This standard specifies the terms and definitions of the basic concepts, product names, performance parameters, parts, accessories and materials, test methods, etc. of non-destructive testing instruments. This standard is applicable to the formulation of non-destructive testing instrument standards, the preparation of technical documents, the compilation of teaching materials and books, and the translation of literature. JB/T 7406.2-1994 Testing machine terminology Non-destructive testing instrument JB/T7406.2-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7406.2-94
Terms of Testing Machine
Non-destructive Testing Instruments
Published on August 23, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on May 1, 1995
Subject Content and Applicable Schematic
Basic Concepts
Penetrant Flaw Detection
Magnetic Particle Flaw Detection
Eddy Current Detector
Ultrasonic Tester
Acoustic Emission Detection Instrument
Radiographic Flaw Detector| |tt||Appendix A Chinese Index (reference)
Appendix B English Index (reference)
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1 Subject Content and Scope of Application
Mechanical Industry Standards of the People's Republic of China
Testing Machine Terminology
Non-destructive Testing Instruments
JB/T7406.2-94
This standard specifies the terms and definitions of the basic concepts, product names, performance parameters, parts, accessories and materials, test methods, etc. of non-destructive testing instruments.
This standard is applicable to the formulation of non-destructive testing instrument standards, the preparation of technical documents, the compilation of teaching materials and books and periodicals, and the translation of literature. Note: The words in square brackets [] of this standard are words that can be omitted without confusion, and the words in round brackets () are synonymous with the former except for explanation.
2 Basic concepts
non-destructive testing (inspection) 2.1 Non-destructive testing
Do not destroy the test object, check its surface and internal defects; measure its certain physical properties and geometric properties. 2.2 Non-destructive testing instrument non-destructive testing (inspection) instrument is an instrument designed based on various physical principles such as electromagnetic, ultrasonic, and radiation, and is used for non-destructive testing. Currently, magnetic particle flaw detectors, eddy current detectors, ultrasonic flaw detectors, ultrasonic thickness gauges, radiographic flaw detectors, and acoustic emission testing instruments are widely used. 3 Penetrant testing
3.1 Basic concepts
3.1.1 Wetting action
wetting action
The ability of a liquid to spread or adhere to a solid surface. 3.1.2 Capillary action capillaryaetion In penetrant testing, small defects (such as cracks and seams) with surface openings are similar to capillaries. The penetrant penetrates into such defects due to surface tension and adhesion. 3.1.3 Bleedout
The effect of liquid penetrant flowing from the defect to the surface to form a display. 3.1.4 Blotting
The effect of the developer absorbing the penetrant from the defect to the surface to accelerate the development. 3.1.5 Background
The appearance state (brightness and color) of the surface of the specimen being tested during penetrant testing. It can be the natural surface of the specimen or the coating of the developer on the surface.
Approved by the Ministry of Machinery Industry on August 23, 1994
Implemented on May 1, 1995
3.1.6 Contrast
JB/T7406.2-94
The degree of difference between the visibility of the defect trace after display and the visibility (brightness or color) of the background. 3.1.7 Penetrant inspection, flaw detection With the help of the display agent, the penetrant liquid sucked out from the surface defects of materials or parts is observed to show the defects, including color penetrant inspection and fluorescent penetrant inspection.
3.1.8 Dye-penetrant inspection, dyeflaw detection uses a color penetrant to observe the indicator traces of defects under visible light. According to the properties of the penetrant, it can be divided into water-washable dye penetrant inspection; post-emulsification dye penetrant inspection; solvent-removable dye penetrant inspection. 3.1.9 Fluorescent penetrant inspection, fluorescent flaw detection uses fluorescent penetrant to observe the defect traces through the excited fluorescence under ultraviolet light. According to the properties of the penetrant, it is divided into water-washable fluorescent penetrant inspection; post-emulsification fluorescent penetrant inspection; solvent-removable fluorescent penetrant inspection. 3.1.10 Blacklight blacklight
Also known as ultraviolet light.
