CN111896612A - Calibration method of Lorentz force micro-particle detection method - Google Patents
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- 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
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Abstract
A calibration method of a Lorentz force micro-particle detection method belongs to the detection field and comprises the following steps: firstly, three groups of sensor arrays are arranged outside a conductor to be measured, the included angle of adjacent sensor arrays in the circumferential direction is 120 degrees, and each sensor array consists of an annular Halbach magnetic system and a force sensor; then, the numerical calibration: carrying out numerical value calibration by taking a measured value obtained when the centroid of the microparticle is positioned on the axis of the conductor to be measured as a reference value, and correcting a detection result of the microparticle positioned at a certain distance from the axis; and finally, performing mathematical analysis on the measuring force obtained by the microparticles through each sensor, so as to solve the problem that the detection signals are different due to different position distributions of the microparticles on the cross section of the conductor to be detected, namely, calibrating. The method can effectively calibrate the influence of microparticles on the detection result due to different positions of the cross section of the conductor, and can be used for detecting the metallic conductor inclusions in situ, on line and in real time.
Description
Technical Field
The invention belongs to the technical field of metallurgy, electromagnetic monitoring and nondestructive testing, and particularly relates to a calibration method of a Lorentz force micro-particle detection method.
Background
In metal smelting, small amounts of slag, refractory materials and reaction products from the smelting may enter the molten metal, form non-metallic inclusions and have a very adverse effect on the process and the service performance. For example, the mechanical properties of the metal are reduced, in particular the plasticity, toughness and fatigue limit. In the severe case, the metal may be cracked during hot working and heat treatment or may be brittle when used. Therefore, the online, in-situ and quantitative monitoring of the cleanliness of the molten metal in the metallurgical process is of great significance for ensuring the key process and obtaining high-quality metal material products.
The LiMCA technology based on the Coulter principle, which is proposed by the Canada McGill university, solves the problem of realizing in-situ and quantitative detection in molten metals with the melting point temperature lower than 700 ℃, such as aluminum, and the like, and obtains practical application. However, when the method is used for monitoring the molten metal at the temperature higher than 700 ℃, great challenges are met, because the method is a contact method, a measuring electrode is directly contacted with the molten metal, and the measurement is difficult to overcome due to thermal shock, deformation of a test hole and the like. Therefore, to accomplish the task of monitoring the cleanliness of metals with higher melting points, a non-contact measurement method must be adopted.
Common nondestructive testing methods include ultrasonic testing, radiographic testing, coil eddy current testing, and the like. However, due to differences in the implementation principles, these methods are limited in accuracy and cannot be used to detect molten metal cleanliness or defects in thin wires.
The Lorentz force micro-particle detection method is a unique electromagnetic detection method for detecting micro-particles in liquid metal (DE 102013006182.2) and defects in wires (DE 102013018318.9) by utilizing the Lorentz force. The basic principle is that a small permanent magnet is arranged near a conductor to be measured to provide a magnetic field and moves relative to the conductor to be measured. According to ohm's law, induced currents (or eddy currents) are generated in the conductors, the induced currents interact with the magnetic field to generate lorentz forces, and according to newton's third law, the permanent magnets will be subjected to the reaction force of the lorentz forces, which is measurable. The force is related to the magnetic flux density of the permanent magnet, the relative speed of movement and the electrical conductivity of the conductor. This force remains constant when no microparticles (defects) are present in the conductor to be tested; when the conductor to be detected contains microparticles (or inclusion defects), the induced current is redistributed due to the difference of the conductivity of the conductor and the metal matrix, so that the Lorentz force is changed, and the microparticles and the microdefects can be quantitatively detected by measuring the force acting on the magnetic system. Due to the non-contact characteristic of the method, the defects of the traditional detection method are overcome, and the online, in-situ and quantitative detection of the cleanliness of the molten metal at any melting point temperature can be realized.
