Online detection device and method for internal defects of drawn tube

Abstract

The present invention relates to the field of detection technology, and provides an online detection method for internal defects of a drawn tube, comprising: emitting ultrasonic waves to the surface of each detection area at a first angle and multiple second angles and receiving echo signals; obtaining ultrasonic incident signals, ultrasonic basic echo signals at a first angle, and multiple ultrasonic comparative echo signals at a second angle; obtaining a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal; obtaining an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value; obtaining an abnormal characteristic value according to the amplitude of the ultrasonic basic echo signal and the multiple ultrasonic comparative echo signals and the abnormal attribute value; obtaining a defect abnormality index according to the amplitude difference and abnormal characteristic value of adjacent peaks in the ultrasonic basic echo signal, and then judging whether there is a defect, and using this method to obtain accurate defect detection results. The present invention also provides an online detection device for internal defects of a drawn tube.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to an online detection device and method for internal defects of a drawn tube. Background Art

[0002] Drawing is a process for manufacturing metal pipes. Drawn tubes have good corrosion resistance and thermal conductivity, so they are often used to produce components such as condensers and evaporators in automotive air-conditioning systems. However, due to gas residue or uneven melting in the metal material inside the drawn tube, pores and bubbles will appear inside the drawn tube. These defects may cause the corrosion resistance and thermal conductivity of the drawn tube to be impaired, which in turn affects the working efficiency of the automotive air-conditioning system. Therefore, online detection of pores and bubble defects inside the drawn tube has important application significance.

[0003] Existing methods often use ultrasonic flaw detection to perform online detection of pores and bubble defects inside drawn tubes. During ultrasonic flaw detection, the probe sends a transmission signal to the detection area inside the drawn tube. The defect will cause the medium in the detection area to be mixed, which will cause the transmission signal to be reflected in the detection area at the defect, generating an echo signal with a higher amplitude. Existing ultrasonic flaw detection is based on the analysis of the amplitude characteristics in the echo signal. However, due to the differences in the defect conditions of different pores and bubble defects, the signal changes in the echo signal are complex, resulting in this method of analysis based on the amplitude characteristics of the echo signal cannot accurately reflect the defect conditions inside the drawn tube, so the detection accuracy of the defects inside the drawn tube is not high enough. Summary of the invention

[0004] In order to solve the technical problem that the detection accuracy of internal defects of drawn tubes is not high enough, the purpose of the present invention is to provide an online detection device and method for internal defects of drawn tubes. The technical solution adopted is as follows:

[0005] An online detection method for internal defects of a drawn tube, the online detection method comprising:

[0006] Transmitting ultrasonic waves to the surface of each detection area at a first angle and multiple second angles and receiving echo signals; acquiring ultrasonic incident signals, ultrasonic basic echo signals at the first angle, and multiple ultrasonic comparative echo signals at the second angle;

[0007] Obtaining a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal;

[0008] Obtaining an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value;

[0009] Obtaining an abnormal characteristic value according to the amplitudes of the ultrasonic basic echo signal and the plurality of ultrasonic contrast echo signals and the abnormal attribute value;

[0010] Obtaining a defect abnormality index according to the amplitude difference between adjacent wave peaks in the ultrasonic basic echo signal and the abnormal characteristic value;

[0011] Whether there is a defect is determined based on the defect abnormality indicator.

[0012] Preferably, the time difference attribute value obtained according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal is obtained by calculating the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal in each detection area, and the time difference attribute value is obtained by analyzing the differences between the time differences in each detection area.

[0013] Preferably, the time difference attribute value is obtained by analyzing the difference between the time differences of each detection area, calculating the difference between the time differences of each detection area, taking the absolute value and averaging the difference, and then calculating the time difference attribute value using a normalization function.

[0014] Preferably, the step of obtaining the abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value comprises:

[0015] Calculate the amplitude mean of the ultrasonic basic echo signal in each detection area;

[0016] The echo amplitude abnormality factor of each detection area is calculated by using the amplitude mean of the ultrasonic basic echo signal of each detection area;

[0017] The abnormal attribute value is obtained according to the echo amplitude abnormal factor and the time difference attribute value.

