CN110568061A - magnetic powder detection method for circumferential defects of inner wall of hole - Google Patents
magnetic powder detection method for circumferential defects of inner wall of hole Download PDFInfo
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- CN110568061A CN110568061A CN201910873356.9A CN201910873356A CN110568061A CN 110568061 A CN110568061 A CN 110568061A CN 201910873356 A CN201910873356 A CN 201910873356A CN 110568061 A CN110568061 A CN 110568061A
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- 239000006247 magnetic powder Substances 0.000 title claims abstract description 33
- 238000001514 detection method Methods 0.000 title claims abstract description 31
- 230000007547 defect Effects 0.000 title claims abstract description 24
- 238000005286 illumination Methods 0.000 claims abstract description 13
- 238000005507 spraying Methods 0.000 claims abstract description 13
- 230000005347 demagnetization Effects 0.000 claims abstract description 9
- 238000011156 evaluation Methods 0.000 claims abstract description 5
- 238000007689 inspection Methods 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 238000009825 accumulation Methods 0.000 claims abstract description 4
- 238000004140 cleaning Methods 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 6
- 229910000976 Electrical steel Inorganic materials 0.000 claims description 3
- 239000006249 magnetic particle Substances 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 230000005415 magnetization Effects 0.000 description 6
- 230000035699 permeability Effects 0.000 description 5
- 230000004907 flux Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000009659 non-destructive testing Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
- G01N27/83—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws by investigating stray magnetic fields
- G01N27/84—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws by investigating stray magnetic fields by applying magnetic powder or magnetic ink
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
The invention discloses a magnetic powder detection method for circumferential defects of the inner wall of a hole, which comprises the following steps: cleaning the surface of an inner hole of a workpiece, and removing impurities which influence magnetic powder accumulation and carrier liquid flow; passing a high-permeability core rod along the central position of an inner hole of a workpiece and placing the core rod in a magnetizing coil; alternating current taking the direction as the circumferential direction is led into the magnetizing coil, and the current value of the alternating current is set; pre-spraying the inner hole wall of the workpiece; firstly, spraying and magnetizing the workpiece, then stopping spraying and magnetizing the workpiece for 1-2 times, wherein the time for magnetizing the workpiece every time is 1-2 s; observing whether the surface of the inner hole of the workpiece has magnetic marks or not under the proper illumination condition, and evaluating according to the product quality requirement; after the evaluation is finished, alternating current demagnetization and subsequent treatment are carried out. According to the invention, the high-permeability core rod penetrates into the inner hole of the workpiece, and the workpiece is magnetized by using the coil, so that the magnetic powder detection of circumferential defects of the inner hole wall is effectively realized, and a special magnetic powder inspection device is not required.
Description
Technical Field
the invention relates to a magnetic powder detection method for circumferential defects of an inner wall of a hole.
Background
The magnetic powder detection method can find defects which form a certain included angle with the direction of the magnetic field (when the defects are perpendicular to the direction of the magnetic field, the effect is optimal), and in order to find circumferential defects, a coil method or an induction current method is mostly adopted to magnetize the workpiece. However, when alternating current is applied in the coil method, due to the influence of the skin effect, the magnetic field of the inner wall of the workpiece hole is weak, effective magnetization cannot be obtained, and circumferential defects of the inner wall of the workpiece hole cannot be detected (except for thin-walled parts); when direct current is applied to the coil method, although circumferential defects of the inner wall of the hole can be detected, the workpiece is difficult to demagnetize, and the detection efficiency is low because several minutes or even dozens of minutes are needed; the induction current method is only suitable for thin-wall parts, and once the wall thickness of a workpiece is large, the difference of the magnetic field intensity of the inner wall and the outer wall is large (the magnetic field intensity of the inner wall is large), so that the sensitivity difference is large, and special magnetic powder inspection equipment is needed.