It should be noted that the spatial distribution of the magnetic field generated by the permanent magnet has a great influence on the measurement, and in general, the magnetic field generated by the regular permanent magnet decays rapidly with the distance from the conductor to be measured, and the magnetic flux density is mainly concentrated near the permanent magnet. In the lorentz force micro-particle detection method, the magnetic field needs to fully penetrate into the conductor, and the distribution of the magnetic field has great influence on the accuracy of measurement. On the other hand, since the lorentz force microparticle detection method is based on the principle of eddy current redistribution, the measurement results are different when the microparticles are located at different positions in the electromagnetic sensitive region (the region of the conductor where the electromagnetic field is strong). In the patents for detecting micro-particles in liquid metals (DE 102013006182.2) and defects in solid materials (DE 102013018318.9), no way of calibrating the micro-particles (micro-defects) at different positions in the electromagnetically sensitive region is given.
Disclosure of Invention
The invention provides a calibration method of a Lorentz force micro-particle detection method, which aims to solve the technical problem of detecting defects in thin wires and improve the detection precision of the Lorentz force micro-particle detection method.
The design concept of the invention is as follows: with the relative movement between the small permanent magnet and the thin wire, lorentz forces will be generated in the conductor according to the electromagnetic induction principle, and when there are micro-particles in the conductor, eddy currents in the conductor will be redistributed (large difference in electrical conductivity between micro-particles and conductor), and the reaction forces of the lorentz forces will act on the magnetic system and be measurable. The relationship between the force and the reaction force according to newton's third law: they are equal in size and opposite in direction. By detecting this change in force, quantitative characteristics of the size and concentration (or frequency) of the microparticles can be obtained.
It should be noted that, because the present invention is based on the principle of electromagnetic induction, when the micro-particles are located at different positions of the cross-section of the conductor, such as P1 (located on the axis) in fig. 2, P2, P3 (close to the edge, but different from the magnet, P2 closer, P3 farther) and P4 (neither at the axis nor at the edge), the distribution of the corresponding eddy currents is different, for example, when the micro-particles are close to the edge of the conductor to be measured, after entering the magnetic sensitive region, the eddy current distribution around the micro-particles is limited by the boundary condition of the conductor, and due to the conductive property, the eddy current cannot pass through the edge, but needs to be tangential to the edge. In view of this, even microparticles of the same size, when they are located at the center, or at different radii, or even at different distances from the magnetic field at the same radius, will cause the amplitude of the pulse signal measured on the force sensor to be different, which is why the calibration method of the present invention is used to calibrate the measurement process.
The invention is realized by the following technical scheme.
A calibration method of a Lorentz force micro-particle detection method comprises the following steps:
s1, arranging three groups of sensor arrays coaxially and at equal intervals outside the conductor to be detected along the axial direction of the conductor to be detected, wherein the included angle of the adjacent sensor arrays in the circumferential direction is 120 degrees, each sensor array consists of an annular Halbach magnetic system and a force sensor, the annular Halbach magnetic system is electrically connected with the force sensors, and the annular Halbach magnetic system is a relatively uniform magnetic field distributed in an electromagnetic sensitive area;
s2, numerical calibration: the method comprises the following steps of performing numerical value calibration by taking a measured value obtained when the centroid of the micro-particle is positioned on the axis of the conductor to be detected as a reference value, and correcting a detection result of the micro-particle positioned at a certain distance away from the axis, wherein the method comprises the following specific steps:
the micro-particles are randomly distributed in the cylindrical conductor to be detected, which also means that the distance of each micro-particle from the axis on the section of the conductor to be detected is also randomly distributed, the calibration sensor is used for detecting a measurement signal of the micro-particle passing through the electromagnetic sensitive area, the reaction force of the lorentz force obtained when the centroid of the micro-particle is located on the axis of the conductor to be detected is used as a reference value to carry out numerical calibration, the relation between the measurement force and the size of the micro-particle is obtained, and the detection result of the micro-particle located at any radius of the cross section of the conductor to be detected is calibrated and corrected;
the numerical calibration method comprises the following steps: the speed of the conductor to be measured is constant speed V, and a force signal delta F' can be measured on a magnetic system on the assumption that the microparticles are positioned on an axis; while the velocity V of the conductor was kept constant, a series of fine particles having respective radii of sizes R1, R2, … and Rn were used to calculate the reaction force (Δ F ') to the Lorentz force obtained by the fine particles'R1，ΔF′R2，...，ΔF′Rn) Determining the relation between the measuring force delta F' and the volume of the microparticles by a curve fitting method;
s3, when the micro-particles pass through the electromagnetic sensitive area of each sensor at any distance from the axis, the measurement signals corresponding to each particle are respectively delta F according to the distance on the axis of each force sensor and the movement speed of the conductor to be measured1″，ΔF2″，ΔF3″，…，ΔFnAnd obtaining a measured force signal Δ F "corresponding to the microdefect or inclusion by performing weighted average on the measured values, and determining the size of the microparticles according to the calibration process of step S2 to complete the detection of one microparticle.
