Automatic straight rolling system for multi-flow square billet

Abstract

The present application relates to a kind of line bar multi-flow square billet automatic straight rolling system, belong to metallurgical industry metal continuous casting and rolling technical field.The technical scheme is: containing the cut-off roller way (3) after being set in the hydraulic shear of multi-flow continuous casting machine or fire cutting machine (1) sequentially, billet outlet roller way (6) and straight rolling roller way (9), cut-off roller way (3) and billet outlet roller way (6) are equipped with lifting baffle A (4), and lifting baffle B (8) is equipped between billet outlet roller way (6) and straight rolling roller way (9), cut-off roller way (3) is equipped with casting blank waiting position A (5), billet outlet roller way (6) is equipped with casting blank waiting position B (7), and hot check switch (10) is equipped on straight rolling roller way (9);The cut-off roller way (3) and billet outlet roller way (6) are arranged in same span.The beneficial effects of the present application are: it is beneficial to prolong the waiting time of casting blank, also beneficial to reduce casting blank process temperature drop, simple operation, and the straight rolling rate is maximized.

Description

Technical Field

[0001] This invention relates to an automatic direct rolling system for multi-flow square billets of wire rods, belonging to the field of metal continuous casting and rolling technology in the metallurgical industry. Background Technology

[0002] The direct rolling technology without heating is the production mode that requires the highest billet temperature, has the lowest heat loss, the most significant energy saving, and the most compact process among all hot billet charging technologies. Since the direct rolling technology without heating eliminates the traditional heating furnace, its advantages in saving energy, reducing emissions, and lowering overall costs are even more prominent.

[0003] Currently, in the existing production process of direct rolling of high-temperature square billets without heating, due to unreasonable process layout and non-standard billet feeding rules, there are problems such as long distances between continuous casting plants, difficulty in controlling stepped billet exit, large deviations in billet feeding temperature measurement caused by iron oxide scale on the billet surface, inability to guarantee the accuracy of hot-delivered billet temperature, low direct rolling rate of multi-flow billets, and large waiting time for billet temperature drop. Therefore, reasonable process layout and billet feeding rules are the key to improving the direct rolling rate. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic direct rolling system for multi-flow square billets of wire rods, which is beneficial for extending the waiting time of the billet casting process, reducing the temperature drop during the casting process, and is simple to operate, thereby maximizing the direct rolling rate and solving the problems existing in the background technology.

[0005] The technical solution of this invention is: An automatic direct rolling system for multi-strand square billets of wire rod includes a cutting roller table, an exit roller table, and a direct rolling roller table sequentially arranged after the hydraulic shear or fire cutter of the multi-strand continuous casting machine. The cutting roller table and the exit roller table are equipped with lifting baffles A, and the exit roller table and the direct rolling roller table are equipped with lifting baffles B. The cutting roller table is equipped with a billet waiting position A, the exit roller table is equipped with a billet waiting position B, and the direct rolling roller table is equipped with a heat detection switch.

[0006] The cutting roller conveyor and the billet exit roller conveyor are arranged in the same span.

[0007] The billet waiting position A on the cut roller conveyor is equipped with a heat insulation cover.

[0008] The above-mentioned multi-strand square billet automatic direct rolling system for wire rods determines the corresponding minimum continuous casting speed V during rolling using the following method. rmin The waiting time T1 for the billet at waiting position A and the waiting time T2 for the billet at waiting position B: a. Determine the minimum continuous casting speed V corresponding to the actual torque percentage during rolling. rmin ; C x >D; Among them, Cx C represents the percentage of mill torque at different drawing speeds. x In this context, x represents the mill number, and D is the discrimination threshold, where D ≥ 80; when the pulling speed is greater than V... rmin The percentage of torque for each rolling mill corresponding to the hot billet is less than or equal to D, and the drawing speed is equal to V. rmin When the percentage of torque corresponding to each rolling mill for the hot billet is greater than D, this casting speed can be determined as the minimum casting speed V that the rolling mill can roll in continuous casting. rmin ; b. Determine the waiting time T1 for waiting bit A; ; Where V is the continuous casting speed (m / min); L is the billet length (m); L1 is the distance from the starting point of the hot billet to the front end of waiting position A (m); t1 is the cutting time from the start of cutting to the end of cutting (s); t2 is the conveying time of the billet to waiting position A after cutting (s); a is the safety time coefficient to avoid collision between billets in the same flow on the conveyor rollers; and T1 is an inverse proportional function of the casting speed. c. Determine the waiting time T2 for waiting bit B; ; Where T1 is the waiting time for bit A; T r The time taken to roll a continuous casting billet on the first rolling mill, in seconds; N is the actual number of castings.