Electromagnetic radiation in the near-ultraviolet region. The wavelength is about (3.3~3.9)×10\m. 3.1.11 Fluorescence
Visible light emitted in the process of absorbing black light when certain substances are irradiated by black light. 3.1.12 Precleaning
Before penetration inspection, clean the surface of the test piece to remove surface dirt and metal debris that may affect the inspection results. 3.1.13 Immersion rinse The method of immersing the test piece in a stirring pool or cleaning tank to remove excess penetrant. 3.1.14 Overemulsification Overemulsification Due to excessive emulsifier and (or) too long emulsification time, the useful penetrant in the defect is removed. Overwashing
3.1.15 Ultra-cleaning
Due to too long and (or) too strong washing, the useful penetrant in the defect is removed. 3.2 Flaw detection equipment
3.2.1 Penetrant flaw detection unit
Penetrant flaw detection unit Equipment used in penetrant flaw detection test. Usually composed of penetrant device, emulsification device, display device, cleaning device and drying device. In addition to the above devices used in fluorescent penetrant flaw detection, black light lamp and inspection darkroom are also provided. 3.2.2 Black light lamp blacklightlamp
Also known as ultraviolet lamp.
Fluorescent flaw detector is a device that emits black light in fluorescent penetrant flaw detection or magnetic particle flaw detection. It is generally composed of a high-pressure mercury quartz lamp with a filter and a controller.
3.2.3 Blacklight filter Blacklight filter is also called ultraviolet filter.
A filter device that can transmit near-ultraviolet radiation and absorb radiation of other wavelengths. 3.2.4 Precleaning unit Equipment for cleaning and drying the inspected specimens before penetrant testing. It is generally composed of a degreasing device, a solvent cleaning tank, a flushing spray gun, etc. 3.2.5 Degreasing unit Degreasing unit A device for holding degreasing liquid. Usually a heater is installed at the bottom, a serpentine condenser and a grid for supporting parts are installed at the top. 3.2.6 Penetrating unit A device for holding penetrant liquid during penetrant testing. It is equipped with a dripping table and a grid for supporting the specimen. 3.2.7 Emulsifier unit Emulsifier unit A device for holding emulsified liquid during penetrant testing. It is usually made of stainless steel plate or aluminum alloy plate, with a grid and drainage hole at the bottom. 3.2.8 Washing unit (station) 2
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A washing unit used in penetrant testing. It is usually composed of a nozzle, water pressure regulation, water temperature regulation, flow regulation, etc., and is equipped with a pressure gauge, thermometer, etc.
3.2.9 Drying oven drying oven
In penetrant testing, an oven used to accelerate the evaporation rate of washing water and water quality indicator, etc. It is usually an air circulation box with a constant temperature control device.
3.2.10 Electrostatic spraying device electrostatic spraying device Equipment used for electrostatic spraying during penetrant testing. It generally includes an electrostatic generator, a powder funnel cabinet, a high-pressure air pump, a penetrant spray gun, an indicator spray gun, etc.
3.2.11 SprayerbzxZ.net
A sealed pressure container. It contains penetrant and aerosol, which are usually loaded in liquid form and vaporized at room temperature to form a pressure spray.
3.3 Accessories and materials
3.3.1 Vehicle
Aqueous or non-aqueous liquid that can dissolve or suspend penetrant. 3.3.2 Penetrant
A solution made by mixing oil with strong penetrating power and colored dye or fluorescent dye in a certain proportion. It is divided into water-washable penetrant, post-emulsified penetrant, and solvent-removable penetrant. 3.3.3 Fluorescent penetrant Fluorescent penetrant A penetrant containing fluorescent substances that emits fluorescence under black light. 3.3.4 Dye penetrant Dye penetrant
A penetrant that contains colored dyes and is visible under ordinary light. 3.3.5 Dual-purpose penetrant Dual-purpose penetrant A penetrant that can produce fluorescence under black light and color contrast under visible light. 3.3.6 Water-washable penetrant Water-washable penetrant A penetrant containing an emulsifier that can be washed with water. It is divided into water-washable colored penetrant and water-washable fluorescent penetrant. 3.3.7 Postemulsifiable penetrant An oil-based penetrant without an emulsifier that must be washed with water after the application of an emulsifier. It is divided into postemulsifiable fluorescent penetrant and postemulsifiable colored penetrant.
solventremovablepenetrant
3.3.8 Solvent removable penetrant
A liquid penetrant that can be wiped in the same direction with a cloth or paper with a cleaning agent. It can be divided into solvent removable fluorescent penetrant and solvent removable colored penetrant.
