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GB/T 6519-2013 English PDF (GBT6519-2013)

GB/T 6519-2013 English PDF (GBT6519-2013)

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GB/T 6519-2013: Ultrasonic inspection of wrought aluminium and magnesium alloy products

This standard specifies the overview of inspection methods, inspection personal, environment, equipment and materials, sample preparation, inspection method requirements and records, reports, results explanations, of the wrought aluminum and magnesium alloy products, by the use of ultrasonic A-type pulse reflection technology. The methods, which are specified in this standard, are applicable to the ultrasonic inspection of rolled, extruded, forged aluminum and magnesium alloy products.
GB/T 6519-2013
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 77.040.20
H 26
Replacing GB/T 6519-2000
Ultrasonic inspection of wrought aluminum and magnesium
alloy products
ISSUED ON: NOVEMBER 27, 2013
IMPLEMENTED ON: AUGUST 01, 2014
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions... 6
4 Method overview ... 6
5 Inspectors ... 6
6 Inspection environment ... 6
7 Inspection equipment and materials ... 7
8 Sample preparation ... 11
9 Inspection method ... 12
10 Inspection records ... 22
11 Inspection report ... 23
12 Explanation of inspection results ... 23
Appendix A (Normative) Standard test block and comparative test block ... 25 Appendix B (Normative) Test method of combined use performance of ultrasonic tester and probe ... 38
Ultrasonic inspection of wrought aluminum and magnesium
alloy products
1 Scope
This standard specifies the overview of inspection methods, inspection personal, environment, equipment and materials, sample preparation, inspection method requirements and records, reports, results explanations, of the wrought aluminum and magnesium alloy products, by the use of ultrasonic A-type pulse reflection technology. The methods, which are specified in this standard, are applicable to the ultrasonic inspection of rolled, extruded, forged aluminum and magnesium alloy products. The applicable product specifications are as follows:
- Plates and forgings, which have a thickness of not less than 6 mm;
- Profiles, which have a cross-sectional area of not less than 70 mm2 and a thickness of not less than 6 mm;
- Round, square, hexagonal bars, which have an inscribed circle diameter of not less than 10 mm;
- Thick-walled pipes, which have a wall thickness of not less than 20 mm. This standard does not apply to castings, welded parts, sandwich structures. 2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard.
GB/T 9445 Non-destructive testing - Qualification and certification of personnel GB/T 12604.1 Non-destructive testing - Terminology - Terms used in ultrasonic testing
GB/T 18694 Non-destructive testing - Ultrasonic inspection - Characterization of search unit and sound field
GB/T 18852 Ultrasonic non-destructive testing - Reference blocks and test procedures for the characterization of contact search unit beam profiles JB/T 9214 Non-destructive testing - Test methods for evaluating performance characteristics of A-scan pulse-echo ultrasonic testing systems
JB/T 10061 Commonly used specification for A-mode ultrasonic flaw detector using pulse echo technique
JB/T 10063 Specification for No.1 standard test block used in ultrasonic flaw detection
3 Terms and definitions
Terms and definitions, which are defined in GB/T 12604.1, apply to this document. 4 Method overview
When the ultrasonic wave propagates in the sample to be inspected, the reflected wave and refracted wave, which are generated at the interface of different acoustic impedance media, are received by the probe. The parameters of the instrument are adjusted, to compare the reflected wave signal, which is received by the probe, with the reflected wave signal of artificial defect on the specified comparative test block, to evaluate the quality of the inspected samples.
5 Inspectors
5.1 Personnel, who are engaged in ultrasonic inspection, shall meet the requirements of GB/T 9445.
5.2 Ultrasonic inspectors can only engage in technical work corresponding to their technical grade qualification certificates.
6 Inspection environment
6.1 The temperature and humidity of the inspection site shall not affect the stability and reliability of the inspection of the ultrasonic tester.
6.2 The inspection site shall not be in an environment, where there is strong magnetism, vibration, high frequency, large dust, high mechanical noise, corrosive gas. The site shall be safe, with moderate light; the working space shall be such, that it will not affect the correct operation and result evaluation of ultrasonic inspection personnel. 7 Inspection equipment and materials
7.1 Test block
7.1.1 Standard test block
7.1.1.1 The standard test block is a test block, which is used for instrument and probe system?€?s performance calibration and inspection calibration. The standard test block shall comply with the provisions of Appendix A.1.
