Rapid detection method for shrinkage strain ratio of pipe

Abstract

The invention belongs to the technical field of measurement, and relates to a rapid detection method for the shrinkage strain ratio of a pipe, which comprises the following steps of: realizing axial fixation and vertical axial rotation of the pipe on the basis of a rotating assembly; the axial lineation of the pipe is realized based on a translation assembly capable of axially moving parallel to the pipe and a contact assembly capable of adjusting the position of the external coating lineation device relative to the pipe; line marking in the circumferential direction of the section of the pipe is achieved based on a set of oppositely-arranged fixing chucks and a contact assembly which is installed on a translation assembly and can adjust the position of an external coating line marking device relative to the pipe. Based on the contrast difference between the lineation area and the pipe area, identification and size measurement of the pipe outer contour and the lineation area before and after shrinkage strain are achieved, and the pipe shrinkage strain ratio is obtained. The defects that the edge of the obtained line is rough, automatic identification is difficult to achieve, only manual identification and measurement can be achieved, the identification and measurement precision is poor, and the measurement efficiency is low when marking is conducted in a marking spraying mode such as manual marking, laser printing and ink-jet printing are overcome.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to a method for quickly detecting the shrinkage strain ratio of a pipe. Background Art

[0002] The shrinkage strain ratio (CSR) is one of the important indicators for measuring the deformation performance of metal pipes, reflecting the deformation capacity of the pipe in the radial direction (circumferential strain) and the wall thickness (radial strain). The shrinkage strain ratio between 1.3 and 2.5 indicates that the pipe has good process performance such as expansion and bending. Therefore, the shrinkage strain ratio is an important technical indicator for evaluating pipe performance.

[0003] To measure the shrinkage strain ratio of the pipe, it is necessary to draw lines on the pipe as required, measure the change in the pipe size before and after stretching, and calculate the CSR value. The marking line of the shrinkage strain ratio specimen consists of the following aspects:

[0004] a) Axial scale lines: 4 equally spaced lines of 90°±2°, parallel to the axis;

[0005] b) Circumferential markings: 3 circumferential markings with a spacing of 25 mm ± 1 mm.

[0006] The existing technology uses manual marking, laser printing, inkjet printing and other spray marking methods to mark lines. The edges of the lines obtained are rough and difficult to achieve automatic recognition. They can only be recognized and measured manually, and have the defects of poor recognition and measurement accuracy and low measurement efficiency. Summary of the invention

[0007] In view of the above analysis and in view of the deficiencies in the prior art, the present invention aims to provide a method for rapid detection of pipe shrinkage strain ratio, so as to solve at least one of the problems existing in the prior art, such as poor measurement accuracy, low measurement efficiency and large human influence.

[0008] The purpose of the present invention is mainly achieved through the following technical solutions:

[0009] The present invention discloses a method for quickly detecting the shrinkage strain ratio of a pipe, comprising:

[0010] A rotating assembly comprising a set of relatively arranged fixed chucks is used to achieve axial fixation of the pipe and rotation in a direction perpendicular to the axial direction;

[0011] Axial marking of the pipe is achieved based on a translation assembly capable of moving parallel to the axial direction of the pipe and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe;

[0012] Based on a group of relatively arranged fixed chucks and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, marking in the circumferential direction of the pipe cross section is achieved;

[0013] Based on the contrast difference between the marked area and the pipe area, the outer contour of the pipe and the marked area before and after shrinkage strain can be identified and the size can be measured;

[0014] The shrinkage strain ratio of the pipe is obtained based on the dimensional measurement results.

[0015] Preferably, the reflectivity of the ink or dye used in the external marking device is greater than the reflectivity of the outer surface of the pipe and greater than 0.

[0016] Preferably, the difference between the reflectivity of the ink or dye used in the external coating and marking device and the reflectivity of the outer surface of the pipe is ≥15%.

[0017] Preferably, the reflectivity of the ink or dye used in the external coating marking device is ≥75%.

[0018] Preferably, S1, based on a translation assembly capable of axially moving parallel to the pipe, a group of relatively arranged fixed chucks, and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, the axial marking of the pipe and the circumferential marking of the pipe section are achieved;

[0019] S2. Adjust the first axial line to the center of the visual detector's field of view; based on the contrast difference between the line area and the tube surface, identify all line areas in the field of view and output the sizes of all line areas;

[0020] S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas;

[0021] S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain;

[0022] S5, subjecting the pipe to a shrinkage strain test, and repeating S2-S3 to obtain the size information of all the marked areas after the shrinkage strain;

[0023] S6. Obtain the pipe shrinkage strain ratio CSR based on the dimension information of all the marked areas before and after the shrinkage strain.

[0024] Preferably, step S2 and step S3 include:

[0025] S231: Acquire a digitized image based on a visual detector;

[0026] S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field;

[0027] S233: Setting a specific range contrast to filter out the outline of the lined area;

[0028] S234: Dimension the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L before shrinkage strain 0 and the circumferential diameter D of the pipe before shrinkage strain 0 .

