Alternating current electromagnetic field array detection device, imaging method and system for uneven welding seam

Abstract

The invention discloses an uneven welding seam alternating current electromagnetic field array detection device, imaging method and system. The device comprises a test piece; the ACFM array probe is arranged on the upper side of the test piece; the linear guide rail is arranged on the side surface of the ACFM array probe; according to the method, by using an ACFM array probe comprising eight-channel Bz and Bx magnetic field signal receiving coils, simultaneous collection of multi-channel signals is achieved, the signals are processed through a specific algorithm, the signals are corrected with a Bz signal as the reference so as to obtain accurate defect length information, and the defect depth is estimated through a Bz peak value; the influence of the uneven surface of the weld defect on different channels is eliminated through lift-off compensation, the consistency of signals is improved, and a base metal area, a heat affected area and a weld area of the weld defect are divided and subjected to area signal compensation; and finally, drawing the processed signal into a three-dimensional imaging graph of the weld defect, so that the contour of the defect is more intuitive and clearer.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to an alternating current electromagnetic field array detection device for uneven welds and an imaging method and system thereof. Background Art

[0002] As an emerging electromagnetic nondestructive testing method, ACFM technology has attracted much attention due to its non-contact detection, no need to remove the surface attachments of the workpiece, and strong adaptability to external environmental conditions. The principle of this technology is to use the detection probe to generate a uniform current on the surface of the workpiece to be inspected. The current generates disturbances around the defect, causing the spatial magnetic field to be distorted. The existence and nature of the defect are evaluated by detecting these distorted magnetic fields.

[0003] At present, ACFM technology mainly relies on characteristic signals Bx and Bz or the butterfly diagram formed by them to judge defects in practical applications. Among them, Bx and Bz signals are magnetic field signals parallel and perpendicular to the workpiece surface respectively. However, relying only on these two characteristic signals can achieve defect location or simple quantitative analysis, but it is difficult to intuitively display the specific size and shape information of the defect.

[0004] However, although the existing ACFM detection technology has improved the detection efficiency to a certain extent, due to the significant differences in the material structure of the weld defect area (including the weld area, heat-affected zone and base material area), coupled with the lift-off effect caused by the uneven weld surface, it is difficult to ensure the consistency of the signals of each channel of the ACFM array probe during the detection process, which in turn leads to large errors in defect evaluation. This poses a challenge to achieving comprehensive coverage detection of all areas of the weld, improving signal sensitivity, and obtaining imaging images that can clearly present the defect contour morphology. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide an uneven weld AC electromagnetic field array detection device, imaging method and system. The method realizes the simultaneous acquisition of multi-channel signals by using an ACFM array probe including eight-channel Bz and Bx magnetic field signal receiving coils, and also processes the signal through a specific algorithm, including correcting the Bx signal based on the Bz signal to obtain accurate defect length information, and using the Bz peak to estimate the defect depth. The lift-off compensation eliminates the impact of the uneven surface of the weld defect on different channels, thereby improving the consistency of the signal. The base material area, heat-affected zone and weld area of ​​the weld defect are divided and regional signal compensation is performed; finally, the processed signal is used to draw a three-dimensional imaging diagram of the weld defect, making the outline of the defect more intuitive and clear.

[0006] According to a first aspect of the present invention, there is provided an AC electromagnetic field array detection device for uneven welds, comprising:

[0007] A test piece, wherein a weld defect is provided on a surface of the test piece;

[0008] An ACFM array probe disposed above the weld defect, the ACFM array probe comprising a probe housing, a U-shaped magnetic yoke, an excitation coil, and eight-channel Bz and Bx magnetic field signal receiving coils; and

[0009] A linear guide rail is arranged on the side of the ACFM array probe, and adsorption parts are arranged at both ends of the linear guide rail. The adsorption parts are also provided with knobs. During detection, the position of the linear guide rail must be determined first, and then the knob is rotated to make the linear guide rail tightly adsorbed on the test piece. After the detection is completed, the knob is reset to separate the linear guide rail from the test piece.

