Shearing control method for optimizing shearing precision of flying shear before finish rolling of high-speed wire rod

Abstract

The present application relates to the field of wire rod rolling, in particular to a shearing control method for optimizing the shearing precision of a flying shear before high-speed wire rod finish rolling. The method comprises: receiving a shearing instruction, and controlling the swivel guide tube to swing from the breaking position to the steel passing position or from the steel passing position to the breaking position after the flying shear blade passes a preset position by a delay time T'; T' = T - [(D - d) / 2 - L] / a; T represents the delay time of the time when the action of the calibration swivel is controlled relative to the time when the flying shear blade passes the preset position in the process of shearing calibration wire rod so that the shearing mark formed by the flying shear blade is located at the center of the flying shear blade; D represents the inner diameter of the swivel guide tube; d represents the diameter of the wire rod before finish rolling; L represents the position deviation of the calibration wire rod passing through the swivel guide tube when the swivel guide tube swings relative to the normal steel passing time; and a represents the position deviation of the shearing mark on the flying shear blade per unit delay time. The present application can keep the shearing mark at the center of the flying shear blade and improve the overall shearing precision when producing multiple specifications and steel grades.

Description

Technical Field

[0001] This invention relates to the field of wire rod rolling, and more specifically to a shearing control method for optimizing the shearing accuracy of a flying shear before high-speed wire rod finishing rolling. Background Technology

[0002] The pre-rolling shear in the finishing mill is an auxiliary device used for head shearing, tail shearing, and accidental breakage of rolled products. It is an extremely important piece of equipment for high-speed wire rod mills.

[0003] A high-speed wire rod mill uses a Morgan 800 flying shear before its finishing mill. This flying shear is a continuous disc shear. The mechanical part of the flying shear mainly consists of two continuously rotating discs, one above the other. The flying shear has a set of cutting blades, one on each of the upper and lower discs. When the blades overlap, they cut the passing steel. Figure 1 As shown, a deflector is installed in front of the flying shear blade 6. The swing of the deflector is controlled by a Siemens servo motor. The swing stroke of the deflector guide 4 corresponds to three positions of the flying shear: the breaking position, the shearing position, and the steel passing position. Because the flying shear is very fast, with a maximum speed of about 22 m / s, the deflector guide 4 can generally complete the swing from the breaking position to the steel passing position (head cutting) within 0.15 seconds. When passing the shearing position, the flying disc blade 6 just overlaps and cuts the wire 5. The cut head enters the breaking shear along the breaking position guide groove 1. The remaining steel follows the deflector guide 4 to the steel passing position, passes through the steel position guide groove 2, and enters the finishing mill for further rolling.

[0004] The shear blade 6 of this flying shear is 40mm wide. When the flying shear cuts, the wire 1 (red steel) will leave a mark on the shear blade 6. This mark is called the cutting mark. The cutting mark clearly shows whether the flying shear's cutting position is accurate. A certain high-strength wire rod mill produces many specifications on its second line, covering... Specifications. The diameter of wire rod 1 passing through the flying shear before finishing rolling varies from 16mm to 32.4mm. During actual production, the manufacturer found that some large-diameter steel pieces, if cut slightly off-center and not completely severed, would cause significant steel blockage before the flying shear. Small-diameter steel pieces, even if cut slightly off-center, could be severed, but the cut material would collide with the triangular plate 3 or the looper after the flying shear, also causing significant steel blockage before the flying shear. Therefore, solving the problem of slightly off-center cutting by the flying shear is very necessary. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a shearing control method for optimizing the shearing accuracy of flying shear before high-speed wire rod finishing rolling. It can keep the shearing mark at the center of the flying shear blade and improve the overall shearing accuracy when producing various specifications and steel grades.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a shearing control method for optimizing the shearing accuracy of a flying shear before high-speed wire rod finishing rolling, wherein the flying shear is a continuous disc shear used to shear the wire rod during the process of the deflector action causing the deflector guide to swing; the method includes:

[0007] Upon receiving the shearing command, after a delay T' from when the flying shear blade passes the preset position, the deflector is controlled to swing from the breakage position to the steel-passing position or vice versa, where T' = T - [(Dd) / 2 - L] / a;

[0008] T represents the time delay between the moment when the shearing mark formed by the flying shear blade is located at the exact center of the flying shear blade during the shearing of the calibration wire and the moment when the flying shear blade passes the preset position.

[0009] D represents the inner diameter of the deflector conduit;

[0010] d represents the diameter of the wire rod before finishing rolling;

[0011] L represents the positional deviation of the calibration wire passing through the calibration bend guide when it swings, relative to the normal overstiffness state, which is half the difference between the inner diameter of the calibration bend guide and the diameter of the calibration wire.

[0012] 'a' represents the positional offset of the cutting mark on the flying shear blade within a unit delay time when the flying shear is cutting the wire.