[0018] Preferably, the echo amplitude anomaly factor is calculated using a normalization function; the product of the echo amplitude anomaly factor and the time difference attribute value is the anomaly attribute value.

[0019] Preferably, the step of obtaining the abnormal characteristic value according to the amplitudes of the ultrasonic basic echo signal and the plurality of ultrasonic contrast echo signals and the abnormal attribute value comprises:

[0020] Calculating an angle characteristic factor, where the angle characteristic factor is a difference between an amplitude mean of an ultrasonic contrast echo signal and an amplitude mean of the ultrasonic basic echo signal;

[0021] Obtaining an angle attribute value according to the angle characteristic factor;

[0022] The abnormal feature value is obtained according to the angle attribute value and the abnormal attribute value.

[0023] Preferably, the angle attribute value is calculated using an inverse proportional function; the product of the angle attribute value and the abnormal attribute value is the abnormal characteristic value.

[0024] Preferably, the step of obtaining the defect abnormality index according to the amplitude difference between adjacent peaks in the ultrasonic basic echo signal and the abnormal characteristic value includes:

[0025] Extracting all peak points in the ultrasonic basic echo signal;

[0026] Calculating a signal amplitude difference factor, wherein the signal amplitude difference factor is a signal amplitude difference between a previous wave crest point and an adjacent next wave crest point;

[0027] Obtaining an adjustment factor according to the signal amplitude difference factor;

[0028] Obtaining an initial defect abnormality indicator according to the abnormal characteristic value;

[0029] The defect abnormality index is obtained according to the initial defect abnormality index and the adjustment factor.

[0030] Preferably, judging whether a defect exists based on the defect abnormality indicator is: if the defect abnormality indicator is higher than a preset threshold, a defect exists.

[0031] An online detection device for internal defects of a drawn tube, the online detection device comprising:

[0032] An ultrasonic detector, used for emitting ultrasonic waves to the surface of each detection area at a first angle and a plurality of second angles and receiving echo signals;

[0033] A signal acquisition module, used to acquire an ultrasonic incident signal, an ultrasonic basic echo signal at a first angle, and a plurality of ultrasonic contrast echo signals at a second angle;

[0034] A data processing module, used to obtain a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal; obtain an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value; obtain an abnormal characteristic value according to the amplitude of the ultrasonic basic echo signal and the multiple ultrasonic comparison echo signals and the abnormal attribute value; obtain a defect abnormality index according to the amplitude difference between adjacent peaks in the ultrasonic basic echo signal and the abnormal characteristic value;

[0035] A judgment module is used to judge whether there is a defect based on the defect abnormality indicator.

[0036] The present invention has the following beneficial effects: the online detection method and equipment for internal defects of a drawn tube proposed in the present invention can obtain the time difference attribute value at each position in the drawn tube by analyzing the time difference characteristics of the echo signal and the incident signal; obtain the abnormal attribute value at each position in the drawn tube based on the time difference attribute value combined with the amplitude characteristics of the echo signal; obtain the abnormal characteristic value of each detection area in the drawn tube based on the abnormal attribute value combined with the relationship between the echo signal and the ultrasonic incident angle; and obtain the final defect abnormality index based on the abnormal characteristic value combined with the characteristics of multiple echo signals, and then determine whether there is a defect based on the final defect abnormality index, thereby obtaining an accurate defect detection result.

[0037] The present invention can preliminarily obtain the time difference attribute value reflecting the flatness of the inner surface of the drawn tube through the time difference feature, and then further confirm the possibility of defects in combination with the amplitude characteristics of the echo signal to obtain the abnormal attribute value, and then consider the influence of different incident angles to obtain the abnormal characteristic value. In addition, multiple echo signal characteristics are introduced for analysis to obtain the final defect abnormality index, and multiple signal characteristics are fully considered and utilized to make the detection result more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic flow chart of an online method for detecting internal defects of a drawn tube provided by a first embodiment of the present invention;

[0040] Figure 2 A schematic flow chart of an online detection method for internal defects of a drawn tube provided in an implementation manner of the first embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a sub-flow chart of step S3 in a method for online detection of internal defects of a drawn tube provided in the first embodiment of the present invention;