[0010] Furthermore, the linear guide rail is provided with a first sliding bar and a handle in the horizontal direction for controlling the movement of the ACFM array probe; the linear guide rail is also provided with a second sliding bar in the vertical direction for controlling the lifting height of the ACFM array probe; the second sliding bar is provided with two nuts for fixing after the lifting height is determined.

[0011] Furthermore, the eight-channel Bz and Bx magnetic field signal receiving coils need to be assigned channel numbers in order of their positions in the ACFM array probe.

[0012] Furthermore, the weld defects include a weld zone, a heat-affected zone and a base material zone.

[0013] According to a second aspect of the present invention, there is provided an uneven weld seam AC electromagnetic field array detection imaging method, which is implemented by using the above-mentioned uneven weld seam AC electromagnetic field array detection device, and comprises:

[0014] S100, scanning the parent metal area, heat-affected zone and weld area surface of the plane weld defect calibration specimen respectively, obtaining the average amplitude of the magnetic field signals Bz and Bx in the three areas, calculating the critical judgment coefficient according to the average amplitude, and extracting the peak value of the magnetic field signal Bz in the three areas as the regional compensation coefficient;

[0015] S200, obtaining magnetic field signals Bz at different lift-off distances, extracting peak values ​​of the magnetic field signals Bz at different lift-off distances and performing normalization processing, and obtaining a functional relationship through linear fitting;

[0016] S300, using the ACFM array probe to scan along the weld defect surface of the test piece, setting n equally spaced position points in the scanning path of the ACFM array probe, recording the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and constructing signal matrices respectively:

[0017]

[0018] In the formula, i is the channel number, i = 1, 2, 3, ..., 8.

[0019] S400, repeating step S300 for the signals of the eight channels in sequence to obtain the peak values ​​of the eight-channel magnetic field signals Bz and the average amplitudes of the eight-channel magnetic field signals Bz and Bx, and calculating the actual lifting distances of the eight channels according to the peak values ​​of the eight-channel magnetic field signals Bz and the functional relationship; distinguishing the defect areas corresponding to the eight channels according to the average amplitudes of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient;

[0020] S500, according to different regions, the corresponding magnetic field signal matrix B i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi;

[0021] S600, drawing two-dimensional imaging diagrams of eight channels according to the regional compensation matrix DBi, and then arranging them from top to bottom in the order of channel numbers, and drawing a three-dimensional imaging diagram of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

[0022] Furthermore, step S300 also includes: pre-determining the shape of the weld defect on the test piece; if it is a convex shape, measuring the distance between the highest convexity and the linear guide rail as the height of the array probe, and adjusting the second slide bar for height leveling before detection; if it is a flat or concave shape, no height leveling is required and detection can be performed directly.

[0023] Furthermore, step S300 further includes: extracting the position coordinates Xmax and Ymax corresponding to the peak values ​​of the magnetic field signals Bz and Bx, respectively, determining whether Xmax is equal to Ymax, and if not, performing the calculation of the first column element [Y1 Y2 Y3 ... Y n ] T Perform coordinate matching correction to form a new defect length correction matrix CBi. The formula includes:

[0024] Y j ′=Y j -(Y max -X max ),j=1,2,3...n

[0025] Where Y j ′ is the corrected new coordinate, which is the first column element of matrix CBi; j is the first column element of the matrix Bi.

[0026] Further, step S600 includes: drawing a two-dimensional imaging diagram of eight channels with the element values ​​of the first column in the matrix DBi as the X-axis coordinate and the element values ​​of the second column in the matrix DBi as the Y-axis coordinate, and then arranging them from top to bottom in order of channel numbers, and drawing a three-dimensional imaging diagram of the surface contour of the weld defect based on the actual lifting height of the eight channels as the Z-axis coordinate.

[0027] Furthermore, the ACFM array probe must always be located directly above the weld defect during the detection process.

