A magnetic flaw detection device for annular workpieces

Abstract

The present invention relates to a magnetic flaw detection device for annular workpieces, and belongs to the field of magnetic flaw detection technology. The two ends of the central magnetic conductive rod respectively pass through the center of the inner hole of the exciting magnetizing coil, and the two ends of the central magnetic conductive rod respectively pass through the center of the corresponding exciting magnetizing coil, and also include a copper conductive bar, an insulating partition and a conductive copper plate. The upper left rear side of the first copper conductive bar and the upper left front side of the second copper conductive bar are overlapped with each other through the insulating partition, and the lower right rear side of the first copper conductive bar and the lower right front side of the second copper conductive bar are overlapped with each other through the conductive copper plate to form the first "U"-shaped loop; the lower right rear side of the second copper conductive bar of the previous "U"-shaped loop is overlapped with the lower right front side of the first copper conductive bar of the next "U"-shaped loop through the insulating partition, and multiple "U"-shaped loops are sequentially connected head to tail in the thickness direction of the coil to form a square spiral loop. The present invention has a small volume, a large current, a concentrated magnetic field, and a good magnetic flaw detection effect.

Description

Technical Field

[0001] The invention relates to a magnetic flaw detection device for an annular workpiece, belonging to the technical field of magnetic flaw detection. Background Art

[0002] After the workpiece made of ferromagnetic material is magnetized, magnetic lines of force will pass through the workpiece. If the workpiece itself has no defects, the magnetic lines of force are evenly and continuously distributed inside it. However, when there are defects inside the workpiece, such as cracks, inclusions, pores and other non-ferromagnetic materials, the magnetic resistance is very large and the magnetic permeability is low, which will inevitably cause the distribution of magnetic lines of force to change. The magnetic lines of force at the defect cannot pass through and will bend to a certain extent. When the defect is located at or close to the surface of the workpiece, the magnetic lines of force will not only bend inside the workpiece, but also leak through the surface of the workpiece into the air to form a tiny local magnetic field. This magnetic field formed by the leakage of magnetic flux into the air near the defect due to the change in the magnetic permeability of the medium is called leakage magnetic field. The leakage magnetic field is detected by a certain method to determine the location of the defect, including the size of the defect. This is the principle of magnetic flaw detection.

[0003] The induction current method, also known as the flux penetration method, is to insert the iron core into the annular workpiece, treat the workpiece as the secondary coil of the transformer, and generate a circumferential induced current in the workpiece through the change of the magnetic flux in the iron core. This method of magnetizing the workpiece with induced current to generate an open-circuit magnetic field is the best method to detect circumferential defects in annular or cylindrical workpieces. At present, a large number of special flaw detection flux coils of different specifications have been produced in China, but they are all stacked coils. This type of coil has a small current, a large volume, and a non-concentrated magnetic field. Therefore, it is particularly important to prepare a coil with a small volume, a large current, and a concentrated magnetic field. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art and provide a magnetic flaw detection device for annular workpieces, which has small size, large current, concentrated magnetic field and good magnetic flaw detection effect.

[0005] The present invention provides a magnetic flaw detection device for an annular workpiece, comprising a central magnetic conductive rod, the central magnetic conductive rod and the annular workpiece are coaxial, the annular workpiece is located in the middle of the central magnetic conductive rod, the two ends of the central magnetic conductive rod respectively pass through the center of the inner hole of the excitation magnetization coil, the excitation magnetization coil comprises a plurality of copper conductive bars, an insulating partition and a conductive copper plate, the copper conductive bars comprise a plurality of first copper conductive bars and second copper conductive bars, the first copper conductive bars are L-shaped, the second copper conductive bars are "7"-shaped, the upper left rear side of the first copper conductive bar and the upper left front side of the second copper conductive bar are overlapped with each other through the insulating partition, the lower right of the first copper conductive bar The rear side of the upper end and the front side of the lower right end of the second copper conductive bar are overlapped with each other through a conductive copper plate to form a first "U" shaped loop; in this way, multiple identical "U" shaped loops are overlapped in the thickness direction of the coil; the rear side of the upper left end of the second copper conductive bar of the previous "U" shaped loop is overlapped with the front side of the upper left end of the first copper conductive bar of the next "U" shaped loop through a conductive copper plate, and the rear side of the lower right end of the second copper conductive bar of the previous "U" shaped loop is overlapped with the front side of the lower right end of the first copper conductive bar of the next "U" shaped loop through an insulating partition, and multiple "U" shaped loops are connected in series end to end in the thickness direction of the coil to form a square spiral loop.