[0029] Preferably, the contrast in S233 is set to 70% to 80%.

[0030] Preferably, S233 further comprises the step of setting a contrast different from that when screening the outline of the marked area to screen out the outline of the pipe.

[0031] Preferably, the contrast of the screened tube profile is set to 90-100%.

[0032] Preferably, the visual detector is a flash detector.

[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0034] (1) The present invention realizes accurate marking of the pipe in the axial direction and the circumferential direction of the pipe cross section by utilizing a translation assembly capable of parallel axial movement of the pipe, a group of relatively arranged fixed chucks, and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe. The present invention also realizes identification and size measurement of the outer contour of the pipe and the marked area before and after the shrinkage strain by utilizing the contrast difference between the marked area and the pipe area, and obtains the shrinkage strain ratio of the pipe. Through the above method, the present invention realizes automatic, fast and accurate detection of the shrinkage strain ratio of the pipe, and overcomes the existing technology of using manual marking, laser printing, inkjet printing and other spray marking methods to mark, resulting in rough edges of the lines, which are difficult to realize automatic recognition and can only be recognized and measured manually, and has the defects of poor recognition and measurement accuracy and low measurement efficiency.

[0035] (2) The present invention utilizes the contrast difference between the marked area and the pipe area to realize automatic recognition and size measurement of the outer contour of the pipe and the marked area, reaching the level of the existing technical methods operated by skilled workers and being less affected by human factors than the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0037] Figure 1 It is a structural schematic diagram of a pipe shrinkage strain ratio test specimen marking device of the present invention;

[0038] Figure 2 It is a schematic diagram of the structure of a rotating assembly of a pipe shrinkage strain ratio test specimen marking device of the present invention;

[0039] Figure 3 It is a schematic diagram of the structure of a contact assembly of a pipe shrinkage strain ratio test specimen scribing device of the present invention;

[0040] Figure 4 It is a schematic diagram of the structure of a translation assembly of a pipe shrinkage strain ratio test specimen marking device according to the present invention;

[0041] Figure 5 It is a schematic diagram of the base structure of a pipe shrinkage strain ratio test specimen marking device of the present invention;

[0042] Figure 6 This is a flow chart of pipe shrinkage strain detection according to the present invention;

[0043] Figure 7 A schematic diagram of pipe marking area identification according to the present invention;

[0044] Figure 8 This is a schematic diagram of pipe marking according to the present invention.

[0045] Reference numerals:

[0046] 1. Base; 11. Chuck slide rail; 12. Limiting slide rail;

[0047] 2. Contact assembly; 22. Clamp; 23. Tighten nut; 24. Electric push rod; 26. Contact bracket;

[0048] 3. Translation assembly; 31. Mobile motor; 32. Third bearing; 33. Lead screw; 34. Slider; 35. Guide column; 36. Fourth bearing; 37. Translation bracket;

[0049] 4. Rotating assembly; 41. Rotating motor; 42. First bearing; 43. Main three-jaw chuck; 44. Secondary three-jaw chuck; 45. Second bearing; 46. Chuck fixing bracket; 47. Chuck moving bracket;

[0050] 51. Control panel; 52. Control box bracket; 53. Electric control box;

[0051] 6. Pipe; 7. External coating marking device; 8. Pressure sensor;

[0052] 001, first circumferential direction of the line; 002, second circumferential direction of the line; 003, third circumferential direction of the line;

[0053] 01, first axial line; 02, second axial line; 03, third axial line; 04, fourth axial line. DETAILED DESCRIPTION

[0054] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0055] In one aspect, the present invention discloses a method for quickly detecting a shrinkage strain ratio of a pipe, comprising:

[0056] A rotating assembly comprising a set of relatively arranged fixed chucks is used to achieve axial fixation of the pipe and rotation in a direction perpendicular to the axial direction;

[0057] Axial marking of the pipe is achieved based on a translation assembly capable of moving parallel to the axial direction of the pipe and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe;

[0058] Based on a group of relatively arranged fixed chucks and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, marking in the circumferential direction of the pipe cross section is achieved;

[0059] Based on the contrast difference between the marked area and the pipe area, the outer contour of the pipe and the marked area before and after shrinkage strain can be identified and the size can be measured;

[0060] The shrinkage strain ratio of the pipe is obtained based on the dimensional measurement results.

