT: 7.1. The examination shall be conducted with an ultrasonic pulse-echo type equipment capable of operating at frequencies over the range of at least 1 MHz to 5 MHz and shall be equipped with a stepped gain control in units of 2.0 dB or less. The equipment shall comply with the requirements of EN 12668 (all parts)

01

A pulse-echo type of Ultrasonic Instrument like Krautkrammer USK 7, USM 35, Penametrics Epouch - series or equivalent shall be used for this examination 7.2. Search Unit: 7.3.1

The transducer frequency shall be between 2 to 5 MHz unless variables, such as material grain structure, require the use of other frequencies to assure adequate penetration or better resolution. Search units with contoured contact wedges may be used to aid ultrasonic coupling. The angle beam transducers used shall be 45°, 60°, or 70° with an accuracy of ±2°. Frequencies of 1 Mhz may be used for testing at long sound paths where the material shows attenuation is above average. Adaption of probes to curved scanning surfaces: ƒ The gap between test surface and probe bottom (wedge) shall not be greater than 0.5 mm. ƒ For cylindrical or spherical surfaces this requirement will normally be met when the following equation is fulfilled g = a 2/ D Where “D” is the diameter of the component (mm), “a” is the dimension of probe shoe in the direction of testing (mm) Curved probe shoes shall be used when above requirement is not met. o o

ƒ 01

8.

7.3.2

Crystal size for weld examination range from 6 mm to 12 mm or rectangular elements of equivalent area. For ranges greater than 100 mm for normal beam probes and greater than 200 mm for angle beam probes, an element size of 12 mm to 24 mm shall be used.

7.3.3

The shape of the element shall be rounded for straight beam and rectangular for angle beam transducers.

GENERAL EXAMINATION REQUIREMENTS: 8.1. Examination Coverage - The test volume shall include entire weld and at least 10 mm on each side of the weld or the width of the heat affected zone, whichever is greater. The volume shall be examined by moving the search unit over the scanning surface so as to scan the entire GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 6 of 16

examination volume for each required search unit. Each pass of the search unit shall overlap a minimum of 50% of the transducer (piezo-electric element) dimension perpendicular to the weld axis. 8.2. Rate of Search Unit movements - The rate of search unit movement for examination shall not exceed 100mm/second unless calibration is verified at scanning speed. 8.3. Probe manipulation – During angle probe scanning, a slight swiveling movement up to an angle of 10° on either side of nominal beam direction shall be applied to the probe. 8.4. Transfer Correction – A suitable transfer correction technique shall be utilized. If the difference is less than 2 db, correction is not required. If the differences are greater than 2 db but smaller than 12 db, they shall be compensated. Over 12 db transfer loss, the reason for transfer correction shall be considered and further preparation of the scanning surfaces shall be carried out, if required. 8.5. Method - The examination shall be performed by the direct contact methods. 8.6. Reference point – A reference point shall be marked on the weld/testing surface. All the measurement shall be made in respect to this reference point

9.

BASIC CALIBRATION BLOCK(S): 9.1. The basic calibration reflectors shall be used to establish a primary reference response of the equipment. The basic calibration reflectors may be located either in the component material or in a basic calibration block.

01

9.2. The calibration block reflector shall be a 3 mm diameter side drilled hole (SDH). The calibration block reflector shall be located at least 25mm away from any edges (edges of block and edges of other SDH). The length of the calibration block reflector shall be greater than the width of the sound beam measured at -20 dB. 9.3. Selection of the block thickness and reflectors shall be in accordance with below table for the range of weld thickness. 9.3.1. A general purpose block of uniform low attenuation and specified surface

finish, and having a thickness within ±10 % of the test object; or 9.3.2. A block of the same acoustic properties, surface finish, shape and curvature

as the test object. Note: If 9.3.1 is used, correction for any differences in attenuation, curvature and coupling losses may be necessary before the Distance Amplitude Curve can be directly applied.