Disclosure of Invention
Aiming at the problems, the invention provides a magnetic powder detection method for circumferential defects of the inner wall of a hole.
in order to achieve the purpose, the invention adopts the following technical scheme:
A magnetic particle detection method for circumferential defects of the inner wall of a hole comprises the following steps:
cleaning the surface of an inner hole of a workpiece, and removing impurities which influence magnetic powder accumulation and carrier liquid flow;
Step two, passing a high-permeability core rod along the central position of the inner hole of the workpiece, and placing the core rod in a magnetizing coil;
Thirdly, alternating current taking the direction as the circumferential direction is introduced into the magnetizing coil, and the current value of the alternating current is set according to the inner diameter of the magnetizing coil, the material and the size of the high-permeability core rod and the material and the size of the workpiece;
fourthly, pre-spraying the inner hole wall of the workpiece;
fifthly, spraying and magnetizing the workpiece, stopping spraying and magnetizing the workpiece for 1-2 times, wherein the time for magnetizing the workpiece every time is 1-2 s;
step six, setting the ambient white light illumination of the detection area not more than 20lx and the ultraviolet light illumination of the detection area not less than 1000 muW/cm during fluorescent magnetic powder detection2(ii) a When non-fluorescent magnetic powder is detected, setting the white light illumination of a detection area to be not lower than 1000lx, observing whether the surface of an inner hole of a workpiece has magnetic marks or not under the illumination condition, and evaluating according to the product quality requirement;
And seventhly, after the evaluation is finished, carrying out alternating current demagnetization and subsequent treatment.
And step seven, when demagnetizing, firstly, placing the workpiece at the position where the workpiece is positioned when magnetizing, and then, introducing gradually-reduced alternating current into the magnetizing coil to demagnetize the workpiece.
and further, the high-permeability core rod in the step two is a silicon steel sheet core rod.
further, in the sixth step, if the observation is influenced by the high-permeability core rod during evaluation, the high-permeability core rod is taken out and then observed.
Further, in the seventh step, the high-permeability core rod is located at the same or a similar position of the magnetized workpiece during demagnetization.
Has the advantages that:
1. according to the invention, the high-permeability core rod penetrates into the inner hole of the workpiece, and the workpiece is magnetized by using the coil, so that the magnetic powder detection of circumferential defects of the inner hole wall is effectively realized, and a special magnetic powder inspection device is not required.
2. according to the invention, because the high-permeability core rod penetrates into the inner hole of the workpiece, induced current can be generated in the workpiece, and further a magnetic field can be generated on the wall of the inner hole of the workpiece, so that the circumferential defects of the wall of the inner hole can be detected.
3. the invention adopts alternating current magnetization, so that alternating current demagnetization can be directly adopted, thereby solving the problem of difficult workpiece demagnetization.
4. the invention is suitable for both thin-wall parts and thick-wall parts, and although the magnetic field generated by the induced current on the outer wall of the workpiece is smaller, the magnetic field of the magnetizing coil on the outer wall of the workpiece is larger, the two magnetic fields have the same direction and are mutually superposed, thereby realizing magnetic powder detection.
Drawings
FIG. 1 is a schematic diagram of the detection principle of the present invention;
In the figure: 1-a magnetizing coil; 2-a high magnetic permeability core rod; 3-a workpiece; 4-inner hole wall circumferential defect; 5-direction of magnetization current; 6-direction of magnetic force line in the high magnetic conductivity core rod; 7-inducing a current direction in the workpiece; 8-inducing current to generate magnetic field direction on the inner hole wall of the workpiece.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
The invention provides a magnetic powder detection method for circumferential defects of the inner wall of a hole, as shown in figure 1, on the basis of a general magnetic powder flaw detector, a high-permeability core rod 2 (a common silicon steel sheet core rod) is utilized to penetrate into an inner hole of a workpiece 3, and is arranged in a magnetizing coil 1, alternating current with the direction of 5 is conducted in the magnetizing coil 1, longitudinal magnetic lines of force are generated around the magnetizing coil 1, wherein a larger part of the magnetic flux passes through the high magnetic permeability core rod 2, the magnetic flux lines in the high magnetic permeability core rod 2 pass through the workpiece 3 along the direction 6, the magnetic lines of force are alternated, so that an induced current with the direction of 7 can be generated on the workpiece 3, the induced current then generates a magnetic field direction 8 which is parallel to the longitudinal direction on the inner hole wall of the workpiece 3, and then, a leakage magnetic field is formed at the circumferential defect 4 of the inner hole wall, and the existence of the circumferential defect of the inner hole wall can be judged through a conventional magnetic powder display mode. The method comprises the following specific steps:
Cleaning the surface of an inner hole of a workpiece 3, and removing impurities which influence magnetic powder accumulation and carrier liquid flow;
secondly, a high-permeability core rod 2 penetrates through the center position of the inner hole of the workpiece 3 to ensure that the magnetic field intensity of the inner hole wall of the workpiece 3 is uniform, and the core rod is placed in a magnetizing coil 1;
thirdly, alternating current taking the direction as the circumference is led into the magnetizing coil 1, the current value of the alternating current is set according to the inner diameter of the magnetizing coil 1, the material and the size of the high-permeability core rod 2 and the material and the size of the workpiece 3, and the current value of the alternating current can be specifically set and verified according to the method specified in GB/T15822.1 part 1-general rule of nondestructive testing magnetic powder testing;
Fourthly, pre-spraying the inner hole wall of the workpiece 3, wherein the conventional magnetic powder detection process can reduce the magnetization times and improve the magnetization efficiency;
Step five, spraying and magnetizing the workpiece 3, then stopping spraying and magnetizing the workpiece 31-2 times, wherein the time for magnetizing the workpiece 3 every time is 1-2s, and the conventional magnetic powder detection process needs enough time because the leakage magnetic field attracts magnetic powder to reach the defect, so that the magnetizing time cannot be too short, but the overlong magnetizing time can improve the requirement on the power supply of equipment and even damage the power supply; the formed magnetic traces can be prevented from being washed away by the magnetic suspension liquid by magnetization after the spraying is stopped;
Step six, setting the ambient white light illumination of the detection area not more than 20lx and the ultraviolet light illumination of the detection area not less than 1000 muW/cm during fluorescent magnetic powder detection2(ii) a During non-fluorescent magnetic powder detection, setting the white light illumination of a detection area to be not lower than 1000lx, specifically observing the conditions of nondestructive testing penetration testing and magnetic powder testing observation in ISO 3059-2012, observing whether the surface of an inner hole of a workpiece 3 has magnetic traces under the illumination condition, and evaluating according to the product quality requirement;
And seventhly, after the evaluation is finished, carrying out alternating current demagnetization and subsequent treatment. The alternating current demagnetization is to place the workpiece 3 at the position where the workpiece is magnetized, and then to energize the magnetizing coil 1 with decreasing alternating current to demagnetize the workpiece 3. When demagnetizing, the high magnetic conductivity core rod 2 should be in the same or similar position of the magnetized workpiece 3; when evaluating, if the observation is influenced by the high magnetic permeability core rod 2, the high magnetic permeability core rod 2 can be taken out and then observed.
The limitation of the protection scope of the present invention is understood by those skilled in the art, and various modifications or changes which can be made by those skilled in the art without inventive efforts based on the technical solution of the present invention are still within the protection scope of the present invention.
Claims (5)
1. a magnetic particle detection method for circumferential defects of the inner wall of a hole is characterized by comprising the following steps:
cleaning the surface of an inner hole of a workpiece (3) and removing impurities which influence magnetic powder accumulation and carrier liquid flow;
Secondly, a high-permeability core rod (2) penetrates through the center position of the inner hole of the workpiece (3) and is placed in the magnetizing coil (1);
Thirdly, alternating current taking the direction as the circumferential direction is introduced into the magnetizing coil (1), and the current value of the alternating current is set according to the inner diameter of the magnetizing coil (1), the material and the size of the high-permeability core rod (2) and the material and the size of the workpiece (3);
Fourthly, pre-spraying the inner hole wall of the workpiece (3);
Fifthly, spraying and magnetizing the workpiece (3) at first, then stopping spraying and magnetizing the workpiece (3) for 1-2 times, wherein the time for magnetizing the workpiece (3) every time is 1-2 s;
Step six, setting the ambient white light illumination of the detection area not more than 20lx and the ultraviolet light illumination of the detection area not less than 1000 muW/cm during fluorescent magnetic powder detection2(ii) a When non-fluorescent magnetic powder is detected, setting the white light illumination of a detection area to be not lower than 1000lx, observing whether the surface of the inner hole of the workpiece (3) has magnetic marks or not under the illumination condition, and evaluating according to the product quality requirement;
and seventhly, after the evaluation is finished, carrying out alternating current demagnetization and subsequent treatment.