3.3.9 Emulsifier
A substance that can react with oily substances to make it easy to wash with water. It is divided into hydrophilic emulsifiers and lipophilic emulsifiers. 3.3.10 Hydrophilic emulsifier A water-based liquid of a hydrophilic surfactant that interacts with the penetrant oil to make it easy to wash with water. 3.3.11 Lipophilic emulsifier: An oil-based liquid of a lipophilic surfactant that interacts with the oil in the penetrant to make it easy to wash with water. 3.3.12 Detergent: A volatile solvent that can dissolve the penetrant and is used to remove excess penetrant on the surface of the inspected workpiece. 3.3.13 Developer: A substance that can accelerate the absorption of the penetrant that has penetrated into the surface defects of the test piece and enhance the display contrast. It can be divided into various types of developers such as dry, liquid film, soluble and suspended.
3.3.14 Dry developer: A dry fine powder developer. 3
JB/T7406.2-94
3.3.15 Liquid film developer: A suspension of a developer. After drying, a layer of resin or polymer film is formed on the inspection surface. 3.3.16 Soluble developer A non-suspended developer that is completely soluble in a solvent. After drying, it forms an adsorbed coating. 3.3.17 Suspension developer Aqueous or non-aqueous suspension of developer particles. 3.3.18 Wetting agent A substance added to a liquid to reduce its surface tension. 3.3.19 Penetrant flaw detection agent A general term for a complete series of penetrant flaw detection materials required in penetrant flaw detection. Including penetrant fluid, emulsifier, cleaning agent, developer, etc. 3.3.20 Ultraviolet radiation meter An instrument for measuring the intensity of black light in fluorescent penetrant flaw detection and magnetic particle flaw detection. 3.3.21 Reference block, reference test pieces In penetrant flaw detection, a test block with artificial defects used to evaluate the flaw detection effect or device performance. 3.4 Performance parameters
blacklightintensity
3.4.1 Blacklight intensity
The amount of light reaching a unit area per unit time, expressed as the illuminance at a certain distance from the light source. 3.4.2 Dwelltime
The total time that the penetrant or emulsifier is in contact with the surface of the specimen. It includes the application time and the removal time. 3.4.3 Draintime
The time to remove excess penetrant or emulsifier from the component. It is a part of the dwelling time. 3.4.4 Femulsificationtime
The time that the emulsifier combines with the penetrant on the surface of the specimen before the penetrant is drained. 3.4.5 Dryingtime
The time required to dry the rinsed or wet-displayed specimen. 3.4.6 Developingtime
The time to wait after the application of the developer in order to absorb the penetrant in the defect and form a defect mark. 3.4.7 Indication
The trace formed by a sufficient amount of penetrant seeping out of the defect that can indicate the existence of the defect. 3.5 Test method
water washable fluorescent penetrant testing method3.5.1 Water washable fluorescent penetrant testing method
Fluorescent penetrant testing using water washable fluorescent penetrant and clean water as cleaning agent. 3.5.2 Postemulsifiable fluorescent penetrant testing methodPostemulsifiable fluorescent penetrant testing methodUsing postemulsifiable fluorescent penetrant, adding an appropriate amount of emulsifier to the surface after penetration treatment, and then rinsing with clean water. 3.5.3 Solvent removable fluorescent penetrant testing methodSolvent removable fluorescent penetrant testing methodUsing solvent removable fluorescent penetrant, wiping with cloth or paper dipped in cleaning agent in the same direction. water washable dye penetrant testing method3.5.4 Water washable dye penetrant testing method
Dye penetrant testing using water washable dye penetrant and clean water as cleaning agent. 3.5.5 Postemulsifiable dye penetrant testing method Postemulsifiable dye penetrant testing method Use postemulsifiable dye penetrant, add appropriate amount of emulsifier on the surface after penetration treatment, and then rinse with clean water. 3.5.6 Solvent removable dye penetrant testing method Solvent removable dye penetrant testing method Use solvent removable dye penetrant and wipe with cloth or paper dipped in cleaning agent in the same direction. 3.5.7 Electrostatic spraying Electrostatic spraying is a spraying method in which a high voltage charge is added to the sprayed material and the test piece is grounded. 4