[0061] During implementation, a set of fixed chucks fix the two axial ends of the pipe respectively, and can realize rotation in the vertical axial direction and adjust the rotation angle at the same time; when the rotation angle is fixed, the external coating marking device is brought into contact with the surface of the pipe by translating the translation assembly to realize axial marking of the pipe; while the external coating marking device is in contact with the surface of the pipe, the pipe is rotated in the vertical axial direction to realize marking in the circumferential direction of the pipe cross section;

[0062] There are multiple marking lines on the circumference of the pipe section to identify and detect the pipe diameter;

[0063] A plurality of marking lines are arranged in the axial direction of the parallel tube, and intersect the marking lines in the circumferential direction perpendicularly. The intersection of the marking lines in the axial direction of the parallel tube and the marking lines in the circumferential direction is used to give a specific distance in the axial direction of the parallel tube;

[0064] Before shrinkage strain, identify and record the average value of the maximum distance between the intersection of the axial line and the circumferential line of the parallel pipe, that is, the average value of the axis gauge length L before shrinkage strain. 0 and the average value of the pipe circumference diameter D 0 ;

[0065] After shrinkage strain, identify and record the average value of the maximum distance between the intersection points of the axial line and the circumferential line parallel to the pipe, that is, the average value of the line gauge length L after shrinkage strain. 1and the average value of the pipe circumference diameter D 1 ;

[0066] Based on L 0 , D 0 , L 1 , D 1 Obtain the pipe shrinkage strain ratio CSR.

[0067] Specifically, the pipe shrinkage strain ratio CSR satisfies:

[0068]

[0069] Compared with the prior art, the present invention realizes accurate marking of the pipe in the axial direction and the circumferential direction of the pipe cross section by utilizing a translation assembly capable of moving parallel to the axial direction of the pipe, a group of relatively arranged fixed chucks, and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, and realizes identification and size measurement of the outer contour of the pipe and the marked area before and after the shrinkage strain by utilizing the contrast difference between the marked area and the pipe area, and obtains the shrinkage strain ratio of the pipe. Through the above method, the present invention realizes automatic, fast and accurate detection of the shrinkage strain ratio of the pipe, overcomes the prior art of using manual marking, laser printing, inkjet printing and other spray marking methods for marking, and the edges of the obtained lines are rough, which is difficult to realize automatic recognition and can only be recognized and measured manually, and has the defects of poor recognition and measurement accuracy and low measurement efficiency.

[0070] Specifically, the axial fixation and the vertical axial rotation of the tube are achieved based on a rotating assembly including a group of relatively arranged fixed chucks, including: rotating and clamping the tube 6 with the rotating assembly 4.

[0071] Specifically, the rotating assembly 4 includes a rotating motor 41, a first bearing 42, a main three-jaw chuck 43, a secondary three-jaw chuck 44, a second bearing 45, a chuck fixing bracket 46 and a chuck moving bracket 47. The chuck fixing bracket 46 is fixedly connected to the top of the base 1 by multiple bolts, and the chuck moving bracket 47 slides in the chuck slide rail 11. The main three-jaw chuck 43 is rotatably connected to the side end of the chuck fixing bracket 46 through the first bearing 42, and the secondary three-jaw chuck 44 is rotatably connected to the side end of the chuck moving bracket 47 through the second bearing 45. The main three-jaw chuck 43 and the secondary three-jaw chuck 44 clamp the two end sides of the pipe 6, and the rotating motor 41 is fixedly connected to the side end of the chuck fixing bracket 46. The rotating motor 41 and the main three-jaw chuck 43 are connected by a coupling.

[0072] In the present invention, the chuck fixing bracket 46 is used to rotate and connect the first bearing 42, thereby realizing the rotation connection of the main three-jaw chuck 43, and the chuck moving bracket 47 slides in the chuck slide rail 11, so that the chuck moving bracket 47 slides horizontally in the chuck slide rail 11, and is adapted to move the auxiliary three-jaw chuck 44 with different lengths of pipes 6. At the same time, the chuck moving bracket 47 is used to rotate and connect the second bearing 45, thereby realizing the rotation connection of the auxiliary three-jaw chuck 44. The main three-jaw chuck 43 is used to clamp and fix one end of the pipe 6, and the auxiliary three-jaw chuck 44 is used to clamp and fix the second shaft. The other end of the bearing 45 can limit the sliding of the chuck moving bracket 47 by clamping and fixing the pipe 6 through the main three-jaw chuck 43 and the auxiliary three-jaw chuck 44. The rotating motor 41 drives the main three-jaw chuck 43 to rotate through the coupling, and then drives the pipe 6 to rotate, which is convenient for circular marking of the pipe 6. After the external coating marking device 7 contacts the pipe 6, the rotating motor 41 drives the main three-jaw chuck 43 to rotate, so that the pipe 6 rotates, and the external coating marking device 7 draws a closed circle on the circumferential surface of the pipe 6, thereby drawing a circumferential line on the circumferential surface of the pipe 6.

[0073] Specifically, the axial marking of the pipe is realized based on a translation assembly capable of moving parallel to the axial direction of the pipe and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, including:

[0074] The translation assembly 3 is used to push the movement of the outer coating marking device 7 , and the contact assembly 2 is used to lift the outer coating marking device 7 .

[0075] The contact assembly 2 is arranged on the top of the translation assembly 3 , and the two are arranged independently relative to the rotation assembly 4 .

