Barkhausen noise signal detection equipment

Abstract

The invention provides Barkhausen noise signal detection equipment which comprises an H-shaped magnet yoke and a Barkhausen noise signal detection coil, the H-shaped magnet yoke comprises a transverse column and two foot columns, the transverse column is connected between the two foot columns, and the side faces, close to the transverse column, of the two foot columns are bonded with copper foil parts and are grounded through the copper foil parts. According to the Barkhausen noise signal detection equipment provided by the invention, the copper foil parts are adhered to the side surfaces, close to the transverse column, of the two foot columns of the H-shaped magnet yoke and are grounded through the copper foil parts, so that the magnetization effect of the test piece can be enhanced, and meanwhile, the influence of an excitation source on Barkhausen noise signal receiving can be reduced; and the detection precision of the Barkhausen noise signal detection equipment is improved.

Description

Technical Field

[0001] The present invention generally relates to the technical field of nondestructive testing, and in particular to a Barkhausen noise signal detection device. Background Art

[0002] During the long-term thermal aging process, the microstructure of P92 steel material will change, resulting in changes in mechanical properties such as material hardness, yield strength and impact absorption energy. These factors work together to aggravate the decline in creep strength of P92 steel material and reduce its service life. In order to avoid failure of P92 steel material, it will be tested by Barkhausen noise signal detector to obtain the service life of P92 steel material.

[0003] The existing Barkhausen noise signal detector includes a detection coil and a magnetic yoke. Due to the limitation of the miniaturized design of the detector, the distance between the detection coil and the magnetic yoke is small, which further affects the detection accuracy of the Barkhausen noise signal detector. Summary of the invention

[0004] In view of the above defects or deficiencies in the prior art, it is desirable to provide a Barkhausen noise signal detection device.

[0005] The present application provides a Barkhausen noise signal detection device, including an H-type yoke and a Barkhausen noise signal detection coil, the H-type yoke includes a cross column and two legs, the cross column is connected between the two legs, and the sides of the two legs close to the cross column are both bonded with copper foil parts and grounded through the copper foil parts.

[0006] Furthermore, the H-shaped yoke is formed by pressing 40 layers of oriented silicon steel sheets, and the thickness of the oriented silicon steel sheets is 0.2 mm.

[0007] Furthermore, it also includes an excitation coil, which is tightly wound on the horizontal column of the H-shaped magnetic yoke in the same direction.

[0008] Furthermore, it also includes an I-shaped magnetic core, and the material of the I-shaped magnetic core is manganese-zinc ferrite.

[0009] Furthermore, the Barkhausen noise signal detection coil is tightly wound on the I-shaped magnetic core in the same direction, and the Barkhausen noise signal detection coil and the I-shaped magnetic core constitute a Barkhausen noise signal detector.

[0010] Further, the Barkhausen noise signal detector is located in the middle of the two foot columns.

[0011] Furthermore, the bottom surface of the Barkhausen noise signal detector is coplanar with the bottom surface of the H-shaped magnetic yoke.

[0012] The Barkhausen noise signal detection device provided in the present application can not only enhance the magnetization effect of the test piece, but also reduce the influence of the excitation source on the reception of the Barkhausen noise signal, thereby improving the detection accuracy of the Barkhausen noise signal detection device, by bonding copper foil portions to the sides of the two legs of the H-shaped magnetic yoke close to the cross column and grounding through the copper foil portions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0014] Figure 1 A schematic diagram of the structure of a Barkhausen noise signal detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0015] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0016] Please refer to the attached Figure 1 The embodiment of the present application provides a Barkhausen noise signal detection device, comprising an excitation coil 1, an H-shaped magnetic yoke 2, a shielding layer, a Barkhausen noise signal detection coil 4, an I-shaped manganese-zinc ferrite core 5 and a sensor housing 7. The excitation coil 1 is tightly wound on the horizontal column of the H-shaped magnetic yoke 2 along a fixed direction. When the excitation signal acts on the excitation coil 1, an alternating magnetic field is generated in the magnetic yoke 2. The magnetic field is transmitted to the test piece 6 close to the magnetic yoke 2 to generate a Barkhausen noise signal on its surface. The noise signal is received using the Barkhausen noise signal detection coil 4 wound on the I-shaped manganese-zinc ferrite. The detector is fixed in the middle position of the two legs of the H-shaped silicon steel sheet magnetic yoke 2 and is located in the same plane as the bottom of the magnetic yoke 2. The copper foil part 3 is pasted on the inner wall of the two legs of the magnetic yoke 2 to reduce the interference between the magnetic yoke 2 and the detector, and finally tightly packaged together with the sensor housing 7.

