Q SPACE Engineering Oil & Gas Services
PHASED ARRAY UT PROCEDURE FOR WELDS
PHASED ARRAY ULTRASONIC INSPECTION GENERAL PROCEDURE FOR WELDS
QSE/JV Revision 00, issued: 03-09
P.O. Box 534, Doha, State of Qatar, Office Tel +974 4110939, Fax:+974 4764239, Mobile: 0974-3120085 Email:
[email protected]
Q SPACE Engineering Oil & Gas Services
PHASED ARRAY UT PROCEDURE FOR WELDS
CONTENTS DESCRIPTION PAGE COVER PAGE 1 CONTENTS 2 SECTION 1.0 INTRODUCTION 3 2.0 PURPOSE AND SCOPE 3 3.0 REFERENCES 3 4.0 PERSONNEL QUALIFICATION 3 5.0 PREPARATION OF EXAMINATION AREA 4 6.0 EQUIPMENT 4 7.0 CALIBRATION 6 8.0 EXAMINATION AND RECORDING CRITERIA 8 9.0 ACCEPTANCE CRITERIA 12 10.0 REPORTING 12
QSE/JV P.O. Box 534, Doha, State of Qatar, Office Tel +974 4110939, Fax:+974 4764239, Mobile: 0974-3120085 Email:
[email protected]
Q SPACE Engineering Oil & Gas Services Revision 00, issued: 03-09-09, page 2 of 2
PHASED ARRAY UT PROCEDURE FOR WELDS 1.0 INTRODUCTION This procedure describes the contact ultrasonic method in which the probe makes direct contact with the material and the ultrasonic instrument is a phased array unit. The probes addressed by the instrument may be phased array or single element probes. 2.0 PURPOSE AND SCOPE This procedure defines the requirements of mechanized pulse echo mode contact ultrasonic examination of welds. This procedure shall apply to the general aspects of ultrasonic inspection of welds using the phased array techniques and equipment. These aspects include; • • • • • • •
monitoring the performance of the equipment configuring the display and data acquisition parameters calibration of time base and sensitivity description of the recording criteria identification and layout of the components to be tested surface conditions required details of the equipment used and the volumes covered
Details of scanning shall be found in the associated technique sheets. Scanning for transverse flaws may be done using either manual, fully automatic or mechanised techniques. This procedure is applicable to ultrasonic examination of welded components for new and in service welds Provisions are incorporated into this procedure and the special adaptations unique to their implementation are described in this procedure and the associated standard practices referenced by this procedure. Since the qualification of this procedure and associated standard practices and techniques is unique to the TD Handy Scan instrument, this procedure is not valid with any other instrument. This procedure is valid for only those techniques that are identified and are recorded in the latest revision of this procedure. 3.0 REFERENCES The following documents shall be referenced with this procedure: GSOP5003, Q Space Eng/JV Written Practice for Training, Qualification and Certification of NDT Personnel to ASNT SNT-TC-1A GSOP5004, Procedure for Training, Qualification and Certification of NDT Personnel to CP-189 EN 473, Qualification and Certification of NDT Personnel BS 7706, Guide to Calibration and Setting-up of the Ultrasonic Time-of-Flight Diffraction (ToFD) technique for Detection, Location and Sizing of Flaws ASNT SNT-TC-1A, Recommended Practice for Training, Qualification and Certification of NDT Personnel ASNT CP-189, ASNT Standard for Training, Qualification and Certification of NDT Personnel ASME Section V, Non-destructive Examination
P.O. Box 534, Doha, State of Qatar, Office Tel +974 4110939, Fax:+974 4764239, Mobile: 0974-3120085 Email:
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Q SPACE Engineering Oil & Gas Services 4.0 PERSONNEL QUALIFICATION 4.1 Personnel shall be qualified in accordance with QSPACE/JV Written Practice as referenced in item 3.0 above. 4.2 Personnel evaluating phased array ultrasonic inspection results shall be qualified to a minimum of Level II. 4.3 The responsibility for the accuracy and completeness of an examination report is verified by either Level II or III qualified ultrasonic personnel. Level I operators may perform specific duties required for the examination if under the direct supervision of a Level II or III certified technician. 5.0 PREPARATION OF EXAMINATION AREA 5.1 Surface Preparation The scanning area shall be rendered free of dirt, loose scale, weld splatter, machining particles, or corrosion products. Where the surface cannot be made suitable for ultrasonic inspection by light brushing and wiping, the Client representative and Q Space/JV shall be advised. The base material or weld shall be prepared as needed to permit examination. 