Furthermore, the wave number k of the annular Halbach magnetic system is 2, and the degree of uniformity of the magnetic field distribution in the conductor to be measured on the middle section can be ensured to be greatly optimized compared with the cubic permanent magnet described in the patent (DE102013006182.2, DE102013018318.9) through numerical simulation calculation optimization, so that the influence of the nonuniformity of the magnetic field on the measurement result is reduced. The sensor array is provided with three groups at equal intervals along the axis direction of the conductor to be measured, and the axial distance between adjacent sensor arrays is based on that the electromagnetic sensitive areas of the magnetic systems of adjacent annular Halbach magnetic systems are not mutually overlapped.
Further, the conductor to be tested is a solid wire prepared by a casting process of the metal liquid to be tested or a solid wire prepared by a drawing process of the metal wire; the axial moving speed of the conductor to be measured is 0.1-10m/s, and the diameter of the conductor to be measured is less than or equal to 1 mm.
Further, the microparticles are oxides, nitrides, sulfides or other nonmetallic inclusions, and the particle size of the microparticles is micron-sized.
Further, the nominal size of the microparticles is 10-500 μm.
Further, the calibration error for the microparticle size is less than 6%.
Compared with the prior art, the invention has the beneficial effects that:
1. the method has a simple measurement principle, and can detect the microparticles in the conductor to be detected only by measuring the reaction force of the Lorentz force;
2. the invention can obtain relatively uniform magnetic field by designing and manufacturing permanent magnet with specific shape;
3. the invention uses a micro force sensor, has high measurement precision and can detect micron-sized micro particles of the conductor to be measured;
4. the invention has high detection speed and can detect the impurities in the metal conductor to be detected on line, quickly and in real time.
In conclusion, the calibration method based on the Lorentz force micro-particle detection method can effectively correct the influence of the micro-particles on the detection result due to different positions of the cross section of the conductor, and can be used for detecting the impurities in the metal conductor to be detected in situ, on line and in real time.
Drawings
FIG. 1 is a schematic diagram of the dimension range of the conductor and the microparticles to be measured in the flow channel with the circular cross section.
FIG. 2 is a schematic diagram of the micro-particles of the present invention located at different positions on the cross-section of the conductor to be measured.
FIG. 3 is a vector diagram of the distribution of the magnetic induction intensity of the cross section of the conductor to be measured when the magnetic system is a 1mm cubic permanent magnet calculated by numerical simulation in the invention.
Fig. 4 is a diagram showing an eddy current distribution of the conductor to be measured containing microparticles when the magnetic system is a 1mm cubic permanent magnet calculated by numerical simulation in the present invention.
Fig. 5 is a vector diagram of the distribution of the magnetic induction intensity of the cross section of the conductor to be measured when the magnetic system is an annular Halbach magnetic system with the wave number k being 2, which is calculated through numerical simulation.
Fig. 6 is an eddy current distribution diagram of a micro-particle contained in a conductor to be measured when a magnetic system calculated by numerical simulation is an annular Halbach magnetic system with a wave number k being 2.