[0076] The translation assembly 3 includes a moving motor 31, a third bearing 32, a lead screw 33, a slider 34, a guide column 35, a fourth bearing 36 and a translation bracket 37. Two translation brackets 37 are provided, and the two translation brackets 37 are fixed to the top of the base 1 by bolts. The third bearing 32 is fixedly connected to the top of one translation bracket 37, and the fourth bearing 36 is fixedly connected to the top of the other translation bracket 37. Two guide columns 35 are provided, and the moving motor 31 is fixedly installed on the side end of one translation bracket 37. The two guide columns 35 are fixedly connected between the third bearing 32 and the fourth bearing 36. The lead screw 33 is rotatably connected between the third bearing 32 and the fourth bearing 36. One end of the lead screw 33 is fixedly connected to the output end of the moving motor 31, and the slider 34 is sleeved on the circumferential surface of the lead screw 33 and the two guide columns 35.

[0077] In the present invention, two translation brackets 37 are used to support and fix the fourth bearing 36 and the third bearing 32. The fourth bearing 36 and the third bearing 32 are used to support the lead screw 33 and two guide pillars 35. The two guide pillars 35 are used to guide and support the slider 34. The lead screw 33 realizes the lateral movement of the slider 34 by sliding cooperation with the slider 34, and then pushes the movement of the contact bracket 26 to realize the horizontal movement of the external coating and marking device 7. The output end of the mobile motor 31 is fixedly connected with the lead screw 33 to drive the lead screw 33 to rotate, providing power for the lateral movement of the contact bracket 26. When the external coating and marking device 7 contacts the pipe 6, the mobile motor 31 starts to drive the lead screw 33 to rotate. The lead screw 33 achieves the movement of the slider 34 by sliding cooperation with the slider 34. The movement of the slider 34 pushes the movement of the contact bracket 26, and the horizontal movement of the external coating and marking device 7 is realized, so that the external coating and marking device 7 performs lateral marking on the circumferential surface of the pipe 6.

[0078] The contact assembly 2 includes a chuck 22, a tightening nut 23, an electric push rod 24 and a contact bracket 26. The chuck 22 is sleeved on the top of the external coating marking device 7. The chuck 22 and the external coating marking device 7 are fixedly connected by multiple tightening nuts 23. The contact bracket 26 is fixedly connected to the top of the slider 34 by multiple bolts. The electric push rod 24 is fixedly connected to the side end of the contact bracket 26, and the output end of the electric push rod 24 is fixedly connected to the chuck 22.

[0079] In the present invention, the chuck 22 and the external coating marking device 7 are sleeved to accommodate the external coating marking device 7, and a plurality of tightening nuts 23 are used to thread and fasten the external coating marking device 7. The external coating marking device 7 is adjusted and fixed at different heights by a plurality of tightening nuts 23, so that the initial height of the external coating marking device 7 can be adjusted according to the pipes 6 of different diameters. The contact bracket 26 is used to support and fix the electric push rod 24, and the electric push rod 24 is used to push the chuck 22 up and down, so that the external coating marking device 7 can fit the circumferential surface of the pipes 6 of different diameters. Before marking, the external coating marking device 7 is fixed to the circumferential surface of the pipes 6 of different diameters. The marking device 7 is inserted into the chuck 22, and the outer marking device 7 is threadedly fastened by multiple tightening nuts 23, so that the bottom of the outer marking device 7 fits against the circumferential surface of the pipe 6. During the marking process, the chuck 22 is lifted by the output end of the electric push rod 24, so that the outer marking device 7 can approach or move away from the circumferential surface of the pipe 6. When the outer marking device 7 approaches the circumferential surface of the pipe 6, the outer marking device 7 marks the pipe 6. When the outer marking device 7 moves away from the circumferential surface of the pipe 6, the marking of the circumferential surface of the pipe 6 can be stopped.

[0080] Specifically, the external coating marking device 7 may be a marking stylus pen, which can apply ink or dye to the outer surface of the pipe along a predetermined track when in contact with the outer surface of the pipe.

[0081] Preferably, the marking device used in the marking method further comprises: a base 1;

[0082] A chuck slide rail 11, which is fixedly mounted on the top of the base 1;

[0083] The top of the base 1 is fixedly connected to a limited slide rail 12, and the limited slide rail 12 is slidably matched with the slider 34;

[0084] The translation assembly 3 is arranged at the top of the base 1, the contact assembly 2 is arranged at the top of the translation assembly 3, the contact assembly 2 is connected to the limiting slide rail 12, the rotation assembly 4 is arranged at the top of the base 1, the contact assembly 2 is connected to the limiting slide rail 12; the rotation assembly 4 is connected to the chuck slide rail 11 and the pipe 6.

[0085] In the present invention, the limiting slide rail 12 is used to limit the maximum distance of the lateral movement of the slider 34 , thereby preventing the slider 34 from colliding with the guide column 35 and the third bearing 32 , and eliminating the potential safety hazard of the movement of the slider 34 .

[0086] The side end of the contact bracket 26 is fixedly connected with a pressure sensor 8 , and the bottom of the pressure sensor 8 is connected to the clamp 22 .