7.1.1.2 The newly purchased standard test block shall be authenticated by a metrological verification agency; it shall have an authentication certificate issued. 7.1.1.3 The standard test block shall be sent to the verification agency for authentication, every 5 years. The user shall regularly check the appearance of the standard test block, for surface damage that affects the use. If there is any damage, it shall be sent to the authentication agency for appraisal. It can only be used, after passing the authentication. 7.1.2 Comparative test block
7.1.2.1 The comparative test block is used, to adjust the sensitivity of the inspection system, the inspection range, AND to evaluate the equivalent size and position of the defect, thereby ensuring the reproducibility of test results.
7.1.2.2 The comparative test block shall comply with the provisions of Appendix A.2. For the requirements for the comparative test block and the artificial defect reflector for the inspected sample, which has special shape, it shall be determined through negotiation, between the supplier and the buyer.
7.1.2.3 The comparative test block shall be marked with the material designation, the artificial defect size, the comparative test block number.
7.2 Probes
7.2.1 The probe performance test should be carried out, in accordance with GB/T 18694 and GB/T 18852.
7.2.2 The appropriate probe shall be selected, according to the geometry, thickness, surface condition of the sample to be inspected, the minimum size and type of defect equivalent to be detected, the surface resolution, etc. The probe size shall be selected, according to the geometric shape and thickness of the inspected part of the sample to be inspected, as well as the inspection range. The probe frequency shall be selected, within the range of 2 MHz ~ 15 MHz. If other frequencies need to be selected, they shall be determined through negotiation, between the supplier and the buyer. The selection of the inspection frequency shall be able to effectively detect, distinguish, evaluate defects. Frequency, size, category, and other parameters shall be identified. in JB/T 9214. The supplier and the buyer may also negotiate to select the same model of instrument, AND negotiate to determine the technical indicators and test methods, to meet the inspection requirements of a certain product.
7.3.3 The use performance of the ultrasonic tester shall be verified at least once a year; the data of each verification shall be kept for future reference. The performance index test of the new instrument shall be carried out, before use or after the instrument is overhauled.
7.3.4 When the signal amplitude of the ultrasonic tester is adjusted to 50% of the full scale of the display screen, if the amplitude change, which is caused by the voltage fluctuation, exceeds ??2.5% of the full scale, a voltage stabilizer shall be added OR the battery shall be replaced.
7.4 Auxiliary devices
7.4.1 Auxiliary devices mainly refer to auxiliary parts, such as liquid tank and probe used to meet the requirements of liquid immersion inspection, sample coupling device, scanning device, special fixture for probe, automatic inspection mechanical transmission device, electrical control. The auxiliary device shall enable the sound energy to be effectively transmitted into the sample to be tested, has strong anti- interference ability, is convenient to operate, safe to use, stable and reliable to run. 7.4.2 The liquid tank or water supply device shall be able to immerse the inspected part of the sample to be inspected, so that the thickness of the liquid layer meets the inspection requirements.
7.4.3 During the automatic inspection of water immersion, the transmission device shall make the probe move smoothly, within the required inspection range; it shall be able to accurately adjust the probe angle. The bridge shall have sufficient strength, to provide rigid support for the manipulator AND be able to accurately position the probe. During the inspection process, the scanning positioning accuracy of the probe shall meet the inspection requirements. When the special probe?€?s support fixture can meet the specified requirements of the manipulator and the bridge, so that the test results are equivalent, THEN, these special fixtures can be used.
7.4.4 During inspection by contact method, the probe is usually placed on the inspection surface of the sample to be inspected, during the inspection process. If the special fixture can ensure the consistency of the inspection results, this special fixture can be used, when the contact method is used.
7.4.5 During inspection by manual liquid immersion method, a holder, that can control the water layer distance and the probe beam angle, shall be used. The probe holder shall ensure that the probe and the sample to be inspected maintain a certain water layer distance. During the inspection process, it shall make the probe angle unchanged and the water distance stable.
