JB/T 5000.15-1998 General technical conditions for heavy machinery Non-destructive testing of forged steel parts
Some standard content:
ICS19.100
J04
JB
Machinery Industry Standard of the People's Republic of China
JB/T5000.15-1998
General Technical Conditions for Heavy Machinery|| tt||Non-destructive testing of forgings
The heaw mechanical gener al techniques and standardsNon-destructive testing of forging1998-09-30 released
National Machinery Industry Bureau
released||tt| |1998-12-01Implementation
JB/T5000.15-1998
Foreword
Scope
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2
Quoted standards ·
3Definition
4General requirements
5
Ultrasonic flaw detection and its quality level
6 Magnetic particle flaw detection and its quality level
7 Penetrant flaw detection and its quality grade
item
times
Appendix A (Appendix to the standard) Shear wave flaw detection method and quality acceptance requirements for forged steel parts Appendix B (Appendix to the standard) Quality acceptance Level selection 2
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15
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JB/T5000.15-1998||tt| |Foreword
Appendix A and Appendix B of this standard are appendices to the standard. This standard is proposed and administered by the Metallurgical Machinery Equipment Standardization Technical Committee of the Ministry of Machinery Industry. The unit responsible for drafting this standard: Second Heavy Machinery Group Company. The organization participating in the drafting of this standard: Xi'an Heavy Machinery Research Institute. The main drafters of this standard: Wang Guoyuan and Fan Luhui. I
1 Scope
Machinery Industry Standards of the People's Republic of China
General Technical Conditions for Heavy Machinery
Non-destructive testing of steel forgings
forging1.1 This standard specifies three non-destructive testing methods and quality levels: ultrasonic, magnetic particle and penetrant. 1.2 The various non-destructive testing methods described in this standard are suitable for testing all types of ordinary steel forgings. JB/T5000.15-1998
1.3 After selecting this standard, the type of flaw detection method required, the specific flaw detection location and the quality acceptance level of different defect types must be marked on the corresponding forging drawing. Additional quality may also be added. Acceptance level. 1.4 Ultrasonic flaw detection in this standard is not applicable to longitudinal wave flaw detection of forgings with a radius of curvature less than 125mm and detection thickness less than 50mm, as well as ultrasonic shear wave flaw detection of annular or cylindrical forgings with a ratio of inner and outer diameters less than 75%. It is also not suitable for ultrasonic flaw detection of coarse-grained materials such as austenitic stainless steel.
1.5 This standard may involve hazardous materials, operations and equipment. This standard is not intended to address safety issues related to use. Users of this standard are responsible for formulating relevant safety protection and health care implementation methods before use, and should determine management regulations related to the scope of application. 2 Referenced standards
The provisions contained in the following standards constitute provisions of this standard by being quoted in this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. GB3721—83
GB5097—85
GB 9445—88
GB/T12604.1~12604.6—90
ZB J04 001—87
ZB J04 003—87
ZB Y23084
ZB Y231—84
ZBY232—84
3 Definitions
This standard adopts the following definitions.
3.1 Defects in dense areas
Magnetic particle flaw detector
Indirect assessment method of black light source
General rules for technical qualifications of non-destructive testing personnel Non-destructive testing terminology
Type A Pulse reflection ultrasonic flaw detection system working performance test method Method for controlling the quality of penetrant flaw detection materials
General technical conditions for type A pulse reflection ultrasonic flaw detector Performance test method of probe for ultrasonic flaw detection
No. 1 for ultrasonic flaw detection The technical condition of the standard test block is that there are 5 or more defect reflection signals at the same time within the sound path range of the fluorescent screen scanning line equivalent to 5amm; or there are 5 or more defect reflection signals within the same depth range on the 50mm×50mm detection surface. The above defects reflect signals. The reflection amplitudes are all greater than the reflection amplitude of a certain specific defect standard. | |tt | The ratio of the sub-bottom wave amplitude to BF is represented by the sound pressure level (dB) value.
