Multi-mode hot continuous rolling production line, production process and cross production control method

Abstract

The invention relates to a multi-mode hot continuous rolling production line, a production process and a cross production control method, and belongs to the technical field of steel hot rolling. The production line has a single plate blank rolling production mode and a semi-endless plate blank rolling production mode and is composed of a multi-strand continuous casting machine and a rolling line on the downstream of the continuous casting machine, and a temperature compensation device is arranged between an outlet of the continuous casting machine and a rolling line gas heating furnace, and the center line of the continuous casting machine and the rolling line gas heating furnace coincide. And at least one space for discharging the plate blank from the rolling line gas heating furnace to the rolling line is reserved between the tail end of the temperature compensation device and the downstream rough descaling machine. When the semi-headless mode is adopted for production, only the first coil is threaded, and the last coil is thrown, so that high-proportion production of 1.2 mm thin strip steel on the basis of traditional hot continuous rolling is facilitated, even the lower limit of 1.2 mm thickness is broken through, and stable coiling production of the hot continuous rolling thin strip steel is realized. And meanwhile, the situation that a semi-endless rolling gap is long and is supplemented by single block rolling is fully considered, the situation that a rolling mill waits for continuous casting is avoided, and the influence of introduction of a semi-endless mode on the productivity of a production line is reduced to the maximum extent.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot rolling of steel, and relates to a multi-mode hot continuous rolling production line, a production process and a cross-production control method. Background Art

[0002] In the technical field of hot rolling of steel, traditional hot continuous rolling mainly focuses on rolling a single slab with the weight of a single coil of steel. However, due to the inevitable threading and tailing during the rolling stage in the rolling of a single slab, the finished thickness cannot be stably controlled below 1.5 mm. To solve this problem, endless casting and rolling technology has been developed. The endless casting and rolling technology uses the technology of directly feeding the slab to the rolling line for rolling and quickly reheating the intermediate slab, eliminating the threading and tailing between coils, and only shearing and splitting the coil before coiling, and can directly roll hot-rolled thin strip steel with a thickness less than 1.2 mm, realizing hot instead of cold. At the same time, since the process of the whole coil of steel is consistent from beginning to end, the dimensional and property uniformity of the strip steel in the longitudinal direction is better than that of traditional hot continuous rolling.

[0003] However, the endless casting and rolling technology also has some limitations. First, limited by the continuous casting casting speed, the product variety range of endless casting and rolling is less than that of traditional hot continuous rolling. Second, due to the lack of long-term heating of the slab before rolling, the softening effects of secondary recrystallization and precipitation solid solution are not fully exerted, resulting in a high yield ratio and poor deep drawability of the continuous casting and rolling products, and the comprehensive quality of the products is inferior to that of traditional hot continuous rolling.

[0004] Therefore, if the advantages of traditional hot continuous rolling and the existing endless casting and rolling technology can be combined, so that both traditional single-piece production and a certain semi-endless production can be ensured on one line to achieve multi-mode hot continuous rolling, it will be very meaningful. This will be beneficial for steel enterprises to selectively adopt any production mode according to different customer order requirements, break through the lower limit of the product thickness of traditional hot continuous rolling, expand the variety range of existing endless rolling and improve the comprehensive quality of products. At the same time, the production line fully considers that the semi-endless rolling gap is relatively long and is supplemented by single-piece rolling, avoiding the situation of the rolling mill waiting for continuous casting, and minimizing the impact of introducing the semi-endless mode on the production capacity of the production line. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a multi-mode hot continuous rolling production line, a production process and a cross-production control method, which combine the advantages of traditional hot continuous rolling and the existing endless casting and rolling technology, and can ensure both traditional single-piece production and a certain semi-endless production on one line to achieve multi-mode hot continuous rolling.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A multi-mode hot continuous rolling production line, comprising:

[0008] A multi-strand continuous casting machine, wherein the center line of at least one strand of the continuous casting machine coincides with the center line of the rolling line;

[0009] A supplementary heating device arranged downstream of the continuous casting machine, the supplementary heating device is arranged along the center line of the rolling line and is used for continuously heating or heat preservation of long slab billets;

[0010] A gas heating furnace, arranged perpendicular to the center line of the rolling line, is connected to the continuous casting machine through a steel turning device and a conveying roller table, and is used for heating a single slab billet;

[0011] A movable billet transport trolley, configured on the center line of the rolling line or moved out of the rolling line, and is used for transporting the single slab billet output by the gas heating furnace to the downstream process in the single-piece production mode;

[0012] A rough descaling machine, arranged downstream of the supplementary heating device and the gas heating furnace;

[0013] A tandem rough rolling mill unit and a finishing rolling mill unit, arranged in sequence downstream of the rough descaling machine;

[0014] A post-rolling cooling device, a cutting device, a coiling switching device and a coiler, arranged downstream of the finishing rolling mill;

[0015] A heat preservation cover and / or an intermediate billet reheating device, arranged on the conveying roller table between the rough rolling mill unit and the finishing rolling mill unit;

[0016] Wherein, a space is reserved between the supplementary heating device and the rough descaling machine, allowing the single slab billet output by the gas heating furnace to enter the rolling line through the billet transport trolley.

[0017] Optionally, the supplementary heating device includes a tunnel furnace and / or an induction heating device.

[0018] Optionally, the tunnel furnace is arranged to move along a direction perpendicular to the rolling line, and the induction heating device is arranged to move into or out of the rolling line along the center line of the rolling line.