[0013] Furthermore, to reduce the size of the deflector conduit, the method also includes:

[0014] Select the appropriate inner diameter of the deflector guide tube based on the diameter range of the wire rod before finishing rolling.

[0015] Furthermore, when the diameter of the wire before finishing rolling is 15-25mm, the inner diameter of the selected deflector guide tube is 25mm;

[0016] Alternatively, if the diameter of the wire before precision rolling is 20-25mm, the inner diameter of the selected deflector guide tube is 31mm.

[0017] Alternatively, if the diameter of the wire before precision rolling is 25-30mm, the inner diameter of the selected deflector guide tube is 38mm.

[0018] Alternatively, if the diameter of the wire before precision rolling is 30-35mm, the inner diameter of the selected deflector guide tube is 42mm.

[0019] Furthermore, a is 1.2 mm / ms.

[0020] Furthermore, to prevent accidents, the delay T' is followed by the activation of the control switch; including:

[0021] Determine whether T' is within the preset delay interval. If it is, control the turntable to move after a delay of T'; otherwise, control the turntable to move after a delay of T.

[0022] By adopting the above technical solution, this invention can adjust the shearing position of wire rods of various specifications, improve the control accuracy of the flying shear before finishing rolling, and ensure that the shearing mark is kept in the center of the flying shear blade, thereby avoiding steel blockage. In addition, because the wear program of the deflector guide tube is limited, the use of this method for compensation can also avoid steel blockage caused by wear of the deflector guide tube. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the flying shear operation before finishing rolling;

[0024] Figure 2 This is a flowchart of the shearing control method for the shearing accuracy of the flying shear before high-speed wire rod finishing rolling according to the present invention.

[0025] Figure 3 This is a schematic diagram showing the position of the red steel in the deflector guide tube;

[0026] Figure 4 This is a comparison diagram of the shear marks on the blade of the flying shear before and after using the method of this invention;

[0027] Figure 5 This is a diagram showing the location of the shear marks on the blades of the flying shear after the method in this invention has been used.

[0028] In the diagram, 1. Break-off guide groove; 2. Steel passage guide groove; 3. Post-shear triangular plate; 4. Turning device guide tube; 5. Wire; 6. Flying shear blade;

[0029] Figure 1 (a) is a schematic diagram of the position of the red steel in the deflector guide when the head is not cut off; Figure 1 (b) is a schematic diagram showing the position of the red steel head in the deflector guide after it has been cut off;

[0030] Figure 4 (a) The shearing marks on the blade of the flying shear before applying the method of the present invention; Figure 4 (b) is the shear mark on the blade of the flying shear after applying the method of the present invention. Detailed Implementation

[0031] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0032] To address the issue of slightly off-center cutting by the flying shear, the inventors of this invention have been experimenting with new control methods. Originally, it involved... Figure 1The method of adjusting the zero-position calibration of the flying shear blade 6 position to match the shearing mark has some effect, but the calibration range is sometimes inaccurate, and occasional malfunctions still occur. Through continuous exploration and experience accumulation, it was finally discovered that three parameters—the diameter of the red steel (pre-rolled wire rod 1), the hardness of the red steel (pre-rolled wire rod 1), and the inner diameter of the deflector guide 4—have a regular influence on the shearing mark. Among these, wear and incorrect selection of the deflector guide 4, resulting in an excessive distance between the edge of the red steel and the inner wall of the deflector guide 4, leading to excessive swing amplitude of the shear head, is the most common type of malfunction.

[0033] Based on this, such as Figure 1 As shown, a shearing control method for optimizing the shearing accuracy of a flying shear before high-speed wire rod finishing rolling is disclosed. The flying shear is a continuous disc shear used to shear wire rod 1 during the process of the deflector's action causing the deflector guide 4 to swing. The method includes:

[0034] Upon receiving the shearing command, after a delay T' from when the flying shear blade 6 passes the preset position, the deflector is controlled to swing from the breakage position to the steel-passing position or from the steel-passing position to the breakage position, where T' = T - [(Dd) / 2 - L] / a;

[0035] T represents the time delay between the moment when the shearing mark formed by the shear blade 6 of the flying shear is located at the exact center of the shear blade 6 during the process of the flying shear cutting the calibration wire, and the moment when the shear blade 6 passes the preset position; the preset position can be the zero position, which is the position where the two shear blades 6 of the flying shear overlap.

[0036] D indicates the inner diameter of the deflector conduit 4;

[0037] d indicates the diameter of the wire rod before finishing rolling;

[0038] L represents the positional deviation of the calibration wire passing through the calibration bend guide when it swings, relative to the normal overstiffness state, which is half the difference between the inner diameter of the calibration bend guide and the diameter of the calibration wire.

