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JB/T 5000.15-2007 English PDF (JBT5000.15-2007)

JB/T 5000.15-2007 English PDF (JBT5000.15-2007)

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JB/T 5000.15-2007: Heavy mechanical general techniques and standards. Part 15: Non-destructive inspection of forged steel

This part of JB/T 5000 specifies the technical requirements, inspection rules, test methods, quality certificates and markings for general purpose large forgings. This part applies to the ordering, manufacturing, inspection of the large forgings of carbon steel and alloy structural steel which are free-forged by the hydraulic (oil) press and the forging hammer.
JB/T 5000.15-2007
ICS 25.120.20
H 90
Registration number. 21709-2007
Replacing JB/T 5000.15-1998
Heavy mechanical general techniques and standards -
Part 15. Non-destructive inspection of forged steel
Issued by. National Development and Reform Commission of PRC
Table of Contents
Foreword ... 4
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 General requirements ... 8
4.1 Principles of selection ... 8
4.2 Documentation of testing ... 8
4.3 Testing personnel ... 8
5 Ultrasonic testing and its quality grade ... 9
5.1 Basis of testing ... 9
5.2 Instrument and equipment ... 9
5.3 Probe ... 9
5.4 Coupling agent ... 10
5.5 Test block ... 10
5.6 Test of system?€?s combined performance ... 10
5.7 Preparation of forgings before testing ... 11
5.8 Testing procedures ... 11
5.9 Record of defects ... 15
5.10 Quality grade ... 15
5.11 Ultrasonic testing report ... 16
6 Magnetic-powder testing and its quality grade ... 17
6.1 Basis of testing ... 17
6.2 Requirements of testing surface ... 17
6.3 Testing period ... 18
6.4 Equipment and magnetic-powder ... 18
6.5 Magnetization method ... 19
6.6 Test piece for sensitivity ... 22
6.7 Magnetic-field?€?s strength ... 23
6.8 Application of magnetic-powder and magnetic suspension ... 27
6.9 Demagnetization ... 28
6.10 Retesting ... 28
6.11 Classification of magnetic trace ... 28
6.12 Recording limits and acceptance criteria ... 30
6.13 Magnetic-powder test report ... 30
7 Penetration testing and its quality grades ... 31
7.1 Basis of testing ... 31
7.2 Requirements of testing surface ... 31
7.3 Testing materials ... 31
7.4 Control test block ... 32
7.5 Classification and selection of penetration testing methods ... 33 7.6 Operating procedures ... 34
7.7 Classification of liquid-trace ... 38
7.8 Recording limits and acceptance criteria ... 38
7.9 Penetration test report ... 40
Appendix A (Normative) Transverse-wave testing method and quality
acceptance requirements for forging steel ... 41
A.1 Scope of application ... 41
A.2 Probe ... 41
A.3 Test block for verification ... 41
A.4 Adjustment of testing sensitivity ... 43
A.5 Testing operation ... 43
A.6 Recording and evaluation ... 43
Heavy mechanical general techniques and standards -
Part 15. Non-destructive inspection of forged steel
1 Scope
This Part of the JB/T 5000 specifies the ultrasonic, magnetic-powder and penetration testing methods and quality grades of forged steel.
This Part applies to non-destructive testing of forged steel for heavy machinery. Non-destructive testing methods as specified in this Part may involve
hazardous materials, operations and equipment, so the non-destructive testing personnel shall comply with relevant safety and health regulations.
The method, location, quality grade of the non-destructive testing of forgings shall be indicated in the forging?€?s drawings, technical documents and technical conditions of the ordering.
2 Normative references
The provisions in following documents become the provisions of this Part through reference in this Part of JB/T 5000. For the dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this Part; however, parties who reach an agreement based on this Part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest version of the referenced document applies. GB/T 5097 Indirect assessment method for black light source (GB/T 5097- 1985, eqv 3059.1974)
GB/T 11259 Standard practice for fabrication and control of steel reference blocks used in ultrasonic inspection (GB/T 11259-1999, eqv ASTM
JB/T 8290 Magnetic-powder flaw detectors
JB/T 9214 Test methods for evaluating performance of A-mode ultrasonic
flaw detection using pulse echo technique
JB/T 9216 Methods for controlling the quality of liquid penetrant materials JB/T 10061 Commonly used specification for A-mode ultrasonic flaw
4 General requirements
4.1 Principles of selection
4.1.1 The selection of testing method and quality acceptance level shall be determined according to the specific use and type of forgings, meet the requirements of the corresponding technical documents.
