This standard specifies the method of using ultrasonic pulse reflection technology to inspect the internal defects of copper alloy bars (mainly shrinkage, residual tail, cracks, slag inclusions, inclusions and pores, etc.), including inspection equipment, general requirements, operating procedures, determination of flaw detection results and requirements for flaw detection personnel. This standard is applicable to ultrasonic flaw detection of circular copper alloy bars with a diameter of φ15~220mm and square or hexagonal copper alloy bars with an inscribed circle diameter of φ35mm or more. GB/T 3310-1999 Ultrasonic flaw detection method for copper alloy bars GB/T3310-1999 Standard download decompression password: www.bzxz.net

1 Scope
National Standard of the People's Republic of China
Copper alloy bars-Ultrasonic testing method
Copper alloy bars-Ultrasonic testing methodGB/T3310—1999
Replaces GB/T3310--1982
1.1 This standard specifies the method of using ultrasonic pulse reflection technology to inspect the internal defects of copper alloy bars (mainly shrinkage, residual tail, crack, slag inclusion, inclusion and pore, etc.), including inspection equipment, general requirements, operating procedures, determination of inspection results and requirements for inspection personnel. 1.2 This standard is applicable to the ultrasonic inspection of circular copper alloy bars with a diameter of Φ15~220mm and square or hexagonal copper alloy bars with an inscribed circle diameter of more than $35mm. The bars should be formed by extrusion, hot rolling, cold drawing or cold rolling. There should be no loose oxide layer or other dirt on the surface. 1.3 The inspection method specified in this standard can be a contact method or a liquid immersion method. 2 Principle
The basic principle of A-type pulse reflection ultrasonic flaw detection is that the ultrasonic flaw detector generates high-frequency electric pulses, and the pulse voltage is added to the probe chip through the probe cable. After electroacoustic conversion, the chip generates mechanical vibration, and the ultrasonic wave generated by this mechanical vibration is transmitted to the inspected workpiece through the coupling medium. During the propagation of the ultrasonic wave in the workpiece, it encounters the interface (defect or bottom surface) of the medium with different acoustic impedance, so that the ultrasonic wave is reflected and returns to the probe chip, and then passes through the chip to convert the sound energy into electrical energy, which is received and processed by the instrument, and the depth and equivalent size of the defect are displayed on the display. As shown in Figure 1.
Figure 1 Schematic diagram of ultrasonic flaw detection principle
3 General requirements
3.1 Whether the bar needs to be ultrasonically inspected as a whole should be in accordance with the product standard or determined by negotiation between the supply and demand parties. 3.2 For finished bars with a diameter of less than 950mm and large batches, automatic flaw detection should generally be carried out on the transmission equipment. If manual ultrasonic flaw detection is required, it can be determined by negotiation between the supply and demand parties. 3.3 Manual ultrasonic flaw detection should start from the pressure end of the bar. The tail of the bar shall not have shrinkage, delamination, pores and slag inclusions. 3.4 The background noise of the bar shall not be too large. Under the specified flaw detection sensitivity conditions, the signal-to-noise ratio shall not be less than 16dB. 4 Inspection device
Ultrasonic flaw detector
Use A-type pulse reflection single-channel or multi-channel ultrasonic flaw detector. 4.2 Probe
Approved by the State Administration of Quality and Technical Supervision on July 23, 1999, implemented on March 1, 2000www.bzxz.net
GB/T3310--1999
4.2.1 The probe for manual ultrasonic flaw detection by contact method adopts a single straight flat longitudinal wave probe, or a small angle dual crystal combined longitudinal wave probe (hereinafter referred to as dual crystal longitudinal wave probe). In special cases, it is allowed to use a dual crystal (one transmit and one receive) saddle-shaped curved surface coupled longitudinal wave probe (hereinafter referred to as riding probe). As shown in Figure 2.