[0042] Figure 4 A schematic diagram of a sub-flow chart of step S4 in a method for online detection of internal defects of a drawn tube provided in the first embodiment of the present invention;

[0043] Figure 5 A schematic diagram of a sub-flow chart of step S5 in a method for online detection of internal defects of a drawn tube provided in the first embodiment of the present invention;

[0044] Figure 6A schematic flow chart of an online detection method for internal defects of a drawn tube provided in a specific implementation manner of the first embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of functional modules of an online detection device for internal defects of a drawn tube provided in a second embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the online detection device and method for internal defects of a drawn tube proposed by the present invention, its specific implementation, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0047] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0048] The specific scheme of the online detection device and method for internal defects of a drawn tube provided by the present invention is described in detail below with reference to the accompanying drawings.

[0049] First embodiment

[0050] See also Figure 1 , which shows a schematic flow chart of an online detection method for internal defects of a drawn tube provided by an embodiment of the present invention, the online detection method comprising:

[0051] Step S1, emitting ultrasonic waves to the surface of each detection area at a first angle and multiple second angles and receiving echo signals; acquiring an ultrasonic incident signal, an ultrasonic basic echo signal at a first angle, and multiple ultrasonic comparative echo signals at a second angle;

[0052] Step S2, obtaining a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal;

[0053] Step S3, obtaining an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value;

[0054] Step S4, obtaining an abnormal characteristic value according to the amplitudes of the ultrasonic basic echo signal and the plurality of ultrasonic contrast echo signals and the abnormal attribute value;

[0055] Step S5, obtaining a defect abnormality index according to the amplitude difference between adjacent peaks in the ultrasonic basic echo signal and the abnormal characteristic value;

[0056] Step S6, judging whether there is a defect based on the defect abnormality indicator.

[0057] It can be understood that the steps S2 and S3 are based on the analysis of the ultrasonic basic echo signal, and step S4 is further combined with the ultrasonic contrast echo signal for analysis to obtain the abnormal characteristic value. The steps of emitting ultrasonic waves at the second angle to the surface of each detection area and receiving echo signals and obtaining multiple ultrasonic contrast echo signals at the second angle in step S1 only need to be completed before step S4. That is, Figure 2 As shown, the step S1 includes:

[0058] Step S11, emitting ultrasonic waves at a first angle to the surface of each detection area and receiving echo signals; acquiring ultrasonic incident signals and ultrasonic basic echo signals at the first angle;

[0059] Step S12, emitting ultrasonic waves to the surface of each detection area at multiple second angles and receiving echo signals; obtaining multiple ultrasonic contrast echo signals.

[0060] The online detection method for internal defects of a drawn tube proposed in the present invention can obtain the time difference attribute value at each position in the drawn tube by analyzing the time difference characteristics of the echo signal and the incident signal; obtain the abnormal attribute value at each position in the drawn tube based on the time difference attribute value combined with the amplitude characteristics of the echo signal; obtain the abnormal characteristic value of each detection area in the drawn tube based on the abnormal attribute value combined with the relationship between the echo signal and the ultrasonic incident angle; and obtain the final defect abnormality index based on the abnormal characteristic value combined with the characteristics of multiple echo signals, and then judge whether there is a defect based on the final defect abnormality index, thereby obtaining an accurate defect detection result.

[0061] The present invention can preliminarily obtain the time difference attribute value reflecting the flatness of the inner surface of the drawn tube through the time difference feature, and then further confirm the possibility of defects in combination with the amplitude characteristics of the echo signal to obtain the abnormal attribute value, and then consider the influence of different incident angles to obtain the abnormal characteristic value. In addition, multiple echo signal characteristics are introduced for analysis to obtain the final defect abnormality index, and multiple signal characteristics are fully considered and utilized to make the detection result more accurate.

[0062] The main purpose of the present invention is to obtain defect anomaly indicators inside the drawn tube by analyzing the echo signal characteristics at different positions inside the drawn tube, and then to realize defect detection based on the defect anomaly indicators. The following is a detailed description of each step:

[0063] In step S1, this step first requires collecting echo signal data at different positions inside the drawn tube.

