Instruction Writing - (For Single Vee) [PDF]

Zitiervorschau

Writing instruction (Application for PCN examination) Document No.: PTC.UT.I-001

Issued date:..../....../........

Written by: Phan Hoang Diep -PCN-UT level II

Sign: _______________

Approval by: ______________________

Sign: _______________

1.0 Purpose: This instruction applies for ultrasonic testing to detect discontinuties/defects in parent metal, weld body and HAZ of butt weld carbon steel with weld thickness T mm. 2.0 Reference document: BS EN 1714: 2003 BS EN 1712: 2003 BS EN 583-2:2001 BS EN 583-1:1998 BS EN 473 ASME V 3.0 Personnel qualification: Personnel performing testing in accordance to this instruction shall have a minimum qualification to SNT-TC-1A UT level 1 or equivalent 4.0 Equipment used: 4.1. Flaw detector: An A-can flaw detector with valid calibration certificate. USM 35X-DAC, Seri No……a, cal due date is …./…../…………. 4.2. Probe: a. Compress wave probe: 10 mm dia., Twin crystal, freq. 4 MHz b. Shear wave probe: 70, 60 and 45 degree, single crystal 8x9 mm, freq. 4MHz 4.3. Calibration block: IIW V1, V2 4.4. Reference block: DAC block with 3 mm SDH 4.5. Couplant: oil 4.6. Other: magnet rule, rule, pencil, paper, blank report form… 5.0 Component identification: Specimen No: ..........................................: Size: Length x Width x Thickness

Single V – But weld in carbon steel plate

6.0 Safety Precaution: All operators and supervisors shall be aware of any local safety rules regarding the wearing of safety clothing and footwear, the use of safety equipment and etc. Surface temperature of the component shall not exceed 50oC Component must be securely situated and accessible. 7.0 Testing Area: Parent metal – at maximum full skip for 70 Deg. probe + Weld body + HAZ both side of weld For weld in plate thickness T mm, required area is: 2T*Tan(70) 8.0 Preparation for test: 8.1. Use probe zero and V1 block to calibration time base at range of 100mm and save setting to a data set and change name according to serial number of probe. 8.2. Use V1 block and DAC block to calibrate for each angle probe (45, 60, 70 degree): - Probe index, marking probe index on each probe - Time base 1.5 x 2t/cos for all angle probes 8.3. - Actual reflected angle determine - Build DAC with SDH 3mm until point got sound part > full V-path for every concrete probe. - Build 20dB drop beam profile using IOW block and draw on beam plotting card - After finished calibration for each, save all setting with concrete name for every probe. ( file 0 Deg.; file 45 Deg.; file 60 Deg.; file 70 Deg., file transfer loss built by two 45 Deg. Probes). 8.4. All scanning surface shall be free from loose scale and weld spatter and shall be of uniform contour. For plate T mm, 2T/cos (70 Deg.) mm both side of weld to be cleaning. 8.5. Draw sketch of sample to be test, record its thickness and draw up cross sectional drawing of the joint configuration to the actual measurement. Draw up center line of the weld and 1/2 skip, full skip distance for all angle probe, clearly identify datum point. 8.6. Perform visual inspection of the weld and noted any visual defect found 9.0 Testing procedure: 9.1 Parent metal testing and measure thickness: - Recall file for straight probe, position probe on parent material area free from imperfections, change range setting to 2T mm (T is weld thickness) and adjust gain so that 2nd BWE to 80% FSH - Measure thickness and record thickness in report form - Carry out parent metal examination by scan probe over maximum

required testing area of both side weld, use 6dB drop method to sizing any lamination/inclusion found and record onto rough report. ( See Figure 1) 9.2

Root Scaning: - Recall file of 70 Deg. probe, increate 12 dB, set gate at suitable position, place probe at ½ skip distance with a magnet guide strip after close probe. Moving probe from datum point to end of weld both sides of weld. Evaluation any indication before root echo got maximum amplitude more than 33% DAC at Reference level+ transfer loss. Record any defects found onto rough report. (See Figure 2)

9.3

Body Scaning:

9.3.1 Longitudinal scannig: - Recall file 60 Deg. probe, increate 12 dB, set gate at suitable position.Move the probe back and forth from ½ skip to full skip distance both sides of weld. Evaluation any echo got maximum amplitude more than 33% DAC at reference level + transfer loss. Record any defect found regarding its amplitude, size, type and position onto rough report. (see Figure 3). - Continue for 45 Deg. probe, carry out same 9.4 step for 60 Deg. probe. 9.3.2 Transverse scaning: - Carry out weld body scanning for transverse defect. Place the probe beside the weld cap angled slightly inwards along the weld to scan for transverse defect. Turn the probe around and check in the opposite direction on both sides of the weld. Investigate each signal got maximum amplitude more than 33% DAC at reference level + transfer loss. Record any defect found regarding its amplitude, size, type and position onto rough report. (see Figure 4). Transfer all the defects found onto the standard report form and report shall be submitted to NDT supervisor.

10.0

Scanning Pattern for Single V Butt joint:

130mm (Full skip)

130mm (Full skip)

Figure 1: Scanning for parent metal

½ skip

Guide strip

½ skip

Guide strip

Figure 2: Scanning for critical root Full skip

Full skip ½ skip

½ skip

Figure 3: Scanning for weld body

Figure 4: Scanning for transverse defect

11.0

Acceptance/ Reject: All indication to be record on a standard report and submit to NDT supervisor for recheck and judgement

12.0

Post Test Procedure: Remove all couplant and marking from surface of component and protect with a thin layer of oil. Report all indication on a standard report sheet showing clearly the size, position with reference to datum point, orientation and nature of the defects.

13.0

Non Compliance: If the operator unable to follow this instruction, more guidance shall be sought from the NDT supervisor.

14.0

Reporting: Record to a report at least information for: Client; Test or Project No; Work Location; Technique used; Part Description; Findings / Results; Test Procedure number; Date of Test