Oblique incidence SH wave magnetostrictive ultrasonic transducer

Abstract

The invention discloses an oblique incidence SH wave magnetostrictive ultrasonic transducer, and belongs to the technical field of ultrasonic nondestructive testing. The invention aims to solve the problem of low detection efficiency caused by cumbersome earlier stage processing of a magnetostrictive material patch and a film of an SH wave magnetostrictive ultrasonic transducer in the prior art, and the problem of high detection cost caused by high price and incapability of repeated use of a high-performance magnetostrictive material. The device comprises a wedge-shaped block attached with a magnetostrictive film and a transducer main body, the transducer main body comprises a permanent magnet with a U-shaped structure, a zigzag coil, a magnetostrictive film and a metal shell; the zigzag coil and the permanent magnet are positioned in the metal shell; the zigzag coil is arranged between the permanent magnet and the magnetostrictive film and is used for providing an alternating excitation current signal and receiving an induced voltage signal; the magnetostrictive film is attached to the surface of the inclined face of the wedge-shaped block, the magnetostrictive film is located on the opening side of the metal shell in the using state, and the metal shell is used for avoiding electromagnetic interference.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic nondestructive testing and relates to a magnetostrictive ultrasonic transducer. Background Art

[0002] With the rapid development of my country's national economy, the domestic demand for various metal materials is increasing. However, due to the limitation of processing technology, various metal materials inevitably have defects such as delamination, inclusions, cracks and oxide film during the production process. Therefore, it is necessary to adopt effective detection means to timely detect defective materials and realize their safe and reliable operation.

[0003] The ultrasonic method has the advantages of high sensitivity, high speed and strong ultrasonic penetration, and is applicable to both internal and surface defect detection. Therefore, it has significant advantages in metal material defect detection. In different specimen structures, ultrasonic waves exist in different forms, among which SH waves have relatively simple dispersion characteristics, especially the SH0 mode in the plate, which has the characteristics of non-dispersion, greatly reducing the complexity of detection and is very beneficial for the analysis of received signals.

[0004] In practical applications, since many defects are located in the interior of the specimen structure, at joints (such as welds) or at structural corners and other obstructed locations, conventional SH wave ultrasonic transducers cannot effectively detect them (such as Figure 1 ), so an oblique-incidence SH wave ultrasonic transducer is required. Existing oblique-incidence SH wave ultrasonic transducers mainly include: electromagnetic ultrasonic transducers and magnetostrictive ultrasonic transducers. Among them, the electromagnetic ultrasonic transducer based on the electromagnetic induction principle is easier to excite the required SH wave, but it has the problem of low transduction efficiency and the echo signal is easily interfered by the outside world, making it difficult to effectively identify the received signal.

[0005] The direction of the magnetic field, current, and various forces that excite electromagnetic ultrasound and the direction of the force are as follows: Figure 2 As shown, Figure 2 Where J is the current in the conductor, B0 is the bias magnetic field, and f M is the magnetizing force, f MS Magnetostrictive force, f L is the Lorentz force, of which the magnetizing force and magnetostrictive force are only generated in ferromagnetic materials. SH waveguide has a relatively simple dispersion characteristic, especially the SH0 mode waveguide in the plate, which has the characteristics of non-dispersion, greatly reducing the complexity of detection, which is very beneficial for the analysis of received signals. Compared with traditional magnetostrictive ultrasonic transducers, the transduction efficiency of the patch magnetostrictive ultrasonic transducer based on the magnetostrictive effect can be significantly improved. However, the existing magnetostrictive patch SH wave transducer mainly faces two technical problems:

[0006] First, the existing patch materials are mainly expensive high-performance magnetostrictive materials such as iron-gallium alloys. Before testing, the magnetostrictive patch needs to be pasted on the surface of the test piece, which makes it difficult to control the fit of special-shaped parts and the detection efficiency is low. In addition, since the magnetostrictive patch has been bonded and fixed to the surface of the test piece, it cannot be reused, which increases the cost. It is generally used in application scenarios such as long-term detection of pre-buried pipelines.

[0007] The second reason is that the existing oblique-incidence magnetostrictive ultrasonic transducer changes the propagation angle of the ultrasonic wave in the specimen by controlling the vibration source spacing and the sound wave frequency. However, it is generally limited by the directivity of the sound field and can only achieve a deflection of ±30 degrees. This results in the deflection angle of the SH wave generated by the existing patch-type magnetostrictive ultrasonic transducer being limited, making it difficult to apply to large-angle deflection angle detection occasions, such as Figure 4 shown.