[0087] In the present invention, the pressure sensor 8 is used to monitor the pressure change between the external coating marking device 7 and the pipe 6 in real time, so as to adjust the contact pressure between the external coating marking device 7 and the pipe 6 in real time for the electric push rod 24, provide basic data for adjusting the pressure, ensure the constant contact pressure between the external coating marking device 7 and the surface of the pipe 6, avoid changes in line thickness during the marking process, and change the marking method. Different from laser printing, inkjet printing and other jet marking methods, marking with a pressure sensor plus a contact can accurately control the size of the contact force to make the line thickness uniform and the line edge clear, which can greatly improve the subsequent test efficiency.

[0088] A control box bracket 52 is provided on one side of the base 1 , an electric control box 53 is fixedly connected to the top of the control box bracket 52 , and a control panel 51 is embedded and installed on the side end of the electric control box 53 .

[0089] In the present invention, the control box bracket 52 is used to support and fix the electric control box 53, and the electric control box 53 is used to accommodate the control panel 51. The control panel 51 is electrically connected to the rotating motor 41, the electric push rod 24, the pressure sensor 8 and the moving motor 31. The electric control box 53 is equipped with a central processing unit CPU, a system program memory ROM, a user memory RAM, an input and output interface I / O interface, and a power module. The electric control box 53 is a touch screen display. The electric control box 53 stores an automated program. The parameters are adjusted through the control panel 51. Figure 2The displayed marking program completes the marking action. The moving motor 31 and the rotating motor 41 are automatically controlled by the marking program to link with each other. The parameters are set according to the control box bracket 52 to automatically complete the marking action. The operation method is simple and no professional marking personnel are required. At the same time, the efficiency is significantly improved compared with manual marking.

[0090] In the present invention, both the moving motor 31 and the rotating motor 41 are stepping drive motors to improve the driving accuracy.

[0091] Specifically, the reflectivity of the ink or dye used by the external coating marking device 7>the reflectivity of the outer surface of the pipe>0.

[0092] Preferably, the difference between the reflectivity of the ink or dye used in the external marking device 7 and the reflectivity of the outer surface of the pipe is ≥15%.

[0093] It should be noted that there is a significant difference between the reflectivity of the ink or dye used in the external marking device 7 and the reflectivity of the outer surface of the pipe, and there is a significant difference in the brightness of the field of view. The generated image data is reflected in the large difference in contrast. In order to ensure better differentiation, the internal test background of the visual detector is set to a low-reflection area with a reflectivity of almost 0.

[0094] Specifically, the reflectivity of the ink or dye used in the outer coating marking device 7 should be selected from a high-reflectivity material with a reflectivity greater than 75%.

[0095] Specifically, the pipe shrinkage strain ratio rapid detection method, such as Figure 6 As shown, including:

[0096] S1. Axial marking of the pipe and circumferential marking of the pipe section are achieved based on a translation assembly capable of moving parallel to the axial direction of the pipe, a set of relatively fixed chucks, and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe;

[0097] S2. Adjust the first axial line to the center of the visual detector's field of view; based on the contrast difference between the line area and the tube surface, identify all line areas in the field of view and output the sizes of all line areas;

[0098] S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas;

[0099] S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain;

[0100] S5, subjecting the pipe to a shrinkage strain test, and repeating S2-S3 to obtain the size information of all the marked areas after the shrinkage strain;

[0101] S6. Obtain the pipe shrinkage strain ratio CSR based on the dimension information of all the marked areas before and after the shrinkage strain.

[0102] Specifically, S2 and S3 include:

[0103] S231: Acquire a digitized image based on a visual detector;

[0104] S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field;

[0105] S233: Setting a specific range contrast to filter out the outline of the lined area;

[0106] S234: Dimension the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L before shrinkage strain 0 and the circumferential diameter D of the pipe before shrinkage strain 0 .

[0107] Specifically, S231 includes: converting the visual image acquired by the visual detector into a digitized image of basic pixel units.

[0108] Specifically, S232 includes: assigning values ​​to basic pixel units according to the degree of brightness by a computer.

[0109] It should be noted that S231 to S232 can be automatically performed inside the visual detector.

[0110] Specifically, in S233, the contrast ratio can be set to 70% to 80%, so that the pipe surface with a reflectivity difference of more than 15% can be easily distinguished from the marked area.

[0111] It should be noted that the visual detector software described in S233 and S234 has a built-in annotation function that can mark the dimensions of the contours of the identified areas with different contrasts.

[0112] As an example, Figure 7 As shown, 01 is the axial line under the field of view, the first axial line; 001, 002, 003 are three circumferential lines, the first circumferential line, the second circumferential line, and the third circumferential line set the contrast to 70% to 80%. The automatic marking function of the visual detector software can give the pipe diameter D in the 001, 002, 003 area and the intersection A of the first axial line 01 and the first circumferential line 001. 11 The intersection point A of the first axial line 01 and the third circumferential line 003 13 Distance L, Figure 7 Marked in red.

