PHATECO TECHNICAL SERVICE JSC
Ultrasonic testing instruction
Document No.: PTC.UT.I-001 Revision: 0 Issued date: 25.Dec.2010
Written by: Nguyen Duc Dung – UT level II Sign: _______________
Approval by: ______________________ Sign: _______________
1.0 Purpose
This instruction applies for ultrasonic testing to detect defect in parent metal, weld body and HAZ of butt weld carbon steel plate of thickness 20mm
2.0 Reference document
BS EN 1714: 2003
BS EN 1712: 2003
BS EN 583-2:2001
BS EN 583-1:1998 - General Principles
3.0 Personnel:
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, example USM 35X-DAC S/N 7077a, cal due date is 25.06.2011
4.2. Probe:
a. compress wave probe 0 degree, 10mm dia., single crystal, freq. 5 MHz
b. shear wave probe: 70, 60 and 45 degree, single crystal 8x9mm, freq. 4MHz
4.3. Calibration block: IIW V1, V2
4.4. Reference block: DAC block 20mm with side 3mm SDH
4.5. Couplant: oil
4.6. Other: magnet rule, rule, pencil, paper, blank report form,..
5.0 Component identification:
Specimen No: PL20 – 001:
Size: 350Lx300Wx20mm
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 Area to be test
Parent metal – at maximum full skip of all angle probes + Weld body + HAZ both side of weld
For weld of plate thickness 20mm, required area is 2*20*TAN70 = 110MM
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 (> 2t/cos; range 150 mm for probe 70 degree, 125mm for probe 60 and 45 degree)
- actual reflected angle
- construct DAC with SDH 3mm until point got sound part > full V-path (120mm for probe 70; 80mm for probe 60; 60mm for probe 45) with first DAC point of 80 FSH
- construct 20dB drop beam profile using IOW block and draw on beam plotting card
- After finish calibration for each block, save all setting to a data set and change name according to serial number of each probe
8.3. All scanning surface shall be free from loose scale and weld spatter and shall be of uniform contour. For plate 20mm, 120 mm both side of weld to be cleaning.
8.4. 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.
8.5. 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 data set for straight probe used, put probe on parent material area free from imperfections, change range setting to 40mm (2 time of thickness) and adjust gain to got second back refection echo 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 marking any lamination/inclusion found and record onto rough report
9.2. Recall data set for probe 70, use two probe 70 on DAC block and test surface to measure transfer loss, if transfer loss > 2dB, add transfer loss to correct sensitivity setting. Increase 12 dB sensitivity for scanning
9.3. Carry out critical root scanning by using 70 probe at the ½ skip distance with a guide strip both side of the weld. (Refer to Sketch 2). Record any root defect found onto rough report.
9.4. Carry out weld body scanning for longitudinal defect by move the probe back and forth at ½ skip and full skip distance both side of the weld for weld body testing. Assess each signal got maximum amplitude more than 33% DAC and falls within 0 to ½ skip beam path and ½ skip to full skip beam path range. Record any defect found regarding its amplitude, size, type and position onto rough report. (Refer to sketch 3).
9.5. 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. Assess each signal got maximum amplitude more than 33% DAC. Record any defect found regarding its amplitude, size, type and position onto rough report. (Refer to sketch 4)
9.6. Change the probe angle 45, 60 in turn and repeat step 9.2, use same correct transfer loss of probe 70 for probe 45 and 60
9.7. The length of planar defect shall be measured using 6dB drop method and for the length of the defect shall be measured using 20dB drop method. Type of the defect shall be asses as characteristic of its position on weld. (Crack, LOP, LOF, Slag is have difference location and properties)
9.8. 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
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