Hot rolled strip plane temperature cooling device and control method

Abstract

The present invention discloses a hot-rolled strip plane temperature cooling device and control method, which relates to the field of hot rolling mill temperature control technology. The device comprises: a manifold assembly and a PLC control system; in the manifold assembly, a cooling manifold frame is fixed in a laminar flow area by a frame crossbeam; a plurality of cooling manifolds are fixed side by side on the cooling manifold frame in a plane; the cooling manifolds are connected to the cooling manifold medium supply pipeline in a row; a plurality of nozzles are installed at equal intervals on the cooling manifold; the cooling manifold medium supply pipeline is connected to the medium system; each cooling manifold medium supply pipeline is respectively installed with an electrically controlled adjustable valve; the PLC control system controls the opening and closing and opening size of each electrically controlled adjustable valve according to the width of the strip, selects cooling manifolds of different widths, and controls the medium flow in the cooling manifold. The present invention can achieve transverse temperature control for strips of different widths and specifications, thereby making the strip uniform in transverse structure and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of hot rolling mill temperature control, and in particular to a hot rolled strip plane temperature cooling device and a control method. Background Art

[0002] The 2150 hot rolling mill can produce hot-rolled products with a thickness of 1.8-25.4mm and a width of 1000-2000mm. It is the main force in the hot rolling production line for producing wide and thick specifications and high-strength hot-rolled coils. The production of thick specifications, high strength and high value-added hot-rolled products requires that the products have a uniform microstructure across the width of the coil, thereby ensuring uniform mechanical properties across the width of the coil.

[0003] Hot-rolled strip mills, through extensive data analysis, have concluded that the maximum temperature difference between the coil edge and center can exceed 140°C. Large temperature differences across the width can cause buckling during hot-rolled plate rolling, seriously impacting smooth production. Furthermore, excessively low strip edge temperatures can lead to wrinkles and cracks, impacting product appearance. Furthermore, excessively large temperature differences across the width can cause transverse structural inhomogeneity, leading to significant variations in mechanical properties across the width of the finished coil, potentially causing user problems.

[0004] Currently, the laminar cooling water pipes in the 2150 hot rolling mill are distributed transversely, perpendicular to the rolling line. This cooling effect simultaneously cools the entire cross-section of the strip, accelerating the temperature drop at the edges and contributing to uneven temperature distribution across the strip width. The transverse temperature difference varies for strips of different specifications, necessitating adjustments in cooling water volume based on the type and specification to achieve a more uniform transverse temperature distribution.

[0005] Currently, existing transverse temperature control devices mainly include laminar edge shielding and water blocking nozzles. Shielding specifically blocks water flowing from the edge laminar flow manifolds based on the width of the rolled steel plate, thereby achieving less water at the edges and more water in the center. The control principle is: after the strip passes through the manifold area, the manifolds discharge water in a horizontal row. The edge shielding devices on the manifolds intercept excess water in the horizontal direction, which is a technical concept of transverse control (the horizontal direction is perpendicular to the strip movement). The water blocking nozzle method is similar to the shielding method. Under this control method, only the manifolds are closed, and the amount of water at the edges cannot be precisely adjusted. Consequently, it is impossible to achieve precise control of the flat surface temperature of the hot-rolled strip. The coiling temperature control of hot-rolled coils is a critical control factor. Sometimes, a temperature difference of 20°C to 30°C can lead to significant deviations in the performance of the hot-rolled plate. Therefore, a flat surface cooling solution for hot-rolled strips is urgently needed that can accurately control the transverse temperature of strips of different widths to ensure uniform transverse microstructure and balanced mechanical properties. Summary of the Invention

[0006] In view of this, the present invention provides a planar cooling device and control method for hot-rolled strips, which can accurately adjust the amount of water at the edge, achieve precise control of the transverse temperature of strips of different widths and specifications, and thereby make the transverse structure of the strips uniform and the mechanical properties uniform.

