A steel structure weld detection system and detection method thereof

Abstract

The invention relates to the technical field of weld detection, and specifically discloses a steel structure weld detection system and a detection method thereof, comprising: obtaining a steel structure welding surface, constructing a plane coordinate system with the midpoint of the steel structure welding surface as the origin, constructing a steel structure welding plane rectangular coordinate system with the translation step length of a weld detection probe as the unit length, performing traversal detection on the coordinate points on the steel structure welding surface by the weld detection probe to obtain a steel structure line model; arranging and fitting the steel structure line model with the coordinate points on the steel structure welding surface to obtain a steel structure weld detection model; determining welding defect positions based on the steel structure weld detection model and welding signals measured at the coordinate points on the steel structure welding surface, and performing repair welding to achieve stability in the steel structure welding process, improve welding quality, and provide an effective and intuitive judgment basis for the stability and qualified rate of the steel structure in the welding process.

Description

Technical Field

[0001] The present invention relates to the technical field of weld detection, and in particular to a steel structure weld detection system and a detection method thereof. Background Art

[0002] During the processing and production of steel structure items, it is often necessary to weld the gaps between steel structures. After the existing gaps between steel structures are welded, in order to ensure the effect of the steel structure welds, the steel structure welds need to be inspected, and then repaired to ensure the welding quality of the steel structure;

[0003] In the prior art, the inspection results of welds cannot analyze the size of defective welds through big data, and cannot accurately inspect welds at welded parts of steel structures. In addition, the presentation of welds inside steel structures during the inspection process is not intuitive enough. When welds in steel structures are defective, effective repair welding cannot be performed based on the inspection results. Summary of the invention

[0004] The object of the present invention is to provide a steel structure weld detection system and a detection method thereof to solve the above-mentioned background problems.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A steel structure weld detection method, comprising:

[0007] Obtain the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step length n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y);

[0008] The weld detection probe is used to traverse the coordinate points (x, y) on the weld surface of the steel structure to obtain a steel structure line model;

[0009] The steel structure line model is arranged and fitted with the coordinate points (x, y) on the steel structure welding surface to obtain a steel structure weld detection model;

[0010] Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, the welding defect location is determined and repair welding is performed.

[0011] As a further solution of the present invention: the steps of detecting the coordinate point (x, y) and obtaining the steel structure line model include:

[0012] Step A01: Perform ultrasonic detection at the coordinate point (x, y) on the welding surface of the steel structure through a weld detection probe, and obtain the round-trip time value WFt of the ultrasonic detection during the ultrasonic detection process;

[0013] Step A02: Compare the round-trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt; obtain a welding signal, wherein the welding signal includes a defect signal and a non-destructive signal;

[0014] Step A03: Based on the defect signal, the vertical depth of the steel structure weld at the coordinate point (x, y) on the steel structure welding surface is measured to obtain the critical point of the defect length, wherein the critical point of the defect length includes the upper limit point QDon (x、y) and defect lower boundary point QDdown (x、y) ; and calculate the internal defect height H of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ;

[0015] Step A04: Based on the defect height value H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) Construct steel structure line model.

[0016] As a further solution of the present invention: comparing the round trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt;

[0017] If the round-trip time value WFt is greater than the defect characterization time threshold Qt, a defect signal is generated;

[0018] If the round-trip time value WFt is less than or equal to the defect characterization time threshold Qt, a lossless signal is generated.

[0019] As a further solution of the present invention: the height value H of the internal defect of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) The calculation steps include:

[0020] The weld detection probe travel route is constructed with the coordinate point (x, y) perpendicular to the weld surface of the steel structure, i measurement points are constructed with the travel length m of the weld detection probe as the unit, and the measurement points are marked as i, where i is 1, 2, 3, ...;

[0021] The weld detection probe is placed on each measuring point in turn for measurement; during the measurement process, the weld detection probe emits an ultrasonic pulse at each measuring point and receives the reflected echo; the ultrasonic data is recorded during the measurement process; the ultrasonic data includes: the echo time delay value YT i And the echo signal strength value QX i ; At the same time, the test obtains the propagation velocity value GV of the detection ultrasound in the steel structure; the echo reflection depth value D is calculated i ;

[0022] Then based on the echo reflection depth value D i And the echo signal strength value QX iConstruct echo intensity curve; calculate the upper limit point of defect QDon (x、y) and defect lower boundary point QDdown (x、y) ;

[0023] Then through H (x，y) =QDdown (x、y) -QDon (x、y) Calculate the defect height H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) .