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

: : : :

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 7 of 16

10. CALIBRATION CONFIRMATION: 10.1. Setting of range and sensitivity shall be carried out prior to each test. Calibration check to confirm range and sensitivity settings shall be performed at least every 4 hours and on completion of the testing. Checks should also be carried out whenever a system parameter is changed or changes in the equipment are suspected. 10.2. If deviations are found during these checks the corrections given in the below table shall be carried out.

SENSITIVITY 1

Deviations ≤ 4 dB

The setting shall be corrected before the testing is continued

2

Reduction of the sensitivity > 4 dB

Setting shall be corrected and all testing carried out with the equipment over the previous period shall be repeated

3

Increase in sensitivity > 4 dB

Setting shall be corrected and all recorded indications shall be re-tested

RANGE 1

Deviations ≤ 2 % of the range

The setting shall be corrected before testing is continued

2

Deviations > 2 % of the range

Setting shall be corrected and testing carried out with the equipment over the previous period shall be repeated

11. EXAMINATION OF PARENT MATERIAL:

11.1. Prior to any shear wave examination, the entire surface under angle probe movement shall be first scanned with a longitudinal wave probe in order to confirm the thickness and to ensure that the scanning surface is free from any laminations or other laminar type flaws which could interfere with the shear wave examination. 11.2. The scanning of the adjacent base metal shall be performed to detect reflectors that might affect interpretation of angle beam results and is not to be used as an acceptance-rejection examination. Locations and areas of such reflectors shall be recorded. 11.3. When the weld surface is flush grounded or smoothed, it is recommended to perform scanning over the weld using longitudinal wave probe to detect root and internal reflectors. GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 8 of 16

11.4. 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. 11.5. If any areas of significant thickness variation which could affect flaw location and sizing are located, they shall be noted on the report. 12. EXAMINATION OF WELDS

Weld joints shall be scanned with an angle beam search unit in both parallel and transverse directions to the weld axis, wherever possible. Attachment-III shall be referred for information on scanning directions and sides. 12.1. Beam angle: The search unit shall be of 45 deg or an angle appropriate for the configuration being examined and shall be capable of detecting the calibration reflectors, over the required angle beam path. When two angle probes are used, one of the angle shall be as normal (perpendicular) as possible to weld fusion face. The difference between both angles shall be not less than 10 deg. 12.2. Reflectors Parallel to weld seam Angle beam scanning shall be carried out on both sides of weld with search unit pointing towards the weld and moving perpendicularly with swiveling movement up to an angle of 10 deg to the welds. The search unit shall be manipulated so that the ultrasonic energy passes thru entire weld and adjacent base metal. 12.3. Reflectors transverse to weld Angle beam scanning shall be carried out by moving the search unit parallel to the weld. After completing one full rotation of scanning (eg. clockwise), the search unit shall be rotated to 180° and the examination repeated (eg. Anticlockwise). In case the weld cap is not machined or ground flushed, the examination shall be carried out from the base metal on both sides of weld cap. 12.4. Restricted weld access When weld/joint configuration limits scanning from two directions (eg. Corner, tee joints) using angle beam technique, shall be scanned with straight beam technique to the cover entire weld area. Such restricted areas shall be recorded in the examination report. 12.5. Signal to Noise Ratio During the scanning the noise level shall remain at least 12 db below the below the evaluation level. 12.6. Evaluation: Any imperfection which causes an indication in excess of 20% DAC shall be investigated to the extent that it can be evaluated in terms of the acceptance standards shown in Para 13.0. The echo amplitude shall be maximized by probe movement and recorded in relation to the reference level. 12.7. Sizing: The length of all reportable indications shall be measured using the 6 dB drop method. The GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

: : : :

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 9 of 16

discontinuity indication shall be maximized and the amplitude noted. Move the probe to both sides until the amplitude drops to half. The location where the amplitude falls to half shall be noted. 12.8. Location: An allowance shall be made for effect of curvature on beam angle and sound path distance. The location of all indications shall be defined by reference of co-ordinate system. 13. ACCEPTANCE STANDARDS: 13.1. The acceptance criteria based on the applicable Codes and Standards as required and specified in the project specification or by client. 01

13.2. Acceptance criteria for examinations shall be QCS 2007 Table 5.2 (given in Appendix IV) or BS EN ISO 11666.

14. DOCUMENTATION: 14.1.

Recording Indications: 14.1.1. All discontinuity echo’s equal to or greater than 20 % of reference level shall be located, sized for length. 14.1.2. Rejectable Indications shall be recorded. As a minimum, the type of indication (i.e., crack, non-fusion, slag, etc), location, and extent (i.e., length) shall be recorded.