[0007] To this end, the present invention provides the following technical solutions:

[0008] The present invention also provides a hot-rolled strip plane temperature cooling device, the device comprising: a header assembly and a PLC control system;

[0009] In the manifold assembly, a cooling manifold frame is fixed to the laminar flow area via a frame crossbeam; a plurality of cooling manifolds are fixed to the cooling manifold frame side by side in a plane, and a plurality of nozzles are installed at equal intervals on each cooling manifold, and the nozzles output cooling medium to cool the hot-rolled plates passing below the plane; the cooling manifolds are connected to the cooling manifold medium supply pipeline in a row; the cooling manifold medium supply pipeline is connected to the medium system; and each cooling manifold medium supply pipeline is respectively installed with an electrically controlled adjustable valve;

[0010] The PLC control system controls the opening and closing and the opening size of each electrically controlled adjustable valve according to the different widths of the strip steel, selects different numbers of cooling manifold rows, and controls the flow of the medium in the cooling manifolds.

[0011] Furthermore, the cooling manifold frame is made of metal material.

[0012] Furthermore, each cooling header is made of a metal pipe.

[0013] Furthermore, the medium in the cooling header medium supply pipeline is water.

[0014] Furthermore, the manifold assembly is connected to the flip cylinder, the flip cylinder is connected to the cylinder support, and the end of the manifold assembly is connected to the support leg; the manifold assembly is connected to the main pipeline through the manifold assembly rotating adapter fixing beam, and the main pipeline is connected to the inlet butterfly valve pipeline.

[0015] The present invention also provides a hot-rolled strip plane temperature control method applied to the above-mentioned hot-rolled strip plane temperature cooling device, characterized in that the plane temperature of the hot-rolled strip is controlled by adopting a two-stage control model with the transverse temperature difference of the strip as the target;

[0016] The primary control model collects the temperature and speed of the strip, processes the collected signals and feeds them back to the secondary control model;

[0017] The secondary control model sets the target temperature, the transverse water volume and the longitudinal water volume of the laminar flow device according to the process requirements of the transverse and longitudinal temperatures of the strip; based on the laminar end temperature, strip speed, target temperature, transverse water volume and longitudinal water volume, the temperature control scheme is obtained through feedforward control, feedback control and self-learning control; the temperature control scheme includes: the opening and closing status and opening size of the electronically controlled adjustable valve on the medium supply pipeline of each cooling manifold.

[0018] Furthermore, the first-level control model is also used to obtain the strip moving speed detected by the strip sensor and perform closed-loop control on the strip moving speed.

[0019] Furthermore, the strip temperature is collected by a scanning pyrometer arranged at the end of the laminar flow.

[0020] Furthermore, the feedforward control includes detecting the final rolling temperature and the rolling speed, and controlling the difference between the final rolling temperature and the target temperature;

[0021] Feedback control includes performing control using the detected coiling temperature as a feedback amount of the target temperature.

[0022] Furthermore, the self-learning control includes: learning the control process of the previous hot-rolled plate, and adjusting the control process of the next hot-rolled plate according to the control effect of the previous hot-rolled plate; and

[0023] Learn the control process of hot-rolled plates of the same layer and specification, and adjust the control process of hot-rolled plates based on the control effect of hot-rolled plates of the same layer and specification.

[0024] Advantages and positive effects of the present invention: The present invention can effectively solve the problem of transverse temperature control of hot-rolled strip during laminar cooling. After the strip passes through the manifold, water is supplied longitudinally according to the width calculated by the model, and the amount of water at the edge and the switch are adjusted according to the temperature change. Compared with laminar edge shielding and water plugging, the present invention belongs to the technical idea of ​​longitudinal control (longitudinal is the direction of strip movement), and the amount of water at the edge can be automatically adjusted by a regulating valve, making temperature control more flexible and convenient. The transverse temperature distribution is made uniform during the production process, thereby reducing the transverse temperature difference of the strip, reducing the incidence of buckling, improving the appearance quality of the product edge, and improving the uniformity of the organization and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A top view of a header assembly of a planar temperature cooling device according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic structural diagram of a planar temperature cooling device according to an embodiment of the present invention;

