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GB/T 3310-2023 PDF in English


GB/T 3310-2023 (GB/T3310-2023, GBT 3310-2023, GBT3310-2023)
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GB/T 3310-2023: PDF in English (GBT 3310-2023)

GB/T 3310-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.20
CCS H 26
Replacing GB/T 3310-2010
Ultrasonic testing method of copper and copper alloy bars
ISSUED ON: NOVEMBER 27, 2023
IMPLEMENTED ON: JUNE 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Method principle ... 6
5 General requirements ... 6
6 Instruments and equipment ... 7
7 Selection of testing type ... 7
8 Comparison test blocks ... 8
9 Testing steps ... 10
10 Defect assessment ... 11
11 Quality grades... 12
12 Testing reports ... 13
Ultrasonic testing method of copper and copper alloy bars
1 Scope
This document describes the methods for ultrasonic testing of copper and copper alloy
bars. The content includes method principles, general requirements, instruments and
equipment, selection of testing types, comparison test blocks, testing steps, defect
assessment, quality grades, and testing reports.
This document is applicable to the ultrasonic testing of circular, rectangular, square and
regular hexagonal copper and copper alloy bars (hereinafter referred to as "bars") with
a diameter of not less than 10 mm by the Type A pulse longitudinal wave reflection
method.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 9445, Non-destructive testing -- Qualification and certification of NDT
personnel
GB/T 12604.1-2020, Non-destructive testing -- Terminology -- Ultrasonic testing
JB/T 10061, Commonly used specification for A-mode ultrasonic flaw detector using
pulse echo technique
JB/T 10062, Testing methods for performance of probes used in ultrasonic flaw
detection
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 12604.1-
2020 as well as the followings apply.
3.1 contact method
A testing method that uses one or more ultrasonic probes to directly contact the
workpiece to be tested for scanning.
3.2 immersion method
A testing method in which both the object under test and the ultrasonic probe are
immersed in a liquid used as a couplant or refractive prism.
3.3 6 dB drop method
A method that moves the probe from the position where the maximum echo amplitude
is obtained until the echo amplitude is reduced to half of it (a drop of 6 dB), and uses
this moving range to evaluate the size of the reflector.
[Source: GB/T 12604.1-2020, 6.8.17, modified]
4 Method principle
The high-frequency electrical pulse generated by the ultrasonic flaw detector is applied
to the probe chip, causing the chip to vibrate at high frequencies and produce
electroacoustic conversion. The ultrasonic wave generated by the probe chip is
transmitted to the workpiece to be tested through the coupling medium. When the
ultrasonic wave propagates in the workpiece and encounters the interface of media with
different acoustic impedances (such as defects or bottom surfaces), it is reflected and
returns to the probe chip. After another electroacoustic conversion by the chip, the
sound energy is converted into electrical energy. The signal is received and processed
by the instrument. The depth and size of the flaw are displayed on the flaw detector
display.
5 General requirements
5.1 Ultrasonic testing personnel shall be trained in accordance with the requirements of
GB/T 9445 and obtain an ultrasonic testing technology level qualification certificate
issued by the relevant national authorized department. Only those who have obtained
the technical qualification certificate of appraisal level II or above (including level II)
can be qualified to issue testing reports.
5.2 The surface roughness Ra of the bar being tested shall not be greater than 6.3 μm.
There shall be no scale, rust, oil, etc. that would affect the testing.
5.3 Under the specified testing sensitivity conditions, the signal-to-noise ratio of the bar
being detected shall not be less than 6 dB.
5.4 To ensure the accuracy and stability of the test results, the test site shall not be
located in an environment with strong magnetism, vibration, high frequency, sparks,
etc.
5.5 The coupling agent used in the immersion method shall be bubble-free, impurity-
free, and clean tap water. The coupling agent used in the contact method shall have
good sound transmission, and usually uses engine oil, chemical paste, glycerin, water
glass, etc.
6 Instruments and equipment
6.1 Flaw detector
Type A pulse reflection ultrasonic flaw detector shall comply with the requirements of
JB/T 10061.
6.2 Probe
6.2.1 The performance test of the probe for ultrasonic testing shall be carried out in
accordance with the provisions of JB/T 10062.
6.2.2 The probe used for contact method testing uses a single crystal straight probe or
a dual crystal straight probe. The frequency is 0.5 MHz~5 MHz.
6.2.3 The probe used for immersion testing uses a longitudinal wave line focusing probe
or a point focusing probe. The frequency is 5 MHz~10 MHz.