[0024] As a further solution of the present invention: Calculate the echo reflection depth value D i .

[0025] As a further solution of the present invention: the process of constructing the echo intensity curve includes:

[0026] The echo reflection depth value D i As the horizontal axis, the echo signal strength value QX i The echo intensity coordinate system is constructed as the ordinate, and then the echo reflection depth value D at the measurement point is i and echo signal strength value QX i Fitting is performed to construct echo intensity coordinate points (D i , QX i ), the echo intensity coordinate point (D i , QX i ) is input into the echo intensity coordinate system, and then the echo intensity coordinate points are connected in sequence to obtain the echo intensity curve.

[0027] As a further solution of the present invention: the upper limit point QDon (x、y) and defect lower boundary point QDdown (x、y) The way to obtain is:

[0028] Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ;

[0029] Based on the echo signal strength change rate BQ at the measurement point i , obtain the maximum value BQax of the echo signal strength change rate and the minimum value BQi n of the echo signal strength change rate;

[0030] Based on the maximum value of the echo signal intensity change rate BQax, the corresponding echo reflection depth value is obtained, which is the upper boundary point of the defect QDon (x、y); Based on the minimum value of the echo signal intensity change rate BQ in, the corresponding echo reflection depth value is obtained, which is the lower boundary point of the defect QDdown (x、y) .

[0031] As a further solution of the present invention: Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i .

[0032] As a further solution of the present invention: if there is a peak in the echo intensity curve, that is, it first rises and then decreases, then there is a continuous defect; if there are two peaks in the echo intensity curve, then according to the echo signal intensity change rate, the maximum value and the minimum value of the echo signal intensity change rate of the two peaks rising and falling are selected to obtain two defect points, and then the heights of the two unconnected defect points are calculated.

[0033] As a further solution of the present invention: a steel structure weld detection system, comprising:

[0034] Data acquisition module: used to obtain the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y);

[0035] Line model building module: used to traverse and detect the coordinate points (x, y) on the welding surface of the steel structure through the weld detection probe to obtain the steel structure line model;

[0036] Detection model building module: used to arrange and fit the steel structure line model with the coordinate points (x, y) on the steel structure welding surface to obtain the steel structure weld detection model;

[0037] Processing module: Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, the welding defect location is determined and repair welding is performed.

[0038] Beneficial effects of the present invention:

[0039] In the present invention, by constructing a coordinate plane for the welding surface of the steel structure and performing traversal detection of coordinate points based on the coordinate plane on the welding surface, accurate weld detection can be achieved for each detection point on the welding surface of the steel structure. At the same time, when the weld detection probe performs ultrasonic detection on each detection point, it is judged whether there is a weld at the welding point of the steel structure under the detection point based on the round-trip time of the ultrasonic detection during the detection process. When the detection point generates a defect signal, that is, there is a defect, the weld defect height under the welding surface at that location is calculated based on the data measured by the weld detection probe, and then a steel structure line model is generated. Then, a steel structure weld detection model is constructed based on the steel structure line model, so that the model construction of the steel structure weld can be realized, and then the defect position in the steel structure welding can be located and repaired based on the steel structure weld detection model, so as to achieve stability in the steel structure welding process, improve welding quality, and provide an effective and intuitive judgment basis for the stability and qualified rate of the steel structure in the welding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the accompanying drawings.

[0041] Figure 1 It is a schematic flow chart of the method of the present invention;

[0042] Figure 2 It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention 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.