4.1.2 For ferromagnetic forgings which requires surface testing, it shall give priority to the magnetic-powder testing method. If the magnetic-powder test cannot be used due to structural shape and resource conditions, etc., it selects the penetration testing.
4.2 Documentation of testing
4.2.1 When forgings are tested in accordance with this Part, if necessary, it may follow the provisions of this Part to establish a non-destructive testing procedures which complies with the relevant specifications.
4.2.2 The testing procedures and results shall be correct, complete and signed and approved by the responsible personnel. The period of storage of test records, reports, etc. shall not be less than five years. After five years, if the user needs it, it can be transferred to the user for safekeeping.
4.2.3 In the testing documentation, the corresponding qualification grades and validity period of the testing items undertaken by the testing personnel shall be recorded.
4.2.4 The performance of the instruments and equipment used for the testing shall be periodically calibrated and have calibration records, which can only be used after passing the calibration.
4.3 Testing personnel
4.3.1 Any person engaged in non-destructive testing shall hold the
corresponding qualification certificate issued by the relevant state department. 4.3.2 Non-destructive testing personnel?€?s technical grades are divided into high, medium and primary. Personnel of all technical grades who have obtained different non-destructive testing methods can only engage in non-destructive testing corresponding to this grade and bear corresponding technical
5.3.4 Probe?€?s performance test method is as specified in JB/T 10062.
5.4 Coupling agent
5.4.1 The coupling agent shall have good wettability. It may use the oil, glycerin, paste or water of the full-loss system as a coupling agent. For finished forgings, it is recommended to use the oil L-AN46 of the full-loss system as the coupling agent.
5.4.2 Different coupling agents cannot be compared. Therefore, the coupling agents which are used for the performance test, sensitivity adjustment, calibration of the testing system must be the same as the coupling agent used in the testing.
5.5 Test block
5.5.1 The test block shall be made of the same or approximate acoustic
properties as the workpiece being tested. When the material is tested by a straight probe, there shall be no defects greater than the equivalent diameter of the ??2 mm flat-bottom hole.
5.5.2 The reflector for calibration use may be flat-bottom hole and V-shaped groove. When calibrating, the main sound-beam of the probe shall be aligned with the reflector, perpendicular to the reflecting surface of the flat-bottom hole, perpendicular to the axis of the V-shaped groove.
5.5.3 The dimensions of the test block shall be representative of the
characteristics of the workpiece to be tested. The thickness of the test block shall correspond to the thickness of the workpiece to be tested. The error does not exceed 10% of the tested thickness.
5.5.4 The manufacturing requirements of the test block shall comply with the provisions of GB/T 11259.
5.5.5 In case of field testing, it may also use other types of equivalent test blocks. 5.6 Test of system?€?s combined performance
The test of the system?€?s combined performance is as specified in JB/T 9214. in accordance with Appendix A. Whenever the manufacturer or user conducts a review or reassessment, it shall use comparable instruments, probes, and coupling agents whenever possible. Forgings can be tested at rest or in a rotating condition (turning by a lathe or a rotating tire). If the user does not specify, the manufacturer can make selection arbitrarily. When the thickness of forging is more than 400 mm, it shall carry out testing from two opposite planes.
5.8.2 Sensitivity of testing In principle, use the AVG method to determine the testing sensitivity. For forgings which is limited by its geometry and whose testing thickness
approaches to the length of near-field, use the test block comparison method. The testing sensitivity shall be based on the initially recorded equivalent value, the reference wave height shall not be less than 40% of the full screen height. When assessing defects, it shall adjust the evaluation sensitivity in the intact part of the forging. Re-verification of testing sensitivity.
a) The detection sensitivity must be re-verified in one of the following cases. - When the calibrated probe, coupling agent, instrument?€?s knob, etc. are subjected to any changes;
- When the external power supply voltage fluctuates greatly or the
operator suspects that the testing sensitivity changes;
- When the it continuously works for 4 hours and at the end of work.
b) When the testing sensitivity is reduced by more than 2 dB, the forgings shall be re-tested completely; when it is increased by more than 2 dB, all recorded signals shall be re-evaluated. Adjustment method of testing sensitivity.
a) For the solid cylindrical forgings and the forgings whose testing surface is parallel to the reflection surface, when the sound-path is more than 3 times the near-field, it shall use the formula (1) to calculate the dB value which needs to increase.
defect?€?s equivalent diameter according to formula (6).