8.5 The geometry and surface roughness of the sound beam incident surface of the inspected sample shall be the same as or similar to those of the comparative test block; it shall be corrected and compensated, if there is any influence.
8.6 Bars, plates, thick-walled pipes, that are automatically inspected by the water immersion method, shall be straight; the curvature per meter shall not exceed 2 mm; the full-length curvature shall not exceed 5 mm.
8.7 The inspection blind area of the sample to be inspected shall be confirmed, through negotiation between the supplier and the buyer.
9 Inspection method
9.1 Selection of inspection methods
9.1.1 Ultrasonic longitudinal wave testing technology shall be used, to inspect the samples to be inspected. The liquid immersion method should be used, for inspecting the bars, which have diameters of less than 40 mm.
9.1.2 Upon negotiation between the supplier and the buyer, additional inspections may also be carried out, using ultrasonic shear wave detection technology.
9.1.3 When the contact method and the liquid immersion method are available, it shall give priority to the liquid immersion method.
9.2 Longitudinal wave inspection
9.2.1 Inspection surface and inspection scope
9.2.1.1 The inspected surface shall be determined, through negotiation between the supplier and the buyer, according to the processing deformation characteristics of the inspected sample, the distribution law of defects, the use requirements. Generally, the selection of the incident direction of the sound beam shall make the central axis of the sound beam perpendicular to the main plane of the defect. The sound beam of forgings, extrusions, rolled parts, etc. shall be perpendicular to the direction of the metal streamline (that is, the inspection surface is parallel to the direction of the metal streamline).
9.2.1.2 For the rectangular section body, which has a length ratio of the long side to the short side of the cross section of less than 3:1, shall be inspected separately, along the two adjacent surfaces.
9.2.1.3 Square free forgings shall be inspected, on at least three adjacent surfaces. 9.2.1.4 When the thickness of the inspected sample is less than 3 times the near-field length, the test block comparison method shall be used for inspection. When the drawing.
9.2.2 Adjustment of inspection benchmark sensitivity
9.2.2.1 According to the requirements of the acceptance criteria and the inspection scope of the sample to be inspected, select a set of comparative test blocks, that are consistent with the acceptance level, according to 9.2.7, for benchmark sensitivity adjustment. Select at least 3 blocks of comparative test blocks of flat-bottomed holes, which have different burial depths, to adjust the reference inspection sensitivity of the instrument.
9.2.2.2 The burial depth of the flat-bottomed hole of the first comparative test block shall not be greater than the machining allowance of the incident surface of the inspected sample. The buried depth of the flat-bottomed hole of the second comparative test block shall be half of the thickness of the inspected sample. The burial depth of the flat-bottomed hole of the third comparative test block shall be the maximum inspection depth, which is required for the sample to be inspected.
9.2.2.3 The probe scans the three comparative test blocks, respectively. Adjust the relevant parameters of the ultrasonic tester. Move the position of the probe, to find the maximum reflected wave of the flat-bottomed hole. Adjust the attenuation or gain of the attenuator, so that the reflected wave height of the flat-bottomed hole, from any comparative test blocks, shall be at least 80% of the full scale of the display screen. Within the inspection range, use the reference block, which has the lowest reflected wave height of the flat-bottomed hole, to adjust the inspection benchmark sensitivity of the system. Sensitivity adjustment shall make the reflected wave height of the flat- bottomed hole equal to 80% of the full scale of the display screen; use this sensitivity to inspect the inspected sample. The distance-amplitude curve may also be used, to adjust the inspection benchmark sensitivity. A comparative test block, which has the lowest response, shall be determined, within the maximum test range of the inspected sample. The benchmark sensitivity of the inspection system shall be adjusted, so that the reflected wave height of the flat-bottom hole of the comparative test block, which has the lowest response, is equal to 80% of the full scale of display screen. At this time, the sensitivity is the benchmark sensitivity of the inspected sample. The adjustment of the benchmark sensitivity of water immersion automatic inspection is determined by distance-amplitude curve.