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3.5.8 Spraying method
aernsol spraying
JB/T7406.2-94
A method of spraying a solvent or suspension into a mist by means of a liquefied aerosol in a pressurized container. 4 Magnetic particle flaw detection
4.1 Basic concepts
4.1.1 Leakage magnetic field leakagemagnetic field The magnetized ferromagnetic material causes a change in the magnetic circuit path at the discontinuity (such as defects) on its surface or near the surface, resulting in partial magnetic flux leakage on the surface of the material, forming a local magnetic field. 4.1.2 Magnetic particle flaw detection magneticparticleflawdetection A non-destructive method that uses magnetic particles to display the distribution of the leakage magnetic field of ferromagnetic materials, thereby discovering defects on the surface or near the surface of the material. 4.1.3 Fluorescent magnetic particle flaw detection Magnetic particle flaw detection uses fluorescent magnetic particles to check for surface and near-surface defects of materials under the irradiation of black light. 4.1.4 Magnetic permeability The ratio of magnetic induction intensity (B) to the external magnetic field intensity (H) that produces magnetic induction. It is usually represented by the symbol u. 4.1.5 Ferromagnetic material Ferromagnetic substance has a large magnetic permeability (μ), and the magnetic permeability changes with the external magnetic field. This type of material includes iron, nickel, cobalt and their alloys. 4.1.6 Hysteresis
A magnetic delay (lag) phenomenon when the applied magnetizing force acting on ferromagnetic materials changes. 4.1.7 Magnetic saturation magnetics saturation The phenomenon that the magnetic flux in the specimen increases significantly when the magnetic field strength applied to the specimen increases to a certain extent. 4.1.8 Residual magnetism
The residual magnetism retained in the specimen after the external magnetic field is removed. 4.1.9 Magnetizing current magnetizing current The current that makes the specimen magnetic. Generally includes alternating current, direct current, half-wave rectified current, full-wave rectified current, pulse current and impact current.
4.1.10 Magnetization
magnetizing
Under the action of an external magnetic field, the internal molecular magnetic moments of ferromagnetic materials are arranged in an orderly manner, thus showing the phenomenon of magnetism. 4.1.1l Circumferential (circular) magnetization is also called annular magnetization.
Magnetization in which the direction of the magnetic field is introduced is along the circumferential direction of the specimen. 4.1.12 Longitudinal magnetization Magnetization in which the direction of the magnetic field is introduced is parallel to the axial direction of the specimen. 4.1.13 Composite magnetization Resultant magnetization Magnetization in which both longitudinal and circumferential magnetic fields are introduced at the same time. 4.1.14 Local magnetization Magnetization of a part of a ferromagnetic material or component. 4.1.15 Multidirectional magnetization Use a rotating magnetic field to magnetize a ferromagnetic material or component in multiple directions in one magnetization. rotationmagnetic field
4.1.16 Rotating magnetic field
Magnetism in which the magnetic field intensity vector changes in a circular, elliptical or spiral shape over time. Demagnetizationmethod
4.1.17 Magnetization method
Methods used to magnetize ferromagnetic specimens. Generally, they include the current method, the support rod method, the central conductor method, the coil method, the yoke method and the induction current method.
4.1.18 Current flow method
eurrent flow method
JB/T7406.2-94
A method of magnetizing the specimen by introducing a magnetizing current into the specimen with the help of a contact or a contact plate. 4.1.19 Prop method
A method of magnetizing a part of the specimen by introducing a magnetizing current into the specimen with the help of a prop contact. 4.1.20 Central conductor method central conductor method is also called the rod method.
A method of magnetizing the specimen by flowing a magnetizing current along a conductor passing through the center hole of the specimen. 4.1.21 Coil method coil method
A method of magnetizing the entire or part of the specimen by flowing a magnetizing current along a coil wound around the specimen. 4.1.22 Yoke method yoke method
Also called the inter-pole method.
