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JB/T 5000.15-2007: PDF in English (JBT 5000.15-2007) JB/T 5000.15-2007
JB
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
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 ON. AUGUST 28, 2007
IMPLEMENTED ON. FEBRUARY 01, 2008
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
E428.1992)
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
responsibilities.
defects.
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 Φ2 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.
5.8.1.8 Whenever the manufacturer or user conducts a review or reassessment,
it shall use comparable instruments, probes, and coupling agents whenever
possible.
5.8.1.9 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.
5.8.1.10 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
5.8.2.1 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.
5.8.2.2 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.
5.8.2.3 When assessing defects, it shall adjust the evaluation sensitivity in the
intact part of the forging.
5.8.2.4 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.
5.8.2.5 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).
Where.
Δ - The dB difference between the defect and the flat-bottom hole of the
test block, in dB;
α - Material’s attenuation coefficient (comparative test block), in dB/mm;
αf - 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.
6.5.1.2 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.
6.5.1.3 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
6.5.2.1 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.
6.5.2.2 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.
6.5.2.3 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.
6.7.2.7 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.
6.8.1.1 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.
6.8.1.2 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.
6.8.1.3 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 μm. 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 steps of various combinations include. pretreatment, infiltration,
removal of excess penetrant, observation, post-treatment.
c) The post-emulsification type is emulsified after infiltration.
d) The water-rinsing type and the post-emulsification type are dried before
development.
e) The non-development type has neither imaging nor drying treatment.
f) Drying is carried out after development by wet-method.
7.5.2 Selection of penetration testing methods
7.5.2.1 The selection of the penetration test method shall be determined
according to the surface roughness of the workpiece to be tested, the sensitivity
of the penetration test, the size of the tested batch, the test environment, etc.
7.5.2.2 For workpieces with smooth surface and high sensitivity requirements,
it should use the post-emulsification coloring method or post-emulsification
fluorimetry or solvent-removal fluorimetry.
7.5.2.3 For workpieces with rough surface and low-testing sensitivity
requirements or large batch sizes, it should use the water-rinsing coloring
method or post-emulsification water-rinsing fluorimetry.
7.5.2.4 It should use the solvent-removal coloring method for the testing of the
non-presence of water source and power source on site.
7.5.2.5 For local testing of large workpieces, it should use solvent-removal
coloring method or solvent-removal fluorimetry.
7.6 Operating procedures
7.6.1 Pre-cleaning
7.6.1.1 All areas to be tested must be pre-cleaned as required by 7.2 before
applying the penetrant.
7.6.1.2 Post-cleaning drying.
The cleaned workpieces shall be dried. Drying methods generally include
heating the workpiece in a drying oven, baking it using an infrared lamp, drying
it using hot compressed air, or drying it naturally at ambient temperature.
penetrating into the defect from removed, it is prohibited to repeatedly wipe the
surface of the workpiece or directly use solvent to rinse the surface of workpiece.
7.6.4 Drying of workpiece
7.6.4.1 The workpiece shall be dried after application of the wet-developer or
prior to application of the dry-developer.
7.6.4.2 The method and requirements for drying treatment are as specified in
7.6.1.2.
7.6.4.3 When using solvent cleaning, it shall be naturally dried.
7.6.4.4 Drying time is usually 5 min ~ 10 min.
7.6.5 Imaging
7.6.5.1 When using a dry-developer, it must be dried first and then sprayed on
the entire surface to be tested evenly by an appropriate method, kept for a
certain period of time.
7.6.5.2 When using a wet-developer, after the surface to be tested has been
cleaned, it may directly spray or paint the developer on the testing surface, or
otherwise dip the workpiece into the developer, then quickly remove the excess
developer, then carry out drying treatment.
7.6.5.3 When using a fast-drying developer, after drying, spray or apply the
developer onto the surface to be tested and then dry it naturally or blow it dry
by the use of low-temperature air.
7.6.5.4 The developer shall be thoroughly stirred before use. The developer
shall be applied thin and uniformly. Do not apply the developer repeatedly in
the same position.
7.6.5.5 When spraying the developer, the distance between the nozzle and the
surface to be tested is 300 mm ~ 400 mm, the spraying direction shall be at an
angle of 30° ~ 40° to the surface to be tested.
7.6.5.6 It is forbidden to pour the quick-drying developer on the tested surface
to avoid flushing or dissolving the penetrant in the defect.
7.6.5.7 The development time depends on the type of developer, the size of the
defect, the surface-temperature of the workpiece to be tested. Generally, it shall
not be less than 7 min.
7.6.6 Observation
7.6.6.1 Observation of the displayed traces shall be carried out within 7 min ~
7.7 Classification of liquid-trace
The following rules shall apply (see Figure 13).
a) When a linear liquid-trace is not lined up with any other linear liquid-traces,
or if it is lined up with another linear liquid-trace but the distance between
them is greater than 5 times the length of the longer liquid-trace in the two
liquid-traces, it shall be regarded as a “single” liquid-trace.
b) The rows of linear liquid-traces are two (or more) linear liquid-traces
arranged in a row. If the distance between the two liquid-traces is less than
or equal to 5 times the length of the longer liquid-trace, it shall be regarded
as a continuous liquid-trace for evaluation. The length of the row of liquid-
trace is the distance between the opposite ends of the two outermost
liquid-traces.
c) The cumulative length of linear liquid-trace is the sum of the lengths of all
linear liquid-traces as detected within the evaluation box (i.e., 148 mm x
105 mm, or A6 frame).
Note. Linear liquid-traces are liquid-traces whose length is at least 3 times
their width.
d) The round liquid-trace is a liquid-trace which has a length less than or
equal to 3 times its width.
e) It shall not consider the false liquid-traces due to the geometry of the
components (cross-section changes or grooves, etc.) or surface
roughness (scarring or machined tool marks).
7.8 Recording limits and acceptance criteria
Five quality grades shall apply to the forging or various parts of the forging.
Appendix A
(Normative)
Transverse-wave testing method and quality acceptance requirements
for forging steel
A.1 Scope of application
For cylindrical annular forgings which have an axial length greater than 50 mm
and an inner-to-outer diameter ratio not less than 75%, it may select the method
as specified in this Appendix, to carry out ultrasonic transverse-wave testing
along the circumferential surface of the forging steel.
A.2 Probe
A.2.1 The probe’s frequency is mainly 2.5 MHz, it may also use 2 MHz.
A.2.2 The area of probe’s wafer is 100 mm2 ~ 400 mm2.
A.2.3 In principle, it uses the K1 probe. However, depending on the geometric
diversity of the forging steel, it may also use other K-value probes. The
principles of selection shall be such that the entire volume of forging can be
tested.
A.3 Test block for verification
A.3.1 It may use the machining margin of the tested forgings in the wall-
thickness direction or length direction to make the test block for verification. On
the inner surface and outer surface of the forgings, respectively machine
parallel V-shaped grooves axially and circumferentially as the standard grooves.
The length of the V-shaped groove is 25 mm, the angle is 60°, the depth is 3%
of the maximum wall-thickness of the forging or 6 mm (whichever is smaller).
The specific production is as shown in Figure A.1.
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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