[0006] Furthermore, the U-shaped loop is provided with five turns in the thickness direction of the coil.

[0007] Furthermore, the upper left corners of each U-shaped loop are connected and fixed to each other via a first bolt, and the lower right corners of each U-shaped loop are connected and fixed to each other via a second bolt, and the first bolt and the second bolt are insulated from each U-shaped loop.

[0008] Furthermore, the thickness of the insulating partition is equal to that of the conductive copper plate, and both the front and rear sides of the first copper conductive bar and the second copper conductive bar are covered with the insulating partition except for the parts in contact with the conductive copper plate.

[0009] Furthermore, the head end of the first copper conductive bar of the first U-shaped loop is provided with a first power terminal connected thereto as an integral unit, and the end of the second copper conductive bar of the last U-shaped loop is provided with a second power terminal connected thereto as an integral unit, and the first power terminal and the second power terminal are in the same phase and extend outwardly in parallel with each other.

[0010] The beneficial effects of the present invention are as follows: (1) copper conductive bars are used as wire turns, which have high conductivity, large cross-sectional area and low self-resistance; the conductive copper plates are used to conduct current between two adjacent turns, and the contact resistance is small. Both the copper conductive bars and the conductive copper plates can carry large currents, and the non-conducting areas can be separated from each other by insulating partitions to achieve insulation. The copper conductive bars can form a continuously rotating spiral coil without rolling, stretching or bending, which solves the problem of extremely large turning radius of large-section copper bars. The excitation magnetization coil manufactured has a small volume, a large current (above kA), a concentrated magnetic field, a good magnetic flaw detection effect, is easy to manufacture and has a low cost.

[0011] (2) The first power terminal of the first turn and the second power terminal of the tail turn are in phase, so that the coil can have a complete and accurate number of turns.

[0012] (3) The present invention has a simple structure and significantly improves the efficiency of magnetic particle detection of transverse defects on the inner hole, outer wall and end face of hollow forgings.

[0013] (4) The coil of the present invention is placed on a magnetic rod, the magnetic rod passes through the hollow workpiece, and magnetic flaw detection is performed after power is applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a working state diagram of the magnetic flaw detection device for annular workpieces of the present invention;

[0015] Figure 2 It is a front view of the exciting magnetizing coil in the present invention;

[0016] Figure 3 for Figure 2 Right view of;

[0017] Figure 4 It is a front view of the first copper conductive bar in the present invention;

[0018] Figure 5 It is a front view of the second copper conductive bar in the present invention;

[0019] Figure 6 This is an expanded view of the exciting magnetizing coil of the annular workpiece of the present invention.

[0020] In the figure: In the figure: A. Excitation magnetizing coil 1; B. Excitation magnetizing coil 2; 1. First copper conductive bar; 1a. First power terminal; 2. Second copper conductive bar; 2a. Second power terminal; 3. Conductive copper plate; 4. Insulating partition; 5. First bolt; 6. Second bolt; 7. Center magnetic rod; 8. Ring-shaped workpiece; 9. Bracket. DETAILED DESCRIPTION

[0021] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0022] like Figure 1 As shown, the magnetic flaw detection device for annular workpieces of the present invention includes a central magnetic conductive rod 7, which is coaxial with an annular workpiece 8. The annular workpiece 8 is located in the middle of the central magnetic conductive rod 7. The two ends of the central magnetic conductive rod 7 pass through the centers of the inner holes of the excitation magnetizing coil A and the excitation magnetizing coil B respectively, and the two end ends of the central magnetic conductive rod 7 are supported on the bracket 9 respectively.