[0008] Compared with the patch-type magnetostrictive ultrasonic transducer, the magnetostrictive coating ultrasonic transducer is directly coated on the surface of the test piece, which can effectively solve the problem of magnetostrictive patch pasting and can detect special-shaped parts. Figure 3 As shown. However, up to now, electromagnetic ultrasonic testing based on magnetostrictive coating technology is still in the laboratory research stage. The main reason why this technology has not been promoted and applied to industrial sites is that high-performance magnetostrictive materials are expensive, resulting in high testing costs, and the coating process requires the use of spraying equipment that is complicated to operate and inconvenient to carry. In view of the problems of cumbersome pre-processing of magnetostrictive material patches and films of SH wave magnetostrictive ultrasonic transducers in the prior art, resulting in low detection efficiency, high-performance magnetostrictive materials are expensive and cannot be reused, resulting in high testing costs, and the generated SH wave deflection angle is limited, no effective solution has been proposed so far. Summary of the invention

[0009] The present invention aims to solve the problem in the prior art that the magnetostrictive material patch and film of the SH wave magnetostrictive ultrasonic transducer are complicated in the early stage processing resulting in low detection efficiency, and the problem that the high-performance magnetostrictive material is expensive and cannot be reused resulting in high detection cost.

[0010] An oblique-incidence SH-wave magnetostrictive ultrasonic transducer comprises at least a wedge-shaped block to which a magnetostrictive film (4) is attached and a transducer body; the transducer body comprises at least a permanent magnet (2), a meandering coil (3), and a metal shell (5);

[0011] The permanent magnet (2) is a U-shaped structure and is located inside the metal shell (5);

[0012] The zigzag coil (3) is located inside the metal shell (5) and is arranged between the permanent magnet (2) and the magnetostrictive film (4), and is used to provide an alternating excitation current signal and receive an induced voltage signal; in the process of providing the alternating excitation current signal, the permanent magnet provides a bias magnetic field in a parallel direction relative to the zigzag coil, and the current directions in the coil wires of any zigzag portion of the zigzag coil (3) are opposite, that is, the current directions in adjacent parallel coil wires are opposite;

[0013] The magnetostrictive film (4) is attached to the inclined surface of the wedge-shaped block (8), and in a use state, the magnetostrictive film (4) is located on one side of the opening of the metal shell;

[0014] The metal shell (5) is used to prevent external electromagnetic interference from affecting the performance of the transducer.

[0015] Furthermore, the oblique-incidence SH-wave magnetostrictive ultrasonic transducer further comprises a copper foil (1), wherein the copper foil (1) is uniformly wrapped around the outer surface of the permanent magnet (2) to eliminate the ultrasonic wave generated by the coil directly in the permanent magnet (2).

[0016] Furthermore, the oblique-incidence SH-wave magnetostrictive ultrasonic transducer further comprises a wave absorbing layer (6), wherein the wave absorbing layer (6) is filled inside the metal shell (5) on the outside of the copper foil (1).

[0017] Furthermore, the oblique-incidence SH-wave magnetostrictive ultrasonic transducer further comprises a wiring port (7), and the wiring port (7) is located on the side wall of the metal shell (5).

[0018] Furthermore, the wiring port (7) comprises a plug interface (11) and a plug connector (12), wherein the plug interface (11) is used to lead out the lead wire of the meander coil (3) of the sensor component and connect it to the host computer signal line, and the plug connector (12) is used to connect the inner shielding layer of the host computer signal line to the metal shell (5) through the outer ring of the signal line.

[0019] Furthermore, the magnetostrictive film (4) is attached to the inclined surface of the wedge block (8) through a spraying process.

[0020] Furthermore, the material of the magnetostrictive film (4) is a material with an electrical conductivity within 10^3 S / m.

[0021] Furthermore, the material of the magnetostrictive film (4) is ferrosoferric oxide.

[0022] Furthermore, the oblique-incidence SH-wave magnetostrictive ultrasonic transducer further comprises an SH-wave coupling agent. When in use, the SH-wave coupling agent is located between the wedge block and the test piece.

[0023] Furthermore, when in use, an SH wave coupling agent, a wedge block and a transducer body are sequentially arranged on the surface of the test piece from near to far.