A method of magnetizing the whole or part of the test piece with the help of an electromagnet or a permanent magnet. 4.1.23 Induced current method inducedcurrentmethod A method of magnetizing the test piece by generating an induced current in the test piece due to the alternating change of magnetic flux in the magnetic conductor passing through the core hole of the test piece. 4.1.24 Demagnetization
A method of reducing the residual magnetism in a magnetized ferromagnetic test piece. Generally, demagnetization is completed when the residual magnetism is reduced to an allowable degree. 4.1.25 Curie point Curie point
The temperature at which ferromagnetic materials cannot be magnetized by external magnetic forces and lose residual magnetism. The Curie point of most metals is about 649 to 871°C. 4.2 Flaw detector
4.2.1 Magnetic particle flaw detector Magnetic particle flaw detector is a flaw detection device that provides the required magnetizing current or magnetic flux for magnetic particle flaw detection. It can be divided into fixed, mobile, portable and other types. 4.2.2 Fluorescent magnetic particle flaw detector A magnetic particle flaw detector that uses fluorescent magnetic particles and is equipped with a black light irradiation device. 4.2.3 Stationary magnetic particle flaw detector A magnetic particle flaw detector that can conveniently clamp parts of various sizes and can conveniently adjust and indicate the magnetizing current and is fixed in a certain place. It generally includes a magnetizing power supply, a clamping device, a magnetic powder dismantling device, an observation device, a demagnetizing device, and other parts. 4.2.4 Mobile magnetic particle flaw detector A magnetic particle flaw detector that installs the magnetizing power supply on a small wheel or a trolley so that it can be moved within a certain range. 4.2.5 Portable magnetic particle flaw detector A portable magnetic particle flaw detector is also called a magnetic particle flaw detector.
A magnetic particle flaw detector that is small in size, light in weight, and easy to carry. It is generally composed of only a magnetizing power supply, a soft cable, and a support rod contact. According to the type of magnetizing power supply, it can be divided into electromagnetic yoke flaw detector, water permanent magnet flaw detector, rotating magnetic field flaw detector, etc. 4.3 Parts, accessories and materials
4.3.1 [Magnetic] chuck contacthead
A device set on the magnetic particle flaw detector to clamp and support the test piece, and can introduce magnetizing current and (or) form a magnetic circuit. 4.3.2 Contact pad contactpad
A replaceable metal pad (usually copper wire braid) placed on the chuck. It provides good electrical contact for the test piece and prevents damage to the electrode.
4.3.3 [Support rod] contact prods
A hand-held rod-shaped electrode mounted on a flexible cable used to introduce magnetizing current from the power supply to the test piece. 4.3.4 Magnetizing coil magnetizingcoil A coil assembly that can magnetize the test piece.
4.3.5 Split coil
A single-turn or multi-turn coil assembly with a plug connector. It can be split and snapped together, and is suitable for magnetizing parts without free ends. 6
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4.3.6 Magnetization power supply
excitation supply
JB/T7406.2-94
A power supply device that provides magnetization current in magnetic particle inspection. It can be divided into AC, DC, half-wave rectification, full-wave rectification, pulse current and other types. 4.3.7 Demagnetizer
A device used to remove the residual magnetism in the magnetized test piece. It is generally composed of a demagnetization power supply, a demagnetization coil, a controller and other parts. According to the type of demagnetization current, it can be divided into DC demagnetizer, AC demagnetizer, ultra-low demagnetizer, etc. 4.3.8 Phase controlled circuit breaker In the residual magnetism method of using AC current for flaw detection, the instrument that controls the phase of AC current power failure to stabilize the residual magnetism of the test piece. 4.3.9 Yoke yoke
An electromagnet or a permanent magnet in the shape of a yoke. It is usually composed of a C-shaped solid or selected layer of soft magnetic material surrounded by a current coil. 4.3.10 Test block testblock
In magnetic particle flaw detection, a sample with artificial or known natural defects used to evaluate the flaw detection effect. Magnetic powder
4.3.11 Magnetic powder
Magnetic powder with good magnetic conductivity.