[0028] According to a third aspect of the present invention, there is provided an uneven weld AC electromagnetic field array detection imaging system, comprising:

[0029] The first module is used to scan the parent metal area, heat-affected zone and weld area of ​​the plane weld defect calibration specimen respectively, calculate and obtain the average amplitude of the magnetic field signals Bz and Bx in the three areas, calculate the critical judgment coefficient based on the average amplitude, and extract the peak value of the magnetic field signal Bz in the three areas as the regional compensation coefficient;

[0030] The second module is used to obtain the magnetic field signal Bz at different lifting distances, extract the peak value of the magnetic field signal Bz at different lifting distances and perform normalization processing, and obtain the functional relationship through linear fitting;

[0031] The third module is used to use the ACFM array probe to scan along the surface of the weld defect to be tested, set n equally spaced position points in the scanning path of the ACFM array probe, record the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and construct signal matrices respectively:

[0032]

[0033] Where i is the channel number, i = 1, 2, 3, ..., 8;

[0034] The fourth module repeats the third module in the order of the eight channels' signals to obtain the peak values ​​of the eight-channel magnetic field signals Bz and the average amplitudes of the eight-channel magnetic field signals Bz and Bx, and calculates the actual lifting distances of the eight channels according to the peak values ​​of the eight-channel magnetic field signals Bz and the functional relationship; and distinguishes the defect areas corresponding to the eight channels according to the average amplitudes of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient;

[0035] The fifth module is to convert the corresponding magnetic field signal matrix B according to different regions i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi;

[0036] The sixth module draws two-dimensional images of eight channels according to the regional compensation matrix DBi, and then arranges them from top to bottom in the order of channel numbers, and draws a three-dimensional image of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

[0037] Beneficial effects of the present invention:

[0038] 1. The imaging method provided by the present invention realizes the simultaneous acquisition of multi-channel signals by using an ACFM array probe including eight-channel Bz and Bx magnetic field signal receiving coils, and also processes the signals through a specific algorithm, including correcting the Bx signal based on the Bz signal to obtain accurate defect length information, and using the Bz peak to estimate the defect depth. The lift-off compensation eliminates the impact of the uneven surface of the weld defect on different channels, thereby improving the consistency of the signal. The base material area, heat-affected zone and weld area of ​​the weld defect are divided and regional signal compensation is performed; finally, the processed signal is used to draw a three-dimensional imaging diagram of the weld defect, making the outline of the defect more intuitive and clear.

[0039] 2. The detection device provided by the present invention realizes the simultaneous acquisition of multi-channel signals by using an ACFM array probe including eight-channel Bz and Bx magnetic field signal receiving coils. In addition, through the preliminary detection of planar weld defect calibration specimens, the differences in magnetic field signals in the parent material area, heat-affected zone, and weld area are clarified, and signal compensation is performed, so that different material areas can be distinguished more accurately during the actual detection process.

[0040] 3. The imaging method provided by the present invention uses an ACFM array probe to scan along the surface of the weld defect, obtains magnetic field signals of multiple channels, and processes the signals through a specific algorithm, including correcting the Bx signal based on the Bz signal to obtain accurate defect length information, and using the Bz peak to estimate the defect depth. Finally, by drawing the processed signal into a two-dimensional imaging diagram and combining the actual lift-off height of different channels, a three-dimensional imaging diagram of the weld defect is drawn, making the outline of the defect more intuitive and clear.

[0041] 4. The imaging method provided by the present invention obtains the detection signal under different lift-off conditions in advance, finds the relationship between the lift-off and the signal, and calculates the actual lift-off height of different channels based on this, thereby solving the lift-off effect problem caused by the uneven surface of the weld, thereby improving the stability and reliability of the detection signal.