[0028] In the figure, 100-manifold assembly includes cooling manifold frame; 200-cooling manifold; 300-cooling manifold medium supply pipeline; 400-electrically controlled adjustable valve; 500-medium system; 1-hexagonal nut; 2-spring washer; 3-manifold assembly; 4-hexagonal head bolt; 5-turn cylinder; 6-support leg; 7-cylinder support; 8-inlet butterfly valve pipeline; 9-PLC control system; A-rotating part; B-manifold assembly rotary joint fixing beam; C-transmission side walkway upper plane; D-manifold assembly rotation support point; E-horizontal center line of hot-rolled plate; F-upper surface of strip conveyor roller. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] The present invention designs a flat temperature cooling device and control method for hot-rolled strips. According to the width variation of the strip, the cooling manifold combination on the cooling device is selected to realize transverse temperature control of strips of different widths and specifications, thereby achieving uniform transverse structure and mechanical properties of the strip.

[0032] The hot-rolled strip plane temperature cooling device in the embodiment of the present invention includes: a header assembly and a PLC control system.

[0033] The header assembly is a large set of laminar water swatters installed above the laminar flow area, and the hot rolled plate is cooled as it passes underneath. Figure 1 As shown, the manifold assembly includes a cooling manifold frame 100, cooling manifolds 200, cooling manifold medium supply lines 300, nozzles (not shown), and electronically controlled adjustable valves 400. The cooling manifold frame 100 is made of a strong metal material and is used to secure the cooling manifolds 200. It is fixed to the laminar flow area via frame crossbeams, and its height and position are consistent with those of conventional laminar flow cooling manifolds. Each cooling manifold 200 is made of metal pipes of the same length. Several cooling manifolds are fixed to the cooling manifold frame 100 in a horizontal arrangement in a plane. Each cooling manifold 200 is connected to the cooling manifold medium supply lines 300 in a row. Several nozzles are installed at equal intervals on each cooling manifold 200. The cooling manifold medium supply lines 300 are connected to the medium system 500. Each cooling manifold medium supply line 300 is equipped with an electronically controlled adjustable valve 400. The opening and closing of the electronically controlled adjustable valves 400 and the flow rate are automatically controlled by a PLC control system.

[0034] The medium in the cooling manifold medium supply pipeline 300 can be water, and accordingly, the medium system connected thereto is a water supply system. The medium in the cooling manifold medium supply pipeline can also be other cooling mediums, and accordingly, the medium system connected thereto is other medium systems.

[0035] The maximum number of cooling manifold rows in the system is determined based on the specific specifications of the hot-rolled plates being produced, with the goal of covering the widest hot-rolled plates. In one specific embodiment, for a 2150 hot-rolling mill production line, there are 10 rows of cooling manifolds, horizontally and side-by-side fixed to the cooling manifold frame. The cooling manifolds have 10 medium supply pipelines, each equipped with two electrically controlled adjustable valves, one for controlling two rows of cooling manifolds. For example, the bottom cooling manifold medium pipeline controls the two outermost rows of cooling manifolds on either side.

[0036] To achieve transverse strip temperature control, cooling manifolds of varying widths are selected based on the strip's width. In the above-described embodiment, since the narrowest production gauge on the 2150 hot rolling mill is 1200mm, the electronically controlled valves of the four central cooling manifold sets are always open, providing basic strip cooling. Therefore, in this specific implementation, the maximum number of cooling manifolds deployed is 10 sets (rows), and the minimum is 4 sets.