[0009] In the aforementioned multi-strand square billet automatic direct rolling system for wire rods, the upstream billet conveying required by the mill is automatically controlled by the billet feeding program. The specific method is as follows: a. The program sets the waiting times T1 and T2 for the billet at waiting positions A and B, respectively. When the actual waiting time of the billet at waiting position A is greater than T1, the billet is automatically transported to waiting position B to continue waiting. When the billet is judged to be a qualified hot billet and the actual waiting time at waiting position B is less than or equal to T2, the system judges it as a direct hot billet. When the billet is an unqualified hot billet or the billet is a qualified hot billet but the actual waiting time at waiting position B is greater than T2, the system judges it as a non-direct hot billet, and the non-direct hot billet goes off the production line via the billet exit roller conveyor. b. When the hot inspection switch detects no hot billet, the rolling mill area requests steel from the continuous casting area; c. When the continuous casting machine receives the "steel needed" signal, it feeds the hot billet directly to the rolling mill; the specific control is as follows: If there is a hot billet directly delivered to waiting position B, it will be conveyed to the rolling mill in the order in which the billets arrive at waiting position B; if there is no hot billet directly delivered to waiting position B, qualified hot billets will be directly conveyed to the rolling mill from waiting position A, and conveyed to the rolling mill in the order in which the billets arrive at waiting position A. d. The lifting baffle B counts one straight-rolled billet for each completed cycle, realizing the automatic counting function of straight-rolled billets.

[0010] The qualified billet discrimination model for the above-mentioned multi-strand square billet automatic direct rolling system for wire rods is as follows: ; in, Let A be the integral of the speed within the fixed length range, A be the discrimination threshold of the qualified hot billet discrimination model, R equals Y for qualified hot billets that can be directly rolled, R equals N for qualified hot billets that cannot be directly rolled, and F be the billet rejection threshold.

[0011] The beneficial effects of this invention are as follows: By adopting a compact continuous casting planar layout with dual waiting positions, it is beneficial to both extend the waiting time of the billet and reduce the temperature drop during the billet casting process, thus solving the problem of difficulty in controlling the billet exit rhythm in multi-flow billet casting. The automatic billet feeding control program with casting speed as the core solves the problem of high hot billet run-off rate caused by the presence of iron oxide scale on the billet surface affecting the low measured temperature of the billet surface, or even not meeting the direct feeding temperature requirements. It is more suitable for the production practice of direct rolling of high-temperature square billets without heating, with simple operation, maximizing the direct rolling rate, and truly realizing "one-click direct rolling", which has broad application prospects. Attached Figure Description

[0012] Figure 1 This is a planar schematic diagram of the present invention; In the diagram: 1-Hydraulic shear / fire cutting machine, 2-High-speed casting billet, 3-Post-cutting roller conveyor, 4-Lifting baffle A, 5-Waiting position A, 6-Bill exit roller conveyor, 7-Waiting position B, 8-Lifting baffle B, 9-Straight rolling roller conveyor, 10-Heat detection switch. Detailed Implementation

[0013] The invention will be further described below with reference to the accompanying drawings and examples.

[0014] See attached document Figure 1 An automatic direct rolling system for multi-strand square billets of wire rod includes a cutting roller table 3, an exit roller table 6, and a direct rolling roller table 9, which are sequentially arranged behind the hydraulic shear or fire cutter 1 of the multi-strand continuous casting machine. The cutting roller table 3 and the exit roller table 6 are provided with lifting baffles A4, and the exit roller table 6 and the direct rolling roller table 9 are provided with lifting baffles B8. The cutting roller table 3 is provided with a billet waiting position A5, the exit roller table 6 is provided with a billet waiting position B7, and the direct rolling roller table 9 is provided with a heat detection switch 10.