[0042] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0044] Figure 1 It is a schematic diagram of an AC electromagnetic field array detection device for uneven welds in an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram of a planar weld defect calibration specimen in an AC electromagnetic field array detection device for uneven welds according to an embodiment of the present invention;

[0046] Figure 3 This is a flow chart of an imaging method of an AC electromagnetic field array detection device for uneven welds according to an embodiment of the present invention;

[0047] In all the drawings, the same figure marks represent the same technical features, specifically: 1-linear guide, 2-ACFM array probe, 3-weld defect, 4-piece to be tested, 5-adsorption piece, 6-first slide bar, 7-second slide bar, 8-handle, 9-nut; 31-weld area, 32-heat affected zone, 33-parent material area. DETAILED DESCRIPTION

[0048] The present invention will be 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 present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0049] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0050] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0051] The present invention provides an AC electromagnetic field array detection device, imaging method and system for uneven welds. The method realizes the simultaneous acquisition of multi-channel signals by using an ACFM array probe including eight-channel Bz and Bx magnetic field signal receiving coils, and also processes the signals through a specific algorithm, including correcting the Bx signal based on the Bz signal to obtain accurate defect length information, and using the Bz peak to estimate the defect depth. The lift-off compensation eliminates the influence of the uneven surface of the weld defect on different channels, thereby improving the consistency of the signal. The base material area, heat-affected zone and weld area of ​​the weld defect are divided and regional signal compensation is performed; finally, the processed signal is used to draw a three-dimensional imaging diagram of the weld defect, so that the outline of the defect is more intuitive and clear.

[0052] Embodiment 1:

[0053] like Figure 1 As shown, an embodiment of the present invention provides an AC electromagnetic field array detection device for uneven welds, comprising: a test piece 4, on which a weld defect 3 is provided; an ACFM array probe 2 arranged on the upper side of the weld defect 3, the ACFM array probe 2 comprising a probe housing, a U-shaped magnetic yoke, an excitation coil, and eight-channel Bz and Bx magnetic field signal receiving coils; and a linear guide 1 arranged on the side of the ACFM array probe 2, wherein adsorption components 5 are provided at both ends of the linear guide 1, and a knob is provided on the adsorption component 5. During detection, it is necessary to first determine the position of the linear guide 1, and then rotate the knob on the adsorption component 5 so that the linear guide 1 is tightly adsorbed on the test piece 4. After the detection is completed, the knob is reset to separate the linear guide 1 from the test piece 4. The linear guide 1 is provided with a first slide bar 6 and a handle 8 in the horizontal direction, which are used to control the movement of the ACFM array probe 2; the linear guide 1 is also provided with a second slide bar 7 in the vertical direction, which is used to control the lift-off height of the ACFM array probe 2; the second slide bar 7 is provided with two nuts 9 for fixing after the lift-off height is determined. The eight-channel Bz and Bx magnetic field signal receiving coils need to be assigned channel numbers according to the position sequence in the ACFM array probe 2; the ACFM array probe 2 needs to be always located directly above the weld defect 3 during the detection process.

[0054] Furthermore, if Figure 2 As shown, the test piece 4 includes a weld zone 31, a heat-affected zone 32 and a base material zone 33;

[0055] Embodiment 2:

[0056] like Figure 3 As shown, based on Example 1, an embodiment of the present invention provides an imaging system of an AC electromagnetic field array detection device for uneven welds, comprising:

[0057] S100, scanning the parent metal area, heat-affected zone and weld area surface of the plane weld defect calibration specimen respectively, calculating and obtaining the average amplitudes of the magnetic field signals Bz and Bx in the three areas, calculating the critical judgment coefficient according to the average amplitudes, and extracting the peak values ​​of the magnetic field signals Bz in the three areas as the regional compensation coefficients;

[0058] Step S100 specifically includes:

[0059] S101, such as Figure 2 As shown, a plane weld defect calibration specimen is prepared, which includes a weld zone 31, a heat-affected zone 32 and a base material zone 33 of the weld defect 3, wherein the weld zone 31 is 200 mm long and 6 mm wide, and the depths of the weld defects are 0.5, 1, 3 and 5 mm, respectively, with a total of four pieces.