[0024] Beneficial effects:

[0025] 1. The magnetostrictive film based on low-conductivity material is attached to the surface of the wedge block through a thermal spraying process. It not only has the characteristics of significantly improving the transducer's energy conversion efficiency, but also can produce a magnetostrictive effect. In addition, the cost of low-conductivity materials is low. More importantly, the use of low-conductivity materials as magnetostrictive films helps to increase the particle vibration speed in the test piece, thereby improving the energy conversion efficiency of the magnetostrictive film transducer, and then replaces the existing high-performance magnetostrictive film materials, taking into account both cost and performance, and solving the problem of high-performance magnetostrictive materials being expensive and high testing costs.

[0026] 2. The magnetostrictive ultrasonic transducer proposed in the present invention can be reused after the magnetostrictive film is tightly bonded to the surface of the wedge block, thereby enabling flexible and efficient detection of the test piece.

[0027] 3. The thin film magnetostrictive ultrasonic transducer with a wedge-shaped block structure of the present invention has the advantages of high transduction efficiency and an incident sound wave angle range that can be expanded to ±60 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the schematic diagram of the wedge-shaped oblique-incidence ultrasonic transducer.

[0029] Figure 2 It is a diagram of the various force mechanisms that excite electromagnetic ultrasound.

[0030] Figure 3 This is a comparison chart between patch type and thin film magnetostrictive transducers.

[0031] Figure 4 It is a schematic diagram of the principle of oblique-incidence SH wave transducer.

[0032] Figure 5 It is a structural schematic diagram based on a U-shaped permanent magnet.

[0033] Figure 6 It is a cross-sectional view of an obliquely incident SH wave magnetostrictive electromagnetic ultrasonic transducer.

[0034] Figure 7 It is a three-dimensional schematic diagram of the oblique-incident SH-wave magnetostrictive ultrasonic transducer body.

[0035] Figure 8 This is a diagram of the magnetostrictive transduction mechanism of Fe3O4.

[0036] Fig. 9This is a comparison chart of the signals measured between Fe3O4 coated steel and bare steel. DETAILED DESCRIPTION

[0037] The main purpose of the present invention is to provide an oblique-incidence SH-wave magnetostrictive ultrasonic transducer to solve the problems in the prior art that the patch-type magnetostrictive ultrasonic transducer cannot be reused and the deflection angle of the generated SH wave is limited. The present invention is further described below in conjunction with specific embodiments.

[0038] Specific implementation method 1: Combination Figure 5-Figure 7 To explain this embodiment,

[0039] This embodiment is an oblique-incidence SH-wave magnetostrictive ultrasonic transducer, comprising a wedge block 8, an SH-wave coupling agent 9 and a transducer body; the transducer body comprises: a copper foil 1, a permanent magnet 2, a zigzag coil 3, a magnetostrictive film 4, a metal shell 5, an absorbing layer 6, and a wiring port 7; the copper foil 1, the permanent magnet 2, the zigzag coil 3 and the absorbing layer 6 are located inside the metal shell 5;

[0040] The permanent magnet 2 is a U-shaped structure, located inside the metal housing 5, and is used to provide the static horizontal bias magnetic field required for the transducer to work;

[0041] The copper foil 1 is evenly wrapped around the outer surface of the permanent magnet 2 to eliminate the ultrasonic wave generated by the coil directly in the permanent magnet 2, thereby avoiding the interference of the normal receiving signal of the coil (i.e., the ultrasonic wave in the test piece);

[0042] The wave absorbing layer 6 is filled inside the metal shell 5 on the outside of the copper foil 1 to absorb ultrasonic interference signals existing in the metal shell and the permanent magnet;

[0043] The zigzag coil 3 is located in the wave absorbing layer and is arranged between the permanent magnet 2 and the magnetostrictive film 4, and is used to provide an alternating excitation current signal and receive an induced voltage signal; in the process of providing the alternating excitation current signal, the permanent magnet provides a bias magnetic field in a parallel direction relative to the zigzag coil, and the current directions in the coil wires of any zigzag part of the zigzag coil 3 are opposite, that is, the current directions in adjacent parallel coil wires are opposite, such as Figure 8 As shown;

[0044] The magnetostrictive film 4 is not a traditional high-performance magnetostrictive material, such as iron-cobalt alloy, terbium-dysprosium-iron alloy, etc., but a material with a certain magnetostrictive effect but very low electrical conductivity. The material with an electrical conductivity of less than 10^3S / m, such as ferroferric oxide, is mainly selected, which will have a very good effect; the magnetostrictive film 4 is closely attached to the inclined surface of the wedge block 8, preferably attached to the surface of the wedge block 8 through a thermal spraying process. When in use, the magnetostrictive film 4 is located on the side of the opening of the metal shell, which is used to improve the conversion efficiency of the magnetostrictive ultrasonic transducer;