[0015] The cutting roller conveyor 3 and the billet discharge roller conveyor 6 are arranged in the same span, with a compact layout and minimal space constraints. This span includes two lifting baffles, lifting baffles A5 and B7, used to block and release continuously cast billets. These two lifting baffles are spaced a certain distance apart, and a waiting position is set in front of each of them: waiting positions A5 and B7 are used to hold hot billets. When the billets at waiting positions A / B are being conveyed, lifting baffles A / B are in the lowered position; after conveying, lifting baffles A / B return to the raised position. Waiting position A5 is located on the cutting roller conveyor 3, and waiting position B7 is located on the billet discharge roller conveyor 6. A hot detection switch 10 is installed on one side of the straight rolling roller conveyor 9 to detect hot billets horizontally and control the billet feeding rhythm.

[0016] A heat insulation cover is installed above waiting position A5 to reduce the temperature drop of the billet during the waiting period; the billet exit roller conveyor 6 has no heat insulation cover, serving to transport direct-rolled billets on one hand and to remove unqualified direct-rolled billets from the line on the other. Optional post-cutting roller conveyors may have some rollers without heat insulation covers to handle situations where billets cannot be cut. The aforementioned automated direct rolling system for multi-strand square billets determines the minimum continuous casting speed V that the mill can roll. rmin The waiting time T1 for the billet at waiting position A and the waiting time T2 for the billet at waiting position B are determined as follows: (1) Determine the minimum continuous casting speed V that the rolling mill can roll based on the actual percentage of the rolling torque. rmin ; C x >D; Among them, C x C represents the percentage of mill torque at different drawing speeds. x In this context, x represents the mill number, and D is the discrimination threshold, typically chosen to be D ≥ 80. When the pulling speed is greater than V... rmin The percentage of torque for each rolling mill corresponding to the hot billet is less than or equal to D, and the drawing speed is equal to V. rmin When the percentage of torque corresponding to each rolling mill for the hot billet is greater than D, this casting speed can be determined as the minimum casting speed V that the rolling mill can roll in continuous casting. rmin .

[0017] (2) Determine the waiting time T1 for waiting bit A; ; Where V is the continuous casting billet pulling speed (unit: m / min), L is the billet length (unit: m), L1 is the distance from the starting point of the hot billet to the front end of the waiting position A (unit: m), t1 is the cutting time from the start of cutting to the end of cutting (unit: s), t2 is the conveying time of the billet to the waiting position A after cutting (unit: s), and a is a safety time coefficient to avoid collision between billets in the same flow on the conveyor rollers. Generally, a > 0 is selected, but the value of a can also be appropriately increased when setting to consider the manual handling time for billets that cannot be cut during shearing. Especially when the production billet length is fixed and the continuous casting machine layout is determined, T1 is an inverse proportional function of the pulling speed.

[0018] (3) Determine the waiting time T2 for waiting bit B; ; Where T1 is the waiting time for waiting bit A as described above, T r The time (in seconds) for rolling a continuous casting billet on the first rolling mill, where N is the actual number of castings.

[0019] In direct rolling, the upstream billet conveying required by the rolling mill is automatically controlled by the billet feeding program, as follows: (1) Set the waiting time T1 and T2 for the billet at waiting position A and waiting position B in the program; when the actual waiting time of the billet at waiting position A is greater than T1, the billet is automatically transported to waiting position B to continue waiting; when the billet is judged to be a qualified hot billet and the actual waiting time at waiting position B is less than or equal to T2, the system judges it as a direct hot billet; when the billet is an unqualified hot billet or the billet is a qualified hot billet but the actual waiting time at waiting position B is greater than T2, the system judges it as a non-direct hot billet, and then it goes off the line via the billet exit roller table.

[0020] (2) Generally, the lifting baffle A / lifting baffle B is normally in the raised position to block the passage of the casting billet. (3) When the hot inspection switch detects no hot billet, the rolling mill area requests steel from the continuous casting area.

[0021] (4) When the continuous casting receives the "request steel" signal, it delivers a direct hot billet to the rolling mill. Specifically: if there is a direct hot billet at waiting position B, the billet that arrives at waiting position B first is delivered to the rolling mill according to the order in which the billets arrive at waiting position B; if there is no direct hot billet at waiting position B, a qualified hot billet is delivered directly to the rolling mill from waiting position A, and the qualified hot billet that arrives at waiting position A first is delivered to the rolling mill according to the order in which the billets arrive at waiting position A.

[0022] (5) The lifting baffle B counts one straight rolling billet for each cycle of operation, realizing the automatic counting function of straight rolling billets.