[0060] S102. Use a conventional ACFM probe to scan the parent material area, heat-affected zone and weld area of ​​the plane weld defect calibration specimen respectively to obtain the corresponding magnetic field signals Bz and Bx. By analyzing the waveform of the signal, it can be seen that the signal has obvious changes at the junction of different areas.

[0061] S103. Calculate the average amplitudes a1, a2, a3 and b1, b2, b3 of the magnetic field signals Bz and Bx in the three regions, (a1-a2) and (b1-b2) are used as the critical judgment coefficients between the base material zone and the heat affected zone, (a2-a3) and (b2-b3) are used as the critical judgment coefficients between the heat affected zone and the weld zone.

[0062] S104 , extracting peak values ​​c1 , c2 , and c3 of the magnetic field signal Bz in the three regions as compensation coefficients for different regions.

[0063] S200, obtaining magnetic field signals Bz at different lift-off distances, extracting peak values ​​of the magnetic field signals Bz at different lift-off distances and performing normalization processing, and obtaining a functional relationship through linear fitting;

[0064] Step S200 specifically includes:

[0065] S201. Place a conventional ACFM probe above the base metal area of ​​a planar weld defect calibration specimen, change the lift-off distance h from the probe to the surface of the calibration specimen, obtain the magnetic field signal Bz at different lift-off distances, extract the peak value of the signal Bz and perform normalization processing to obtain d, and obtain the functional relationship between h and d by linear fitting calculation: d = f(h). The lift-off distance h is set to change at an interval of 0.5 mm, and the maximum lift-off distance h is m Set to 5mm.

[0066] S300, use the ACFM array probe to scan along the surface of the weld defect to be measured, set n equally spaced position points in the scanning path of the ACFM array probe, record the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and construct signal matrices respectively.

[0067] Step S300 specifically includes:

[0068] S301. Determine the shape of the weld defect to be tested. If it is convex, measure the distance between the highest convexity and the linear guide rail as the height of the array probe. Before testing, adjust the second slide bar 7 for height leveling. If it is flat or concave, there is no need for height leveling and the test can be carried out directly.

[0069] S302, setting 50 equally spaced position points in the scanning path of the ACFM array probe with a spacing of 1 mm, recording the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and constructing signal matrices Ai and Bi respectively, where i is the channel number, i=1, 2, 3, ..., 8;

[0070] S303, respectively extract the position coordinates Xmax and Ymax corresponding to the peak values ​​of the magnetic field signals Bz and Bx. If it is determined that Xmax is not equal to Ymax, perform coordinate matching correction on the first column element in the Bx signal matrix Bi to obtain new coordinates, and re-compose the defect length correction matrix CBi with the second column element of the matrix Bi. The coordinate matching is calculated according to the formula:

[0071] Y j ′=Y j -(Y max -X max ),j=1,2,3...n

[0072] Where Y j ′ is the corrected new coordinate, which is the first column element of matrix CBi; j is the first column element of the matrix Bi.

[0073] S400, repeating step S300 for the signals of the eight channels in sequence to obtain the peak value of the eight-channel magnetic field signal Bz and the average amplitude of the eight-channel magnetic field signals Bz and Bx, and calculating the actual lifting distances of the eight channels according to the peak value of the eight-channel magnetic field signal Bz and the functional relationship; distinguishing the defect areas corresponding to the eight channels according to the average amplitude of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient;

[0074] Step S400 specifically includes:

[0075] S401. Repeat steps S5 and S6 for the signals of the eight channels in sequence, respectively obtain the peak values ​​Bzmax1~Bzmax8 of the magnetic field signal Bz, perform normalization processing and substitute them one by one as d values ​​into the function relationship d=f(h) obtained in S2, and invert to obtain the actual lift-off height h1~h8 of each channel.