[0037] In another embodiment, the hot-rolled strip plane temperature cooling device can be lifted up 90 degrees to realize rotation as a whole. Figure 2As shown, the manifold assembly 3, fixed beam, tilting cylinder 5, and support legs 6 together constitute the rotating section A. The manifold and fixed beam are fixedly connected using hexagonal nuts 1, spring washers 2, and hexagonal bolts 4. In rotating section A, the manifold assembly 3 is connected to the tilting cylinder 5, which is in turn connected to the cylinder support 7. The ends of the manifold assembly 3 are connected to the support legs 6. The manifold assembly 3 in rotating section A is connected to the main pipeline via the manifold assembly rotating adapter fixed beam B. The main pipeline is connected to the inlet butterfly valve pipeline 8. The PLC control system 9 controls the inlet butterfly valve and the electrically controlled adjustable valves in the manifold assembly 3. If an emergency occurs on-site, the entire manifold can be lifted to facilitate handling. Furthermore, the manifold reversal facilitates routine maintenance.

[0038] The temperature control method of the PLC control system is described in detail below.

[0039] On the basis of the plane temperature cooling device in the above embodiment, the PLC control system uses a two-level control model to control the plane temperature of the hot-rolled plate with the transverse temperature difference of the strip as the target, and controls the transverse temperature of the strip while ensuring the longitudinal coiling temperature of the strip. Among them, the first-level control model mainly uses signal acquisition equipment such as pyrometers, strip detection sensors, and strip speed detection sensors to collect signals such as strip temperature and speed, processes the collected signals and feeds them back to the second-level control model, and also performs closed-loop control on the strip speed. The second-level control model realizes temperature control through various control means such as feedforward control, feedback control, and self-learning control; the temperature control specifically includes: controlling the opening and closing state and opening size of the electrically controlled adjustable valve on the medium supply pipeline of each cooling manifold, controlling the number of cooling manifolds put into use by the opening and closing state, and controlling the flow size of the medium in the cooling manifold by the opening size. More specifically, the control method of the PLC control system includes the following steps:

[0040] S1. Obtaining the strip temperature measured by a scanning pyrometer disposed at the end of the laminar flow;

[0041] S2. Obtaining the strip moving speed detected by the strip sensor and performing closed-loop control on the strip moving speed;

[0042] S3. According to the process requirements of the transverse and longitudinal temperatures of the strip, set the target temperature, the transverse and longitudinal water volume of the laminar flow device;

[0043] S4. Based on the laminar end temperature, strip speed, target temperature, transverse water volume and longitudinal water volume, the transverse temperature of the strip is controlled through various control methods such as feedforward control, feedback control and self-learning control;

[0044] The control of the transverse temperature of the strip is achieved by controlling the opening and closing state and the opening size of the electrically controlled adjustable valve on the medium supply pipeline of each cooling manifold. The number of cooling manifolds put into use is controlled by the opening and closing state, and the flow rate of the medium in the cooling manifold is controlled by the opening size.

[0045] Among them, the feedforward control includes detecting the final rolling temperature and rolling speed, and controlling the difference between the final rolling temperature and the target temperature.

[0046] The feedback control is specifically performed by using the detected coiling temperature as the feedback amount of the target temperature.

[0047] Self-learning control involves two aspects: one is learning the control process of the previous hot-rolled plate and adjusting the control process of the next hot-rolled plate based on the control results of the previous hot-rolled plate to achieve better control results; the other is learning the control process of hot-rolled plates of the same layer and specification and adjusting the control process of hot-rolled plates based on the control results of the same layer and specification. Self-learning control can improve the accuracy of the plane temperature calculation model.

