GB/T 29711-2023 (GB/T 29711-2013) PDF English
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GB/T 29711-2013: Non-destructive testing of welds -- Ultrasonic testing -- Characterization of indications in welds
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Non-destructive testing of welds.Ultrasonic testing.Characterization of indications in welds
ICS 25.160.40
J33
National Standards of People's Republic of China
Non-destructive testing of welds
Display features in welds
(ISO 23279.2010, IDT)
Published on.2013-09-18
2014-06-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Content
Foreword III
1 Scope 1
2 Normative references 1
3 Principle 1
4 Guideline 2
4.1 Overview 2
4.2 Echo amplitude criteria (steps 1 and 2) 2
4.3 Directional Reflection Guidelines (Step 3) 2
4.4 Static Echo Waveform Guidelines (Step 4) 3
4.5 Lateral Dynamic Echo Waveform Guidelines (Step 5) 3
4.6 Additional detection 3
Appendix A (Normative) Internal Display Classification Flow Chart in Welds 4
Appendix B (informative) Directional reflection 6
Appendix C (informative) Basic dynamic waveform of the reflector 7
Reference 12
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard uses the translation method equivalent to ISO 23279.2010 "weld joint non-destructive testing ultrasonic inspection of the display characteristics in the weld".
The documents of our country that have a consistent correspondence with the international documents referenced in this standard are as follows.
---GB/T 11345-2013 Non-destructive testing of welds Ultrasonic testing technology, inspection level and assessment (ISO 17640.2010,
MOD).
This standard makes the following editorial changes to ISO 23279.2010.
--- Removed the preface to international standards;
--- The ISO standard cited in ISO 23279.2010 is replaced by the corresponding standard in China;
--- According to ISO 11666.2010, the English title is described in the "References" of this standard.
This standard is under the jurisdiction of the National Welding Standardization Technical Committee (SAC/TC55).
This standard was drafted. Shanghai Materials Research Institute, China Special Equipment Inspection and Research Institute, Jiangsu Fangtian Power Technology Co., Ltd., Jining Rui
Xiang Mould Co., Ltd. (Shandong Jining Mould Factory).
The main drafters of this standard. Jiang Yan, Jin Yufei, Ding Jie, Zhuang Zhiqiang, Zheng Hui, Ma Junpeng, Wei Zhongrui, Wang Sen, Zhang Wenjie, Ma Jun, Yan Lifeng.
Non-destructive testing of welds
Display features in welds
1 Scope
This standard specifies how to characterize internal displays, ie classify them as planar or non-planar.
This standard also applies to the display exposed on the surface of the weld after removal of the weld height.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
ISO 17640 weld non-destructive testing ultrasonic testing technology, inspection grade and assessment (Non-destructivetestingof
welds-Ultrasonictesting-Techniques,testinglevels,andassessment)
3 principles
Classify the display as flat or non-planar based on the following parameters.
a) welding technology;
b) the geometric position of the display;
c) the maximum echo amplitude;
d) directional reflection;
e) static echo waveform (eg A-scan);
f) Dynamic echo waveform.
Taking into account each of the above parameters, accurate classification results will be obtained.
As a guide, Figure A.1 gives a classification of the internal display of welds suitable for routine applications. Figure A.1 should incorporate the first two listed above.
The parameters are applied and cannot be examined separately.
The classification process specified in this standard is also suitable for removing the classification displayed on the surface of the weld after the weld height is removed (see Figure 1).
The unit is mm
Description.
A---flattened weld.
Figure 1 shows the position in the weld
4 guidelines
4.1 Overview
The display is sorted in order by the following criteria.
a) echo amplitude;
b) directional reflection;
c) static echo waveform (A-scan);
d) Dynamic echo waveform.
The above criteria can be implemented through a flow chart (see Appendix A).
When judging and characterizing the display, it is recommended to use the same probe. The flow chart will show the classification system standardization. Pass and distance
Several thresholds (in decibels) compared to the amplitude curve (DAC) or compared to the maximum echo amplitude from different directions in discontinuities
Said).
The thresholds used in the different steps in the flow chart are shown in Table A.1.
The flow chart is divided into 5 steps.
a) Step 1.Very low echo amplitude display, no classification;
b) Step 2.High echo amplitude display, classified as flat;
c) Step 3.The main classification is not fused;
d) Step 4.Mainly classify inclusions;
e) Step 5.Mainly classify cracks.
Note. According to the flow chart, the hybrid display that exists between the inclusions and the unfused contract is classified as a flat type. An example of this type of injury is shown in Figure A.2.
4.2 Echo amplitude criteria (steps 1 and 2)
4.2.1 Low echo amplitude (step 1)
The echo amplitude is lower than the rating specified in ISO 11666 (defined as T1 in Figure A.1). The display is irrelevant and should not be performed.
The levy can be accepted.
For special applications, the T1 value can be reduced if specified in the technical agreement.
4.2.2 High echo amplitude (step 2)
The echo amplitude is not less than the display level of 6dB (defined as T2 in Figure A.1), and the classification is displayed.