?? - The dB difference between the defect and the flat-bottom hole of the test block, in dB;
?? - Material?€?s attenuation coefficient (comparative test block), in dB/mm; ??f - Material?€?s attenuation coefficient at the defect?€?s position, in dB/mm; x - The depth of the flat-bottom hole, in mm.
b) When the sound-path is less than 3 times near-field, it shall use the test block for direct comparison or otherwise use the measured AVG curve to
determine the defect?€?s equivalent diameter.
5.9 Record of defects
5.9.1 Record the defect whose equivalent diameter is not less than the initially recorded equivalent and its coordinate position on the forging.
5.9.2 Record of a cluster of defects.
a) Record the distribution range of a cluster of defects.
b) Record the depth of the defect of the maximum equivalent diameter in a cluster of defects, the equivalent, its coordinate position on the forging. 5.9.3 Recording of extended defects.
Record the depth, length range, maximum equivalent, position coordinates of the start and end points of the extended defect.
5.9.4 Record of loss of back reflection caused by defects BG/BF (dB).
Record the difference in dB between the first bottom-wave?€?s amplitude BG in the intact area near the defect and the first bottom-wave?€?s amplitude BF in the defect area when reaching to the same reference wave?€?s height.
5.10 Quality grade
5.10.1 A single, discrete defect in the forging that is less than the initially recorded equivalent is not counted.
sensitivity and adjustment method, instrument model, forging?€?s surface
condition, testing period.
5.11.2 Manufacturer's marking number, product?€?s contract number, forging name, drawing number, material, furnace number, card number, etc.
5.11.3 It shall draw a sketch of the workpiece, indicating the actual dimensions of the forging, the size of the untested area and the origin of the defect positioning due to factors such as geometry.
5.11.4 The defect record shall contain the coordinate position, equivalent, approximate distribution.
5.11.5 Evaluation of test results.
5.11.6 The date of testing and the signature of the testing personnel.
6 Magnetic-powder testing and its quality grade
6.1 Basis of testing
6.1.1 Relevant requirements of the user or design process department for the magnetic-powder testing for forged steel.
6.1.2 Methods for establishing sensitivity, selection of instruments and equipment, selection of magnetization methods, requirements for magnetic- field?€?s strength shall be consistent with this Part.
6.1.3 Explain whether there is a demagnetization requirement and the degree of demagnetization required.
6.2 Requirements of testing surface
6.2.1 The sensitivity of magnetic-powder testing is highly dependent on the surface condition of the forged part being tested. If the irregular surface condition affects the display or evaluation of the defect, the surface to be tested must be treated by grinding, machining or other means.
6.2.2 There shall be no dirt, grease, cotton fiber, oxide scale or other foreign matter affecting the magnetic-powder testing in the surface of the tested area and in the vicinity of 50 mm.
6.2.3 The removal of foreign matter can be carried out by any method that does not affect the magnetic-powder testing. It may use current directly on the workpiece to magnetize the forgings. It may also use the central conductor or coil to generate an induced magnetic- field to magnetize the forgings. It may use either the AC power or the DC power as the magnetizing power source. In the circumferential magnetization, since the ?€?skin effect?€? of the alternating current reduces the maximum depth of the tested defect, it shall use direct-current power source for the defects below the main tested surface. It may use one or a combination of the following five magnetization methods.
a) Contact method;
b) Longitudinal magnetization;
c) Circumferential magnetization;
d) Yoke method;
e) Multi-directional magnetization.