3.3 The rest of the definitions are in accordance with the provisions of GB/T12604.112604.6 4 General requirements
4.1 Selection principles
4.1.1 The selection of testing methods and quality acceptance levels should be based on the specific use of forgings and type are determined, and comply with the requirements of the corresponding technical documents. 4.1.2 For ferromagnetic forgings that require surface testing, magnetic particle testing should be preferred. If magnetic particle testing cannot be used due to structural shape and other reasons, penetrant testing should be used. | |tt |
4.2.2 The testing procedures and results should be correct, complete and signed and approved by the corresponding responsible personnel. The retention period of inspection records and reports shall not be less than 5 years. After 5 years, it can be transferred to the user for safekeeping if the user needs it. 4.2.3 In the inspection files, there should be records of the corresponding qualification levels and validity periods of inspection personnel undertaking inspection projects. 4.2.4 The performance of instruments and equipment used for testing should be inspected regularly. They can only be used after passing the inspection, and inspection records should be kept. 4.3 Testing personnel
4.3.1 All personnel engaged in non-destructive testing must undergo technical training and be assessed and appraised in accordance with GB9445. 4.3.2 The technical levels of non-destructive testing personnel are divided into high, medium and elementary. Personnel of various technical levels who have obtained different non-destructive testing methods can only engage in non-destructive testing work corresponding to that level and bear corresponding technical responsibilities. 4.3.3 In addition to having good physical fitness, all personnel engaged in non-destructive testing must meet the following requirements: 4.3.3.1 The corrected visual acuity shall not be less than 1.0, and shall be inspected once a year. 4.3.3.2 Personnel engaged in surface inspection must not be color blind or color weak. 5 Ultrasonic flaw detection and its quality level
5.1 Inspection basis
5.1.1 Whenever this standard is adopted, the user or the design process department should explain and provide the range of parts and quality acceptance levels for ultrasonic flaw detection of forgings.
5.1.2 The method of establishing sensitivity, the selection of instruments and equipment, and performance testing should be consistent with the provisions of this standard. 5.2 Instruments and Equipment
5.2.1 Use pulse reflection ultrasonic flaw detector with at least a frequency range of 1~5MHz. 5.2.1.1 The vertical linearity of the ultrasonic flaw detector shall be linearly displayed within at least 80% of the screen height, its error shall be within ±5%, and the horizontal linear error shall be ±2%. The linearity of the instrument should be qualified according to the requirements in ZBY230. 5.2.1.2 The sensitivity margin of the instrument should be above 30dB, and its measurement method should be carried out according to the requirements in ZBJ04001. 5.3 Probes
5.3.1 Various probes should be used at the calibrated frequency. In principle, 2~2.5MH is used , Straight probe with a chip diameter of 20~30mm. 2
JB/T5000.15—1998
5.3.2 The main sound beam of the probe should have no obvious double peaks, and the deflection of the sound beam line should be less than 2°. 5.3.3 Various probes should have corresponding AVG curve charts. 5.3.4 Other probes can be replaced to evaluate defects and accurately locate defects. 5.3.5 Probe performance test method, see ZBY231. 5.4 Coupling agent
5.4.1 Coupling agent should have good wettability. Engine oil, glycerin, paste or water can be used as coupling agent. It is recommended for finished forgings No. 30 engine oil acts as a coupling agent.
5.4.2 Different couplants cannot be compared. Therefore, the flaw detection system performance test, sensitivity adjustment and correction must be the same as the couplant used during flaw detection.
5.5 Test Block
5.5.1 The test block should be made of materials with the same or similar acoustic properties as the workpiece being inspected. When the material is tested with a straight probe, there must be no defects larger than the equivalent diameter of a flat-bottomed hole of Φ2mm.
5.5.2 The reflector for calibration can be a flat-bottomed hole or a V-shaped groove. During calibration, the main sound beam of the probe should be aligned with the reflector and be perpendicular to the reflecting surface of the flat-bottomed hole and perpendicular to the axis of the V-shaped groove. 5.5.3 The outer dimensions of the test block should be able to represent the characteristics of the workpiece to be inspected, and the thickness of the test block should correspond to the thickness of the workpiece to be inspected. The error does not exceed 10% of the detected thickness.