14.2. A record of inspection itemizing test conditions and findings shall be maintained on form “Report of Ultrasonic Examination” (Attachment - I) and made available to the customer or inspection agency concerned. A copy of this procedure specification shall be readily available to the NDT personnel performing these functions. 14.3. Areas not covered due to scanning limitations shall be recorded including the detail of obstruction whether it is temporary or permanent. 14.4. The following minimum data shall be recorded at the time of each test: 14.4.1. 14.4.2. 14.4.3. 14.4.4. 14.4.5. 14.4.6. 14.4.7. 14.4.8. 14.4.9. 14.4.10. 14.4.11.

procedure identification and revision; ultrasonic instrument identification (including serial number); search unit(s) identification (serial number, frequency, and size); beam angle(s) used; instrument reference level gain and, if used, damping and reject setting(s); Calibration data and time base setting for each probes; Scanning Sensitivity, including transfer correction; Calibration block used; identification & location of weld or volume scanned; surface from which examination is conducted, including surface condition; Any restrictions or departures from approved procedure; GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS 14.4.12. 14.4.13. 14.4.14. 14.4.15. 14.4.16. 14.4.17. 14.4.18.

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 10 of 16

Sketch of the weld showing the position and dimensions of all reportable flaws: map or record of indications detected or areas clear; areas of restricted access or inaccessible welds; couplant, brand name or type; basic calibration block identification; examination personnel identity and qualification level; place date examinations were performed.

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

ULTRASONIC EXAMINATION OF WELDS

: : : :

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 11 of 16

ATTACHMENT – I

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

: : : :

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 12 of 16

ATTACHMENT – II This Appendix provides general techniques for Angle beam Range calibration using A1 block, alternatively A2 block or SDH block may be used. SWEEP RANGE CALIBRATION a) Position the search unit for the maximum first indication from the 4” inch (100 mm) radius while side to side to also maximize the second reflector indication. b) Without moving the search unit, adjust the range and delay controls so that the indication start at their respective metal path distance. c) Repeat the delay and range control adjustments until the two screen indication are at their proper metal path on the screen

SENSITIVITY AND DISTANCE-AMPLITUDE CORRECTION -SDH (a) Position the search unit for maximum response from the hole which gives the highest amplitude (b) Adjust the sensitivity control to provide an 80% (± 5%) of full screen height. Mark the peak of the indication on the screen. (c) Position the search unit for maximum response from another SDH. (d) Mark the peak of the indication on the screen. (e) Position the search unit for maximum amplitude from the third SDH and mark the peak on the screen. (f) Position the search unit for maximum amplitude from the ¾T SDH after the beam has bounced from the opposite surface. The indication should appear near sweep line 10. Mark the peak on the screen for the ¾T position. (g) Connect the screen marks for the SDHs to provide the distance-amplitude curve.

GLOBAL INSPECTION SERVICES

Procedure Initial Issue Date Rev. No. Revised Date TITLE:

: : : :

ULTRASONIC EXAMINATION OF WELDS

OPS-PR-BSUT-029A10 20-Nov-11 01 12-May-12 Page 13 of 16

ATTACHMENT – III

ULTRASONIC EXAMINATION LEVEL B BUTT JOINTS IN PLATE AND PIPE

1. Side 1 2. Top view 3. Side 2 4. Side view 5. Scanning zone width (SZW) related to skip distance p Whenever possible, all scans shall be carried out from both sides (1 and 2)

Thickness of parent material 

No. of  probe  angles 

Probe  position 

Scanning zone  width (skip  distance) 

Total no  of scans 

Notes 

8 ≤ t