6.2.4 The probe element diameter (or diagonal) is 6 mm~25 mm.
6.3 Transmission equipment
6.3.1 The base and probe holder of the immersion probe shall be able to conveniently
and reliably adjust the distance of the water layer and the incident angle of the ultrasonic
wave, as well as the concentricity between the probe and the transmission equipment.
If necessary, floating tracking devices can be used.
6.3.2 The transmission equipment can be such that the probe rotates and the bar moves
forward in a straight line. It can also be that the probe does not move and the bar rotates
forward.
6.3.3 The transmission equipment shall run at a constant speed to ensure that the relative
displacement speed between the probe and the bar is stable during the testing process.
7 Selection of testing type
The dual crystal straight probe contact method and the single crystal straight probe
contact method are generally tested by manual scanning. Immersion method testing
shall be carried out automatically on transmission equipment. The selection of testing
types is shown in Table 1.
9 Testing steps
9.1 Adjustment of testing sensitivity
9.1.1 When testing by the liquid immersion method, the distance between the water
layer and the perpendicularity between the ultrasonic sound beam and the axial
direction of the bar must be correctly adjusted so that the ultrasonic sound beam can
enter the bar vertically. First, place the probe above the artificial defect in the flat-
bottomed hole with a burial depth of 0.5D in the comparison test block shown in Table
1 and Figure 1, which has the same diameter as the bar being tested. Move the probe so
that the reflected wave is the highest. At the same time, adjust the instrument gain knob
so that the reflected wave height is 80% of the full amplitude. Then move the probe
above the artificial defect of the flat-bottomed hole with a burial depth of 0.75D. Also
set the reflected wave height to 80% of the full width. The difference between the two
attenuator readings is less than 2 dB. At this point, the testing sensitivity has been
adjusted.
9.1.2 When testing with the dual crystal straight probe contact method, place the probes
above the flat-bottom hole artificial defects with burial depths of 0.5D and 0.75D in the
comparison test blocks shown in Table 1 and Figure 1, respectively, with the same
diameter as the bar being tested. Adjust the instrument gain knob so that the reflected
wave height of the artificial defect in the flat-bottomed hole is 80% of the full amplitude.
When the gain reading of the instrument is adjusted to be high, the reflected wave height
of the flat-bottomed hole is 80% of the full width as the testing sensitivity.
9.1.3 When testing with the single crystal straight probe contact method, place the probe
above the artificial defect in the flat-bottomed hole with a depth of 10 mm in the
comparison test block shown in Figure 2, which has the same diameter as the bar to be
tested. Adjust the instrument gain knob so that the reflected wave height of the artificial
defect in the flat-bottomed hole is 80% of the full amplitude, which is used as the testing
sensitivity. When the sound path is greater than 3 times the near-field area, the first
bottom wave of the bar can be used to adjust the testing sensitivity. First, adjust the
height of the first bottom wave of the bar to 80% of the full width. Then calculate the
required gain value A according to formula (1). Increase the instrument gain by A . At
this point, the testing sensitivity has been adjusted.
Where,
A - the gain value that needs to be increased, in decibels (dB);
λ - the wavelength, in millimeters (mm);
d - the diameter of the bar to be tested, in millimeters (mm);
π - the circular constant;
ϕ - the diameter of the flat-bottomed hole, in millimeters (mm).
9.2 Scanning sensitivity
During actual testing, an additional 6 dB is added to the above testing sensitivity as the
scanning sensitivity. When a defect is found, the sensitivity is reduced by 6 dB to
determine the defect.
9.3 Scanning speed
The scanning speed during contact method testing shall not be greater than 150 mm/s.
The scanning speed during immersion testing shall be 5 m/min~25 m/min.
9.4 Scanning range
The probe scans 100% along the axial and circumferential directions of the bar. The
effective cross-section of the scanning sound beam shall have 15% coverage.
10 Defect assessment
10.1 Defect location
10.1.1 Determination of defect plane location
By moving the probe on the surface of the bar being tested, the position of the highest
reflected wave of the defect can be obtained, thereby determining the plane position of
the defect.
10.1.2 Determination of defect burial depth
Determine by comparing with a comparison test block, or use the diameter of the bar to
determine by the proportion method.
10.2 Assessment of defect equivalent
When the depth of the tested defect is not less than 3 times the length of the near-field
area, the DGS method and calculation method are used to determine the defect
equivalent. When the depth of the tested defect is less than 3 times the length of the
near-field area, the test block comparison method is used to determine the defect
equivalent.
NOTE: The DGS method is the distance-gain-size method (DGS) method. It uses a DGS curve to
represent the height of the echo from a reflector as a flat-bottomed hole. The equivalent echo is
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.