[0076] S402, calculate the average amplitudes e1-e8 and f1-f8 of the eight channel magnetic field signals Bz and Bx. Compare the average amplitudes of the first four channels (e i+1 -e i ) and (f i+1 -f i ) and the critical judgment coefficient, where i is the channel number, i = 1, 2, 3, 4. When |(e i+1 -e i )-(a1-a2)|+|(f i+1 -f i )-(b1-b2)| is the smallest, the corresponding i1 is considered to be the critical channel number between the parent material zone and the heat affected zone, that is, the channels numbered from 1 to i1 are the parent material zone channels; when |(e i+1 -e i )-(a2-a3)|+|(f i+1 -f i )-(b2-b3)| is the smallest, the corresponding i2 is considered to be the critical channel number between the heat affected zone and the weld zone, that is, the channels from i1 to i2 are the heat affected zone channels, and the channels from i2 to 4 are the weld zone channels; compare the last four channels one by one (e i -e i+1 ) and (f i -f i+1 ) and the difference between the critical judgment coefficient, where i is the channel number, i = 5, 6, 7, 8. |(e i -e i+1 )-(a1-a2)|+|(f i -f i+1)-(b1-b2)| is the smallest, the corresponding i3 is considered to be the critical channel number between the parent material zone and the heat affected zone, that is, the channels numbered from i3 to 8 are the parent material zone channels; when |(e i -e i+1 )-(a2-a3)|+|(f i -f i+1 )-(b2-b3)| is the smallest, the corresponding i4 is considered to be the critical channel number between the heat affected zone and the weld zone, that is, the channels numbered from i4 to i3 are the heat affected zone channels, and the channels numbered from 5 to i3 are the weld zone channels.

[0077] S500, according to different regions, the corresponding magnetic field signal matrix B i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi;

[0078] Step S500 specifically includes: multiplying all the elements in the second column of the Bx coordinate correction matrix of the base material zone channel by c1 to obtain the regional compensation matrix DBi, multiplying all the elements in the second column of the Bx coordinate correction matrix of the heat affected zone channel by c2 to obtain the regional compensation matrix DBi, and multiplying all the elements in the second column of the Bx coordinate correction matrix of the weld zone channel by c3 to obtain the regional compensation matrix DBi.

[0079] S600, drawing two-dimensional imaging diagrams of eight channels according to the regional compensation matrix DBi, and then arranging them from top to bottom in the order of channel numbers, and drawing a three-dimensional imaging diagram of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

[0080] Step S600 specifically includes: drawing two-dimensional imaging images of eight channels respectively, with the X-axis coordinates being the element values ​​of the first column in the matrix DBi and the Y-axis coordinates being the element values ​​of the second column in the matrix DBi, and further converting them into grayscale images. Arrange them from top to bottom in the order of channel numbers to form an overall surface contour image of the weld defect. The actual lift-off heights h1 to h8 of different channels are used as the Z-axis coordinates of each channel to draw a three-dimensional imaging image of the surface contour of the weld defect.

[0081] Embodiment 3:

[0082] An embodiment of the present invention provides an imaging system of an AC electromagnetic field array detection device for uneven welds, comprising:

[0083] The first module is used to scan the parent metal area, heat-affected zone and weld area of ​​the plane weld defect calibration specimen respectively, calculate and obtain the average amplitude of the magnetic field signals Bz and Bx in the three areas, calculate the critical judgment coefficient based on the average amplitude, and extract the peak value of the magnetic field signal Bz in the three areas as the regional compensation coefficient;

[0084] The second module is used to obtain the magnetic field signal Bz at different lifting distances, extract the peak value of the magnetic field signal Bz at different lifting distances and perform normalization processing, and obtain the functional relationship through linear fitting;

[0085] The third module is used to use the ACFM array probe to scan along the surface of the weld defect to be tested, set n equally spaced position points in the scanning path of the ACFM array probe, record the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and construct signal matrices respectively:

[0086]

[0087] Where i is the channel number, i = 1, 2, 3, ..., 8;