4.3.12 Fluorescent magnetic powder fluorescent magnetic powder Magnetic powder that can emit fluorescence under ultraviolet light. 4.3.13 Magnetic inks
Suspended liquid formed by mixing magnetic powder and medium liquid in a certain proportion. 4.3.14 Magnetic field meter (magnetic field meter) An instrument for measuring magnetic field strength. It can be divided into two types: magnetometer and fluxmeter. 4.3.15 Residual magnetic field measure meter An instrument for checking the residual magnetic field size of a magnetized specimen after demagnetization. 4.3.16 Sutherland flask Sutherland flask is also called pear-shaped sedimentation tube.
A flask used to measure the content of magnetic powder separated from a known volume of magnetic ink under the action of gravity. It is shaped like an inverted pear, and the bottom transitions to a small tube with a uniform cross-section and a scale. 4.3.17 Magnetic powder spreader powderbluwe
A device that uses compressed air to apply magnetic powder to the surface of the test piece. 4.3.18 [Amperemeter] Shunt
ammetershunt
A low-resistance precision resistor with high current-cutting capacity connected in parallel with the ammeter. 4.4 Performance parameters
4.4.1 Repetition utilization
repetitionutilization
The ratio of power-on time to total working time (power-on time plus rest time). 4.4.2 Magnetizing time magnetizing time The time for the magnetic particle flaw detector to magnetize the test piece under inspection. 4.4.3 Rated circumferential magnetizing current maximum rated circumferential magnetizing current The maximum axial current that the magnetic particle flaw detector can provide when clamping a test piece of corresponding diameter and length. 4.4.4 Ampere turns ampere turns The product of the current flowing through the magnetizing coil and the number of turns of its coil. 4.4.5 Magnetic Pole Distance The distance between the two contacts of the magnetic particle flaw detector. Generally, it can be adjusted according to the needs of flaw detection. 4.5 Test Method
Residual Method
4.5.1 Residual Method
A method of magnetic particle flaw detection using the residual magnetism of the test piece. 4.5.2 Continuous Method
JB/T7406.2-94
A method of magnetic particle flaw detection by applying magnetic powder or magnetic suspension under the action of an external magnetic field. 4.5.3 Dry Powder Method Dry Method
A method of magnetic particle flaw detection by applying dry magnetic powder to the surface of the test piece. 4.5.4 Wet Powder Method Wet Method
A method of magnetic particle flaw detection by applying magnetic suspension to the surface of the test piece. 4.5.5 Magnetic Particle Indication An image formed by the accumulation of magnetic powder in the leakage magnetic field caused by defects and other factors. 5 Eddy current detector
5.1 Basic concepts
5.1.1 Eddy current
The eddy current induced in the conductor due to the change of magnetic field in time or space (or both). 5.1.2 Electromagnetic induction The phenomenon of generating induced electromotive force in a closed loop when the magnetic flux changes. 5.1.3 Eddy current testing Eddy current testing A method of non-destructive testing by measuring the change of induction quantity using the electromagnetic induction phenomenon of conductive materials. Note: Conductive materials in an alternating magnetic field generate eddy currents due to electromagnetic induction, forming a superimposed magnetic field. Changes in the physical properties of conductive materials (defects, materials, conductivity, magnetic permeability, residual stress, size) will affect the change of eddy current distribution state, so the superimposed magnetic field will also change. Therefore, the properties or defects of conductive materials can be detected by measuring the change of superimposed magnetic field. 5.1.4 Normalized resistance The increase of coil resistance under load and no-load conditions is divided by the reactance of the no-load coil. 5.1.5 Normalized reactance normalizedreactance The reactance of the loaded coil divided by the reactance of the unloaded coil. 5.1.6 Normalized impedance normalizedimpedance The complex impedance with the normalized resistance as the real part and the normalized reactance as the imaginary part. 5.1.7 Impedance plane diagram impedanceplanediagram The plane trajectory diagram showing the impedance change points of the test coil. 5.1.8 Effective permeability effectivepermeability The assumed parameter that describes the permeability of a magnetic material. It is an empirical parameter obtained experimentally under a known set of physical conditions (such as a cylindrical specimen in a toroidal coil at a specific test rate). This parameter is different under different physical conditions (specimen geometry, relative position of the surrounding coils and magnetic field properties, etc.). 5.1.9 Incremental permeability The incremental permeability of a magnetic material at a point on the magnetization curve is equal to the ratio of the incremental magnetic flux density to the incremental magnetic field intensity at that point. 5.1.10 Absolute permeability The ratio of the magnetic flux density of a magnetic material to the magnetic field strength that produces it. 5.1.11 Relative permeability The ratio of absolute permeability to vacuum permeability. ① Relative permeability is a pure number that is the same in all unit systems. The quantity and dimension of absolute permeability are determined by the unit system used.