4.3 Directional Reflection Guidelines (Step 3)
4.3.1 Determination of applicability based on display length
Step 3 in the flowchart should only be used to display longer than.
a) t, 8mm ≤ plate thickness t ≤ 15mm;
b) t/2 or 15mm, whichever is greater, when the thickness is t >15mm.
If there is no display exceeding the above specified length, proceed as in step 4.
4.3.2 Application conditions
Perform the following application conditions.
a) the echoes compared should be from the same reflector;
b) The echo comparison should be made when the displayed echo reaches the highest position Hd,max;
c) When using both straight and oblique probes, select the appropriate probe frequency so that the wavelengths of the shear and longitudinal waves are approximately equal (eg
4MHz longitudinal wave and 2MHz transverse wave);
d) When using two or more oblique probes, the difference between the nominal refraction angles should be greater than or equal to 10°;
e) If the echo passing through the weld is compared to the echo only through the parent metal, the attenuation in the weld should be considered.
4.3.3 Guidelines
For the same display, compare the highest echo amplitude Hd,max with the lowest echo amplitude Hd,min obtained from other directions.
To meet directional reflection, the following conditions should be met.
a) Hd,max≥T3 (reference level -6dB);
b) The difference between the displayed echo amplitudes obtained from 2 different directions |Hd,max-Hd,min|, at least.
1) 9dB, only with a transverse wave oblique probe, or
2) 15dB, with 1 transverse wave oblique probe and 1 longitudinal wave straight probe.
Directional reflection depends on the angle of refraction and the detection conditions (half span, full span).
For an example of different detection directions, see Figure B.1.
For an example of applying this guideline, see Figure B.2.
4.4 Static Echo Waveform Guidelines (Step 4)
In this step, the static echo waveform of the displayed static echo waveform (for example. A-scan) and the reference reflector (3 mm diameter transverse hole)
Compare.
If the static echo waveform is single and smooth, the display is classified as non-planar.
If the static echo waveform is neither single nor smooth, proceed as in step 5.
It should be tested in at least 2 directions to comply with this Code.
4.5 Lateral Dynamic Echo Waveform Guidelines (Step 5)
The displayed horizontal dynamic echo waveform is the echo obtained when the probe moves in the direction perpendicular to the display length according to ISO 17640.
Envelope. In the analysis, not only the envelope but also the echo changes in the envelope should be considered.
The classification shown depends on the waveform obtained.
a) Waveform 1.a single non-planar display;
b) waveform 2.a non-planar display that does not belong to waveform 1;
c) Waveform 3 and Waveform 4.Flat display, if the highest reflection in 2 directions is observed, or if only 1 reflection is observed
To, use additional testing (see 4.6);
d) Waveform 5.Dense non-planar display.
The waveform classification rules are given in Appendix C.
It should be tested in at least 2 directions to comply with this Code.
4.6 Additional testing
Perform additional tests if there is suspicion, such as.
a) increase the direction of reflection or the probe;
b) Analyze the echo envelope obtained when the probe is moved parallel to the display length. [See Figure C.1c), Figure C.2c),
Figure C.3c), Figure C.4c) and Figure C.5c)];
c) Results obtained using other non-destructive testing methods (eg radiographic testing).
The items listed above are not restricted.
Appendix A
(normative appendix)
Internal display classification flow chart in weld
The flow chart is shown in Figure A.1.
Description.
Hd --- shows the amplitude of the echo;
Hd,max --- the highest echo amplitude;
Hd,min---lowest echo amplitude;
L --- length;
Lspec --- prescribed length;
T1, T2, T3, T4--- see Table A.1.
Figure A.1 Flowchart
Table A.1 Thresholds used in flowcharts
Threshold T1 T2 T3 T4
Threshold rating level reference level 6dB reference level -6dB 9dBa or 15dBb
a Transverse wave.
b between the transverse wave and the longitudinal wave reflection.
Step 1 (T1, for example rating). When all echo amplitudes ≤ T1 are displayed, they are not classified.
Step 2 (T2, for example, reference level 6 dB). When the display reaches at least 2 times the reference echo, it is classified as a flat type.
Step 3 (T3, for example, reference level -6dB). When the displayed echo amplitude is at least half of the reference echo, and the reflected echo amplitude difference
Greater than or equal to T4, classified as a flat display.
--- When both probes are used for shear wave detection, T4 = 9dB;
---When one probe is used for transverse wave detection and the other probe is for longitudinal wave detection, T4=15dB;
The angle of the ultrasound beam incident on the display should be at least 10° apart.
The comparison should be made in the same area shown.
Steps 4 and 5.Compliance with this Code should be performed in at least 2 directions.
Step 5.If the dynamic echo waveform does not match the graph 3, it is classified as non-planar.
See Appendix C for definitions of echo waveforms.
The mixed type display of inclusions and unmelted contracts is classified into a flat type in the flow chart, as shown in Figure A.2.