[0088] The fourth module repeats the third module in the order of the eight channels' signals to obtain the peak values ​​of the eight-channel magnetic field signals Bz and the average amplitudes of the eight-channel magnetic field signals Bz and Bx, and calculates the actual lifting distances of the eight channels according to the peak values ​​of the eight-channel magnetic field signals Bz and the functional relationship; and distinguishes the defect areas corresponding to the eight channels according to the average amplitudes of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient;

[0089] The fifth module is to convert the corresponding magnetic field signal matrix B according to different regions i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi;

[0090] The sixth module draws two-dimensional images of eight channels according to the regional compensation matrix DBi, and then arranges them from top to bottom in the order of channel numbers, and draws a three-dimensional image of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

[0091] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0092] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An AC electromagnetic field array detection device for uneven welds, characterized in that: include: A test piece (4), wherein a weld defect (3) is provided on a surface of the test piece (4); An ACFM array probe (2) disposed above the weld defect (3), the ACFM array probe (2) comprising a probe housing, a U-shaped magnetic yoke, an excitation coil, and eight-channel Bz and Bx magnetic field signal receiving coils; and A linear guide rail (1) is arranged on the side of the ACFM array probe (2), and adsorption components (5) are arranged at both ends of the linear guide rail (1). The adsorption components (5) are also provided with a knob. During detection, the position of the linear guide rail (1) must be determined first, and then the knob is rotated so that the linear guide rail (1) is tightly adsorbed on the test object (4). After the detection is completed, the knob is reset so that the linear guide rail (1) is separated from the test object (4).

2. The uneven weld AC electromagnetic field array detection device according to claim 1, characterized in that: The linear guide rail (1) is provided with a first slide bar (6) and a handle (8) in the horizontal direction for controlling the movement of the ACFM array probe (2); the linear guide rail (1) is also provided with a second slide bar (7) in the vertical direction for controlling the lifting height of the ACFM array probe (2); the second slide bar (7) is provided with two nuts (9) for fixing after the lifting height is determined.

3. The uneven weld AC electromagnetic field array detection device according to claim 1, characterized in that: The eight-channel Bz and Bx magnetic field signal receiving coils need to be assigned channel numbers in the order of their positions in the ACFM array probe (2).

4. The uneven weld AC electromagnetic field array detection device according to claim 1, characterized in that: The weld defect (3) comprises a weld zone (31), a heat-affected zone (32) and a parent material zone (33).

5. An uneven weld seam AC electromagnetic field array detection imaging method, implemented by using an uneven weld seam AC electromagnetic field array detection device according to any one of claims 1 to 4, characterized in that: include: S100, scanning the parent metal area, heat-affected zone and weld area surface of the plane weld defect calibration specimen respectively, obtaining the average amplitude of the magnetic field signals Bz and Bx in the three areas, calculating the critical judgment coefficient according to the average amplitude, and extracting the peak value of the magnetic field signal Bz in the three areas as the regional compensation coefficient; S200, obtaining magnetic field signals Bz at different lift-off distances, extracting peak values ​​of the magnetic field signals Bz at different lift-off distances and performing normalization processing, and obtaining a functional relationship through linear fitting; S300, using the ACFM array probe (2) to scan along the surface of the weld defect (3) of the test piece (4), setting n equally spaced position points in the scanning path of the ACFM array probe (2), recording the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and constructing signal matrices respectively: Where i is the channel number, i = 1, 2, 3, ..., 8; S400, repeating step S300 for the signals of the eight channels in sequence to obtain the peak values ​​of the eight-channel magnetic field signals Bz and the average amplitudes of the eight-channel magnetic field signals Bz and Bx, and calculating the actual lifting distances of the eight channels according to the peak values ​​of the eight-channel magnetic field signals Bz and the functional relationship; distinguishing the defect areas corresponding to the eight channels according to the average amplitudes of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient; S500, according to different regions, the corresponding magnetic field signal matrix B i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi; S600, drawing two-dimensional imaging diagrams of eight channels according to the regional compensation matrix DBi, and then arranging them from top to bottom in the order of channel numbers, and drawing a three-dimensional imaging diagram of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