[0023] The qualified hot billet discrimination model is: ; in, Let A be the integral of the speed within the fixed length range, A be the discrimination threshold of the qualified hot billet discrimination model, R equals Y for qualified hot billets that can be directly rolled, R equals N for qualified hot billets that cannot be directly rolled, and F be the billet rejection threshold.

[0024] In this embodiment, refer to the appendix Figure 1 The specific requirements are as follows: (1) A 6-strand continuous casting machine corresponds to a bar straight rolling line, casting steel grade HRB400E, billet size 165mm×165mm, fixed length L=12m, continuous casting machine 6 strands not in operation to match converter rhythm, actual casting number N=5, 1 / 2 / 3 / 4 / 5 strands in normal operation, and all using the same inner diameter slider, casting speed V=3.6m / min, distance from hot billet starting point to waiting position A front end L1=19m, cutting time from starting point to cutting end t1=8s, after cutting, billet conveying time to waiting position A t2=15s, safety time coefficient a=10, the length of the billet exit roller table without heat insulation cover is 3m, the time T taken for the first stand to roll a continuous casting square billet r =40s.

[0025] (2) Based on the actual torque percentage of the rolling mill, in the example, D=90. When the hot billet drawing speed is greater than 3.5m / min, the torque percentage of each rolling mill is less than 90. When V=3.5m / min, the torque percentage of each rolling mill is less than 90 except for the fourth rolling mill which has a torque percentage of 92. Therefore, the minimum rollable drawing speed V is set. rmin =3.5m / min.

[0026] (3) According to the aforementioned method, calculate T1=[60×19-60×12-3.6×(8+15)] / 3.6-10=83, T2=40×(5-1)-83=77, and set it on the billet feeding program.

[0027] (4) Determine whether each hot billet is a qualified hot billet according to the discrimination model, and determine whether it is a direct hot billet according to the actual waiting time of the qualified hot billet at waiting position B.

[0028] (5) When the hot inspection switch does not detect a hot billet, the rolling mill sends a "request steel" signal to the continuous casting. After receiving the "request steel" signal, if there is a hot billet directly delivered to waiting position B, the billet that arrives at waiting position B first is transported towards the rolling mill according to the order in which the billets arrive at waiting position B. During the transport, the lifting baffle B is in the lowered position, and after the transport is completed, the lifting baffle B returns to the raised position. If there is no hot billet directly delivered to waiting position B, a qualified hot billet is directly transported to the rolling mill from waiting position A. According to the order in which the billets arrive at waiting position A, the qualified hot billet that arrives at waiting position A first is transported to the rolling mill. During the transport, the lifting baffles A / B are in the lowered position, and after the transport is completed, the lifting baffles A / B return to the raised position.

[0029] In the embodiments: 1. After the 1-flow billet is cut, it waits for 5 seconds at waiting position A before being directly fed to the rolling mill; 2. After the 2-flow billet is cut, it waits for 70 seconds at waiting position A before being automatically conveyed to waiting position B and waits for 10 seconds at waiting position B before being fed to the rolling mill; 3. After the 3-flow billet is cut, it waits for 30 seconds at waiting position A before being directly fed to the rolling mill; 4. After the 4-flow billet is cut, it waits for 50 seconds at waiting position A before being fed to the rolling mill; 5. After the 5-flow billet is cut, it waits for 60 seconds at waiting position A before being fed to the rolling mill.

[0030] Compared with existing direct rolling technologies, this method, by adopting a compact continuous casting planar layout with dual waiting positions, not only extends the waiting time of the billet but also reduces the temperature drop during the billet casting process, thus doubly solving the problem of the difficulty in controlling the billet exit rhythm of multi-flow billets. The innovative use of an automatic billet feeding control program centered on casting speed solves the problem of high hot billet run-off rates caused by the presence of iron oxide scale on the billet surface, resulting in low measured surface temperatures that do not even meet the direct feeding temperature requirements. This method is more suitable for production practices of direct rolling of high-temperature square billets without heating, is simple to operate, maximizes the direct rolling rate, truly achieves "one-click direct rolling," and has broad prospects for widespread application.