2. the magnetic powder inspection method for circumferential defects of the inner wall of the hole according to claim 1, wherein in the seventh step, the workpiece (3) is placed at the position where the workpiece is magnetized when demagnetized, and then the workpiece (3) can be demagnetized by introducing gradually decreasing alternating current into the magnetizing coil (1).
3. The magnetic powder detection method for the circumferential defects of the inner wall of the hole according to claim 1, wherein the high-permeability core rod (2) in the second step is a silicon steel sheet core rod.
4. The magnetic particle inspection method for circumferential defects of the inner wall of the hole according to claim 1, wherein in the sixth step, if the observation is influenced by the high-permeability core rod (2), the high-permeability core rod (2) is taken out and then observed.
5. the magnetic powder detection method for circumferential defects of the inner wall of the hole according to claim 1, wherein in the seventh step, the high-permeability core rod (2) is positioned at the same or a similar position of the magnetized workpiece (3) during demagnetization.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910873356.9A CN110568061A (en) | 2019-09-17 | 2019-09-17 | magnetic powder detection method for circumferential defects of inner wall of hole |
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| CN201910873356.9A CN110568061A (en) | 2019-09-17 | 2019-09-17 | magnetic powder detection method for circumferential defects of inner wall of hole |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111458402A (en) * | 2020-03-31 | 2020-07-28 | 中国航发动力股份有限公司 | Induction current device |
| CN112505058A (en) * | 2020-11-24 | 2021-03-16 | 国电锅炉压力容器检验有限公司 | Defect eliminating and detecting method for ferromagnetic metal workpiece cracks |
| CN112505137A (en) * | 2020-10-30 | 2021-03-16 | 哈尔滨飞机工业集团有限责任公司 | Magnetic particle detection method and tool for small-diameter through hole steel part |
| CN112666247A (en) * | 2020-12-18 | 2021-04-16 | 南京迪威尔高端制造股份有限公司 | Magnetic powder detection device and method for circumferential defects of inner wall and outer wall of ferromagnetic product hole |
| CN112834608A (en) * | 2021-01-06 | 2021-05-25 | 广东核电合营有限公司 | Hole wall defect detection method for nuclear power station |
| CN114264720A (en) * | 2021-11-05 | 2022-04-01 | 中国航发北京航科发动机控制系统科技有限公司 | Magnetic powder detection method for end surface cracks of semi-hollow shaft |
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| CN108120763A (en) * | 2017-11-27 | 2018-06-05 | 江阴市永兴机械制造有限公司 | A kind of high-frequency impulse magnetic powder inspection method |
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| JPH08110322A (en) * | 1994-10-11 | 1996-04-30 | Eishin Kagaku Kk | Magnetic powder flaw detection magnetizing apparatus |
| JPH10177928A (en) * | 1996-10-15 | 1998-06-30 | Minebea Co Ltd | Molding device for cylindrical radial anisotropic magnet |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111458402A (en) * | 2020-03-31 | 2020-07-28 | 中国航发动力股份有限公司 | Induction current device |
| CN111458402B (en) * | 2020-03-31 | 2023-08-29 | 中国航发动力股份有限公司 | Induced current device |
| CN112505137A (en) * | 2020-10-30 | 2021-03-16 | 哈尔滨飞机工业集团有限责任公司 | Magnetic particle detection method and tool for small-diameter through hole steel part |
| CN112505058A (en) * | 2020-11-24 | 2021-03-16 | 国电锅炉压力容器检验有限公司 | Defect eliminating and detecting method for ferromagnetic metal workpiece cracks |
| CN112666247A (en) * | 2020-12-18 | 2021-04-16 | 南京迪威尔高端制造股份有限公司 | Magnetic powder detection device and method for circumferential defects of inner wall and outer wall of ferromagnetic product hole |
| CN112834608A (en) * | 2021-01-06 | 2021-05-25 | 广东核电合营有限公司 | Hole wall defect detection method for nuclear power station |
| CN112834608B (en) * | 2021-01-06 | 2022-10-28 | 广东核电合营有限公司 | Hole wall defect detection method for nuclear power station |
| CN114264720A (en) * | 2021-11-05 | 2022-04-01 | 中国航发北京航科发动机控制系统科技有限公司 | Magnetic powder detection method for end surface cracks of semi-hollow shaft |
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