[0044] Embodiment 1

[0045] See also Figure 1 As shown, the present invention is a steel structure weld detection method, comprising:

[0046] Step 1: Obtain the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y);

[0047] Step 2: Perform traversal detection on the coordinate points (x, y) on the welding surface of the steel structure through the weld detection probe to obtain the steel structure line model. It should be noted that the traversal detection is to detect all the detection coordinate points on the welding surface of the steel structure in sequence;

[0048] Specifically, the steps of detecting the coordinate point (x, y) and obtaining the steel structure line model include:

[0049] Step A01: Perform ultrasonic detection at the coordinate point (x, y) on the welding surface of the steel structure through a weld detection probe, and obtain the round-trip time value WFt of the ultrasonic detection during the ultrasonic detection process;

[0050] Step A02: Compare the round-trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt; obtain a welding signal, wherein the welding signal includes a defect signal and a non-destructive signal;

[0051] If the round-trip time value WFt is greater than the defect characterization time threshold Qt, a defect signal is generated; at this time, step A03 is executed;

[0052] If the round-trip time value WFt is less than or equal to the defect characterization time threshold Qt, a non-destructive signal is generated; it means that there is no weld at the steel structure welding point under the detection coordinate point (x, y), and step 04 is directly executed to generate a steel structure line model;

[0053] Step A03: Based on the defect signal, the vertical depth of the steel structure weld at the coordinate point (x, y) on the steel structure welding surface is measured to obtain the critical point of the defect length, wherein the critical point of the defect length includes the upper limit point QDon (x、y) and defect lower boundary point QDdown (x、y) ; and calculate the internal defect height H of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ;

[0054] Specifically include:

[0055] The weld detection probe travel route is constructed with the coordinate point (x, y) perpendicular to the weld surface of the steel structure, i measurement points are constructed with the travel length m of the weld detection probe as the unit, and the measurement points are marked as i, where i is 1, 2, 3, ...;

[0056] It should be noted that the travel route is a straight line, and the more measurement points there are on the travel route of the weld inspection probe, the more accurate the determination of the weld defect position is;

[0057] The weld detection probe is placed on each measuring point in turn for measurement; during the measurement process, the weld detection probe emits an ultrasonic pulse at each measuring point and receives the reflected echo; the ultrasonic data is recorded during the measurement process; the ultrasonic data includes: the echo time delay value YT i And the echo signal strength value QX i ; At the same time, the test obtains the propagation velocity value GV of the detection ultrasound in the steel structure;

[0058] Then through Calculate the echo reflection depth value D i ;

[0059] Then based on the echo reflection depth value D i And the echo signal strength value QX i Construct the echo intensity curve; specifically: based on the echo reflection depth value D i As the horizontal axis, the echo signal strength value QX i The echo intensity coordinate system is constructed as the ordinate, and then the echo reflection depth value D at the measurement point is i and echo signal strength value QX i Fitting is performed to construct echo intensity coordinate points (D i , QX i ), the echo intensity coordinate point (D i , QX i ) is input into the echo intensity coordinate system, and then the echo intensity coordinate points are connected in sequence to obtain the echo intensity curve;

[0060] pass Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ;

[0061] Based on the echo signal strength change rate BQ at the measurement point i , obtain the maximum value BQax of the echo signal strength change rate and the minimum value BQi n of the echo signal strength change rate,

[0062] Based on the maximum value of the echo signal intensity change rate BQax, the corresponding echo reflection depth value is obtained, which is the upper boundary point of the defect QDon (x、y) ; Based on the minimum value of the echo signal intensity change rate BQ in, the corresponding echo reflection depth value is obtained, which is the lower boundary point of the defect QDdown (x、y) ;

[0063] Then through H (x，y) =QDdown (x、y) -QDon (x、y) Calculate the defect height H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ;

[0064] Step A04: Based on the defect height value H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) Construct steel structure line model;

[0065] Step 3: Arrange and fit the steel structure line model with the coordinate points (x, y) on the steel structure welding surface to obtain the steel structure weld detection model;

[0066] Step 4: Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, determine the location of the welding defect and perform repair welding.

[0067] It should be noted that when traversing the coordinate points on the welding surface of the steel structure, in addition to using a single weld detection probe to detect a single coordinate point, a parallel weld detection probe can also be used to detect multiple coordinate points at the same time, which can improve the detection efficiency and quickly build a steel structure weld detection model;

[0068] By constructing a coordinate plane for the welding surface of the steel structure and performing traversal detection of coordinate points based on the coordinate plane on the welding surface, accurate weld detection can be achieved for each detection point on the welding surface of the steel structure. At the same time, when the weld detection probe performs ultrasonic detection on each detection point, it is judged whether there is a weld at the welding point of the steel structure under the detection point based on the round-trip time of the ultrasonic detection during the detection process. When the detection point generates a defect signal, that is, when a defect exists, the weld defect height under the welding surface at that location is calculated based on the data measured by the weld detection probe, and then a steel structure line model is generated. Then, a steel structure weld detection model is constructed based on the steel structure line model, which can realize model construction of the steel structure weld. Then, based on the steel structure weld detection model, the defect position in the steel structure welding is located and repaired, so as to achieve stability in the steel structure welding process, improve welding quality, and provide an effective and intuitive judgment basis for the stability and qualified rate of the steel structure in the welding process.