Figure A.2 Mixed display example for inclusions and unmelted contracts
Appendix B
(informative appendix)
Directional reflection
Description.
A, B, C--- probe position;
L --- longitudinal wave;
T --- transverse wave;
1 --- Welded parts of the weld.
Figure B.1 Example of detection direction
Description.
1 --- position 1;
2 --- position 2;
3 --- reference level;
4 --- reference level -9dB;
d --- sound path;
H---Echo amplitude.
Figure B.2 Application example of directional reflection criteria
Appendix C
(informative appendix)
Basic dynamic waveform of the reflector
C.1 waveform 1
Similar to the waveform of a point reflector, see Figure C.1.When the probe is in any position, the A type is shown as a single sharp echo. Probe
When moving, the A sweep echo smoothly rises to the highest wave and then smoothly drops to the noise level.
a) Probe position and echo amplitude variation for A-scan
b) Typical example in the thickness direction c) Typical example in the length direction
Description.
1 ---A type scanning;
2 --- peak change;
3 --- reflector;
4 --- weld;
d --- the baseline range at the level;
H---the amplitude of the echo;
x --- Probe position.
Figure C.1 Waveform of the ultrasonic response 1
C.2 Waveform 2
A smooth reflector waveform with a certain extension length, see Figure C.2.When the probe is in any position, the A type is shown as a single sharp echo.
When the ultrasonic beam moves along the reflector, the A sweep wave smoothly rises to a certain height and keeps the peak value within 4 dB. Sound beam separation
When the reflector is turned on, it is smoothly reduced to the noise level.
a) Probe position and echo amplitude variation for A-scan
b) Typical example in the thickness direction c) Typical example in the length direction
Description.
1 ---A type scanning;
2 --- peak change;
3 --- reflector;
d --- the baseline range at the level;
H---the amplitude of the echo;
x --- Probe position.
Figure C.2 Waveform of the ultrasonic response 2
C.3 Waveform 3
There are two kinds of rough reflector waveforms with a certain extension length. There are two kinds of waveform changes, which are mainly determined by the incident beam of the probe incident on the reflector.
angle.
Type 1.The probe beam is approximately perpendicular to the reflector, as shown in Figure C.3.When the probe is in any position, the A type is displayed as a single
Jagged echoes. When the probe moves, A sweeps back a significant ( >±6dB) random echo amplitude change. The main source of this phenomenon
Because the reflected echoes come from different faces of the reflector, or the reflected echoes of multiple faces are generated by random interference.
a) Probe position and echo amplitude variation for A-scan
b) Typical example in the thickness direction c) Typical example in the length direction
Description.
1 ---A type scanning;
2 --- peak change;
3 --- reflector;
d --- the baseline range at the level;
H---the amplitude of the echo;
x --- Probe position.
Figure C.3 Waveform of the ultrasonic response 3
C.4 Waveform 4
The second type. the probe beam is obliquely incident on the reflector, and the waveform is “walking echo waveform”, as shown in Figure C.4.Probe at any position
At the same time, the peaks show fluctuations in multiple high points. The peak envelope is shown in a bell shape. When the probe moves, each peak changes in the envelope
Inside, and in turn rise to the maximum of the envelope centerline, and then fall to the noise level. All echo peaks will cause significant ( >±6dB)
Random fluctuations in amplitude.
a) Probe position and echo amplitude variation for A-scan
b) Typical example in the thickness direction c) Typical example in the length direction
Description.
1 ---A type scanning;
2 --- echo envelope;
3 --- peak change;
4 --- reflector;
d --- the baseline range at the level;
H---the amplitude of the echo;
x --- Probe position.
Figure C.4 Waveform of the ultrasonic response 4
C.5 Waveform 5
The waveform of the dense reflector is shown in Figure C.5.When the probe is in any position, the A type shows a bundle-shaped echo. Within a certain range,
Dense echoes can sometimes resolve adjacent echoes, sometimes indistinguishable adjacent echoes. When the probe moves, the amplitude of the echo rises and falls randomly,
If adjacent echoes are discernible, each individual reflector signal can be found to reveal the waveform of waveform 1.
a) Probe position and echo amplitude variation for A-scan
b) Waveform of the ultrasonic response in the thickness direction 5 c) Waveform of the ultrasonic response in the longitudinal direction 5
Description.
1 ---A type scanning;
2 --- Peak change.
Solid line. long range signal;
Dotted line. short range signal;
d --- the baseline range at the level;
H---the amplitude of the echo;
x --- Probe position.
Figure C.5 Waveform of the ultrasonic response 5
references
[1] GB/T 11345-2013 Non-destructive testing of welds Ultrasonic testing techniques, testing levels and assessment (ISO 17640.2010,
MOD)
[2] GB/T 29712-2013 Non-destructive testing of welds Ultrasonic testing acceptance level (ISO 11666.2010, MOD)
[3] ISO 11666 Non-destructivetestingofwelds-Ultrasonictesting-Acceptancelevels
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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