4.2.2 Liquid immersion ultrasonic probe can be a straight liquid immersion probe or a line focusing liquid immersion probe. As shown in Figure 3. Bird
Dual crystal longitudinal wave probe
Riding probe
Figure 2 Schematic diagram of dual crystal longitudinal wave probe and riding probeFigure 3 Schematic diagram of liquid immersion probe
4.2.3 The nominal frequency of the probe chip is 1.25~5.0MHz. The chip diameter (or diagonal) is 8~20mm. 4.2.4 In order to determine the defect echo amplitude, the difference between the probe echo frequency and the nominal frequency should be within ±10%. 4.3 Coupling agent
4.3.1 The contact method coupling agent uses N32~N68 engine oil or other media. 4.3.2 The coupling agent of the liquid immersion method is water or N32 engine oil. 4.4 Transmission equipment
4.4.1 The base and probe holder of the immersion probe should be able to conveniently and reliably adjust the water layer distance, the incident angle of the ultrasonic sound beam, and the concentricity between the probe and the transmission equipment. If necessary, a floating tracking device can be used. 4.4.2 The transmission equipment can be a probe rotating and the bar moving forward in a straight line; or it can be a probe not moving and the bar rotating and moving forward. 4.4.3 The transmission equipment should make the flaw detection speed uniform. During the flaw detection process, the relative displacement between the probe and the bar shall not affect the accuracy of the flaw detection results.
5 Standard artificial defect test block
5.1 The material selection of the standard artificial defect test block shall be the same as that of the inspected bar, with the same material (brand), specification, processing technology and processing status, and shall not have natural defects that affect the flaw detection results. 5.2 Standard artificial defects can be short transverse holes or flat bottom holes according to the flaw detection method. 5.2.1 The processing of the short transverse hole standard artificial defect test block shall comply with the provisions of Figure 4. The short transverse hole should be drilled in a direction parallel to the central axis of the test block, and its diameter and burial depth should comply with the provisions of Table 1. The diameter deviation of the short transverse hole shall not exceed ±0.05mm; the depth deviation of the hole shall not exceed ±0.50mm.
Table 1 Diameter and burial depth of short transverse holes
Standard test block diameter D
>25～50
>50～100
Short transverse hole diameter d
Burial depth H
1/2D～1/6D
1/2D~1/6D
1/2D～1/6D
Standard test block diameter D
>100～160
>160～220
GB/T 3310—1999
Table 1 (end)
Short transverse hole diameter d
Figure 4 Processing diagram of short transverse hole standard artificial defect test block Buried depth H
1/2D～1/6D
1/2D~1/6D
5.2.2 The processing of the flat bottom hole standard artificial defect test block shall comply with the provisions of Figure 5. The flat bottom hole shall be drilled along the radial direction of the test block, and its hole diameter and burial depth shall comply with the provisions of Table 2. The hole diameter deviation of the flat bottom hole shall not exceed ±0.05mm; the hole depth deviation shall not exceed ±0.10mm. 60
Standard test block diameter D≤50m
Standard test block true diameter D>50mm
Figure 5 Flat-bottom hole standard artificial defect test block processing Chart 2 Flat-bottom hole diameter and burial depth
Standard test block diameter D
>25～50
>50～100
≥100～160
>160～220
6 Flaw detection method
Short horizontal hole diameter d
Select the probe and flaw detection method according to different material specifications. 6.1 Ultrasonic flaw detection of small diameter bars (g15～50mm) 6.1.1 Contact flaw detection
6. 1. 1. 1
The buried depth H
-Generally, a dual crystal longitudinal wave probe should be used, and a riding probe with the same diameter as the bar to be inspected can also be used. 6.1.1.2 Place the probe above the flat bottom hole artificial defect with a buried depth of 1/2D in the test block, move the probe so that the reflected wave after the ultrasonic beam is incident is the best, and at the same time, adjust the instrument so that the wave height of this reflected wave is 80% of the full amplitude, and use this as the flaw detection sensitivity.
