Device and method for determining CEC action point of stretch reducing mill

Abstract

The invention relates to a device and method for determining a CEC action point of a stretch reducing mill, and belongs to the field of hot-rolled steel pipe rolling equipment in the ferrous metallurgical industry. The correlation type photoelectric switch is arranged in front of the head rack of the stretch reducing mill, the distance between an emitter and a receiver in the correlation type photoelectric switch is adjusted, and meanwhile the distance between the correlation type photoelectric switch and the head rack of the stretch reducing mill is adjusted; according to the detected time of the steel pipe end recorded by the correlation type photoelectric switch, the time when the steel pipe reaches a first rack of the stretch reducing mill is calculated; then, the current sudden change moment of a motor of the first rack of the stretch-reducing mill is obtained, and the CEC action time point is calculated by combining the moment when the steel pipe reaches the first rack of the stretch-reducing mill; according to the method, the time point when the steel pipe actually reaches the head rack of the stretch reduction mill can be determined, and the action time point of the CEC is finally determined, so that the problem of advanced or delayed action of the CEC is avoided, the control accuracy of the head and tail wall thicknesses of the steel pipe and the production efficiency are improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of hot-rolled steel pipe rolling equipment in the iron and steel metallurgical industry, relates to a tension-reducing machine, and in particular to a device and method for determining a CEC action point of a tension-reducing machine. Background Art

[0002] Stretch reducing mills, which continuously roll steel pipes through a series of pass profiles, subject them to radial compression and axial stretching. These mills are widely used in seamless steel pipe production lines. Pipe end thickening is a characteristic of pipe stretch reducing. During the process, the tension typically passes through three to four mill stands to reach the fixed average tension required by the process. This results in a smaller reduction effect on the ends of the pipe than in the middle. This process-induced thickening results in thicker end walls than in the middle. Under these conditions, the ends of the stretched pipe are often cut off due to unacceptable wall thickness. Therefore, eliminating pipe end thickening is crucial to improve pipe rolling quality, reduce head and tail losses, and increase material yield.

[0003] Currently, the most important and advanced technology for reducing the thickening section at the end of steel pipes is Crop End Control (CEC). The basic idea of ​​CEC control is to compensate for the lack of tension at the pipe end. This is achieved by adjusting the additional speed of the stand rollers during the insertion and ejection of the pipe end, increasing the speed difference between the stands rolling the pipe end, and generating additional axial tension at both ends of the steel pipe. This compensates for the tension missing under normal conditions and reduces the length of unqualified pipe ends after stretching.

[0004] Ideally, the CEC system provides the correct additional speed at the pipe end to minimize the thickening section. However, during production, two situations often occur, causing the CEC system's action point in the stretcher to drift and become inaccurately determined. First, due to processing reasons, the diameter of the conveyor rollers before the stretcher may deviate from the designed dimensions. As the pipe's transport speed changes, the CEC system still calculates the action time based on the preset pipe transport speed, resulting in an incorrect calculation of the CEC action time, ultimately advancing or delaying the action point and inaccurately controlling the wall thickness at the beginning and end of the product. Second, as production progresses, the conveyor rollers before the stretcher gradually wear and reduce their diameter. This can also lead to an incorrect calculation of the CEC action time, ultimately advancing the action point and inaccurately controlling the wall thickness at the beginning and end of the product. If CEC is triggered after the pipe end arrives, the CEC action range extends beyond the pipe end, resulting in a "pull-negative" situation. If CEC is triggered before the pipe end arrives, the CEC effect is weakened, directly affecting the accuracy of the model. In the above two situations, the only way to make rough adjustments is through manual work based on experience, which is inefficient and causes economic losses. Therefore, accurately determining the action time point of the CEC system of the tension-reduction machine is of great significance for controlling the head and tail wall thickness of the product and the cutting length. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a device and method for determining the CEC action point of a tension-reduction machine, so as to solve the problem that the action point of the CEC system of the tension-reduction machine cannot be accurately determined after drift, and the efficiency of manual adjustment based on experience is low, thereby meeting the requirements of actual production and improving the ability to control product quality during production.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for determining a CEC action point of a tension-reduction machine, the method comprising: firstly, setting a through-beam photoelectric switch in front of a front frame of the tension-reduction machine, adjusting the distance between a transmitter and a receiver in the through-beam photoelectric switch, and simultaneously adjusting the distance between the through-beam photoelectric switch and the front frame of the tension-reduction machine;