[0045] The metal housing 5 is used to prevent external electromagnetic interference from affecting the performance of the transducer;

[0046] The wiring port 7 is located on the side wall of the metal shell 5, and includes a plug interface 11 and a plug connector 12, wherein the plug interface 11 is used to lead out the lead wire of the sensor component meander coil 3 and connect it to the host computer signal line, and the plug connector 12 is used to connect the inner shielding layer of the host computer signal line to the metal shell 5 through the outer ring of the signal line;

[0047] When in use, an SH wave coupling agent 9, a wedge block 8 and a transducer body are arranged on the surface of the test piece 10 in sequence from near to far; the wedge block 8 is located between the metal shell 5 and the SH wave coupling agent 9, and is used to generate a preset angle. The transducer body generates an oblique incident SH wave of a preset angle through the wedge block 8.

[0048] The SH wave coupling agent 9 is located between the wedge block 8 and the test piece 10, and is used to improve the acoustic impedance matching between the transducer and the test piece, so that the SH wave is coupled and transmitted to the test piece.

[0049] The present invention has the following characteristics:

[0050] 1. The magnetostrictive film 4 based on low conductivity material is attached to the surface of the wedge block 8 through a thermal spraying process, which not only has the characteristics of significantly improving the transducer efficiency, but also can produce a magnetostrictive effect. In addition, the cost of low conductivity magnetostrictive film materials (such as Fe3O4) is low. Compared with high conductivity iron gallium alloy and iron cobalt alloy (about 5×10 6 S / m), etc. Low conductivity magnetostrictive film materials have extremely low conductivity (1×10 4 S / m), which helps to increase the vibration speed of the particles in the specimen, thereby improving the conversion efficiency of the magnetostrictive film transducer. At the same time, compared with the high conductivity iron gallium alloy and iron cobalt alloy (about 5×10 6 S / m), etc. Fe3O4 also has a relatively high saturation magnetostriction coefficient (its saturation magnetostriction strain coefficient is 167ppm), which takes into account both cost and performance, and solves the problem of high price and high detection cost of high-performance magnetostrictive materials.

[0051] Since the low-conductivity magnetostrictive material film has the advantages of low relative magnetic permeability and extremely low conductivity, according to the particle vibration velocity expression, this characteristic helps to increase the particle vibration velocity in the specimen, thereby improving the conversion efficiency of the magnetostrictive film transducer. Fig. 9As shown in the figure, when the coil is lifted off at a distance of 0.1 mm, the received signal waveforms of Fe3O4 coated steel and bare steel measured by the transducer are compared. It can be seen that the received signal amplitude measured by the coated steel specimen is much larger than the test result of the bare steel specimen, and the amplitude ratio of the echo signal is 18.3, which greatly improves the transducer efficiency.

[0052] The magnetostrictive film based on low conductivity material is attached to the surface of the wedge block through the thermal spraying process, which not only has the characteristics of significantly improving the transducer's energy conversion efficiency, but also can produce magnetostrictive effect. In addition, the cost of low conductivity materials is low. More importantly, according to the particle vibration velocity expression: Where: j is an imaginary number; σ ij is the component of the stress tensor; ρ is the specimen density; η is the Poisson's ratio; E is the Young's modulus; ε t is the magnetostrictive strain coefficient; ω is the angular frequency; μ0 is the magnetic permeability in air; μ r is the relative magnetic permeability in the specimen; σ is the electrical conductivity in the specimen; is the bias magnetic field parallel to the specimen surface; ——The horizontal dynamic magnetic field generated by the EMAT coil in the surface of the specimen.

[0053] From the above formula, it can be seen that the vibration velocity of the particles in the specimen is proportional to the density, Poisson's ratio, excitation frequency, magnetostrictive strain coefficient, and dynamic magnetic field on the specimen surface, and inversely proportional to Young's modulus, relative magnetic permeability, electrical conductivity, and bias magnetic field. Therefore, using low-conductivity materials as magnetostrictive films helps to increase the vibration velocity of particles in the specimen, thereby improving the conversion efficiency of magnetostrictive film transducers, and then replace existing high-performance magnetostrictive film materials, taking into account both cost and performance, and solving the problem of high-performance magnetostrictive materials being expensive and high testing costs.