[0113] Furthermore, if Figure 8As shown, the axial lines in the other three fields of view are the second axial line 02, the third axial line 03, and the fourth axial line 04. Based on the same method, the circumferential diameter D of the pipe in the 001, 002, and 003 areas in the other three fields of view and the intersection A of the first axial line 01 and the first circumferential line 001 can be obtained. 11 The intersection point A of the first axial line 01 and the third circumferential line 003 13 Distance, axis gauge length L;

[0114] Calculate the average value of all the pipe circumference diameters D before shrinkage strain 0 , calculate the average value of the axis gauge length L before the shrinkage strain 0 ;

[0115] Furthermore, according to the above method, the marked area of ​​the pipe after shrinkage strain is identified to obtain the outline size of the marked area, and then the average value D of the circumferential diameter D of all pipes after shrinkage strain is obtained. 1 , the average value of the axis gauge length L 1 ;

[0116] Furthermore, the pipe shrinkage strain ratio CSR is calculated based on the following formula:

[0117]

[0118] In a preferred embodiment, S233 further includes the step of setting a contrast different from that when screening the outline of the marked area to screen out the outline of the pipe.

[0119] During implementation, setting another specific range of contrast to screen out the tube outline from the image background helps to improve the accuracy of locating the tube circumferential diameter by the first circumferential direction line 001 , the second circumferential direction line 002 , and the third circumferential direction line 003 .

[0120] Preferably, the contrast of the screened tube profile is set to 90-100%.

[0121] Preferably, the visual detector may be a flash detector.

[0122] Preferably, the field of view of the flash tester is not less than 70mm×50mm.

[0123] In order to better illustrate the present invention, the following embodiments and comparative examples are further provided:

[0124] Example 1

[0125] This embodiment discloses a method for quickly detecting the shrinkage strain ratio of a pipe. The pipe to be tested is a TA18 pipe with a specification of 9.52 mm×0.48 mm, including:

[0126] S1. Use the method of invention patent CN115674129A to draw axial lines according to the requirements of GB / T 34645: 4 lines of 90° equally divided, parallel to the axis; draw circumferential lines: 3 circumferential lines with a spacing of 25mm; name the 4 longitudinal lines 01, 02, 03, 04, and the three annular lines 001, 002, 003.

[0127] S2. Adjust the first axial marking line to the center of the visual detector's field of view; based on the contrast difference between the marking area and the tube surface, identify all the marking areas in the field of view and output the sizes of all the marking areas.

[0128] S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas;

[0129] S231: Acquire a digitized image based on a visual detector; convert the visual image acquired by the visual detector into a digitized image of a basic pixel unit;

[0130] S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field; assigning values ​​to the basic pixel units according to the brightness by a computer;

[0131] S233: setting a specific range contrast to filter out the outline of the lined area; setting different contrasts twice to filter out the pipe outline and the lined area outline; setting the contrast of the filtered pipe outline to 100%; and setting the contrast of the filtered lined area outline to 80%;

[0132] The reflectivity of the ink or dye used in the outer coating marking device 7 is selected to be a high-reflectivity ink paste of >75%.

[0133] S234: Dimension the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L before shrinkage strain 0 and the circumferential diameter D of the pipe before shrinkage strain 0 .

[0134] S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain;

[0135] S5. Use the test method of GB / T228.1 to stretch the pipe with a strain of 3.75%. Install the stretched pipe on the rotating fixture, repeat the above steps, calculate the average value of the gauge length L1 of the pipe axis and the circumferential diameter D of the pipe after stretching, and obtain the average value D of the circumferential diameter D of all pipes after shrinkage strain. 1 , the average value of the axis gauge length L 1 ;

[0136] Furthermore, the pipe shrinkage strain ratio CSR is calculated based on the following formula:

[0137] The calculation results are shown in Table 1 below:

[0138] Table 1 Pipe shrinkage strain ratio data measured in Example 1

[0139]

[0140]

[0141] Example 2

[0142] This embodiment discloses a method for quickly detecting the shrinkage strain ratio of a pipe. The pipe to be tested is a TA18 pipe with a pipe specification of 15.88 mm×0.81 mm, including:

[0143] S1. Use the method of invention patent CN115674129A to draw axial lines according to the requirements of GB / T 34645: 4 lines of 90° equally divided, parallel to the axis; draw circumferential lines: 3 circumferential lines with a spacing of 25mm; name the 4 longitudinal lines 01, 02, 03, 04, and the three annular lines 001, 002, 003.

[0144] S2. Adjust the first axial marking line to the center of the visual detector's field of view; based on the contrast difference between the marking area and the tube surface, identify all the marking areas in the field of view and output the sizes of all the marking areas.