[0008] Then, operate the through-beam photoelectric switch and record the moment when the through-beam photoelectric switch detects the end of the steel pipe, and calculate the moment when the steel pipe reaches the first frame of the tensioning and reducing machine;

[0009] Finally, the moment of current mutation of the motor of the first frame of the tension and reduction machine is obtained, and the CEC action time point is calculated based on the moment when the steel pipe arrives at the first frame of the tension and reduction machine.

[0010] Furthermore, two groups of opposing photoelectric switches are sequentially arranged in the direction of the rolling center line at the front edge of the first frame of the tensioning and reducing machine.

[0011] Furthermore, in each group of the opposing photoelectric switches, the distance between the emitter and the receiver is 150 mm to 1000 mm, and the center line of the emitter and the receiver should coincide with the rolling center line.

[0012] Furthermore, among the two groups of the opposing photoelectric switches, the distance between the group of opposing photoelectric switches close to the front frame of the tensioner and reducer and the front frame of the tensioner and reducer is not greater than 1000 mm.

[0013] Furthermore, two sets of the opposing photoelectric switches are operated, and the times t1 and t2 when the two sets of the opposing photoelectric switches detect the ends of the steel pipe are recorded. The time when the steel pipe reaches the first frame of the tensioning and reducing machine is calculated based on t1 and t2:

[0014]

[0015] Where t3 represents the time when the steel pipe reaches the first frame of the tensioning and reducing machine, L2 represents the distance between the through-beam photoelectric switch close to the first frame of the tensioning and reducing machine and the first frame of the tensioning and reducing machine, v represents the moving speed of the steel pipe, and L1 represents the distance between the two sets of through-beam photoelectric switches.

[0016] Obtain the current mutation time t4 of the motor of the first frame of the tensioning and reducing machine, and calculate the CEC action time point based on the time t3 when the steel pipe arrives at the first frame of the tensioning and reducing machine:

[0017] Furthermore, a device for use with this method is proposed, comprising a first set of through-beam photoelectric switches, a second set of through-beam photoelectric switches, a first bracket, a second bracket, and a computer. The transmitter and receiver of the first set of through-beam photoelectric switches are fixed to the first bracket and the second bracket, respectively, while the transmitter and receiver of the second set of through-beam photoelectric switches are fixed to the first bracket and the second bracket, respectively. The first and second sets of through-beam photoelectric switches are used to detect the end of a steel pipe and transmit the time point of detection to the computer, which is used to calculate the CEC action time point of the tension-reduction machine.

[0018] The beneficial effects of the present invention are as follows: the present invention proposes a device and method for determining the CEC action time point of a tensioning and reducing machine. The present invention uses two sets of fixed-position opposing photoelectric switches to detect the end of a steel pipe, and then combines the signal time fed back by the two sets of opposing photoelectric switches when the end of the steel pipe passes, the distance between the two sets of opposing photoelectric switches, and the distance between the opposing photoelectric switches and the head frame of the tensioning and reducing machine to calculate the time point when the steel pipe enters the head frame. Combined with the time point of the current mutation of the motor of the head frame, the action time point of the CEC system can be determined.