[0064] The first angle is preferably 90°, i.e. vertical incidence. Specifically, the electromagnetic ultrasonic probe of the ultrasonic detector (or ultrasonic flaw detector) is first placed in the inner area of ​​the drawn tube, and at the same time, for a certain detection area inside the drawn tube, the electromagnetic ultrasonic probe sends a transmission signal (i.e., transmits ultrasonic waves) to the detection area in a manner perpendicular to the surface of the detection area, and then the detection area reflects the transmission signal, so that the detector obtains the echo signal after the reflection of the detection area, and at the same time moves the position of the probe inside the drawn tube (the vertical height of the probe and the detection area remains unchanged during the movement), so as to obtain the echo signals of all the detection areas inside the drawn tube.

[0065] The second angles may be three or more. It can be understood that the incident angle can be changed by adjusting the probe. Preferably, the multiple second angles are 30°, 45°, and 60°, respectively. Because there should be an infinite number of situations when the incident angle and the detection plane are at a fixed angle, preferably, at the same angle, probes at multiple different positions are selected to emit ultrasonic waves. Specifically, the present invention selects the incident angles of any three different positions when the incident angle and the detection plane are at a fixed angle as the incident angle situation of the present invention. That is, the present invention selects the incident direction of the probes at any three different positions to present an incident situation of 30 degrees to the detection plane, 45 degrees, and 60 degrees in the same way, thereby obtaining a total of 9 different incident angle situations.

[0066] In step S2, it can be understood that when ultrasonic flaw detection is performed on each detection area inside the drawn tube, the transmission signal is sent by the probe, and the echo signal is obtained by reflection from the detection area, and then the echo signal is received by the ultrasonic detection instrument. The time difference from sending the transmission signal to receiving the echo signal can be obtained through the high-precision clock system equipped with the detection instrument. This time difference can reflect the distance between the probe and the detection area. At the same time, because the surface flatness of the normal area inside the drawn tube should be high, and because the probe of the ultrasonic detection instrument is at the same vertical height as the detection area during detection, the time difference characteristics between normal detection areas should be relatively similar, while the defective area has poor surface flatness, which will lead to a large difference in the time difference between the detection area at the defect and other detection areas.

[0067] Based on the above logic, this step is to analyze the defect situation according to the time difference. The time difference attribute value obtained according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal is preferably obtained by calculating the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal of each detection area, and the time difference attribute value is obtained by analyzing the difference between the time differences of each detection area. Furthermore, the time difference attribute value obtained by analyzing the difference between the time differences of each detection area is to calculate the difference between the time differences of each detection area, and the time difference attribute value is calculated by taking the absolute value of the difference and averaging it, and then using a normalization function to calculate it.

[0068] Specifically, the calculation formula for the time difference attribute value is constructed:

[0069]

[0070] In the formula, represents the time difference attribute value of the i-th detection area inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; Indicates the time difference value of the i-th detection area inside the drawn tube (i.e., the time difference from sending the transmission signal to receiving the echo signal, which can be obtained by the high-precision clock system equipped with the detection instrument); Indicates the time difference value of the jth detection area inside the drawn tube; represents the normalization function, Represents the absolute value function.

[0071] That is, the absolute value of the difference between the time difference between the i-th detection area and other detection areas inside the drawing tube is averaged to obtain , the larger the value, the greater the difference between the time difference value of the i-th detection area inside the drawn tube and the time difference value of other detection areas, which means that the distance from the i-th detection area inside the drawn tube to the detection probe is more different than the distance from other detection areas, which means that the probability of abnormality of the i-th detection area inside the drawn tube is higher. Then, the time difference attribute value of each detection area inside the drawn tube is obtained through the normalization function .

[0072] In step S3, when the transmitting signal emitted by the ultrasonic flaw detection instrument hits the detection area, if there are defects in the detection area, the medium in the detection area will become mixed, resulting in a larger reflection coefficient at the interface of the detection area, which in turn causes the transmitting signal to be reflected at the interface of the detection area, generating an echo signal with a higher amplitude. For a normal detection area without defects, due to its uniform medium, its reflection coefficient will be smaller, resulting in a lower amplitude of the echo signal generated at the interface of the normal detection area. Therefore, if the amplitude level of the echo signal of a certain detection area inside the drawing tube is higher than that of other detection areas, it means that the possibility of defects in the detection area is higher.