[0069] Embodiment 2

[0070] Based on the above embodiments, this embodiment provides a more accurate method for calculating the critical point of defect length; specifically:

[0071] In the process of measuring the measuring points after the construction of the weld detection probe travel route is completed, the weld detection probe can be measured sequentially from bottom to top on the weld detection probe travel route;

[0072] At the same time, the weld detection probe can also be measured sequentially from top to bottom along the weld detection probe travel route;

[0073] The calculation is performed using the data from the two measurements, and then the upper boundary point and the lower boundary point of the defect measured on both sides are subtracted and the absolute value is taken to obtain the upper boundary point deviation value WPon and the lower boundary point deviation value WPdown;

[0074] Then the upper boundary point deviation value WPon and the lower boundary point deviation value WPdown are compared with the boundary point deviation threshold value WPY respectively;

[0075] If the upper boundary point deviation value WPon and the lower boundary point deviation value WPdown are both less than the boundary point deviation threshold WPY, a defect boundary point accurate signal is generated; at this time, it means that both sets of measurement data are in an accurate state, and any set can be selected as the accurate value to calculate the defect height value inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure;

[0076] If the upper boundary point deviation value WPon and / or the lower boundary point deviation value WPdown is less than the boundary point deviation threshold WPY, a repositioning signal is generated;

[0077] At this time, based on the repositioning signal, a set of measurement data is obtained by re-measurement, and then the measurement data of the upper boundary point deviation value WPon and the lower boundary point deviation value WPdown in the two sets of data are selected, and then the defect boundary point accurate signal is generated based on this; at this time, the two sets of measurement data are in an accurate state, and any set can be selected as the accurate value to calculate the defect height value inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure;

[0078] It should be noted that when adding a set of measurement data still cannot obtain the accurate signal of the defect boundary point, it is still necessary to continue to measure again and obtain a new set of measurement data, and then continue to calculate the upper boundary point deviation value WPon and the lower boundary point deviation value WPdown until the accurate signal of the defect boundary point is obtained.

[0079] Based on the first and second embodiments, in the process of calculating the defect height value inside the steel structure, an echo intensity curve is first constructed. If the echo intensity curve has a peak, that is, it first rises and then decreases, there is a continuous defect. If the echo intensity curve has two peaks, the maximum value of the echo signal intensity change rate of the two peaks rising and falling and the minimum value of the echo signal intensity change rate are selected according to the echo signal intensity change rate, and two defect points are obtained. Then, the heights of the two unconnected defect points are calculated;

[0080] Similarly, during the verification process, the heights of the two defect points are calculated and tested separately to obtain accurate signals of the defect boundary points;

[0081] When performing weld inspections on each point on the welding surface of the steel structure, accurate calculation of the weld defect height can be achieved through two or more weld inspections, thereby improving the accuracy of the steel structure weld inspection model and providing intuitive data support for the use and production of steel structure welding.

[0082] Embodiment 3

[0083] A steel structure weld detection system, comprising:

[0084] Data acquisition module: used to obtain the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y);

[0085] Line model building module: used to traverse and detect the coordinate points (x, y) on the welding surface of the steel structure through the weld detection probe to obtain the steel structure line model;

[0086] Detection model building module: used to arrange and fit the steel structure line model with the coordinate points (x, y) on the steel structure welding surface to obtain the steel structure weld detection model;

[0087] Processing module: Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, the welding defect location is determined and repair welding is performed.

[0088] Based on the data measured by the weld detection probe, the height of the weld defect under the welding surface is calculated, and then the steel structure line model is generated. Then, the steel structure weld detection model is constructed based on the steel structure line model. The model construction of the steel structure weld can be realized, and then the defect position in the steel structure welding can be located and repaired based on the steel structure weld detection model, so as to achieve stability in the steel structure welding process, improve welding quality, and provide an effective and intuitive judgment basis for the stability and qualified rate of the steel structure in the welding process.