5.2 Weld Marking and Inspection Area Location Numbers allocated to welds being examined shall designate inspection areas. Each weld designated for inspection shall be marked with a reference index and/or position numbers marked on the examination surface during initial examination. This shall include a method for identifying the location of the weld centerline. If welds are to be permanently marked, low stress stamps or vibra-tools may be used such that the marks are not deeper than 1mm. Unless specifically noted otherwise, all circumferential measurement shall be made clockwise from the zero reference position on the weld when looking in the direction of product flow. When scans are made from a pipe to a flange or fitting where no scan access is had on the flange or fitting, the circumferential measurement shall be made clockwise when looking at the flange or fitting from the pipe side. 6.0 EQUIPMENT 6.1 Examination Equipment 6.1.1 Ultrasonic Test Instruments This procedure shall use the TD Handy Scan phased array ultrasonic inspection unit exclusively. The ultrasonic flaw detection instrument shall be used in the pulse echo or pitch-catch mode with an A-Scan presentation used for calibration. The instrument is equipped with a stepped gain control calibrated in units of 1dB or less. The equipment is capable of amplitude control over its useful range and Time Corrected Gain (TCG) shall be used in lieu of a simple Distance Amplitude Correction (DAC) curve. 6.1.2 Search Units Search units used for weld examinations shall operate at a frequency between 2 MHz and 10 MHz. either phased array or single element probes may be used. Phased array linear array configurations shall have 16 elements or more having element width of 6mm to 15mm. Element spacing will be search unit design specific and based on the calculations for element pitch to provide beam steering of +/- 20°. For typical shear wave applications the phased array probe will P.O. Box 534, Doha, State of Qatar, Office Tel +974 4110939, Fax:+974 4764239, Mobile: 0974-3120085 Email:
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Q SPACE Engineering Oil & Gas Services be placed on a refracting wedge of suitable material and refracting angle as to be compatible with the requirement to provide beam steering of +/- 20°. In addition to phased array search units, pulse-echo single element probes may be used where geometry or resolution or other factors dictate that there is advantage to do so such as for thickness assessments, transverse scanning and TOFD techniques. 6.1.3 Couplant Couplant used shall contain no ingredients deemed harmful to the test piece. For automated or mechanised scanning, water shall be used. Alternatively, Ultragel or Glycerine may be used and diluted with water to reduce viscosity so as to facilitate its movement through irrigation lines. Ultragel or Glycerine is also approved for use on the work piece when performing manual transverse scans. 6.1.4 Calibration Blocks Weld inspections using the TD Handy Scan shall be calibrated using standard calibration blocks and blocks fabricated from material that is acoustically similar to that being inspected and which has been subjected to minimum heat treatment required by the material specification. The surface of calibration blocks is finished to approximately 10 micron Ra. At no time shall the calibration block surface be inferior to the test piece surface. Calibration blocks are of 2 types i.e. range setting calibration blocks and sensitivity setting calibration blocks. 6.1.4.1 Range Setting Calibration Blocks Blocks used to set instrument range include: a) International Institute of Welding (IIW) (BS A2) for range calibration b) Din 54-122 (V2) (BS A4) alternative for range calibration c) Standard Thickness Calibration Block (ladder step wedge) Other range setting blocks may be used provided they are demonstrated to provide the accuracy required for the materials examined. 6.1.4.2 Sensitivity Setting Calibration Blocks 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 the various calibration reflectors. When the component material to be examined is clad, the block shall be clad by the same welding process as the production part. For ultrasonic examinations the design requirements for the basic calibration block are provided in Table 2. Hole placement and hole dimensions are detailed in Table 2. Aspects of design such as minimum block dimensions should be considered based on the ultrasonic techniques used. Reference blocks shall be made with thickness and side-drilled holes in accordance with Table 2. Table 1 Ultrasonic Reference Block Requirements P.O. Box 534, Doha, State of Qatar, Office Tel +974 4110939, Fax:+974 4764239, Mobile: 0974-3120085 Email:
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Q SPACE Engineering Oil & Gas Services Thickness of Material to be inspected (mm) 10< t≤50
Thickness of block (mm)
50 < 100
75 or t
100