② Vacuum permeability, which Americans call the carbon constant =. ? is a scalar with different values. Determined by each electromagnetic unit system. In the cgs (house meter, gram, second) system, m=1Gs/Oe; in the MKSA practical unit system, m=4 yuan×10\7H/m. 5.1.12 Initial permeability The slope of the magnetization curve at zero magnetic field intensity after the magnetic material is demagnetized. 8
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5.1.13 Phase analysis phase analysis
An analysis technique to identify the physical properties and defects of materials by detecting the change state of the signal phase angle. 5.1.14 Impedance analysis impedance analysis A method to study the changes in the resistance and reactance of the secondary coil and analyze the physical properties and defects of the material. 5.1.15 Harmonic analysis harmonic analysis Analysis of the vibration, phase or both of one or more harmonics of the signal received during the electromagnetic induction test. 5.1.16 Modulation analysis modulation analysis Separates or separates the modulated signal into different rates or frequency bands to identify the influence of different physical properties of the material on the total magnetic field. 5.1.17 Filling factor filling factor
The ratio of the cross-pole area of ​​the tested piece to the effective cross-sectional flux area of ​​the primary coil. speed effect
5.1.18 Speed ​​effect
The phenomenon that the signal voltage changes due to the change in the relative speed between the test piece and the test coil components. 5.1.19 Lift-off effect When the detection coil is moved away from the surface of the test piece, the magnetic coupling between them changes, resulting in a change in impedance. 5.1.20 Edge effect edge effect
Due to the sudden change in the geometry of the test piece (at the boundary), the magnetic field and eddy currents change, resulting in an impact on the output. 5.1.21 Depth of penetration depth of penetration The depth at which the current density under the surface of the test piece is equal to 37% of the current density value on the surface of the test piece. 5.1.22 Skin effect skin effect
The phenomenon that the depth of current penetration in a conductor decreases as the current frequency increases. 5.1.23 Electrical center electrical center The center of the test coil determined by the electromagnetic field distribution. 5.1.24 Coupling
In two circuit systems, the current in one circuit causes the other circuit to generate voltage. 5.2 Testing instruments
5.2.1 Eddy current testing instrument eddy current testing instrument An instrument designed using the principle of electromagnetic induction and used for eddy current testing. Currently, eddy current flaw detectors, eddy current thickness gauges, eddy current conductivity meters, eddy current separators, etc. are widely used.
5.2.2 Eddy current flaw detector eddy current flaw detector An instrument that uses the property of conductive materials to generate eddy currents in an alternating magnetic field to detect the changing signals of the superimposed magnetic field of conductive materials to characterize material defects. It is divided into [manual] eddy current flaw detector and automatic eddy current flaw detector. 5.2.3 [manual] eddy current flaw detector [manual] eddy current flaw detector The operator holds the probe and moves it back and forth on the workpiece to scan and check, and judges whether there are defects by the indication of the display instrument or the graphics on the oscilloscope. It generally includes the excitation unit, detection unit, signal processor, display, recorder and other parts. automaticeddycurrentflawdetector5.2.4 Automatic eddy current flaw detector
The eddy current flaw detector is an instrument that automates the entire process of material feeding, display, recording, and sorting. It generally includes an excitation unit, a detection unit, a signal processor, a display, a recorder, an alarm, an automatic loading and unloading device, an automatic sorting device, and other parts. 5.2.5 Eddy current thickness gauge eddy current thickness gauge is an eddy current detection instrument designed using phase analysis and phase detection methods to measure thickness. It is mainly used for thickness measurement of metal strips, foils, pipes, and coatings.
5.2.6 Eddy current conductivity meter eddy current conductivity meter is an instrument that measures conductivity by using changes in the conductivity of the test piece to cause changes in the impedance of the detection line. It is mainly used to measure the conductivity of non-ferromagnetic metals.
5.3 Parts, accessories, and materials
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