A cold-rolled continuous running unit strip steel weld crescent position detection system

Abstract

The application discloses a cold-rolled continuous operation unit strip steel weld seam crescent position detection system, which comprises two sets of detection grating devices arranged at intervals at a weld seam detection position, and each set of detection grating device is connected with a unit PLC through a communication cable; in a production process, the strip steel sequentially passes through the first set of detection grating device and the second set of detection grating device and moves forward, the unit PLC acquires the number of light axes of the two sets of detection grating devices blocked by the strip steel in real time, calculates the difference N of the number of light axes of the second set of detection grating device and the first set of detection grating device blocked by the strip steel, compares the difference N with a set threshold Y, and when N >= Y, it is determined that the strip steel position corresponding to the light axis of the first set of detection grating device is the weld seam crescent position. The application takes the weld seam crescent gap as the weld seam position detection mark, can accurately detect the weld seam crescent position and correct it in the production process, and the process does not need to punch the mark hole, thereby avoiding the problem of the mark hole passing through the air knife.

Description

Technical Field

[0001] This invention belongs to the field of cold rolling technology, specifically relating to a crescent position detection system for strip weld seams in a cold rolling continuous operation unit. Background Technology

[0002] Continuous cold rolling mills, including continuous pickling mills, continuous pickling and rolling mills, continuous hot-dip galvanizing mills, and continuous annealing mills, are all currently equipped with weld inspection stations. Weld detectors (WPDs) are installed at these stations to detect the location of welds. For example... Figure 1 As shown, the WPD includes a transmitter A1 and a receiver A2. Its principle is as follows: During the welding process of two coils of strip steel at the entrance section, a hole A0 (also called a marking hole, approximately 12mm in diameter) is punched at the tail of the preceding strip steel using a punching machine. The position of this hole is then detected at a subsequent position on the unit to determine the weld position, and the precise position of the strip steel is corrected in the control system PLC. Calibration is necessary because factors such as wear on the rollers used for strip steel position tracking, elongation of the strip steel after high-temperature heating in the furnace, stretching of the strip steel at the leveling area when the leveling machine is put into operation, and continuous changes in the looper quantity lead to inaccuracies in the weld position obtained solely by the encoder detection. Sometimes the deviation can reach tens of meters, thus requiring correction of the weld position.

[0003] Existing weld detection devices (WPDs) require punching marking holes before weld inspection. Accuracy is only guaranteed with these marking holes; without them, the WPD cannot detect the weld location, leading to a significant deviation between the actual strip position and the theoretical position in the control system. This is especially problematic when the strip changes width, increasing the risk of the strip colliding with the air knife baffle, potentially causing equipment damage or strip breakage and downtime. With increasingly stringent product quality requirements, using marking holes for weld inspection is no longer sufficient. Particularly in continuous hot-dip galvanizing units, welds with marking holes are prone to air knife streaks when passing the air knife at the zinc pot, resulting in unsatisfactory surface quality and reduced yield. Actual testing revealed that these streaks are caused by the punching; without them, no streaks occur. Therefore, developing a technology to detect strip weld locations without punching is imperative. Summary of the Invention

[0004] The purpose of this invention is to provide a crescent-shaped position detection system for strip welds in a cold rolling continuous operation unit. This system can use the crescent-shaped notch at the weld as a weld position detection mark when there are no marking holes, and accurately detect the position of the crescent-shaped weld during the production process.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A crescent position detection system for strip welds in a cold rolling continuous operation unit is characterized by comprising two sets of detection grating devices arranged at intervals at the weld detection position. The two sets of detection grating devices are arranged in parallel with a spacing greater than the width of the crescent shear blade. After installation, multiple optical axis emitting ends of each set of detection grating devices are arranged along the width direction of the strip and the distance between the two optical axis emitting ends is greater than the width of the widest strip of the unit. Each set of detection grating devices is connected to the unit PLC via a communication cable. During the production process, the strip steel passes through the first set of detection grating devices and the second set of detection grating devices in sequence and moves forward. The unit PLC obtains the number of optical axes blocked by the strip steel in real time for the two sets of detection grating devices, and calculates the difference N between the number of optical axes blocked by the strip steel in the second set of detection grating devices and the first set of detection grating devices. The difference N is compared with the set threshold Y. When N≥Y, the strip steel position corresponding to the optical axis of the first set of detection grating devices is determined to be the crescent position of the weld.