[0048] The hot-rolled strip flat-surface temperature cooling device and control method described in the present invention effectively address the issue of transverse temperature control during laminar cooling of hot-rolled strip. This uniformity of transverse temperature distribution during production reduces transverse strip temperature differences, lowers the incidence of buckling, improves product edge appearance, and enhances uniformity of microstructure and mechanical properties.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hot-rolled strip plane temperature cooling device, characterized in that: The device includes: a manifold assembly and a PLC control system; In the manifold assembly, a cooling manifold frame is fixed to the laminar flow area via a frame crossbeam; a plurality of cooling manifolds are fixed to the cooling manifold frame side by side in a plane, and a plurality of nozzles are installed at equal intervals on each cooling manifold, and the nozzles output cooling medium to cool the hot-rolled plates passing below the plane; the cooling manifolds are connected to the cooling manifold medium supply pipeline in a row; the cooling manifold medium supply pipeline is connected to the medium system; and each cooling manifold medium supply pipeline is respectively installed with an electrically controlled adjustable valve; The PLC control system controls the opening and closing and the size of the opening of each electronically controlled adjustable valve according to the different widths of the strip, selects different numbers of cooling manifold rows, and controls the flow of the medium in the cooling manifold; the first-level control model collects the temperature and speed signals of the strip and processes and feeds back, and the second-level control model obtains a temperature control scheme through feedforward control, feedback control, and self-learning control, controls the opening and closing and the size of the opening of each electronically controlled adjustable valve, selects different numbers of cooling manifold rows, and controls the flow of the medium in the cooling manifold.

2. The hot-rolled strip plane temperature cooling device according to claim 1, characterized in that: The cooling manifold frame is made of metal material.

3. The hot-rolled strip plane temperature cooling device according to claim 1, characterized in that: Each cooling header is made of a metal pipe.

4. The hot-rolled strip plane temperature cooling device according to claim 1, characterized in that: The medium in the cooling manifold supply medium pipeline is water.

5. The hot-rolled strip plane temperature cooling device according to claim 1, characterized in that: The manifold assembly is connected to the tilting oil cylinder, the tilting oil cylinder is connected to the oil cylinder support, and the end of the manifold assembly is connected to the support leg; the manifold assembly is connected to the main pipeline through the manifold assembly rotating adapter fixing beam, and the main pipeline is connected to the inlet butterfly valve pipeline.

6. A method for controlling the plane temperature of a hot-rolled strip applied to the hot-rolled strip plane temperature cooling device according to any one of claims 1 to 5, characterized in that: Taking the transverse temperature difference of the strip as the target, a two-level control model is used to control the plane temperature of the hot-rolled plate; The primary control model collects the temperature and speed of the strip, processes the collected signals and feeds them back to the secondary control model; The secondary control model sets the target temperature, the transverse water volume and the longitudinal water volume of the laminar flow device according to the process requirements of the transverse and longitudinal temperatures of the strip; based on the laminar end temperature, strip speed, target temperature, transverse water volume and longitudinal water volume, the temperature control scheme is obtained through feedforward control, feedback control and self-learning control; the temperature control scheme includes: the opening and closing status and opening size of the electronically controlled adjustable valve on the medium supply pipeline of each cooling manifold.

7. The method for controlling the plane temperature of a hot-rolled strip according to claim 6, characterized in that: The primary control model is also used to obtain the strip moving speed detected by the strip sensor and perform closed-loop control on the strip moving speed.

8. The method for controlling the plane temperature of a hot-rolled strip according to claim 6, wherein: The strip temperature is measured by a scanning pyrometer placed at the end of the laminar flow.

9. The method for controlling the plane temperature of a hot-rolled strip according to claim 6, wherein: Feedforward control includes detecting the final rolling temperature and rolling speed, and controlling the difference between the final rolling temperature and the target temperature; Feedback control includes performing control using the detected coiling temperature as a feedback amount of the target temperature.

10. The method for controlling the plane temperature of a hot-rolled strip according to claim 6, wherein: Self-learning control includes: Learning the control process of the previous hot-rolled plate and adjusting the control process of the next hot-rolled plate based on the control effect of the previous hot-rolled plate; and, Learn the control process of hot-rolled plates of the same layer and specification, and adjust the control process of hot-rolled plates based on the control effect of hot-rolled plates of the same layer and specification.

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