[0019] The present invention uses a through-beam photoelectric switch to determine the time point when the steel pipe actually arrives at the first frame of the tensioning and reducing machine, and finally determines the time point of CEC action based on the time point when the steel pipe actually arrives at the first frame in combination with the time point of the current mutation of the motor of the first frame. This can avoid the problem of early or delayed CEC action caused by the inconsistency between the steel pipe transportation speed caused by the diameter of the tensioning and reducing machine transportation roller and the preset speed of the CEC system, thereby improving the control accuracy of the head and tail wall thickness of the steel pipe, improving the production efficiency of the tensioning and reducing machine, and reducing the cut length of the steel pipe end, thereby greatly reducing production costs.

[0020] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0022] Figure 1 Schematic diagram of the arrangement of a beam-type photoelectric switch in one embodiment of the present invention;

[0023] Figure 2 for Figure 1 Front view of

[0024] Figure 3 for Figure 1 Side view of

[0025] Figure 4 Schematic diagram of the principle of determining the CEC action point of the tension-reduction machine by the device of the present invention;

[0026] Figure 5 for Figure 4 Side view of

[0027] Figure 6 This is the calculation flow chart of the CEC action point of the tension-reduction machine.

[0028] Reference numerals: 1 - first transmitter; 2 - first receiver; 3 - second transmitter; 4 - second receiver; 5 - first bracket; 6 - second bracket; 7 - steel pipe; 8 - first stand; 9 - rolling center line. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0030] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0031] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] This invention proposes a device and method for determining the CEC action time of a tensioning and reducing machine. Using two fixed sets of opposing photoelectric switches, the device automatically calculates the time when the steel pipe enters the first rack, combining the signal feedback time from the two sets of switches as the steel pipe passes through, the distance between the two sets of switches, and the distance between the switches and the first rack of the tensioning and reducing machine. This automatically calculates the time when the steel pipe enters the first rack, combined with the time when the current of the first rack motor suddenly changes, and this information is fed back to the CEC system to determine the CEC action time. This invention solves the problem of the inability to accurately determine the action point of the CEC system of a tensioning and reducing machine after drift, and the low efficiency of manual adjustment based on experience.

[0033] Based on this, an embodiment of the present invention provides a device for determining the CEC action point of a tension-reduction machine, such as Figure 1 As shown, the device includes a first set of through-beam photoelectric switches, a second set of through-beam photoelectric switches, and brackets for securing the first and second sets of through-beam photoelectric switches, respectively. Each set of through-beam photoelectric switches includes a transmitter and a receiver, and the transmitter and receiver of each set are mounted on separate brackets and aligned with each other.

[0034] Figure 2 The figure shows the front view of the device. Considering the actual situation on site, the distance between the transmitter and the receiver is adjusted to the optimal value according to the specific model of the through-beam photoelectric switch (BJ7M-TDT-T, ESF61-T300M, ESF61-T1000P).

[0035] Figure 3 The figure shows a side view of the device. Considering the response speed of the through-beam photoelectric switch and economic factors, the distance between the two sets of brackets should be controlled within 150mm to 1000mm, but not limited to this range.

[0036] See Figure 4 and Figure 5 To ensure the accuracy of the signal, the center line of the transmitter and receiver needs to coincide with the rolling center line 9, and the distance between the device and the first frame 8 of the tensioning and reducing machine should be determined according to the actual situation on site, but should not be too large, and should be guaranteed to be within 1000mm.

[0037] The device also includes a computer, which feeds back the time signal measured by the opposing photoelectric switch to the computer, and automatically calculates the time point when the steel pipe enters the first frame of the tensioning and reducing machine through the computer. This is combined with the time point of the current mutation of the motor of the first frame, and finally fed back to the CEC system to determine the action point of the CEC system.

[0038] Another embodiment of the present invention provides a method for calculating the CEC action point based on the feedback signal sent by the beam-type photoelectric switch, such as Figure 6 As shown, the method includes:

[0039] First, obtain the time t1 when the first group of through-beam photoelectric switches provide feedback signals, and obtain the time t2 when the second group of through-beam photoelectric switches provide feedback signals; obtain the distance L1 between the two groups of through-beam photoelectric switches, and obtain the distance L2 between the through-beam photoelectric switch group close to the tensioning and reducing machine and the first frame of the tensioning and reducing machine.