Claims

1. An automated direct rolling system for multi-strand square billets of wire rod, characterized in that: It includes a cutting roller table (3), a billet discharge roller table (6) and a straight rolling roller table (9) arranged sequentially behind the hydraulic shear or fire cutter (1) of the multi-flow continuous casting machine. The cutting roller table (3) and the billet discharge roller table (6) are provided with lifting baffles A (4), and the billet discharge roller table (6) and the straight rolling roller table (9) are provided with lifting baffles B (8). The cutting roller table (3) is provided with a billet waiting position A (5), the billet discharge roller table (6) is provided with a billet waiting position B (7), and the straight rolling roller table (9) is provided with a heat detection switch (10). The minimum continuous casting speed V corresponding to the rolling mill should be determined using the following method. rmin The waiting time T1 for the billet at billet waiting position A (5) and the waiting time T2 for the billet at billet waiting position B (7) are: a. Determine the minimum continuous casting speed V corresponding to the actual torque percentage during rolling. rmin ; C x >D; Among them, C x C represents the percentage of mill torque at different drawing speeds. x In this context, x represents the mill number, and D is the discrimination threshold, where D ≥ 80; when the pulling speed is greater than V... rmin The percentage of torque for each rolling mill corresponding to the hot billet is less than or equal to D, and the drawing speed is equal to V. rmin When the percentage of torque corresponding to each rolling mill for the hot billet is greater than D, this casting speed can be determined as the minimum casting speed V that the rolling mill can roll in continuous casting. rmin ; b. Determine the waiting time T1 for the billet waiting position A (5); ； Where V is the continuous casting speed (m / min); L is the billet length (m); L1 is the distance from the starting point of the hot billet cutting to the front end of the billet waiting position A (m); t1 is the cutting time from the start of cutting to the end of cutting (s); t2 is the conveying time of the billet to the billet waiting position A after cutting (s); a is the safety time coefficient to avoid collision between billets in the same flow on the conveyor rollers; and T1 is an inverse proportional function of the continuous casting speed. c. Determine the waiting time T2 for billet waiting position B; ； Where T1 is the waiting time for the billet waiting position A (5); T r The time taken to roll a continuous casting billet on the first rolling mill, in seconds; N is the actual number of castings.

2. The automatic direct rolling system for multi-strand square billets of wire rod according to claim 1, characterized in that: The cutting roller conveyor (3) and the billet discharge roller conveyor (6) are arranged in the same span.

3. The automatic direct rolling system for multi-strand square billets of wire rod according to claim 1, characterized in that: The billet waiting position A (5) on the cut roller conveyor (3) is equipped with a heat insulation cover.

4. The automatic direct rolling system for multi-strand square billets of wire rod according to claim 3, characterized in that: During rolling, the upstream billet feeding process required by the rolling mill is automatically controlled by the billet feeding program. The specific method is as follows: a. The program sets the waiting time T1 and T2 for the billet at billet waiting position A (5) and billet waiting position B (7). When the actual waiting time of the billet at billet waiting position A (5) is greater than T1, the billet is automatically transported to billet waiting position B (7) to continue waiting. When the billet is judged to be a qualified hot billet and the actual waiting time at billet waiting position B (7) is less than or equal to T2, the system judges it as a direct hot billet. When the billet is an unqualified hot billet or the billet is a qualified hot billet but the actual waiting time at billet waiting position B (7) is greater than T2, the system judges it as a non-direct hot billet. The non-direct hot billet goes off the line via the billet exit roller conveyor (6). b. When the hot inspection switch (10) detects no hot billet, the rolling mill area requests steel from the continuous casting area; c. When the continuous casting machine receives the "steel needed" signal, it feeds the hot billet directly to the rolling mill; the specific control is as follows: If there is a hot billet directly delivered to billet waiting position B (7), it will be conveyed to the rolling mill according to the order in which the billets arrive at billet waiting position B (7); if there is no hot billet directly delivered to billet waiting position B (7), qualified hot billets will be directly conveyed to the rolling mill from billet waiting position A (5), and conveyed to the rolling mill according to the order in which the billets arrive at billet waiting position A (5). d. Lifting baffle B (8) counts one straight rolling billet for each completed cycle action, realizing the automatic counting function of straight rolling billets.

5. The automatic direct rolling system for multi-strand square billets of wire rod according to claim 4, characterized in that: The qualified billet discrimination model is: ; in, Let A be the integral of the speed within the fixed length range, A be the discrimination threshold of the qualified hot billet discrimination model, R equals Y for qualified hot billets that can be directly rolled, R equals N for qualified hot billets that cannot be directly rolled, and F be the billet rejection threshold.

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