[0089] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A steel structure weld detection method, characterized in that: include: Obtain the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step length n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y); The weld detection probe is used to traverse the coordinate points (x, y) on the weld surface of the steel structure to obtain a steel structure line model; The steps of detecting the coordinate points (x, y) and obtaining the steel structure line model include: Step A01: Perform ultrasonic detection at the coordinate point (x, y) on the welding surface of the steel structure through a weld detection probe, and obtain the round-trip time value WFt of the ultrasonic detection during the ultrasonic detection process; Step A02: Compare the round-trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt; obtain a welding signal, wherein the welding signal includes a defect signal and a non-destructive signal; Step A03: Based on the defect signal, the vertical depth of the steel structure weld at the coordinate point (x, y) on the steel structure welding surface is measured to obtain the critical point of the defect length, wherein the critical point of the defect length includes the upper limit point QDon (x、y) and defect lower boundary point QDdown (x、y) ; and calculate the internal defect height H of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ; The height value H of the internal defect of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) The calculation steps include: The weld detection probe travel route is constructed with the coordinate point (x, y) perpendicular to the weld surface of the steel structure, i measurement points are constructed with the travel length m of the weld detection probe as the unit, and the measurement points are marked as i, where i is 1, 2, 3, ...; The weld detection probe is placed on each measuring point in turn for measurement; during the measurement process, the weld detection probe emits an ultrasonic pulse at each measuring point and receives the reflected echo; the ultrasonic data is recorded during the measurement process; the ultrasonic data includes: the echo time delay value YT i And the echo signal strength value QX i ; At the same time, the test obtains the propagation velocity value GV of the detection ultrasound in the steel structure; the echo reflection depth value D is calculated i ;pass Calculate the echo reflection depth value D i ; Then based on the echo reflection depth value D i And the echo signal strength value QX i Construct echo intensity curve; calculate the upper limit point of defect QDon (x、y) and defect lower boundary point QDdown (x、y) ; The process of constructing the echo intensity curve includes: The echo reflection depth value D i As the horizontal axis, the echo signal strength value QX i The echo intensity coordinate system is constructed as the ordinate, and then the echo reflection depth value D at the measurement point is i and echo signal strength value QX i Fitting is performed to construct echo intensity coordinate points (D i , QX i ), the echo intensity coordinate point (D i , QX i ) is input into the echo intensity coordinate system, and then the echo intensity coordinate points are connected in sequence to obtain the echo intensity curve; The upper limit of the defect QDon (x、y) and defect lower boundary point QDdown (x、y) The way to obtain is: Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ; pass Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ; Based on the echo signal strength change rate BQ at the measurement point i , obtain the maximum value BQax of the echo signal strength change rate and the minimum value BQin of the echo signal strength change rate; Based on the maximum value of the echo signal intensity change rate BQax, the corresponding echo reflection depth value is obtained, which is the upper boundary point of the defect QDon (x、y) ; Based on the minimum value of the echo signal intensity change rate BQin, the corresponding echo reflection depth value is obtained, which is the lower boundary point of the defect QDdown (x、y) ; Then through H (x，y) =QDdown (x、y) -QDon (x、y) Calculate the defect height H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ; Step A04: Based on the defect height value H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) Construct steel structure line model; The steel structure line model is arranged and fitted with the coordinate points (x, y) on the steel structure welding surface to obtain a steel structure weld detection model; Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, the welding defect location is determined and repair welding is performed.

2. A steel structure weld detection method according to claim 1, characterized in that: Compare the round trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt; If the round-trip time value WFt is greater than the defect characterization time threshold Qt, a defect signal is generated; If the round-trip time value WFt is less than or equal to the defect characterization time threshold Qt, a lossless signal is generated.

3. A steel structure weld detection method according to claim 1, characterized in that: If there is a peak in the echo intensity curve, that is, it rises first and then decreases, there is a continuous defect. If there are two peaks in the echo intensity curve, then according to the echo signal intensity change rate, the maximum value and minimum value of the echo signal intensity change rate of the two peaks rising and falling are selected to obtain two defect points, and then the height of the two unconnected defect points is calculated.