[0040] Then, based on the information obtained, calculate the moving speed v of the steel pipe:

[0041]

[0042] Calculate the time t3 when the steel pipe reaches the first frame of the tensioning and reducing machine:

[0043]

[0044] Finally, the time point t4 at which the current of the first rack of the Zhangjiang-Jiangsu machine suddenly changes is obtained, and the time point t5 at which the CEC system of the Zhangjiang-Jiangsu machine acts is calculated by combining t3 and t4:

[0045]

[0046] The above times are all accurate to 0.01s, and the distances are all accurate to 0.1mm.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for determining the CEC action point of a tension-reduction machine, characterized in that: The method comprises: firstly, setting a beam photoelectric switch in front of the front frame of the expansion and contraction machine, adjusting the distance between the transmitter and the receiver in the beam photoelectric switch, and simultaneously adjusting the distance between the beam photoelectric switch and the front frame of the expansion and contraction machine; Then, operate the through-beam photoelectric switch and record the moment when the through-beam photoelectric switch detects the end of the steel pipe, and calculate the moment when the steel pipe reaches the first frame of the tensioning and reducing machine; Finally, the moment of current mutation of the motor of the first frame of the tension and reduction machine is obtained, and the CEC action time point is calculated based on the moment when the steel pipe arrives at the first frame of the tension and reduction machine.

2. The method according to claim 1, characterized in that Two groups of opposing photoelectric switches are sequentially arranged in the direction of the rolling center line at the front edge of the first frame of the tensioning and reducing machine.

3. The method according to claim 2, characterized in that In each group of the opposing photoelectric switches, the distance between the emitter and the receiver is 150 mm to 1000 mm, and the center line of the emitter and the receiver should coincide with the rolling center line.

4. The method according to claim 2, characterized in that In the two groups of the opposing photoelectric switches, the distance between the group of opposing photoelectric switches close to the front frame of the tensioning and reducing machine and the front frame of the tensioning and reducing machine is not greater than 1000 mm.

5. The method according to claim 2, characterized in that Run the two sets of the opposing photoelectric switches, and record the times t1 and t2 when the two sets of the opposing photoelectric switches detect the ends of the steel pipe, respectively. Calculate the time when the steel pipe reaches the first frame of the tensioning and reducing machine based on t1 and t2: Where t3 represents the time when the steel pipe reaches the first frame of the tensioning and reducing machine, L2 represents the distance between the through-beam photoelectric switch close to the first frame of the tensioning and reducing machine and the first frame of the tensioning and reducing machine, v represents the moving speed of the steel pipe, and L1 represents the distance between the two sets of through-beam photoelectric switches.

6. The method according to claim 5, characterized in that Obtain the current mutation time t4 of the motor of the first frame of the tensioning and reducing machine, and calculate the CEC action time point based on the time t3 when the steel pipe arrives at the first frame of the tensioning and reducing machine:

7. A device for use with the method according to any one of claims 1 to 6, characterized in that: The device includes a first group of through-beam photoelectric switches, a second group of through-beam photoelectric switches, a first bracket, a second bracket and a computer; the transmitter and receiver of the first group of through-beam photoelectric switches are fixed on the first bracket and the second bracket respectively, and the transmitter and receiver of the second group of through-beam photoelectric switches are fixed on the first bracket and the second bracket respectively; the first group of through-beam photoelectric switches and the second group of through-beam photoelectric switches are used to detect the end of the steel pipe, and transmit the time point when the steel pipe end is detected to the computer, and the computer calculates the CEC action time point of the tensioning and reducing machine based on the time point when the steel pipe end is detected, the current sudden change moment of the motor of the first frame of the tensioning and reducing machine, the distance between the two groups of through-beam photoelectric switches, and the distance between the through-beam photoelectric switch close to the first frame of the tensioning and reducing machine and the first frame of the tensioning and reducing machine.

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