Fig. 7 is a diagram of a measurement force signal change rule of microparticles at eccentric positions of different angles of the cross section of a metal conductor to be measured by numerical simulation calculation when an annular Halbach magnetic system is adopted in the invention, wherein the initial position of an angle theta is positioned at the positive direction of an x axis, and the angle theta is increased along with the counterclockwise rotation.
FIG. 8 is a schematic structural diagram of a device for calibration using a Halbach magnet system array according to the present invention.
FIG. 9 is a schematic structural diagram of a device for calibration using a Halbach magnet system array according to the present invention.
In the figure, 1 is a conductor to be measured, 2 is a microparticle, 3 is a permanent magnet, 4 is a magnetic induction intensity distribution vector, 5 is an induced current, and 6 is an annular Halbach magnetic system.
Wherein S and N are respectively the south and north poles of the permanent magnet. P1, P2, P3 and P4 are different positions of the microparticles on the section of the conductor to be tested. V is the movement speed of the conductor to be measured in uniform movement. The arrows on each magnet unit of the ring-shaped Halbach magnet system indicate the magnetization direction. M1，M2，M3Respectively, the force signals measured by the three force sensors. T is1，T2，T3Three force sensors in the calibration array are respectively. L is the axial spacing between the calibration sensors.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A calibration method of a Lorentz force micro-particle detection method comprises the following steps:
s1, arranging three groups of sensor arrays coaxially and at equal intervals outside the conductor to be detected along the axial direction of the conductor to be detected, wherein the included angle of the adjacent sensor arrays in the circumferential direction is 120 degrees, each sensor array consists of an annular Halbach magnetic system and a force sensor, the annular Halbach magnetic system is electrically connected with the force sensors, and the annular Halbach magnetic system is a relatively uniform magnetic field distributed in an electromagnetic sensitive area;
s2, numerical calibration: the method comprises the following steps of performing numerical value calibration by taking a measured value obtained when the centroid of the micro-particle is positioned on the axis of the conductor to be detected as a reference value, and correcting a detection result of the micro-particle positioned at a certain distance away from the axis, wherein the method comprises the following specific steps:
the micro-particles are randomly distributed in the cylindrical conductor to be detected, the calibration sensor is used for detecting a measurement signal of the micro-particles passing through the electromagnetic sensitive area in the step S1, numerical calibration is carried out by taking the reaction force of the Lorentz force obtained when the centroid of the micro-particles is positioned on the axis of the conductor to be detected as a reference value, the relation between the measurement force and the size of the micro-particles is obtained, and the detection result of the micro-particles positioned at any radius of the cross section of the conductor to be detected is calibrated and corrected;
the numerical calibration method comprises the following steps: the speed of the conductor to be measured is constant speed V, and a force signal delta F' can be measured on a magnetic system on the assumption that the microparticles are positioned on an axis; while the velocity V of the conductor was kept constant, a series of fine particles having respective radii of sizes R1, R2, … and Rn were used to calculate the reaction force (Δ F ') to the Lorentz force obtained by the fine particles'R1，ΔF′R2，...，ΔF′Rn) Determining the relation between the measuring force delta F' and the volume of the microparticles by a curve fitting method;
s3, when the micro-particles pass through the electromagnetic sensitive area of each sensor at any distance from the axis, the measurement signals corresponding to each particle are respectively delta F according to the distance on the axis of each force sensor and the movement speed of the conductor to be measured1″，ΔF2″，ΔF3″，…，ΔFnAnd obtaining a measured force signal Δ F "corresponding to the microdefect or inclusion by performing weighted average on the measured values, and determining the size of the microparticles according to the calibration process of step S2 to complete the detection of one microparticle.
Further, the wave number k of the annular Halbach magnetic system is 2, and the axial distance between adjacent sensor arrays is based on that the electromagnetic sensitive areas of the adjacent annular Halbach magnetic systems do not overlap with each other.
Further, the conductor 1 to be tested is a solid wire prepared by a casting process of the metal liquid to be tested, or a solid wire prepared by a drawing process of the metal wire; the axial moving speed of the conductor 1 to be measured is 0.1-10m/s, and the diameter of the conductor 1 to be measured is less than or equal to 1 mm.