6. The uneven weld AC electromagnetic field array detection imaging method according to claim 5, characterized in that: Step S300 also includes: pre-determining the shape of the weld defect on the test piece (4); if it is a convex shape, measuring the distance between the highest convex point and the linear guide rail (2) as the height of the array probe, and adjusting the second slide bar (7) for height leveling before detection; if it is a flat or concave shape, there is no need for height leveling and detection can be performed directly.

7. The uneven weld seam AC electromagnetic field array detection imaging method according to claim 5, characterized in that: Step S300 also includes: extracting the position coordinates Xmax and Ymax corresponding to the peak values ​​of the magnetic field signals Bz and Bx, respectively, determining whether Xmax is equal to Ymax, and if not, performing the calculation of the first column element [Y1Y2Y3…Y n ] T Perform coordinate matching correction to form a new defect length correction matrix CBi. The formula includes: AND j 'And j -(AND max -X max ),j=1,2,3...n Where Y j ′ is the corrected new coordinate, which is the first column element of matrix CBi; j is the first column element of the matrix Bi.

8. The uneven weld AC electromagnetic field array detection imaging method according to claim 5, characterized in that: Step S600 includes: using the first column element values ​​in the matrix DBi as the X-axis coordinates and the second column element values ​​in the matrix DBi as the Y-axis coordinates, drawing a two-dimensional imaging diagram of the eight channels, and then arranging them from top to bottom in order of the channel numbers, and using the actual lift-off heights of the eight channels as the Z-axis coordinates to draw a three-dimensional imaging diagram of the surface contour of the weld defect.

9. An AC electromagnetic field array detection imaging method for uneven welds according to any one of claims 5-8, characterized in that: The ACFM array probe (2) must always be located directly above the weld defect (3) during the detection process.

10. An AC electromagnetic field array detection imaging system for uneven welds, characterized in that: include: The first module is used to scan the parent metal area, heat-affected zone and weld area of ​​the plane weld defect calibration specimen respectively, calculate and obtain the average amplitude of the magnetic field signals Bz and Bx in the three areas, calculate the critical judgment coefficient based on the average amplitude, and extract the peak value of the magnetic field signal Bz in the three areas as the regional compensation coefficient; The second module is used to obtain the magnetic field signal Bz at different lifting distances, extract the peak value of the magnetic field signal Bz at different lifting distances and perform normalization processing, and obtain the functional relationship through linear fitting; The third module is used to use the ACFM array probe to scan along the surface of the weld defect to be tested, set n equally spaced position points in the scanning path of the ACFM array probe, record the coordinates of the position points and the amplitudes of the magnetic field signals Bz and Bx at the points, and construct signal matrices respectively: Where i is the channel number, i = 1, 2, 3, ..., 8; The fourth module repeats the third module in the order of the eight channels' signals to obtain the peak values ​​of the eight-channel magnetic field signals Bz and the average amplitudes of the eight-channel magnetic field signals Bz and Bx, and calculates the actual lifting distances of the eight channels according to the peak values ​​of the eight-channel magnetic field signals Bz and the functional relationship; and distinguishes the defect areas corresponding to the eight channels according to the average amplitudes of the eight-channel magnetic field signals Bz and Bx and the critical judgment coefficient; The fifth module is to convert the corresponding magnetic field signal matrix B according to different regions i Multiply the elements in the second column by the corresponding regional compensation coefficient to obtain the corresponding regional compensation matrix DBi; The sixth module draws two-dimensional images of eight channels according to the regional compensation matrix DBi, and then arranges them from top to bottom in the order of channel numbers, and draws a three-dimensional image of the surface contour of the weld defect according to the actual lift-off heights of the eight channels.

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