[0006] Furthermore, the detection grating device includes a power supply, a transmitter, a receiver, a synchronization cable, and a power cord. The transmitter and receiver are connected by the synchronization cable, and the transmitter and receiver are respectively connected to the power supply via the power cord. The receiver is connected to the unit PLC via a communication cable.

[0007] Furthermore, the transmitter includes a first transmitter and a second transmitter, and the receiver includes a first receiver and a second receiver; the first transmitter and the first receiver are connected by a first synchronization cable, the second transmitter and the second receiver are connected by a second synchronization cable, and the first receiver and the second receiver are respectively connected to the unit PLC via communication cables.

[0008] Furthermore, during the production process, the distance between the transmitter, receiver and the surface of the strip steel is 300-1000mm.

[0009] Furthermore, the distance between the two optical axis emitting ends on the detection grating device is 200-400mm larger than the width of the widest steel strip of the unit.

[0010] Furthermore, the optical axis spacing of the detection grating device is 2mm-5mm.

[0011] Furthermore, the set threshold Y is calculated and updated by the unit PLC; With the direction of the strip's travel as the front reference, the two sides of the weld are the front strip and the rear strip, respectively; When the width of the strip before the weld is less than or equal to the width of the strip after the weld, Y = 2L / bc; When the width of the strip before the weld is greater than the width of the strip after the weld, Y = (a + 2L) / bc; Where a is the width difference between the strip steel before and after the weld, L is the depth of the crescent shear blade extending out of the stop grating, b is the optical axis spacing of the detection grating device, and c is the error value of the change in the number of optical axes caused by the strip steel deviation.

[0012] The beneficial effects of this invention are: by using the detection system of this invention, the crescent-shaped notch at the weld seam is used as a weld seam position detection mark, and the position of the crescent-shaped notch is accurately detected during the production process. Thus, the position of the strip steel weld seam can be corrected based on the position of the crescent-shaped notch, ensuring accurate positioning.

[0013] Using the solution of the present invention, since there are no marking holes near the weld, air knife stripe defects caused by air knife passing through the marking holes can be avoided, thereby improving the product yield. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a weld seam detector in the prior art.

[0015] Figure 2 This is a schematic diagram of the overall structure of the device of the present invention.

[0016] Figure 3 This is a schematic diagram of the detection grating device of the present invention.

[0017] Figure 4 This is a schematic diagram of another structure of the detection grating device in this invention.

[0018] Figure 5 This is another structural schematic diagram of the detection grating device in this invention.

[0019] Figure 6 This is a diagram illustrating one side of the crescent-shaped scissors.

[0020] Figure 7 This is a schematic diagram of the structure of the first type of weld crescent in this invention.

[0021] Figure 8 This is a schematic diagram of the second type of weld crescent shape in this invention.

[0022] Figure 9 This is a schematic diagram of the third type of weld crescent shape in this invention.

[0023] Among them, 10, the first set of detection grating device, 20, the second set of detection grating device, 1, power supply, 2, transmitter, 3, receiver, 4, synchronization cable, 5, power line, 6, communication cable, 7, unit PLC, Y1, deceleration grating, Y2, stop grating, Y3, crescent blade, Y4, feed cylinder, L, depth of crescent blade extending from the stop grating, D, width of crescent blade. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 2 , 3 As shown, a crescent position detection system for strip welds in a cold-rolled continuous operation unit includes two sets of detection grating devices arranged at intervals at the weld detection positions, namely a first set of detection grating devices 10 and a second set of detection grating devices 20. The two sets of detection grating devices are arranged in parallel with a spacing greater than the width of the crescent blade. After installation, multiple optical axis emitting ends of the detection grating devices are arranged along the width direction of the strip, and the distance between the two optical axis emitting ends is greater than the width of the widest strip of the unit. Specifically, the spacing between the two sets of detection grating devices is 1.5 times the width D of the crescent blade, ensuring that the two sets of detection grating devices will not simultaneously detect the same crescent notch in the weld.