Further, the microparticles are oxides, nitrides, sulfides or other nonmetallic inclusions, and the particle size of the microparticles is micron-sized.
Further, the nominal size of the microparticles is 10-500 μm.
Further, the calibration error for the microparticle size is less than 6%.
As shown in FIG. 1, in the Lorentz force micro-particle detection method, the nominal size D of the conductor 1 to be measured is in the range of 150-1000 μm, wherein the nominal size of the non-metal containing micro-particles 2 is in the range of 10-500 μm, the nominal size of the permanent magnet 3 is in the range of 0.3-1mm, and the distance between the permanent magnet 3 and the conductor 1 to be measured is less than 1mm, so that the magnetic field generated by the permanent magnet 3 can penetrate into the conductor 1 to be measured.
As shown in fig. 2, since the size of the microparticles 2 is smaller than that of the conductor 1 to be tested, in actual industrial practice, the microparticles 2 are randomly distributed on the cross section of the conductor 1 to be tested, and their typical positions are shown as P1, P2, P3 and P4 in fig. 2. Since the lorentz force microparticle detection method is based on the principle of eddy current variation, when the microparticles 2 are located at different positions on the cross section of the conductor 1 to be measured, the eddy current distribution is different, which causes that even microparticles of the same size obtain different signals on the force sensor.
Fig. 3 and 4 are respectively a vector diagram of the distribution of the magnetic induction intensity of the cross section of the conductor to be measured when the magnetic system is a 1mm cubic permanent magnet in the numerical simulation method of the present invention and an eddy current distribution diagram of the conductor to be measured containing microparticles. As shown, the eddy current distribution of microparticles 2 of the same size at the cross-sectional axis and edge is greatly different, and considering the situation of fig. 2, even microparticles of the same size, when they are located at the cross-sectional axis, or at different radii, or even at different angles of the same radius, will have different signals measured by the force sensor due to the different eddy current distribution, which requires calibration of the lorentz force microparticle detection method.
In the lorentz force microparticle detection method, the spatial distribution of the magnetic field generated by the permanent magnet 3 greatly affects the measurement, and in general, the magnetic field generated by a regularly shaped permanent magnet attenuates rapidly as the distance from the conductor to be measured increases, and the magnetic flux density is mainly concentrated near the permanent magnet 3, as shown in fig. 3. The generated magnetic field is required to be fully penetrated into the conductor, and the distribution uniformity of the generated magnetic field has a large influence on the accuracy of measurement. In this embodiment, by designing the annular Halbach magnetic system with the wave number k being 2, as shown in fig. 5, the uniformity of the magnetic induction intensity distribution in the cross section of the conductor 1 to be measured is greatly optimized compared with that in fig. 3, and the adverse effect of the nonuniformity of the magnetic field on the measurement can be reduced. After the uniformity of the distribution of the magnetic induction intensity is improved, the distribution of the induced current of the cross section of the conductor 1 to be detected in the lorentz force micro-particle detection method can be more uniform, as shown in fig. 6.
Specifically, the Halbach magnetic system using the wave number k of 2 is composed of 4n (where n is 3,4,5,6 …) small magnets, each of which has a size equivalent to that of a 1mm cubic permanent magnet, and the magnetization directions of which are regularly arranged, as shown in fig. 5 and 6. As can be seen from a comparison of fig. 3 and 5 and fig. 4 and 6, when the Halbach magnetic system with the wave number k of 2 is used, the uniformity of the magnetic induction intensity distribution is greatly improved compared with the cubic permanent magnet.