[0054] 2. Traditional magnetostrictive patches are located on the surface of the test piece, fixed in position and generally not reusable. However, the magnetostrictive film of the transducer of the present invention is coated on the surface of the wedge block, that is, integrated into the transducer itself, and there is no need to process the magnetostrictive film or patch on the test piece, thus achieving flexible and efficient detection of the test piece, and the excited signal will not be affected and restricted by different ferromagnetic test pieces because it is located on the surface of the test piece, thus solving the problem of low detection efficiency due to cumbersome pre-processing of magnetostrictive material patches and films, and high detection cost due to the inability to be reused.

[0055] 3. The present invention adopts a wedge block structure. Since the propagation speed of ultrasound waves between different materials is different, refraction will occur when it passes through the end faces of different materials. The angle of refraction or refraction depends on the material properties of the paired transducer wedge blocks and the test sample and the incident angle of the ultrasonic signal, thereby expanding the angle range of the incident angle generated by the transducer. Therefore, the wedge block structure of the present invention expands the angle range of the incident sound wave of the electromagnetic ultrasonic transducer and solves the problem of limited deflection angle. Therefore, the thin-film magnetostrictive ultrasonic transducer with a wedge block structure has the advantages of high transduction efficiency and an incident sound wave angle range that can be expanded to ±60 degrees, so that the transducer can be used in large-angle deflection angle detection occasions.

[0056] Example

[0057] The following will be combined with the embodiments and drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Terms such as "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used herein to indicate spatial relative positions are used for the purpose of convenience to describe the relationship of one unit or feature relative to another unit or feature as shown in the accompanying drawings. Terms of spatial relative positions may be intended to include different orientations of the device in use or operation other than the orientation shown in the drawings.

[0059] For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0060] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] The present invention provides an oblique-incident SH wave magnetostrictive ultrasonic transducer, comprising a copper foil 1, a permanent magnet 2, a zigzag coil 3, a magnetostrictive film 4, a metal shell 5, an absorbing layer 6, a wiring port 7, a wedge block 8, and an SH wave coupling agent 9;

[0062] Above the tested object 10, there are SH wave coupling agent 9, wedge block 8, metal shell 5, magnetostrictive film 4, zigzag coil 3, permanent magnet 2 and copper foil outer layer 1 in sequence; the wiring port 7 includes a plug interface 71 and a plug connector 72, which are located on the side wall of the metal shell 5; the copper foil 1, permanent magnet 2, zigzag coil 3 and wave absorbing layer 6 are located inside the metal shell 5;

[0063] In the transducer design, since the surface of the permanent magnet 2 is conductive, high-amplitude ultrasonic waves will be generated on the surface of the permanent magnet. Therefore, a 0.05 mm thick and rough copper foil is evenly wrapped on the surface of the permanent magnet 2. This can effectively reduce the eddy current loss generated in the copper foil by the excitation current in the coil, and at the same time shield the ultrasonic waves from being generated on the lower surface of the permanent magnet.

[0064] The permanent magnet 2 is made of weak magnetic ferrite material, has a U-shaped structure, and has a length, width, and height of 30×20×16 mm, a residual magnetic flux density of 0.12 T, and a distance of 0.5 mm from the wedge block 8. It is used to provide the static bias magnetic field required for the coil 3 transduction process.

[0065] The meander coil 3 is made of printed circuit board technology, and the conductor material is pure copper. The conductor width of the meander coil is 0.1mm, the distance between adjacent conductors is 0.8mm, and the thickness is 35μm. The distance between the meander coil 3 and the wedge block 8 is 0.3mm, which is used to transmit alternating current signals and receive induced voltage signals;

[0066] The magnetostrictive film 4 is made of Fe3O4 material with a thickness of 0.2 mm and is sprayed on the surface of the wedge block 8 by a vacuum thermal spraying method to improve the conversion efficiency of the magnetostrictive ultrasonic transducer;

[0067] The metal shell 5 is made of 304 stainless steel with a length, width and height of 35×25×20 mm and a thickness of 2 mm. The inside includes a copper foil 1, a permanent magnet 2, and a zigzag coil 3. In the installation and testing state, a magnetostrictive film 4 is attached to the surface of the wedge block 8 through a thermal spraying process. The metal shell 5 is used to shield the external electromagnetic interference from affecting the performance of the transducer;

[0068] The wave absorbing layer 6 is made of polyurethane foam glue and is filled inside the metal shell 5 to absorb ultrasonic signals existing in the metal shell and the permanent magnet;