[0073] Based on the above logic, this step is to analyze the defect situation according to the amplitude of the echo signal. Figure 3 As shown, step S3 includes:

[0074] Step S31, calculating the amplitude mean of the ultrasonic basic echo signal of each detection area;

[0075] Step S32, calculating the echo amplitude abnormality factor of each detection area by using the amplitude mean of the ultrasonic basic echo signal of each detection area;

[0076] Step S33, obtaining the abnormal attribute value according to the echo amplitude abnormal factor and the time difference attribute value.

[0077] Preferably, in step S32, the echo amplitude abnormality factor is calculated using a normalization function. In step S33, the product of the echo amplitude abnormality factor and the time difference attribute value is the abnormal attribute value, that is, the echo amplitude abnormality factor and the time difference attribute value are multiplied to obtain the abnormal attribute value.

[0078] Specifically, the calculation formula for abnormal attribute value is constructed:

[0079]

[0080] In the formula, represents the abnormal attribute value of the i-th detection area inside the drawn tube; represents the mean amplitude of the echo signal of the i-th detection area inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; represents the mean amplitude of the echo signal of the jth detection area inside the drawn tube; Represents the normalization function.

[0081] It indicates the abnormal factor of the echo amplitude of the i-th detection area inside the drawn tube. The larger the value is, the higher the amplitude level of the echo signal of the i-th detection area inside the drawn tube is compared with other detection areas, which means that the defect possibility of the i-th detection area inside the drawn tube is higher; It represents the time difference attribute value of the i-th detection area inside the drawn tube. This value is used as a confidence parameter. That is, the larger the value, the higher the possibility of abnormality of the i-th detection area inside the drawn tube. The higher the trustworthiness of the abnormal attribute value of the i-th detection area inside the drawn tube. The two are multiplied to obtain the abnormal attribute value of each detection area inside the drawn tube.

[0082] In step S4, according to the law of reflection, when the reflection effect occurs, the larger the incident angle of the incident light (the angle between the incident direction and the direction perpendicular to the target plane), the stronger the reflected light. Similarly, if a certain detection area inside the drawn tube is closer to normal, the flatness of the area is better. At this time, when the incident signal hits the normal detection area vertically, the amplitude level of the reflected echo signal should be the highest. At this time, if the incident angle of the incident signal is changed, the amplitude level of the echo signal should be lower than the amplitude level of the echo signal generated when it is vertically irradiated.

[0083] However, if the inspection area is a defective area with defects such as pores and bubbles, the pores and bubble defects will cause the surface of the inspection area to be uneven. When the incident signal hits the inspection area that may be defective vertically, the amplitude of the reflected echo signal may not necessarily be the highest among the echo signal amplitude levels corresponding to all incident angles. Therefore, the difference in the amplitude level of the echo signal generated when it hits the inspection area vertically and the amplitude level of the echo signal generated when it hits the inspection area at different incident angles can reflect the flatness of the inspection area, and further reflect the defect probability of the inspection area.

[0084] Based on the above logic, this step is to analyze the defect situation according to the amplitude of the echo signal at different incident angles. Figure 4 As shown, step S4 includes:

[0085] Step S41, calculating an angle characteristic factor, wherein the angle characteristic factor is a difference between an amplitude mean of an ultrasonic contrast echo signal and an amplitude mean of the ultrasonic basic echo signal;

[0086] Step S42, obtaining an angle attribute value according to the angle characteristic factor;

[0087] Step S43, obtaining the abnormal feature value according to the angle attribute value and the abnormal attribute value.

[0088] Better yet, in step S42, the angle attribute value is calculated using an inverse proportional function; in step S43, the product of the angle attribute value and the abnormal attribute value is the abnormal characteristic value, that is, the angle attribute value and the abnormal attribute value are multiplied to obtain the abnormal characteristic value.