[0017] Compared with the U-shaped yoke 2, the H-shaped yoke 2 does not affect the performance, but also facilitates the winding of the excitation coil 1, reducing the difference caused by making sensors of the same style. The material of the Barkhausen sensor yoke 2 is mainly manganese-zinc ferrite or silicon steel sheet. The manganese-zinc ferrite material has the characteristics of high magnetic permeability and high frequency and low loss, but it is easy to appear magnetic saturation at low frequency. Under the action of the excitation signal less than 200Hz, the silicon steel sheet working on the low-frequency excitation signal is more suitable, and also has the advantages of high magnetic permeability, low hysteresis loss, easy demagnetization and suitable for secondary processing. The Barkhausen noise sensor found through experiments is more suitable for using low-frequency excitation signals, so silicon steel sheet is used as the yoke 2 material. The H-shaped yoke 2 is pressed by 40 0.2mm oriented silicon steel sheets, and 300 turns of 0.21mm high temperature and high pressure resistant polyester enameled round copper wire are wound in the same direction on its cross column. The copper wire has good electrical properties and is suitable as an excitation coil 1. It is found through research that the frequency band distribution of Barkhausen noise signal is 1KHz~2MHz, usually concentrated between 1KHz~500KHz, and the signal strength is weak, only at the millivolt level, so a Barkhausen noise signal detection coil 4 with high sensitivity and covering the frequency band of Barkhausen noise signal is selected to detect the signal. The detector is composed of a magnetic core 5 and a Barkhausen noise signal detection coil 4. The magnetic core 5 is in an I-shape and the material is manganese-zinc ferrite. The original magnetic permeability of manganese-zinc ferrite is high and the magnetic loss is low. The Barkhausen noise signal detection coil 4 uses 0.07mm copper enameled wire, and the thermal expansion coefficient and resistivity of the copper enameled wire are low. It is known from the Ferrari electromagnetic induction theorem that when the number of turns of the Barkhausen noise signal detection coil 4 increases, the collected signal strength also increases. When the electromagnetic force is saturated, increasing the number of turns of the coil will increase the coil resistance and reduce the induction ability of the coil. After experimental exploration, the number of turns of the Barkhausen noise signal detection coil 4 is set to 400 turns.

[0018] The height of the H-shaped yoke 2 designed by the present invention is 25mm, the distance between the horizontal column and the upper surface is 3mm, the height of the horizontal column is 5mm, the distance between the two legs is 8mm, the width of each leg is 5mm, and the overall thickness of the silicon steel sheet yoke 2 is 8mm; the number of turns of the excitation coil 1 is 300 turns, the coil diameter is 0.21mm, the number of turns of the Barkhausen noise signal detection coil 4 is 400 turns, and the coil diameter is 0.07mm. The sensor housing 7 is composed of two parts. Since the sensor needs to input the excitation signal and output the signal collected by the detector at the same time, a channel for connecting the coaxial wire is opened on the designed sensor housing 7; a slot is designed to fix the detector in the middle position of the two legs of the yoke 2, and at the same time, the bottom of the detector and the bottom of the H-shaped yoke 2 are in the same horizontal plane.

[0019] The Barkhausen noise signal detection device of the present invention uses silicon steel sheets as the material of the magnetic yoke 2, which greatly reduces the size of the sensor, enhances the local magnetization effect on the test piece 6, and improves the measurement sensitivity.

[0020] like Figure 1 As shown, the Barkhausen noise signal detection device adopts a method of leading the excitation source and the signal line out from the side, which is convenient for connecting the wires and reducing the size of the sensor. The H-shaped yoke 2 has a horizontal column and legs located on both sides of the horizontal column. At the same time, a layer of copper foil 3 is attached to the inner surface of the two legs of the H-shaped yoke 2 and then grounded, which can enhance the magnetization effect of the test piece 6 and reduce the influence of the excitation source on the reception of the noise signal. During the detection, the bottom surface of the sensor is attached to the surface of the test piece 6, and an alternating current passes through the excitation coil 1 to generate an alternating magnetic field to magnetize the test piece 6 within a certain depth range. The signal detector receives the Barkhausen noise signal generated by the test piece 66.

[0021] The H-shaped yoke 2 is designed in the present invention to make the winding of the excitation coil 1 more convenient. The material of the yoke 2 is silicon steel sheet, which is more suitable for the low-frequency excitation signal used in the experimental process. The shielding layer of the copper foil part 3 pasted on the inner side of the foot column on the yoke 2 can effectively reduce the interference of the excitation signal caused by the small distance between the yoke 2 and the detection coil 4. Through the miniaturized design of the sensor, the size of the magnetized area is reduced, the local magnetization effect is enhanced, the sensor has higher sensitivity, and the measurement signal has higher signal-to-noise ratio.

[0022] Research shows that the root cause of thermal aging of P92 steel is nanoscale precipitation phase, matrix damage and grain boundary segregation of impurity elements caused by changes in the microstructure of the material, and the Barkhausen signal is very sensitive to such microstructural changes in ferromagnetic materials. By analyzing the detected Barkhausen noise signal, the changes in the microstructure of the material can be obtained, and the changes in the mechanical properties and service life of the material can be evaluated.

[0023] It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used above to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means more than three.

[0024] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A Barkhausen noise signal detection device, characterized in that: It comprises an H-shaped magnetic yoke and a Barkhausen noise signal detection coil. The H-shaped magnetic yoke comprises a cross column and two foot columns. The cross column is connected between the two foot columns. The sides of the two foot columns close to the cross column are both bonded with copper foil parts and are grounded through the copper foil parts.

2. The Barkhausen noise signal detection device according to claim 1, characterized in that: The H-shaped magnetic yoke is formed by pressing 40 layers of oriented silicon steel sheets, and the thickness of the oriented silicon steel sheets is 0.2 mm.

3. The Barkhausen noise signal detection device according to claim 1, characterized in that: It also includes an excitation coil, which is tightly wound around the horizontal column of the H-shaped magnetic yoke in the same direction.

4. The Barkhausen noise signal detection device according to claim 3, characterized in that: It also includes an I-shaped magnetic core, and the material of the I-shaped magnetic core is manganese-zinc ferrite.

5. The Barkhausen noise signal detection device according to claim 4, characterized in that: The Barkhausen noise signal detection coil is tightly wound on the I-shaped magnetic core in the same direction, and the Barkhausen noise signal detection coil and the I-shaped magnetic core constitute a Barkhausen noise signal detector.

6. The Barkhausen noise signal detection device according to claim 1, characterized in that: The Barkhausen noise signal detector is located in the middle of the two foot columns.

7. The Barkhausen noise signal detection device according to claim 6, characterized in that: The bottom surface of the Barkhausen noise signal detector is coplanar with the bottom surface of the H-shaped magnetic yoke.

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