[0039] 'a' represents the positional offset of the shear mark on the shear blade 6 of the flying shear during a unit delay time when shearing different steel grades.

[0040] Specifically, the time required for the flying shear to rotate one revolution is fixed. The delay between the start of the deflector's action and the moment the flying shear blade 6 passes the preset position is used to control the timing of the coordination between the flying shear blade 6 and the deflector. This adjusts the cutting position of various wire rod specifications 1, improves the overall control accuracy of the flying shear before finishing rolling, and ensures that the cutting mark remains in the exact center of the flying shear blade 6, avoiding steel blockage. In addition, because the wear range of the deflector guide tube 4 is limited, this compensation method can also prevent steel blockage caused by wear of the deflector guide tube 4.

[0041] The technical solutions involved in the above embodiments will be described in detail below with reference to specific examples.

[0042] The deflector guide 4 swings from the breakage position to the steel passage position, where the flying shear cuts the head of the wire. The deflector guide 4 then swings from the steel passage position to the breakage position, where the flying shear cuts the tail. The control principles for the head-cutting and tail-cutting functions are similar; the following description mainly focuses on the head-cutting function.

[0043] Figure 1 In the process, the initial position of the deflector guide 4 points towards the break-off guide groove 1. If the deflector does not operate, the red steel (wire 1) will directly enter the break-off shear through the break-off guide groove 1 for breakage. During normal cutting, the red steel moves at a speed of 20 meters per second (for example). When the head of the red steel enters the break-off guide groove 1, and the distance from the head of the red steel to the flying shear blade 6 reaches X meters (the set cutting length), the deflector quickly moves, causing the deflector guide 4 to swing from the break-off position to the steel-passing position, with a total swing distance of about 10 centimeters. When the deflector guide 4 swings to the middle (the shearing position), the flying shear blade 6 just overlaps and cuts the steel (the steel does not touch the flying shear blade 6 at the steel-passing and break-off positions). The flying shear blade 6 rotates 2.54 meters in one revolution. Based on the typical material size, the time from when the flying shear blade 6 touches the steel to when it completely cuts it can be calculated to be about 0.008 seconds. This time is much smaller than the 0.15 seconds it takes for the deflector guide 4 to swing from the break-off position to the steel-passing position. Therefore, the effect of shear resistance on shearing accuracy is not considered in this invention.

[0044] like Figure 3 As shown, Figure 3 This is the key to the present invention. Figure 3 This shows the state of the red steel (wire rod 1 before finishing) in the deflector guide tube 4. Under normal circumstances, the red steel may be out of round or have "ears" at the head, so the inner diameter of the deflector guide tube 4 is designed to be larger than that of the red steel (wire rod 1 before finishing). When the deflector guide tube 4 oscillates at high speed, the red steel (wire rod 1 before finishing) will inevitably adhere tightly to the inner side of the deflector guide tube 4, such as... Figure 3 The horizontal offset of the position of the red steel in the two states is called the positional deviation.

[0045] Figure 2This is a flowchart of the control method. Of course, to implement this process control, the corresponding parameter library needs to be written in the PLC first. When the PLC reads the corresponding specifications and steel grades, it can clearly know whether it is a soft steel grade or a hard steel grade, and it can also know the standard size of the red steel (wire 1 before finishing rolling) at the flying shear. It can also know the inner diameter of the current turning device guide 4 according to the pre-written specification guide correspondence table.

[0046] Of course, it is also necessary to pre-select and calibrate the deflector guide 4 and wire 1 to determine how much the deflector starts to move relative to the time the flying shear blade 6 passes the preset position when the flying shear cuts this wire 1, ensuring that the cutting mark is formed at the exact center of the flying shear blade 6. Here, the deflector guide 4 is the calibration deflector guide, and the selected wire 1 is the calibration wire. The delay time is denoted as the calibration delay time T. For a common specification of mild steel, the calibration delay time T is 84 milliseconds; for a specification of hard steel, the calibration delay time T is 84.2 milliseconds. Changing the delay time T' is equivalent to changing the timing of the engagement between the flying shear blade 6 and the deflector, making this calibration delay time T adjustable via the human-machine interface. Furthermore, for the calibration deflector guide and calibration wire, the position deviation L of the red steel is 3.95mm during normal steel passage and during the oscillating cutter head operation. The calibration delay time for mild steel is shorter than that for hard steel because the distance between the end of the deflector guide tube 4 and the shear blade is about 30 cm. During the swing of mild steel, the deformation of the steel is greater, and the deflector 4 needs to move slightly earlier, so the calibration delay time for mild steel is slightly shorter.