[0089] Specifically, for the ith detection area, first obtain the mean amplitude of the echo signal generated when the detection probe hits the ith detection area vertically, and then move the detection probe to different positions so that it hits the ith detection area at directions of 30 degrees, 45 degrees, and 60 degrees to the detection plane, respectively (because there should be infinite situations when the incident angle is a fixed angle with the detection plane, the present invention selects the incident angles of any three different positions when the incident angle is a fixed angle with the detection plane as the incident angle situation of the present invention. That is, the present invention selects the incident direction of the probe at any three different positions to be 30 degrees with the detection plane, and the same applies to 45 degrees and 60 degrees, and then obtains a total of 9 different incident angle situations, where the different incident angle situations are set as empirical values) and obtains the mean amplitude of the echo signal under the 9 different incident angle situations. The difference between the amplitude mean of the echo signal generated by the i-th detection area when the probe hits the detection area vertically and the amplitude mean of the echo signal generated by the detection area under the x-th incident angle is defined as the angle characteristic factor of the i-th detection area under the x-th incident angle, and then the angle characteristic factors of the i-th detection area under all incident angles are averaged. The smaller the average, the lower the possibility that the surface of the i-th detection area is flat, and the higher the possibility that the i-th detection area is a defective area. Therefore, the calculation formula of the abnormal characteristic value is constructed according to the above logic:

[0090]

[0091] In the formula, represents the abnormal characteristic value of the i-th detection area inside the drawn tube; M represents the number of all probe incident angle selection situations; It represents the angle characteristic factor of the i-th detection area inside the drawn tube under the x-th incident angle; Represents an inverse proportional exponential function. Among them, the number of all probe incident angle selection situations M does not include the case where the probe hits the detection area vertically, that is, it does not include the case where the ultrasonic wave is emitted at the first angle. The angle characteristic factor It is the difference between the mean amplitude of the echo signal generated by the i-th detection area when the probe hits the detection area vertically and the mean amplitude of the echo signal generated by the detection area under the x-th incident angle.

[0092] It represents the mean value of the angle characteristic factor of the i-th inspection area inside the drawn tube under all incident angles. The smaller the value is, the less the i-th inspection area meets the requirement of vertical impact on the inspection area compared with non-vertical impact on the inspection area. The higher the amplitude of the echo signal generated when the inspection area is hit vertically, the lower the possibility that the surface of the i-th inspection area is flat, and the higher the possibility that the i-th inspection area is a defective area. Represents the angle attribute value. The larger the value, the lower the possibility that the surface of the i-th detection area is flat, and the higher the possibility that the i-th detection area is a defective area. It represents the abnormal attribute value of the i-th detection area inside the drawn tube. This value is used as a confidence parameter. That is, the larger the value, the higher the defect probability of the i-th detection area, and the higher the trustworthiness of the abnormal characteristic value of the i-th detection area. The angle attribute value and the abnormal attribute value are multiplied to obtain the abnormal characteristic value of each detection area inside the drawn tube.

[0093] In step S5, the abnormal characteristic value calculated by the above steps can be used to obtain the initial defect abnormality index. Furthermore, during the ultrasonic flaw detection process, the transmitted signal may be reflected multiple times in the detection area, thereby generating multiple echo signals (multiple echo signals are not expressed as multiple echo signals in the ultrasonic flaw detection results, but as multiple peaks in the same echo signal). In the propagation process of the multiple echo signals, the amplitude level of the echo signals is attenuated (there are two reasons for the attenuation. One reason is that air itself is a medium, and as long as it propagates in the medium, it will cause signal loss; the other reason is that a part of the signal will hit the normal detection area. Because the normal detection area is relatively uniform and flat, the reflection coefficient is small, and more signals will be absorbed instead of reflected). The defective area has a large reflection coefficient due to its uneven surface, which leads to less signal absorption and more reflected signal in the defective area. Therefore, the attenuation rate of the multiple echo signals can be used to reflect the defect situation in the drawn tube; and then the initial defect abnormality index is adjusted to further improve the detection accuracy.