6.1.2 Liquid immersion flaw detection
6.1.2.1 A water-immersed straight longitudinal wave probe or a water-immersed line focusing probe can be used. Correctly adjust the water layer distance and the verticality between the ultrasonic beam and the axial direction of the bar so that the ultrasonic beam can be incident vertically. 6.1.2.2
GB/T 3310—1999
6.1.2.3 Place the probe arm above the flat-bottomed hole artificial defect with a burial depth of 1/2D in the test block, scan to the best reflection point, and adjust the instrument so that the wave height of this reflected wave is 80% of the full amplitude, and use this as the flaw detection sensitivity. Note: Copper alloy bars with a diameter of $15~25mm should be tested by liquid immersion method. 6.2 Ultrasonic flaw detection of large diameter bars ($50~220mm) 6.2.1-Generally, a single straight (longitudinal wave) probe should be used for contact method manual flaw detection. The selection of the wafer diameter and coupling agent should be in accordance with the diameter and surface condition of the bar.
6.2.2 Place the probe above the flat-bottomed hole with a burial depth of 1/2D in the test block. Scan to the best position of the flat-bottom hole reflection. At the same time, adjust the instrument so that the wave height of this reflected wave is 80% of the full amplitude, and use this as the flaw detection sensitivity. 6.2.3 If large-diameter rods need to be tested by liquid diffusion method, refer to the contents of 6.1.2. 7 Operation steps
7.1 According to the different specifications of the above-mentioned rods, select the probe and flaw detection method, and adjust the flaw detection sensitivity according to the corresponding standard artificial defects in Table 1 or Table 2.
7.2 In actual flaw detection, the above-mentioned flaw detection sensitivity can be increased by 2dB as the scanning sensitivity. When defects are found, reduce the sensitivity value by 2dB and judge the defects accordingly. 7.3 During the scanning process of manual flaw detection by contact method, the moving distance of the chip shall not be greater than 1/3 of its effective diameter, and the scanning speed is generally 150m/s.
7.4 During flaw detection, the scanning coverage of the probe relative to the bar should be ensured to reach 100%, and the overlapping area of ​​the probe sound beam shall not be less than 30% of the effective width of the sound beam.
7.5 If a defect is found during the flaw detection process, the burial depth of the defect can be determined by the time proportional axis method. 7.6 If the burial depth of the defect is less than 1/2D, the detection surface should be changed, and the size of the defect should be evaluated by a flat-bottomed hole with a burial depth greater than 1/2D. For bars with a diameter greater than 100mm, distance compensation measures should be taken. 7.7 The defective parts found should be marked. 8 Evaluation of flaw detection results
8.1 If the height of the defect reflection wave is higher than 20% of the full amplitude, it is judged as unqualified ultrasonic flaw detection. 8.2 When the length of the strip defect exceeds the width of the probe's sound beam, the defect wave disappearance method should be used to assess the assumed length of the defect. The area of ​​the assumed length is the defect site, and this site is unqualified for ultrasonic flaw detection. 8.3 When the bottom wave disappears or the bottom wave moves forward, it is confirmed after re-inspection that it is caused by an internal defect of the bar, and the assumed length of the defect should be measured. The area of ​​the assumed length is the defect site, and this site is unqualified for ultrasonic flaw detection. 8.4 If the product standard has other provisions for the evaluation of the results of ultrasonic flaw detection, it should be implemented in accordance with the product standard. If the user has special requirements, it can be determined by negotiation between the supply and demand parties.
10 Qualifications of flaw detection personnel
Ultrasonic flaw detection personnel must undergo professional training and assessment. According to the requirements of the purchaser, the supplier shall provide an ultrasonic flaw detection report issued by a person with a technical qualification certificate of ultrasonic flaw detection level II or above recognized by the relevant department. 11 Ultrasonic flaw detection report
The ultrasonic flaw detection report should include the following contents: a) manufacturer;
b) flaw detection date;
brand, specification, state, batch number, quantity, etc. of the inspected bars;)
d) name and model of ultrasonic flaw detector, main technical parameters for flaw detection sensitivity adjustment;20
GB/T 3310—1999
type of probe, size of wafer and nominal frequency; flaw detection method and coupling agent;
model and number of transmission device;
flaw detection speed;
actual number of flaw detection bars, number of flaw detection scrapped bars, number of defects and length of defective parts, number of qualified bars; flaw detection personnel and their signatures, review personnel and their signatures; filling in blank period.
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