[0047] Through extensive experiments, the inventors of this invention discovered that, taking the cutting head as an example, for every 1 millisecond increase in delay time, the shearing mark of the flying shear shifts 1.2 millimeters towards the breakage point; conversely, for every 1 millisecond decrease in delay time, the shearing mark shifts 1.2 millimeters towards the steel breakage point. Soft and hard steels are roughly classified according to their actual hardness. In the pre-prepared program, 0 represents soft steel and 1 represents hard steel. Based on the data obtained above, the selected calibration delay time can be determined, and the adjustment value of the required delay time can be accurately calculated based on the positional deviation values ​​for different specifications. This yields the delay time T' suitable for the current wire 1, ensuring that the shearing mark is centered (within ±2 millimeters) on the flying shear blade 6 for all specifications and steel types when changing the deflector guide 4. This control method has proven effective in practice, as shown in Table 1, which lists the delay times T' for all specifications. In addition, to prevent accidents, a range is added to the delay time within the theoretical calculation range. The range given in this embodiment is (81, 86). Delay times T' outside the range will not be executed.

[0048] Table 1 shows the delay tables for various specifications ultimately generated by a certain high-speed wire rod mill using the above control methods.

[0049]

[0050]

[0051] The specifications in Table 1 refer to the diameter of the wire after precision rolling.

[0052] Using the control method in this embodiment, it is currently possible to ensure that the shear mark remains at the exact center of the flying shear blade (within ±2 mm) for all specifications under the corresponding deflector guide 4. Figure 4 The image shown is a comparison of the shear mark positions of specifications 10 in Table 1 before and after applying this control method; Figure 5 The diagram shows the positions of several shear marks after adopting this control method.

[0053] The inventors of this invention also considered that using a large tube for a small material size would inevitably lead to shearing failure. However, if each size of material (wire 1 before finishing) were to use a different type of deflector guide tube 4, the number of deflector guide tubes 4 would be too large, and the number of times specifications would be changed on-site would be very high, which would be a huge waste of work. Therefore, the process design incorporated four types of deflector guide tubes 4. Originally, changing the deflector guide tubes 4 was simply based on specifications. Later, the impact of the deflector guide tubes 4 on shearing accuracy was gradually recognized, and the requirements for the use of deflector guide tubes 4 for wire 1 of different size ranges were further specified, as shown in Table 2.

[0054] Table 2 shows the correspondence between the dimensions of four types of conduit 4 and wire 1 used on a certain high-speed railway.

[0055]

[0056] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A shearing control method for optimizing the shearing accuracy of a flying shear before high-speed wire rod finishing rolling, wherein the flying shear is a continuous disc shear used to shear the wire rod during the process of the deflector's action causing the deflector guide tube to oscillate; characterized in that, The methods include: Upon receiving the shearing command, after a delay T' from when the flying shear blade passes the preset position, the deflector is controlled to swing from the breakage position to the steel-passing position or vice versa, where T' = T - [(Dd) / 2 - L] / a; T represents the time delay between the moment when the shearing mark formed by the flying shear blade is located at the exact center of the flying shear blade during the shearing of the calibration wire and the moment when the flying shear blade passes the preset position. D represents the inner diameter of the deflector conduit; d represents the diameter of the wire rod before finishing rolling; L represents the positional deviation of the calibration wire passing through the calibration bend guide when it swings, relative to the normal steel passage, and is half the difference between the inner diameter of the calibration bend guide and the diameter of the calibration wire. 'a' represents the positional offset of the cutting mark on the flying shear blade within a unit delay time when the flying shear is cutting the wire.

2. The shearing control method for optimizing the shearing accuracy of the flying shear before high-speed wire rod finishing rolling according to claim 1, characterized in that, The method also includes: Select the appropriate inner diameter of the deflector guide tube based on the diameter range of the wire rod before finishing rolling.

3. The shearing control method for optimizing the shearing accuracy of the flying shear before high-speed wire rod finishing rolling according to claim 2, characterized in that, When the diameter of the wire before finishing rolling is 15-25mm, the inner diameter of the selected deflector guide tube is 25mm; Alternatively, if the diameter of the wire before precision rolling is 20-25mm, the inner diameter of the selected deflector guide tube is 31mm. Alternatively, if the diameter of the wire before precision rolling is 25-30mm, the inner diameter of the selected deflector guide tube is 38mm. Alternatively, if the diameter of the wire before precision rolling is 30-35mm, the inner diameter of the selected deflector guide tube is 42mm.

4. The shearing control method for optimizing the shearing accuracy of the flying shear before high-speed wire rod finishing rolling according to claim 1, characterized in that, a is 1.2 mm / ms.

5. The shearing control method for optimizing the shearing accuracy of the flying shear before high-speed wire rod finishing rolling according to claim 1, characterized in that, The delay T' followed by the control of the inverter action includes: Determine whether T' is within the preset delay interval. If it is, control the turntable to move after a delay of T'; otherwise, control the turntable to move after a delay of T.

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