[0026] The detection grating device includes a power supply 1, a transmitter 2, a receiver 3, a synchronization cable 4, and a power cord 5. Transmitter 2 and receiver 3 are connected via the synchronization cable 4. Transmitter 2 and receiver 3 are symmetrically installed, with the transmitting end of the optical axis of transmitter 2 corresponding one-to-one with the receiving end of the optical axis of receiver 3. Transmitter 2 and receiver 3 are each connected to the power supply via power cord 5; receiver 3 is connected to the unit's PLC 7 via communication cable 6. Transmitter 1 and receiver 2 employ synchronous detection and time-division scanning to improve anti-interference capabilities.

[0027] like Figure 3 As shown, the optical axis of the detection grating device is evenly distributed along the entire line, spanning the entire width of the strip. The distance between the two ends of the optical axis emission point is 200-400mm larger than the maximum strip width. After being installed in the center, the width extending beyond the strip on each side is 100-200mm. This avoids detection errors caused by strip misalignment. Of course, since the optical axis detection only needs to cover the crescent-shaped notch area and extend slightly on both sides, the middle part does not need to be designed with an optical axis. Figure 4 As shown. Alternatively, a detection assembly can be installed on each side of the strip, such as... Figure 5 As shown, the transmitter includes a first transmitter 21 and a second transmitter 22, and the receiver includes a first receiver 31 and a second receiver 32. The first transmitter 21 and the first receiver 31 are connected by a first synchronization cable 41, and the second transmitter 22 and the second receiver 32 are connected by a second synchronization cable 42. The first receiver 31 and the second receiver 32 are respectively connected to the unit PLC via communication cables. When calculating the number of optical axes blocked by the steel strip, the total number is obtained by summing within the PLC.

[0028] In actual production, when the strip passes between transmitter 2 and receiver 3, the distance between transmitter 2 and the upper surface of the strip is 300-1000mm; the distance between receiver 3 and the lower surface of the strip is also 300-1000mm. The spacing between transmitter 2, receiver 3, and the strip reduces damage to transmitter 2 and receiver 3 caused by machine malfunctions such as strip breakage. The spacing between transmitter 2 and the strip can be the same as or different from the spacing between receiver 3 and the strip; the difference in spacing does not affect the performance. Specifically, for example... Figure 3 As shown, transmitter 2 and receiver 3 are installed above and below the strip, respectively. In actual application, receiver 3 is installed above the strip and transmitter 2 is installed below the strip, which can achieve the same effect.

[0029] During production, the strip steel passes sequentially through the first set of detection grating devices 10 and the second set of detection grating devices 20 and moves forward. The unit's PLC acquires in real time the number of optical axes blocked by the strip steel in both sets of detection grating devices, and calculates the difference N between the number of optical axes blocked by the strip steel in the second set of detection grating devices 20 (S2) and the number of optical axes blocked by the strip steel in the first set of detection grating devices 10 (S1), where N = S2 - S1. The difference N is compared with a set threshold Y. When N ≥ Y, the strip steel position corresponding to the optical axis of the first set of detection grating devices is determined to be the crescent position of the weld.

[0030] Specifically, the optical axis spacing of the detection grating device is 2mm-5mm, and the specific optical axis spacing can be designed according to the actual situation.