[0145] S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas;

[0146] S231: Acquire a digitized image based on a visual detector; convert the visual image acquired by the visual detector into a digitized image of a basic pixel unit;

[0147] S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field; assigning values ​​to the basic pixel units according to the brightness by a computer;

[0148] S233: setting a specific range contrast to filter out the outline of the lined area; setting different contrasts twice to filter out the pipe outline and the lined area outline; setting the contrast of the filtered pipe outline to 95%; and setting the contrast of the filtered lined area outline to 70%;

[0149] The reflectivity of the ink or dye used in the outer coating marking device 7 is selected to be a high-reflectivity ink paste of >80%.

[0150] S234: Dimension the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L before shrinkage strain 0 and the circumferential diameter D of the pipe before shrinkage strain 0 .

[0151] S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain;

[0152] S5. Use the test method of GB / T228.1 to stretch the pipe with a strain of 3.75%. Install the stretched pipe on the rotating fixture, repeat the above steps, calculate the average value of the gauge length L1 of the pipe axis and the circumferential diameter D of the pipe after stretching, and obtain the average value D of the circumferential diameter D of all pipes after shrinkage strain. 1 , the average value of the axis gauge length L 1 ;

[0153] Furthermore, the pipe shrinkage strain ratio CSR is calculated based on the following formula:

[0154] The calculation results are shown in Table 1 below:

[0155] Table 2 Pipe shrinkage strain ratio data measured in Example 2

[0156]

[0157] Example 3

[0158] This embodiment discloses a method for quickly detecting the shrinkage strain ratio of a pipe. The pipe to be tested is a TA18 pipe with a specification of 9.52 mm×0.48 mm, including:

[0159] S1. Use the method of invention patent CN115674129A to draw axial lines according to the requirements of GB / T 34645: 4 lines of 90° equally divided, parallel to the axis; draw circumferential lines: 3 circumferential lines with a spacing of 25mm; name the 4 longitudinal lines 01, 02, 03, 04, and the three annular lines 001, 002, 003.

[0160] S2. Adjust the first axial marking line to the center of the visual detector's field of view; based on the contrast difference between the marking area and the tube surface, identify all the marking areas in the field of view and output the sizes of all the marking areas.

[0161] S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas;

[0162] S231: Acquire a digitized image based on a visual detector; convert the visual image acquired by the visual detector into a digitized image of a basic pixel unit;

[0163] S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field; assigning values ​​to the basic pixel units according to the brightness by a computer;

[0164] S233: setting a specific range contrast to filter out the outline of the lined area; setting different contrasts twice to filter out the pipe outline and the lined area outline; setting the contrast of the filtered pipe outline to 100%; and setting the contrast of the filtered lined area outline to 80%;

[0165] The reflectivity of the ink or dye used in the outer coating marking device 7 is selected to be a high-reflectivity ink paste of >75%.

[0166] S234: Dimension the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L before shrinkage strain 0 and the circumferential diameter D of the pipe before shrinkage strain 0 .

[0167] S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain;

[0168] S5. Use the test method of GB / T228.1 to stretch the pipe with a strain of 3.75%. Install the stretched pipe on the rotating fixture and repeat the above steps to calculate the gauge length L of the stretched pipe axis. 1 The average value of the circumferential diameter D of all tubes after shrinkage strain is obtained by calculating the average value of the circumferential diameter D of the tubes. 1 , the average value of the axis gauge length L 1 ;

[0169] Furthermore, the pipe shrinkage strain ratio CSR is calculated based on the following formula:

[0170] The calculation results are shown in Table 1 below:

[0171] Table 3 Pipe shrinkage strain ratio data measured in Example 3

[0172]

[0173] Comparative Example 1

[0174] This comparative example discloses a method for quickly detecting the shrinkage strain ratio of a pipe. The measured sample is exactly the same as that in Example 1. The existing video instrument is used to rotate the lead screw for manual measurement. The manual measurement is performed by skilled workers. Figure 7 As shown:

[0175] S1: Use a 20x objective lens to observe the pipe, with the pipe axis as the X-axis, the vertical X-axis direction in the video instrument detection plane as the Y-axis, and the vertical video instrument detection plane direction as the Z-axis. Rotate the pipe so that the first axial line 01 of the pipe coincides with the horizontal line of the video instrument. Rotate the lead screw and move the X-axis so that the vertical red line of the video instrument coincides with the left line of 001. Clear the X-axis data. Rotate the lead screw to move the Y-axis so that the Y-axis red line coincides with the upper edge of the pipe. Clear the Y-axis data. Rotate the lead screw so that the Y-axis red line coincides with the lower edge of the pipe to obtain the diameter at 001.