6.5.2 Magnetic-powder testing method Continuous method
The magnetic-powder or magnetic suspension is applied to the surface of the forged part to be tested while the magnetizing current is not interrupted and the externally-applied magnetic-field acts. In the case of continuous current supply, the shortest duration of energization shall be 1/5 s ~ 1/2 s. Fluctuation method
This method is limited to the use of direct-current. Apply a higher magnetizing force first, then lower the magnetizing force to a lower value. Apply magnetic- powder or magnetic suspension while maintaining this lower magnetizing force. Residual magnetic method
After cutting off the magnetizing current and removing the externally-applied magnetic-field, apply the test medium. Use the residual magnetism on the workpiece for testing. This method is generally not used to check forgings. To use it, it must obtain the user?€?s consent.
6.5.3 Magnetization direction
Except for the multi-directional magnetization method, each test part shall be tested at least twice, the magnetization direction shall be substantially vertical. It is not allowed to perform magnetization in two or more directions at the same b) When the material?€?s thickness is less than 20 mm, it shall select the magnetization force of 3 A ~ 4 A for each millimeter of contact?€?s spacing; when it is greater than 20 mm, select the magnetization force of 4 A ~ 5 A. c) The contact?€?s spacing shall be controlled between 75 mm and 200 mm,
the power-on time shall not be too long. To avoid burns to the workpiece, it may use any effective method that does not affect the testing sensitivity to maintain good contact between the contact and the workpiece. The
open-circuit?€?s voltage must not exceed 24 V.
d) There shall be sufficient overlap in the testing, to ensure 100% coverage at the set sensitivity. Yoke method.
a) The magnetic pole?€?s spacing shall be controlled within 50 mm ~ 200 mm. The lifting force of the yoke shall be at least 45 N for the AC solenoid yoke, or at least 180 N for DC solenoid yoke.
b) The effective testing zone shall be limited to 1/4 of the maximum pole?€?s spacing on both sides of the connection between two magnetic poles. The pole?€?s spacing shall have an overlap of more than 25 mm each time.
6.8 Application of magnetic-powder and magnetic suspension
6.8.1 When the forging is properly magnetized, it may use one of the following methods to apply the magnetic-powder. When using the dry-powder method, it may use the manual sieve, the mechanical sieve, the powder sprayer or the mechanical blower to apply the magnetic-powder. The sieve can only be used for surfaces that are placed flatly up, the dust sprayer and blower may be used on facades and downward surface. The magnetic-powder shall be uniformly applied to the surface of the forging; the color of the dry-powder shall have an appropriate contrast; the magnetic- powder should not be applied too much; when blowing off the excess magnetic- powder, take care not to damage the magnetic traces. When using the wet method, it shall use the hose to spray the magnetic suspension to the test piece or otherwise use the dipping method to apply the magnetic suspension to the test piece, to make the entire surface to be tested is completely covered. When using the continuous method, the magnetizing current shall be turned on before the application of the magnetic suspension, then magnetize it while applying the magnetic suspension, so that the surface to be tested is covered by the magnetic suspension. The magnetization is repeated at least application method, magnetization method and specification requirements, verification of testing sensitivity, specification model of test piece. 6.13.3 Manufacturer's logo number, product?€?s contract number, forging name, drawing number, material, furnace number, card number.
6.13.4 Defect record, workpiece?€?s sketch, evaluation of test results.
6.13.5 The date of testing and the signature of the testing personnel.
7 Penetration testing and its quality grades
7.1 Basis of testing
User or design process department?€?s requirements for penetration testing of forged steel.
7.2 Requirements of testing surface
7.2.1 The surface of the testing area and the adjacent 25 mm shall be dry and free of dirt, grease, cotton fiber, oxide scale, oil or other foreign matter which covers the opening defects at surface.
7.2.2 Removal of foreign matter can be carried out by any method that does not affect the penetration test.
7.2.3 The maximum roughness Ra of the machining surface of the forgings is 6.3 ??m. If it can be proved that its surface status does not affect the penetration testing, it is not subject to this limit.
7.2.4 The temperature of the testing surface shall be controlled within 15 ??C ~ 50 ??C.
7.3 Testing materials
7.3.1 Penetration testing materials generally include penetrants, emulsifiers, cleaning agents, imaging agents.
7.3.2 The quality control of the penetration test material shall comply with the requirements of JB/T 9216.
7.3.3 The testing agent must have good testing performance and no corrosion to the workpiece; it is basically non-toxic to the human body.
infiltration, emulsification, removal of excess penetrant, drying,
development, drying, observation, post-treatment.
b) The testing...

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