[0023] like Figures 2 to 6 As shown, the excitation magnetization coil includes a plurality of copper conductive bars, an insulating partition 4 and a conductive copper plate 3, the copper conductive bars include a plurality of first copper conductive bars 1 and second copper conductive bars 2, the first copper conductive bars 1 are L-shaped, the second copper conductive bars 2 are "7"-shaped, the upper left rear side of the first copper conductive bar 1 and the upper left front side of the second copper conductive bar 2 are overlapped with each other through the insulating partition 4, the lower right rear side of the first copper conductive bar 1 and the lower right front side of the second copper conductive bar 2 are overlapped with each other through the conductive copper plate 3, forming a first "U"-shaped loop; in this way, multiple identical "U"-shaped loops are overlapped in the thickness direction of the coil,

[0024] The upper left rear side of the second copper conductive bar 2 of the previous U-shaped loop is overlapped with the upper left front side of the first copper conductive bar 1 of the next U-shaped loop through the conductive copper plate 3, and the lower right rear side of the second copper conductive bar 2 of the previous U-shaped loop is overlapped with the lower right front side of the first copper conductive bar 1 of the next U-shaped loop through the insulating partition 4, so that multiple U-shaped loops are connected in series end to end in the thickness direction of the coil to form a square spiral loop.

[0025] The U-shaped loop can be provided with five turns in the thickness direction of the coil to obtain the best magnetic field flaw detection effect.

[0026] The upper left corners of each U-shaped loop are connected and fixed to each other via a first bolt 5, and the lower right corners of each U-shaped loop are connected and fixed to each other via a second bolt 6. The first bolt 5 and the second bolt 6 are insulated from each U-shaped loop.

[0027] The insulating partition 4 has the same thickness as the conductive copper plate 3 , and both the front and rear sides of the first copper conductive bar 1 and the second copper conductive bar 2 are covered with the insulating partition 4 except for the parts in contact with the conductive copper plate 3 .

[0028] The head end of the first copper conductive bar 1 of the first U-shaped loop is provided with a first power terminal 1a connected thereto as an integral unit, and the end of the second copper conductive bar 2 of the last U-shaped loop is provided with a second power terminal 2a connected thereto as an integral unit. The first power terminal 1a and the second power terminal 2a are in the same phase and extend outwardly in parallel with each other.

[0029] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A magnetic flaw detection device for an annular workpiece, comprising a central magnetic rod, the central magnetic rod and the annular workpiece are coaxial, the annular workpiece is located in the middle of the central magnetic rod, and the two ends of the central magnetic rod pass through the center of the inner hole of the excitation magnetization coil respectively, characterized in that: The excitation magnetizing coil comprises a plurality of copper conductive bars, an insulating partition and a conductive copper plate, wherein the copper conductive bars comprise a plurality of first copper conductive bars and second copper conductive bars, wherein the first copper conductive bars are in an L-shape, and the second copper conductive bars are in a "7" shape, wherein the upper left rear side of the first copper conductive bar and the upper left front side of the second copper conductive bar are overlapped with each other through the insulating partition, and the lower right rear side of the first copper conductive bar and the lower right front side of the second copper conductive bar are overlapped with each other through the conductive copper plate, forming a first "U"-shaped loop; thus, a plurality of identical "U"-shaped loops are overlapped in the thickness direction of the coil; The rear side of the upper left end of the second copper conductive bar of the previous U-shaped loop is overlapped with the front side of the upper left end of the first copper conductive bar of the next U-shaped loop through a conductive copper plate, and the rear side of the lower right end of the second copper conductive bar of the previous U-shaped loop is overlapped with the front side of the lower right end of the first copper conductive bar of the next U-shaped loop through an insulating partition, and multiple U-shaped loops are sequentially connected end to end in series in the thickness direction of the coil to form a square spiral loop; The upper left corners of each U-shaped loop are connected and fixed to each other through a first bolt, and the lower right corners of each U-shaped loop are connected and fixed to each other through a second bolt, and the first bolt and the second bolt are insulated from each U-shaped loop; The "U"-shaped loop is provided with five turns in the thickness direction of the coil; The insulating partition is equal to the thickness of the conductive copper plate, and both the front and rear sides of the first copper conductive bar and the second copper conductive bar are covered with the insulating partition except for the parts in contact with the conductive copper plate; The head end of the first copper conductive bar of the first U-shaped loop is provided with a first power terminal connected thereto as an integral unit, and the end of the second copper conductive bar of the last U-shaped loop is provided with a second power terminal connected thereto as an integral unit, and the first power terminal and the second power terminal are in the same phase and extend outwardly in parallel with each other.

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