5.5.4 The manufacturing requirements of the test block should comply with the regulations of ZBY232. 5.5.5 During on-site testing, other types of equivalent test blocks may also be used. 5.6 For the test of system combination performance, see ZBJ04001. 5.7 Preparation of forgings before flaw detection
5.7.1 Unless otherwise specified when ordering, cylindrical surfaces should be machined during radial flaw detection of shaft forgings; The end surface should be processed into a plane perpendicular to the axial direction of the forging, and the surface of pie-shaped and rectangular forgings should be processed into a flat surface. and parallel to each other. 5.7.2 Unless otherwise specified when ordering, the roughness R of the forging surface shall not exceed 63 μm. 5.7.3 The flaw detection surface of forgings should be free of foreign matter, such as scale, paint, dirt, etc. 5.8 Flaw detection procedures
5.8.1 General rules
5.8.1.1 Except for the possibility of flaw detection due to changes in the cross section and local shape of the forging due to rounding, drilling, etc., the entire forging should be inspected as much as possible Perform ultrasonic flaw detection. bZxz.net
5.8.1.2 Forgings should be subjected to ultrasonic flaw detection after heat treatment for mechanical properties (excluding stress relief treatment) and before finishing. If the shape of the forgings after heat treatment is impossible to conduct comprehensive flaw detection, it is allowed to be carried out before heat treatment for performance. Ultrasonic flaw detection is carried out, but after heat treatment, ultrasonic re-detection of the forgings should be carried out as comprehensively as possible. 5.8.1.3 Each movement of the probe should have at least 15% overlap to ensure that the entire forging can be completely scanned. Probe scanning speed: shall not exceed 150mm/s during manual operation and shall not exceed 1000mm/s during automatic flaw detection. 5.8.1.4 Scan all sections of the forging in two mutually perpendicular directions as much as possible. 5.8.1.5 For pie-shaped forgings, in addition to scanning from at least one plane, radial scanning should also be carried out from the circumferential surface as much as possible. 5.8.1.6 When conducting flaw detection on cylindrical solid or hollow forgings, in addition to scanning from the radial direction, auxiliary scanning should also be performed from the axial direction. 5.8.1.7 For flaw detection of ring and cylindrical forgings, refer to Appendix A (standard appendix) at the same time. 3
JB/T5000.15—1998
5.8.1.8 When the manufacturer or user conducts review or re-evaluation, comparable instruments, probes and coupling agents should be used as much as possible. 5.8.1.9 Flaw detection of forgings can be carried out in a static state or in a rotating state (using a lathe or a rotating tire. If the user does not specify, the manufacturer can choose arbitrarily.
5.8.1.10 The thickness of forgings is greater than 40mm, the flaw detection should be carried out from opposite parallel surfaces. 5.8.2 Flaw detection sensitivity
5.8.2.1 In principle, the AVG method is used to determine the flaw detection sensitivity. For forgings that are limited by geometry and the detection thickness is close to the length of the near field zone. Then use the test block comparison method
5.8.2.2 The flaw detection sensitivity shall be based on the initial recorded equivalent value, and its base wave height shall not be less than 40% of the full screen height. 5.8.2.3 When evaluating defects, it shall be Adjustment and evaluation sensitivity of intact parts of forgings 5.8.2.4 Re-calibration of flaw detection sensitivity
a) In case of one of the following situations, the flaw detection sensitivity must be re-calibrated: any problem occurs with the calibrated probe, couplant, instrument knob, etc. When changing; when the external power supply voltage fluctuates greatly or the operator's flaw detection sensitivity changes: after continuous operation for 4 hours and at the end of the operation. b) When the flaw detection sensitivity decreases by more than 2dB, the forging should be fully re-detected; when the flaw detection sensitivity increases by more than 2cB, all recorded signals should be re-evaluated.
5.8.2.5 Adjustment method of flaw detection sensitivity
a) For solid cylindrical forgings and forgings where the flaw detection surface is parallel to the reflecting surface, when the sound path is greater than 3 times the near field, the cB value needs to be increased It should be calculated according to formula (1):
2as
dB=201g
2
where: S - one sound range, mm:
a one - Wavelength, mm;
Φ - Equivalent diameter of flaw detection sensitivity, mm. b) For hollow cylindrical forgings, when the sound path is greater than 3 times the near field, the required increased dB value should be calculated according to formula (②): 2as
dB=201g
t101g||tt ||yuan
where: D——outer diameter of workpiece, mm;
d——inner diameter of workpiece, mm;
+——inner hole detection, concave surface reflection;|| tt||radial detection of the outer circle of a workpiece, convex surface reflection. The remaining symbols are the same as 5.8.2.5a).
5.8.3 Determination of detectability of forgings
D
d
.(1)
2)
When the flaw detection sensitivity After determination, based on the flaw detection sensitivity and the signal-to-noise ratio is greater than or equal to 6dB, the forging is considered to have sufficient detectability, otherwise it will be handled through negotiation between the supplier and the buyer. 5.8.4 Determination of material attenuation coefficient
5.8.4.1 When the sound path is greater than 3 times the near field, in the defect-free area of ??the forging, at least three representative locations are selected to measure the dB of B,/B The difference is the dB difference between the first bottom wave height B and the second bottom wave height B. The material attenuation coefficient a (dB/mm) is calculated according to Equation 4
(3):
where: S - sound range, mm.