[0094] Based on the above logic, this step is to analyze the defect situation based on the abnormal characteristic value combined with the attenuation rate of the echo signal. Figure 5 As shown, preferably, step S5 includes:

[0095] Step S51, extracting all peak points in the ultrasonic basic echo signal;

[0096] Step S52, calculating a signal amplitude difference factor, wherein the signal amplitude difference factor is a signal amplitude difference between a previous peak point and an adjacent next peak point;

[0097] Step S53, obtaining an adjustment factor according to the signal amplitude difference factor;

[0098] Step S54, obtaining an initial defect abnormality index according to the abnormal characteristic value;

[0099] Step S55, obtaining the defect abnormality index according to the initial defect abnormality index and the adjustment factor.

[0100] It can be understood that step S54 only needs to be before step S55. Preferably, in step S53, the adjustment factor is calculated using an inverse proportional function; in step S54, the initial defect abnormality index is the average of the abnormal characteristic values ​​of all detection areas; in step S55, the product of the initial defect abnormality index and the adjustment factor is the defect abnormality index, that is, the defect abnormality index can be obtained by multiplying the initial defect abnormality index and the adjustment factor.

[0101] Specifically, for the i-th detection area in the drawn tube, all the peak points in the echo signal of the i-th detection area are extracted, and the signal amplitude difference between the previous peak point and the adjacent next peak point is used as the signal amplitude difference factor of the previous peak point, and then the signal amplitude difference factors of all peak points in all detection areas are averaged. The smaller the mean value is, the slower the attenuation of multiple echo signals corresponding to each detection area in the drawn tube, which means that the defect probability of each detection area in the drawn tube is higher, which means that the initial defect abnormality index needs to be corrected to be increased; otherwise, it should be reduced.

[0102] Therefore, according to the above logic, the calculation formulas for the initial defect anomaly index and the defect anomaly index can be constructed.

[0103] Among them, the initial defect abnormality index The calculation formula is:

[0104]

[0105] In the formula, Indicates the initial defect abnormality index inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; Represents the abnormal characteristic value of the i-th detection area in the drawn tube.

[0106] Defect Abnormality Index The calculation formula is:

[0107]

[0108] In the formula, It indicates the final defect abnormality index inside the drawn tube after correction based on the attenuation characteristics of multiple echo signals; Indicates the total number of all inspection areas inside the drawn tube; Represents the total number of peak points in the echo signal corresponding to the i-th detection area; Represents the signal amplitude difference factor of the yth peak point in the ith detection area; represents the inverse exponential function; Indicates the initial defect abnormality index inside the drawn tube.

[0109] Represents the adjustment factor. The larger the value, the slower the attenuation of the multiple echo signals corresponding to each detection area in the drawn tube, which means that the defect probability of each detection area in the drawn tube is higher, and the initial defect abnormality index needs to be adjusted up; otherwise, it should be adjusted down. Multiply the adjustment factor by the initial defect abnormality index to obtain the defect abnormality index of each detection area inside the drawn tube.

[0110] In step S6, preferably, a threshold is preset. If the defect abnormality index is higher than the preset threshold, there is a defect. Specifically, the present invention selects the final defect abnormality index threshold as the empirical value of 0.85. The implementer can set the value of the defect abnormality index threshold according to the actual situation. That is, if the final defect abnormality index inside the drawn tube is If it is higher than 0.85, it is considered that there are defects such as pores and bubbles inside the drawn tube, and the drawn tube needs to be defect located and repaired.

[0111] In summary, if Figure 6 As shown, the online detection method for internal defects of drawn tubes provided by the present invention is specifically: collecting original data → drawing tube time difference attribute value → drawing tube abnormal attribute value → drawing tube abnormal characteristic value → initial drawing tube defect abnormality index → ​​final drawing tube defect abnormality index → ​​defect detection.

[0112] Second embodiment

[0113] The present invention also provides an online detection device for internal defects of a drawn tube, such as Figure 7 As shown, the online detection equipment includes:

[0114] An ultrasonic detector 10, used to transmit ultrasonic waves to the surface of each detection area at a first angle and a plurality of second angles and receive echo signals;

[0115] A signal acquisition module 20, configured to acquire an ultrasonic incident signal, an ultrasonic basic echo signal at a first angle, and a plurality of ultrasonic contrast echo signals at a second angle;

[0116] The data processing module 30 is used to obtain a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal; obtain an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value; obtain an abnormal characteristic value according to the amplitude of the ultrasonic basic echo signal and the multiple ultrasonic contrast echo signals and the abnormal attribute value; obtain a defect abnormality index according to the amplitude difference between adjacent peaks in the ultrasonic basic echo signal and the abnormal characteristic value;

[0117] The judgment module 40 is used to judge whether there is a defect based on the defect abnormality indicator.