In this embodiment, due to the symmetry of the Halbach magnetic system, the force signal distribution of the micro-particles in the circumferential direction of the cross section of the metal conductor to be measured at the same radius and different angles should have periodicity, as shown in fig. 7. In fig. 7, the force signal distribution has a similar sinusoidal variation division rule, and if three force sensors are uniformly arranged in the circumferential direction of the conductor to be measured at intervals of 120 °, the force signals measured by the three force sensors can be respectively expressed as:
where Δ F "and C are both constants, θ0For the angle that the first sensor is located, have after summing the left and right sides of the above-mentioned three formulas: Δ F ″ (M)1+M2+M3) The/3 is that the force signals measured by the three sensors are mathematically averaged to obtain a constant value Δ F ", and the constant value is independent of the angle of the sensor, which is a necessary result of the sinusoidal variation law of the force signals. The more in-depth numerical simulation result shows that the deviation between the delta F 'and the force signal delta F' when the micro-particles are positioned at the axis of the section of the conductor 1 to be detected is less than 6 percent, and the aim of calibrating the Lorentz force micro-particle detection method is fulfilled.
In this embodiment, 3 force sensors are configured by being uniformly arranged within 120 ° of the circumferential direction and being axially separated by a certain distance, and are respectively denoted as T1,T2And T3Forming a sensor array, as shown in FIG. 8, T1And T2And T2And T3The magnetic induction directions of (a) and (b) respectively form an included angle of 120 degrees, as shown in fig. 9. From the sine distribution of the force signals in fig. 7, the measurement results of the 3 force sensors are mathematically processed to obtain the calibrated force signal Δ F ″, and then the size of the micro-particles is determined according to the calibration process described above, thereby completing the detection of one micro-particle. The selection of the distance L between the 3 force sensors in the axial direction is based on the fact that the magnetic fields of adjacent magnetic systems do not interfere with each other, so that the interference of the mutual overlapping of the magnetic fields of different sensors on the measurement result is avoided. Fig. 8 and 9 are schematic front and top views, respectively, of an apparatus for calibration using a Halbach magnet system array in the method of the present invention.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (6)
1. A calibration method of a Lorentz force micro-particle detection method is characterized by comprising the following steps:
s1, three groups of sensor arrays are coaxially and equidistantly arranged outside the conductor (1) to be detected along the axial direction of the conductor (1) to be detected, the included angle of the adjacent sensor arrays in the circumferential direction is 120 degrees, each sensor array consists of an annular Halbach magnetic system (6) and a force sensor, the annular Halbach magnetic systems (6) are electrically connected with the force sensors, and the annular Halbach magnetic systems (6) are relatively uniform magnetic fields distributed in an electromagnetic sensitive area;
s2, numerical calibration: the method comprises the following steps of performing numerical value calibration by taking a measured value obtained when the mass center of each microparticle (2) is located on the axis of a conductor (1) to be detected as a reference value, and correcting a detection result of the microparticle (2) located at a certain distance away from the axis, wherein the method comprises the following specific steps:
the method comprises the following steps that microparticles (2) are randomly distributed in a cylindrical conductor (1) to be detected, the calibration sensor is used for detecting a measurement signal of the microparticles (2) passing through an electromagnetic sensitive area in step S1, numerical calibration is carried out by taking the reaction force of Lorentz force obtained when the centroid of the microparticles (2) is located on the axis of the conductor (1) to be detected as a reference value, the relation between the measurement force and the size of the microparticles (2) is obtained, and calibration correction is carried out on the detection result of the microparticles (2) located at any radius of the cross section of the conductor (1) to be detected;
the numerical calibration method comprises the following steps: the speed of the conductor (1) to be measured is constant speed V, and a force signal delta F' can be measured on a magnetic system on the assumption that the microparticles (2) are positioned on an axis; calculating the reaction force (delta F ') of Lorentz force obtained by the microparticles (2) by taking a series of microparticles (2) with the size radiuses of R1, R2, … and Rn respectively and keeping the speed V of the conductor constant'R1，ΔF′R2，...，ΔF′Rn) Determining the relation between the measuring force delta F' and the volume of the microparticles (2) by a curve fitting method;
s3, when the microparticles (2) pass through the electromagnetic sensitive area of each sensor at any distance from the axis, obtaining each distance on the axis of each force sensor and the movement speed of the conductor (1) to be measuredThe measurement signals corresponding to the respective particles are respectively Δ F1″，ΔF2″，ΔF3″，…，ΔFnThe measured force signal Δ F "corresponding to the micro-defect or inclusion is obtained by weighted averaging of the measured values, and then the size of the micro-particles (2) is determined according to the calibration procedure of step S2, completing the detection of one micro-particle (2).