[0031] This invention utilizes the crescent-shaped notch at the weld seam as a weld seam location detection mark. In actual production, after the strip steel is welded, a crescent-shaped notch is cut at the weld seam using crescent shears. The crescent shears consist of two symmetrical parts: a transmission side and an operating side. The following description focuses on the operating side. Figure 6 As shown, four gratings are arranged on the operating side: a deceleration grating Y1 and a stop grating Y2 for the crescent shears to feed. When cutting is required, the feed cylinder Y4 drives the crescent shear blade Y3 to move forward. When the deceleration grating Y1 is blocked by the strip steel, the feed speed is reduced. When both stop gratings Y2 are blocked by the strip steel, the feed cylinder Y4 stops (at this time, the crescent shear blade extends L out of the stop grating), and then cutting is performed to cut a crescent notch at the weld.

[0032] Taking the direction of strip movement as a reference, the two sides of the weld are the front strip and the rear strip, respectively; there are three possible combinations of strips before and after the weld: 1. The front strip and the rear strip have the same width (e.g., Figure 7 ); 2. Front strip is wider than rear strip (e.g.) Figure 8 ); 3. Narrower front strip and wider rear strip (e.g.) Figure 9Based on the tracking function of the unit's PLC, the theoretical width of the strip steel that is about to pass through the detection system can be determined, thus identifying the type of welding combination and calculating the corresponding set threshold Y to determine the position of the weld crescent.

[0033] When the width of the strip before the weld is less than or equal to the width of the strip after the weld, Y = 2L / bc; When the width of the strip before the weld is greater than the width of the strip after the weld, Y = (a + 2L) / bc; Where 'a' represents the width difference between the strip before and after the weld, 'L' represents the depth of the crescent shear blade extending from the stop grating, 'b' represents the optical axis spacing of the detection grating device, and 'c' represents the error value of the number of optical axes caused by strip misalignment. In practical applications, the error value 'c' of the number of optical axes caused by strip misalignment can be set according to specific production requirements.

[0034] The following example illustrates the threshold setting and crescent position determination in this invention using a specific application scenario where the maximum depth of the crescent notch is L=70mm, the optical axis spacing is b=2mm, and the error value of the optical axis number variation caused by strip misalignment is c=15.

[0035] 1. Assuming that the width of both the current strip and the subsequent strip is 1100mm, it belongs to... Figure 7 For the weld seam pattern, the applicable threshold calculation formula is Y=2L / bc. Considering the known maximum crescent notch depth L=70mm, optical axis spacing b=2mm, and the error value c due to strip misalignment causing optical axis number variation of 15, the calculated threshold Y=2L / bc=55.

[0036] During the production process, the number of optical axes of the first set of detection grating devices 10 and the second set of detection grating devices 20 that are blocked by the strip steel is obtained in real time, and the difference N between the number of optical axes of the second set of detection grating devices 20 blocked by the strip steel and the number of optical axes of the first set of detection grating devices 10 blocked by the strip steel is calculated. When N≥55, the strip steel position corresponding to the optical axis of the first set of detection grating devices 10 is determined to be the crescent position of the weld.

[0037] 2. Current row 1200mm, next row 1100mm, belongs to Figure 8 The pattern of passing through the weld seam is defined as follows: the absolute value of the width difference between the strip before and after the weld seam is a = 100. Given the known maximum depth of the crescent-shaped notch L = 70 mm, the optical axis spacing b = 2 mm, and the error value c due to the variation in the number of optical axes caused by strip deviation, the threshold value Y = (a + 2L) / bc = 105 is calculated.

[0038] During the production process, the number of optical axes of the first set of detection grating devices 10 and the second set of detection grating devices 20 that are blocked by the strip steel is obtained in real time, and the difference N between the number of optical axes of the second set of detection grating devices 20 blocked by the strip steel and the number of optical axes of the first set of detection grating devices 10 blocked by the strip steel is calculated. When N≥105, the strip steel position corresponding to the optical axis of the first set of detection grating devices 10 is determined to be the crescent position of the weld.