[0069] The wiring port 7 is located on the side wall of the metal shell 5, and includes a plug interface 11 and a plug connector 12, wherein the plug interface 11 is used to lead out the wiring of the meander coil 3 inside the transducer and connect it to the host signal line, and the plug connector 12 is used to connect the inner shielding layer of the signal line and the metal shell 5;

[0070] The wedge block 8 is made of acrylic resin and is located between the metal housing 5 and the SH wave coupling agent 9, and is used to generate oblique incident SH waves of a preset angle;

[0071] The SH wave coupling agent 9 is made of a high-viscosity resin material and is used to improve the acoustic impedance matching between the transducer and the test piece, so that the SH wave is coupled and transmitted to the test piece;

[0072] The specific detection process is as follows:

[0073] First, install the transducer: put the copper foil 1, permanent magnet 2, and zigzag coil 3 into the metal shell 5 in sequence through the opening of the metal shell 5, then fill in the wave absorbing layer 6, and finally attach the magnetostrictive film 4 to the surface of the wedge block 8 through the thermal spraying process to complete the assembly of the wedge block 8. After the transducer is installed, connect the signal line on the host to the wiring port 7 located on the side wall of the metal shell 5;

[0074] Secondly, apply a proper amount of SH wave coupling agent 9 between the wedge block 8 and the test piece 10. To obtain the best coupling effect, the coupling agent needs to be pressed into a thin layer to make the thickness of the coupling agent as thin as possible. Then, place the transducer at a suitable position on the surface of the test piece 10;

[0075] Finally, the host emits an excitation pulse, which acts on the zigzag coil of the transducer to generate an oblique incident SH wave signal. When the oblique incident SH wave interacts with the defect, a reflected echo is generated. The echo signal is picked up by the transducer and transmitted to the host to complete the defect detection of the test piece.

[0076] The above calculation examples of the present invention are only used to explain the calculation model and calculation process of the present invention in detail, and are not intended to limit the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. An oblique-incidence SH-wave magnetostrictive ultrasonic transducer, characterized in that: It at least comprises a wedge-shaped block with a magnetostrictive film (4) attached thereto and a transducer body; the transducer body at least comprises: a permanent magnet (2), a meandering coil (3), and a metal shell (5); The permanent magnet (2) is a U-shaped structure and is located inside the metal shell (5); The zigzag coil (3) is located inside the metal shell (5) and is arranged between the permanent magnet (2) and the magnetostrictive film (4), and is used to provide an alternating excitation current signal and receive an induced voltage signal; in the process of providing the alternating excitation current signal, the permanent magnet provides a bias magnetic field in a parallel direction relative to the zigzag coil, and the current directions in the coil wires of any zigzag portion of the zigzag coil (3) are opposite, that is, the current directions in adjacent parallel coil wires are opposite; The magnetostrictive film (4) is attached to the inclined surface of the wedge-shaped block (8), and in a use state, the magnetostrictive film (4) is located on one side of the opening of the metal shell; The metal shell (5) is used to prevent external electromagnetic interference from affecting the performance of the transducer.

2. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 1, characterized in that: It also comprises a copper foil (1), wherein the copper foil (1) is evenly wrapped around the outer surface of the permanent magnet (2) and is used to eliminate the ultrasonic waves directly generated by the coil in the permanent magnet (2).

3. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 2, characterized in that: It also comprises a wave absorbing layer (6), wherein the wave absorbing layer (6) is filled inside the metal shell (5) on the outside of the copper foil (1).

4. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 1, characterized in that: It also includes a wiring port (7), which is located on the side wall of the metal shell (5).

5. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 4, characterized in that: The wiring port (7) comprises a plug interface (11) and a plug connector (12); the plug interface (11) is used to lead out the lead wire of the meander coil (3) of the sensor component and connect it to the host computer signal line; the plug connector (12) is used to connect the inner shielding layer of the host computer signal line to the metal shell (5) through the outer ring of the signal line.

6. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 1, characterized in that: The magnetostrictive film (4) is attached to the inclined surface of the wedge block (8) through a spraying process.

7. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 1, characterized in that: The material of the magnetostrictive film (4) is a material with an electrical conductivity within 10^3 S / m.

8. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 1, characterized in that: The material of the magnetostrictive film (4) is ferroferric oxide.

9. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to any one of claims 1 to 8, characterized in that: The device also includes an SH wave coupling agent, which is located between the wedge block and the tested piece when in use.

10. The oblique-incidence SH-wave magnetostrictive ultrasonic transducer according to claim 9, characterized in that: When in use, the SH wave coupling agent, the wedge block and the transducer body are arranged in sequence from near to far on the surface of the tested object.

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