4. A steel structure weld detection system, characterized in that: The system is used to perform the detection method as described in any one of claims 1 to 3, comprising: Data acquisition module: used to acquire the welding surface of the steel structure, construct a plane coordinate system with the midpoint of the welding surface of the steel structure as the origin, and construct a steel structure welding plane rectangular coordinate system with the translation step n of the weld detection probe as the unit length. At this time, the position coordinate point of the weld detection probe is (x, y); Line model building module: used to traverse and detect the coordinate points (x, y) on the welding surface of the steel structure through the weld detection probe to obtain the steel structure line model; The steps of detecting the coordinate points (x, y) and obtaining the steel structure line model include: Step A01: Perform ultrasonic detection at the coordinate point (x, y) on the welding surface of the steel structure through a weld detection probe, and obtain the round-trip time value WFt of the ultrasonic detection during the ultrasonic detection process; Step A02: Compare the round-trip time value WFt of the detection ultrasound with the defect characterization time threshold Qt; obtain a welding signal, wherein the welding signal includes a defect signal and a non-destructive signal; Step A03: Based on the defect signal, the vertical depth of the steel structure weld at the coordinate point (x, y) on the steel structure welding surface is measured to obtain the critical point of the defect length, wherein the critical point of the defect length includes the upper limit point QDon (x、y) and defect lower boundary point QDdown (x、y) ; and calculate the internal defect height H of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ; The height value H of the internal defect of the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) The calculation steps include: The weld detection probe travel route is constructed with the coordinate point (x, y) perpendicular to the weld surface of the steel structure, i measurement points are constructed with the travel length m of the weld detection probe as the unit, and the measurement points are marked as i, where i is 1, 2, 3, ...; The weld detection probe is placed on each measuring point in turn for measurement; during the measurement process, the weld detection probe emits an ultrasonic pulse at each measuring point and receives the reflected echo; the ultrasonic data is recorded during the measurement process; the ultrasonic data includes: the echo time delay value YT i And the echo signal strength value QX i ; At the same time, the test obtains the propagation velocity value GV of the detection ultrasound in the steel structure; the echo reflection depth value D is calculated i ;pass Calculate the echo reflection depth value D i ; Then based on the echo reflection depth value D i And the echo signal strength value QX i Construct echo intensity curve; calculate the upper limit point of defect QDon (x、y) and defect lower boundary point QDdown (x、y) ; The process of constructing the echo intensity curve includes: The echo reflection depth value D i As the horizontal axis, the echo signal strength value QX i The echo intensity coordinate system is constructed as the ordinate, and then the echo reflection depth value D at the measurement point is i and echo signal strength value QX i Fitting is performed to construct echo intensity coordinate points (D i , QX i ), the echo intensity coordinate point (D i , QX i ) is input into the echo intensity coordinate system, and then the echo intensity coordinate points are connected in sequence to obtain the echo intensity curve; The upper limit of the defect QDon (x、y) and defect lower boundary point QDdown (x、y) The way to obtain is: Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ; pass Calculate and obtain the coordinates of each echo intensity point (D i+1 , QX i ) is the echo signal strength change rate BQ at each measurement point i ; Based on the echo signal strength change rate BQ at the measurement point i , obtain the maximum value BQax of the echo signal strength change rate and the minimum value BQin of the echo signal strength change rate; Based on the maximum value of the echo signal intensity change rate BQax, the corresponding echo reflection depth value is obtained, which is the upper boundary point of the defect QDon (x、y) ; Based on the minimum value of the echo signal intensity change rate BQin, the corresponding echo reflection depth value is obtained, which is the lower boundary point of the defect QDdown (x、y) ; Then through H (x，y) =QDdown (x、y) -QDon (x、y) Calculate the defect height H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) ; Step A04: Based on the defect height value H inside the steel structure at the coordinate point (x, y) on the welding surface of the steel structure (x，y) Construct steel structure line model; Detection model building module: used to arrange and fit the steel structure line model with the coordinate points (x, y) on the steel structure welding surface to obtain the steel structure weld detection model; Processing module: Based on the steel structure weld detection model and the welding signal measured at the coordinate point (x, y) on the steel structure welding surface, the welding defect location is determined and repair welding is performed.

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