[0039] 3. Current row 1100mm, next row 1250mm, belongs to Figure 9 For the weld seam pattern, the applicable threshold calculation formula is Y=2L / bc. Considering the known maximum crescent notch depth L=70mm, optical axis spacing b=2mm, and the error value c due to strip misalignment causing optical axis number variation of 15, the calculated threshold Y=2L / bc=55.

[0040] During the production process, the number of optical axes of the first set of detection grating devices 10 and the second set of detection grating devices 20 that are blocked by the strip steel is obtained in real time, and the difference N between the number of optical axes of the second set of detection grating devices 20 blocked by the strip steel and the number of optical axes of the first set of detection grating devices 10 blocked by the strip steel is calculated. When N≥55, the strip steel position corresponding to the optical axis of the first set of detection grating devices 10 is determined to be the crescent position of the weld.

[0041] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cold rolling continuous operation unit strip steel weld crescent position detection system, characterized in that, It includes two sets of detection grating devices arranged at intervals at the weld inspection position. The two sets of detection grating devices are set in parallel and the interval is greater than the width of the crescent blade. After installation, the multiple optical axis emitting ends of each set of detection grating devices are arranged along the width direction of the strip steel and the distance between the two optical axis emitting ends is greater than the width of the widest strip steel of the unit. Each set of detection grating devices is connected to the unit PLC through a communication cable. During the production process, the strip steel passes through the first set of detection grating devices and the second set of detection grating devices in sequence and moves forward. The unit PLC obtains the number of optical axes blocked by the strip steel in real time for the two sets of detection grating devices, and calculates the difference N between the number of optical axes blocked by the strip steel in the second set of detection grating devices and the first set of detection grating devices. The difference N is compared with the set threshold Y. When N≥Y, the strip steel position corresponding to the optical axis of the first set of detection grating devices is determined to be the crescent position of the weld.

2. The cold rolling continuous operation unit strip steel weld crescent position detection system according to claim 1, characterized in that, The detection grating device includes a power supply, a transmitter, a receiver, a synchronization cable, and a power cord. The transmitter and receiver are connected by the synchronization cable, and the transmitter and receiver are respectively connected to the power supply via the power cord. The receiver is connected to the unit PLC via a communication cable.

3. The strip weld crescent position detection system for cold rolling continuous operation units according to claim 2, characterized in that, The transmitter includes a first transmitter and a second transmitter, and the receiver includes a first receiver and a second receiver; the first transmitter and the first receiver are connected by a first synchronization cable, the second transmitter and the second receiver are connected by a second synchronization cable, and the first receiver and the second receiver are respectively connected to the unit PLC through communication cables.

4. The strip weld crescent position detection system for cold rolling continuous operation units according to claim 2, characterized in that, During the production process, the distance between the transmitter, receiver and the surface of the strip steel is 300-1000mm.

5. The strip weld crescent position detection system for cold rolling continuous operation units according to claim 1, characterized in that, The distance between the two optical axis emitting ends of the detection grating device is 200-400mm larger than the width of the widest steel strip of the unit.

6. A crescent position detection system for strip weld seams in a cold-rolled continuous operation unit according to any one of claims 1-5, characterized in that, The optical axis spacing of the detection grating device is 2mm-5mm.

7. The strip weld crescent position detection system for cold rolling continuous operation units according to claim 6, characterized in that, The set threshold Y is calculated and updated by the unit PLC; With the direction of the strip's travel as the front reference, the two sides of the weld are the front strip and the rear strip, respectively; When the width of the strip before the weld is less than or equal to the width of the strip after the weld, Y = 2L / bc; When the width of the strip before the weld is greater than the width of the strip after the weld, Y = (a + 2L) / bc; Where a is the width difference between the strip steel before and after the weld, L is the depth of the crescent shear blade extending out of the stop grating, b is the optical axis spacing of the detection grating device, and c is the error value of the change in the number of optical axes caused by the strip steel deviation.

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