2. The calibration method of claim 1, wherein the calibration method is based on the Lorentz force micro-particle detection method, and comprises the following steps: the wave number k of the annular Halbach magnetic system (6) is 2, and the axial distance between adjacent sensor arrays is based on that the electromagnetic sensitive areas of the adjacent annular Halbach magnetic systems (6) are not mutually overlapped.
3. The calibration method of claim 1, wherein the calibration method is based on the Lorentz force micro-particle detection method, and comprises the following steps: the conductor (1) to be tested is a solid wire prepared by a casting process of molten metal to be tested or a solid wire prepared by a drawing process of a metal wire; the axial moving speed of the conductor (1) to be tested is 0.1-10m/s, and the diameter of the conductor (1) to be tested is less than or equal to 1 mm.
4. The calibration method of claim 1, wherein the calibration method is based on the Lorentz force micro-particle detection method, and comprises the following steps: the micro-particles (2) are oxides, nitrides, sulfides or other nonmetallic inclusions, and the particle size of the micro-particles (2) is micron-sized.
5. The calibration method of claim 1, wherein the calibration method is based on the Lorentz force micro-particle detection method, and comprises the following steps: the nominal size of the microparticles (2) is 10-500 μm.
6. A method of calibrating a particle detector based on Lorentz forces as claimed in any of claims 1, 4 or 5, wherein: the calibration error of the size of the microparticles (2) is less than 6%.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6590200B1 (en) * | 1999-04-02 | 2003-07-08 | Worcester Polytechnic Institute | Systems for detecting measuring inclusions |
| US20080252287A1 (en) * | 2005-09-21 | 2008-10-16 | Technische Universitat Iimenau | Method and Arrangement for the Contactless Inspection of Moving Electrically Conductive Substances |
| DE102013006182A1 (en) * | 2013-04-08 | 2014-10-09 | Technische Universität Ilmenau | Apparatus and method for detecting particles in liquid metals |
| DE102013018318A1 (en) * | 2013-10-25 | 2015-04-30 | Technische Universität Ilmenau | Apparatus and method for detecting defects in electrically conductive wires |
| CN104903717A (en) * | 2012-09-06 | 2015-09-09 | 霍释特博士有限两合公司 | Differential sensor, inspection system and method for the detection of anomalies in electrically conductive materials |
| CN108802170A (en) * | 2017-04-28 | 2018-11-13 | 中国科学院大学 | A kind of electromechanical detection method of whole audience formula defect using electronic speckle technology |
-
2020
- 2020-06-15 CN CN202010544196.6A patent/CN111896612A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6590200B1 (en) * | 1999-04-02 | 2003-07-08 | Worcester Polytechnic Institute | Systems for detecting measuring inclusions |
| US20080252287A1 (en) * | 2005-09-21 | 2008-10-16 | Technische Universitat Iimenau | Method and Arrangement for the Contactless Inspection of Moving Electrically Conductive Substances |
| CN104903717A (en) * | 2012-09-06 | 2015-09-09 | 霍释特博士有限两合公司 | Differential sensor, inspection system and method for the detection of anomalies in electrically conductive materials |
| DE102013006182A1 (en) * | 2013-04-08 | 2014-10-09 | Technische Universität Ilmenau | Apparatus and method for detecting particles in liquid metals |
| DE102013018318A1 (en) * | 2013-10-25 | 2015-04-30 | Technische Universität Ilmenau | Apparatus and method for detecting defects in electrically conductive wires |
| CN108802170A (en) * | 2017-04-28 | 2018-11-13 | 中国科学院大学 | A kind of electromechanical detection method of whole audience formula defect using electronic speckle technology |
Non-Patent Citations (1)
| Title |
|---|
| BO WANG ET AL.: "Numerical calibration of a Lorentz force particle analyzer", 《MEASUREMENT SCIENCE AND TECHNOLOGY》 * |
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