[0176] S2: Move the X-axis to make the vertical red line of the video instrument coincide with the left line of 002, rotate the lead screw to move the Y-axis to make the red line of the Y-axis coincide with the upper edge of the pipe, clear the Y-axis data, rotate the lead screw to make the red line of the Y-axis coincide with the lower edge of the pipe, and obtain the diameter at 002;

[0177] S3: Move the X-axis to make the vertical red line of the video instrument coincide with the left line of 002, rotate the lead screw to move the Y-axis to make the red line of the Y-axis coincide with the upper edge of the pipe, clear the Y-axis data, rotate the lead screw to make the red line of the Y-axis coincide with the lower edge of the pipe, obtain the diameter at 003, and simultaneously obtain the axial gauge length of the pipe; manually rotate the pipe to make the second axial marking line 02 of the pipe coincide with the horizontal line of the video instrument in turn, and repeat the above steps to obtain the diameter at the marking line in the circumferential direction and the length of the axial gauge length;

[0178] S4: Repeat the above steps until the detection of the four axes is completed, and calculate the shrinkage strain ratio CSR of the pipe, as shown in Table 4 below:

[0179] Table 4 Pipe shrinkage strain ratio data measured in comparative example 1

[0180]

[0181] Result analysis:

[0182] From the comparison of Examples 1 to 3 and Comparative Example 1, it can be seen that the time required for a single test of the rapid detection method for shrinkage strain ratio of pipes of the present invention does not exceed 10 minutes, while the prior art is not less than 80 minutes. The present invention greatly reduces the measurement time compared with the prior art and realizes efficient and fast measurement.

[0183] From the comparison between Example 1 and Comparative Example 1, it can be seen that the two methods have the same strain ratio CSR value for the same pipe, which shows that the measurement precision and accuracy of the method of the present invention are high, reaching the level of the existing technical method operated by skilled workers, and is less affected by human factors than the existing technology.

[0184] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for rapid detection of pipe shrinkage strain ratio, characterized in that: include: A rotating assembly comprising a set of relatively arranged fixed chucks is used to achieve axial fixation of the pipe and rotation in a direction perpendicular to the axial direction; Axial marking of the pipe is achieved based on a translation assembly capable of moving parallel to the axial direction of the pipe and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe; Based on a group of relatively arranged fixed chucks and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe, marking in the circumferential direction of the pipe cross section is achieved; Based on the contrast difference between the marked area and the pipe area, the outer contour of the pipe and the marked area before and after shrinkage strain can be identified and the size can be measured; The shrinkage strain ratio of the pipe is obtained based on the dimensional measurement results.

2. The method for rapid detection of pipe shrinkage strain ratio according to claim 1, characterized in that: The reflectivity of the ink or dye used in the external coating marking device is greater than the reflectivity of the outer surface of the pipe and greater than 0.

3. The method for rapid detection of pipe shrinkage strain ratio according to claim 2, characterized in that: The difference between the reflectivity of the ink or dye used in the external marking device and the reflectivity of the outer surface of the pipe is ≥15%.

4. The method for rapid detection of pipe shrinkage strain ratio according to claim 2 or 3, characterized in that: The reflectivity of the ink or dye used in the external coating marking device is ≥75%.

5. The method for rapid detection of pipe shrinkage strain ratio according to claim 4, characterized in that: The method for quickly detecting the pipe shrinkage strain ratio comprises: S1. Axial marking of the pipe and circumferential marking of the pipe section are achieved based on a translation assembly capable of moving parallel to the axial direction of the pipe, a set of relatively fixed chucks, and a contact assembly installed on the translation assembly and capable of adjusting the position of the external coating marking device relative to the pipe; S2. Adjust the first axial line to the center of the visual detector's field of view; based on the contrast difference between the line area and the tube surface, identify all line areas in the field of view and output the sizes of all line areas; S3, adjust the axial marking of the next position in sequence to the center of the visual detector field of view; based on the contrast difference between the marking area and the surface of the pipe, identify all the marking areas in the field of view and output the dimensions of all the marking areas; S4, repeat S3 to obtain the size information of all the marked areas before the shrinkage strain; S5, subjecting the pipe to a shrinkage strain test, and repeating S2-S3 to obtain the size information of all the marked areas after the shrinkage strain; S6. Obtain the pipe shrinkage strain ratio CSR based on the dimension information of all the marked areas before and after the shrinkage strain.

6. The method for rapid detection of pipe shrinkage strain ratio according to claim 5, characterized in that: Step S2 and step S3 include: S231: Acquire a digitized image based on a visual detector; S232: performing contrast numerical processing on the basic unit of the digitized image based on the brightness of the visual field; S233: Setting a specific range contrast to filter out the outline of the lined area; S234: Dimensioning the outline of the marked area based on the annotation function of the visual detector software to obtain the axis gauge length L0 before the shrinkage strain and the circumferential diameter D0 of the pipe before the shrinkage strain.

7. The method for rapid detection of pipe shrinkage strain ratio according to claim 6, characterized in that: In S233, the contrast is set to 70% to 80%.

8. The method for rapid detection of pipe shrinkage strain ratio according to claim 7, characterized in that: S233 also includes the step of setting a contrast different from that when screening the outline of the marked area to screen out the outline of the pipe.

9. The method for rapid detection of pipe shrinkage strain ratio according to claim 8, characterized in that: The contrast of the filtered tube outlines is set to 90-100%.

10. The method for rapid detection of pipe shrinkage strain ratio according to claim 5, characterized in that: The visual detector is a flash detector.

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