[0118] In the embodiment of the online detection device of the present invention, all technical features of the above-mentioned online detection method embodiments are included, and the description and explanation content are basically the same as those of the above-mentioned online detection method embodiments, which will not be repeated here.

[0119] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0120] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for online detection of internal defects of a drawn tube, characterized in that: The online detection method comprises: Transmitting ultrasonic waves to the surface of each detection area at a first angle and multiple second angles and receiving echo signals; acquiring ultrasonic incident signals, ultrasonic basic echo signals at the first angle, and multiple ultrasonic comparative echo signals at the second angle; Obtaining a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal; Obtaining an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value; Obtaining an abnormal characteristic value according to the amplitudes of the ultrasonic basic echo signal and the plurality of ultrasonic contrast echo signals and the abnormal attribute value; Obtaining a defect abnormality index according to the amplitude difference between adjacent wave peaks in the ultrasonic basic echo signal and the abnormal characteristic value; Determine whether there is a defect based on the defect abnormality indicator; The calculation formula of the time difference attribute value is: In the formula, represents the time difference attribute value of the i-th detection area inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; It represents the time difference value of the i-th detection area inside the drawn tube, and the time difference value is the time difference between sending the transmission signal and receiving the echo signal; Indicates the time difference value of the jth detection area inside the drawn tube; represents the normalization function, It represents the absolute value function; The calculation formula of the abnormal attribute value is: In the formula, represents the abnormal attribute value of the i-th detection area inside the drawn tube; represents the mean amplitude of the echo signal of the i-th detection area inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; represents the mean amplitude of the echo signal of the jth detection area inside the drawn tube; represents the normalization function; The calculation formula of the abnormal characteristic value is: In the formula, represents the abnormal characteristic value of the i-th detection area inside the drawn tube; M represents the number of all probe incident angle selection situations; It represents the angle characteristic factor of the i-th detection area inside the drawn tube under the x-th incident angle; represents the inverse exponential function; The calculation formula of the defect abnormality index is: In the formula, It indicates the final defect abnormality index inside the drawn tube after correction based on the attenuation characteristics of multiple echo signals; Indicates the total number of all inspection areas inside the drawn tube; Represents the total number of peak points in the echo signal corresponding to the i-th detection area; Represents the signal amplitude difference factor of the yth peak point in the ith detection area; represents the inverse exponential function; Indicates the initial defect abnormality index inside the drawn tube; Initial defect anomaly indicator The calculation formula is: In the formula, Indicates the initial defect abnormality index inside the drawn tube; Indicates the total number of all inspection areas inside the drawn tube; represents the abnormal characteristic value of the i-th detection area in the drawn tube; Judging whether a defect exists based on the defect abnormality indicator is: if the defect abnormality indicator is higher than a preset threshold, a defect exists.

2. An online detection device for internal defects of a drawn tube, used to implement the steps of an online detection method for internal defects of a drawn tube as claimed in claim 1, characterized in that: The online detection equipment comprises: An ultrasonic detector, used for emitting ultrasonic waves to the surface of each detection area at a first angle and a plurality of second angles and receiving echo signals; A signal acquisition module, used to acquire an ultrasonic incident signal, an ultrasonic basic echo signal at a first angle, and a plurality of ultrasonic contrast echo signals at a second angle; A data processing module, used to obtain a time difference attribute value according to the time difference between the ultrasonic basic echo signal and the ultrasonic incident signal; obtain an abnormal attribute value according to the amplitude of the ultrasonic basic echo signal and the time difference attribute value; obtain an abnormal characteristic value according to the amplitude of the ultrasonic basic echo signal and the multiple ultrasonic comparison echo signals and the abnormal attribute value; obtain a defect abnormality index according to the amplitude difference between adjacent peaks in the ultrasonic basic echo signal and the abnormal characteristic value; A judgment module is used to judge whether there is a defect based on the defect abnormality indicator.

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