JB/T5000.15—1998
(B /B2)- 6
2S
5.8.4.2 When the material attenuation coefficient a exceeds 0.004dB/mm, The flaw detection results must be corrected. 5.8.5 Calculation of the sound beam diameter in the far field area
The calculation of the 6dB sound beam diameter should be based on formula (4): d6 =
where: Ts—a wafer diameter, mm; ||tt ||d6——6dB sound beam diameter, mm.
The remaining symbols are the same as 5.8.2.5a).
5.8.6 Determination of defect equivalent size
5.8.6.1 AVG method quantity
as
Ts
When the sound path is greater than 3 times the near field , the equivalent diameter of the defect should be calculated according to the formula (③: B/B=201g2
1+2a(y -S) ..
s
where: a-- Material attenuation coefficient, dB/mm; - Depth of defect, mm;
Φ - Equivalent diameter of defect, mm;
B, B - dB difference between defect echo and bottom wave, dB The remaining symbols are the same as 5.8.2.5a).
5.8.6.2 Quantitative test block method
a) When the sound path is greater than 3 times the near field, the equivalent diameter of the defect should be calculated according to formula (6): @x+2ax-2atx|| tt |
- material attenuation coefficient (comparison test block), dB/mm; af - material attenuation coefficient at the defect, dB/mm. The remaining symbols are the same as 5.8.6.1.
. (3)
·4
.
b) When the sound path is less than 3 times the near field, the test block should be directly compared or the measured AVG curve should be used To determine the equivalent diameter of the defect. 5.9 Classification of defects
5.9.1 Single defects
Defects with spacing greater than 50mm and equivalent diameter not less than the initial recording equivalent. 5.9.2 Dispersed defects
The distance between defects is less than or equal to 50mm, there are 2 or more and less than 5 defects at the same time, and the equivalent diameter is not less than the initial recording equivalent.
5
5.9.3 Defects in dense areas
Press 3.1. || tt | .5 Extensibility defects
The height of the continuous echo of the defect shall not be lower than the equivalent value of the initial record in at least one direction, and its extension length shall be greater than the maximum equivalent diameter allowed for the defect. The extension size of the extensibility defect is determined by the half-wave height method (6dB method). When determining the extension size, the acoustic field characteristics of the probe shall be considered for correction.
5.9.6 The bottom wave reduction amount BG/BF (dB) caused by the defect shall be in accordance with 3.2.
5.10 Recording of defects
5.10.1 Record the defects with an equivalent diameter not less than the equivalent of the initial record and their coordinate positions on the forging. 5.10.2 Recording of defects in dense areas
5.10.2.1 Record the distribution range of dense areas. 5.10.2.2 Record the depth, equivalent and coordinate position of the defect with the maximum equivalent diameter in the dense area on the forging. 5.10.3 Record of floating defect signal
Record the depth, length range, maximum equivalent and position coordinates of the starting and end points of floating defect signal. 5.10.4 Record of ductility defect
Record the depth, length range, maximum equivalent and position coordinates of the starting and end points of ductility defect. 5.10.5 Record of bottom wave reduction BG/BF (dB) caused by defect Record the dB difference between the first bottom wave amplitude BG in the intact area near the defect and the first bottom wave amplitude BF in the defect area when they reach the same reference wave height.
5.11 Quality grade
5.11.1 Single and scattered defects in forgings that are smaller than the starting record equivalent are not counted. 5.11.2 Any defects determined to be cracks, white spots and shrinkage cavities are not allowed to exist. 5.11.3 If the floating defect signal can be determined as a non-hazardous defect, the quality grade shall be assessed according to the ductility defect; if it is determined to be a hazardous defect, it shall be implemented in accordance with the provisions of 5.11.2. 5.11.4 Except for the bottom wave attenuation caused by geometric reasons, any bottom wave attenuation is not allowed to exceed 26dB5.11.5 Table 1 gives the allowable values ??of quality grades for different types of defects in forged steel parts. Table 1 Classification of quality grades for different types of defects Grade
6
I
Ⅲ
IV
V
VI
VI
VI
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