9.2.2.4 For the bar, thick-walled pipe or the inspected sample whose inspected surface is a curved surface, it shall select the same type of comparative test block, that is consistent with or similar to the radius of curvature of the inspected sample, for the adjustment of the inspection benchmark sensitivity. According to the requirements of the acceptance criteria, select the corresponding flat-bottomed hole for sensitivity adjustment, according to 9.2.7. Find the maximum reflected wave of the flat-bottomed hole, which has different burial depths. Adjust the sensitivity of the instrument, so that one of the flat-bottomed holes, which has the lowest reflected wave height, is 80% of 9.2.4 Measurement of effective beam width
9.2.4.1 For the round wafer probe, place the probe on the comparative test block for scanning, to find the maximum reflected wave height of the flat-bottomed hole. Adjust the sensitivity of the instrument, so that the maximum reflected wave height is 80% of the full scale of the display screen. Move the probe, on both sides along the diameter direction of the flat-bottomed hole, to reduce the reflected wave height to 40%. At this time, the center distance between the two points of the probe is the effective beam width, under this sound path.
9.2.4.2 For dual-element probes and rectangular-element probes, place the probe on the comparative test block for scanning, to obtain the maximum reflected wave height of the flat-bottomed hole. Adjust the sensitivity of the instrument, so that the reflected wave height is 80% of the full scale of the display screen. Respectively, move the probe towards both sides, across the diameter of the flat-bottomed hole, along the longitudinal direction of the acoustic insulation layer of the double-crystal probe OR in a direction parallel to the long axis of the rectangular wafer, so that the reflected wave height is reduced to 40%. At this time, the distance between the two points is the effective width of the beam, under the sound path.
9.2.5 Sample scan
9.2.5.1 All areas to be inspected shall be scanned. In general, the scanning spacing shall not be greater than half of the minimum effective beam width, in the comparative test block, which is selected in 9.2.2.
9.2.5.2 For the dual-crystal combined probe, the longitudinal orientation of the sound insulation layer shall be parallel to the direction, in which the defect may extend. For rectangular wafers, the direction of the long axis of the wafer shall be parallel to the direction, in which the defects may extend.
9.2.5.3 The moving direction of the probe during scanning shall be perpendicular to the direction, in which the defect may extend.
9.2.5.4 During the scanning process, the angle, between the incident ultrasonic beam and the incident surface, shall be maintained at 90?? ?? 2??.
9.2.5.5 The inspection speed shall meet the requirement that, for the sample to be inspected, it can effectively detect the smallest defect, at the specified acceptance level. In general, the scanning speed, during manual inspection, shall not be greater than 254 mm/s. During automatic inspection, when the repetition frequency meets the requirements for scanning speed, the scanning speed can be increased.
9.2.5.6 When evaluating the defect equivalent, where there is a large difference between the inspected sample and the comparative test block, due to surface factors, it shall be corrected. If conditions permit, surface treatment can be performed on the inspection surface, to exclude inspection errors, which are caused by surface roughness. 9.2.5.7 Under the inspection benchmark sensitivity, in case of one of the following three situations, it shall be carefully checked OR analyzed by other methods. 9.2.5.7.1 When the amplitude of the reflected wave of a defect is greater than 40%, it shall be carefully scanned near the defect, to obtain the maximum reflected wave of the defect. In case of inspection by water immersion method, the maximum reflected wave of the defect can be obtained, by adjusting the probe angle.
9.2.5.7.2 When the noise-to-signal-ratio is twice larger than the normal value, it shall check the surface state of the sample to be inspected, OR check the influencing factors, such as whether the probe selection is correct or not.
9.2.5.7.3 When the reflected signal of the bottom wave is reduced by 50%, it check whether the upper and lower surfaces of the inspected part of the inspected sample are inclined, OR check the influencing factors, such as the surface state.
9.2.5.8 During the inspection process, when the inspection parameters change or the parameter knob of the inspection instrument changes, the inspection benchmark sensitivity shall be re-calibrated, according to 9.2.2.
9.2.5.9 After the continuous work for more than 2 h OR the inspection work is completed, the inspection shall be carried out, according to 9.2.2.
9.2.5.10 During the inspection process, if the instrument, probe, probe wire, couplant, etc. are replaced, the inspection sensitiv...

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