[0019] Optionally, the billet transport trolley is provided with a driving roller table, and the gap thereof matches the bearing beam of the billet discharging device of the gas heating furnace, and is used for seamlessly receiving a single slab billet.

[0020] Optionally, a steel turning device is arranged between the continuous casting machine and the gas heating furnace, and is used for adjusting the conveying direction of a single slab billet.

[0021] A multi-mode hot continuous rolling production process, based on the above production line, includes the following steps:

[0022] Single-piece production mode:

[0023] a) The cast billet output by the continuous casting machine is cut into single slab billets by a cutting machine;

[0024] b) The single slab billets are transported to the gas heating furnace for heating through a conveying system;

[0025] c) After the heated single slab is conveyed by the slab transfer car to the rough descaling machine, rough rolling mill, finish rolling mill, and post-rolling cooling device, it is finally coiled by the coiler.

[0026] Semi-endless production mode:

[0027] a) After the long slab output by the continuous caster is continuously temperature-compensated by the temperature compensation device, it directly enters the rough descaling machine.

[0028] b) The long slab is rolled into thin strip steel successively by the rough rolling mill, intermediate slab reheating device, and finish rolling mill.

[0029] c) After the thin strip steel is cut by the slitting device, it is alternately coiled on multiple coilers through the coiling switching device.

[0030] Cross production mode:

[0031] During the semi-endless rolling gap, the gas heating furnace outputs a single slab for rolling to avoid the rolling mill being idle.

[0032] Optionally, in the semi-endless production mode, the length of the long slab is at least twice that of the single slab, and the heating temperature of the temperature compensation device is dynamically adjusted by the model to match the continuous casting drawing speed and the rolling speed.

[0033] Optionally, in the single slab production mode, the temperature compensation device is moved out of the center line of the rolling line, and the slab transfer car occupies the position of the center line of the rolling line.

[0034] A hot strip mill cross production control method, based on the above production process, includes:

[0035] Real-time monitoring of the gap time of semi-endless rolling;

[0036] When the gap time exceeds the threshold, trigger the gas heating furnace to output a single slab;

[0037] Convey the single slab to the rolling line through the slab transfer car to complete the single slab rolling process;

[0038] After the single slab rolling is completed, resume the semi-endless production mode.

[0039] The beneficial effects of the present invention are as follows:

[0040] Multi-mode production: The production line can realize two modes of single slab rolling and semi-endless slab rolling, providing flexible production options for steel enterprises, and can select the appropriate production mode according to different customer order requirements.

[0041] Thin strip steel production: When adopting the semi-endless mode of production, it can effectively reduce threading and tailing, which is beneficial to the production of hot-rolled thin strip steel with a thickness less than 1.2 mm, breaking through the lower limit of the product thickness of traditional hot strip mills.

[0042] Improve product quality: Through the semi-endless continuous casting and rolling technology, the process of the entire coil of steel is consistent from beginning to end, improving the dimensional and performance uniformity of the strip steel longitudinally and enhancing the comprehensive quality of the product.

[0043] Improve production efficiency: The production line design takes into account the problem of the relatively long gap in semi-endless rolling. Through single-piece rolling supplementation, the situation of the rolling mill waiting for continuous casting is avoided, minimizing the impact of introducing the semi-endless mode on the production line capacity.

[0044] Reduce energy consumption: In the semi-endless production mode, the length of the long slab is at least twice the length of a single-piece slab, reducing the temperature drop during air cooling of the slab and thus reducing the heating energy consumption in the tunnel furnace.

[0045] Flexible production mode switching: During the gap period of semi-endless rolling, single-piece slabs can be used for rolling production, improving the flexibility and efficiency of the production line.

[0046] In summary, this solution realizes multi-mode hot continuous rolling, not only improving the product quality and production efficiency, but also reducing energy consumption, providing a more flexible and efficient production method for iron and steel enterprises.

[0047] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0048] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in preferred detail below in conjunction with the drawings, where:

[0049] Figure 1 It is a layout schematic diagram of the embodiment of the present invention during single-piece production;

[0050] Figure 2 It is a layout schematic diagram of the embodiment of the present invention during semi-endless production;

[0051] Figure 3 It is an elevation schematic diagram of the production line during semi-endless production.

[0052] Reference numerals:

[0053] Continuous casting exit section (1);

[0054] Billet cutting machine (11);

[0055] Continuous casting exit conveyor roller table (21);

[0056] Conveyor roller table (22);

[0057] Roller table in front of the furnace (23);

[0058] Roller table at the exit of the tunnel furnace (24);

[0059] Single slab (31);

[0060] Long slab (32);

[0061] Steel turning device (4);

[0062] Tunnel furnace (5);

[0063] Slab transporting trolley (6);

[0064] Rough descaling machine (7);

[0065] Gas heating furnace (8);

[0066] Slab feeding device into the furnace (91);

[0067] Slab discharging device from the furnace (92);

[0068] Induction heating device (10);

[0069] Rough rolling mill set (12);

[0070] Heat preservation cover (13);

[0071] Intermediate billet reheating device (101);

[0072] Finish rolling mill set (14);

[0073] Post-rolling cooling device (15);

[0074] Cutting device (16);

[0075] Coiling switching device (17);

[0076] Coiler (18);

[0077] Finish descaling (19);

[0078] Head shear (20);

[0079] Rolling center line (Ⅰ);

[0080] Tunnel furnace center line (Ⅱ);

[0081] Gas furnace center line (Ⅲ). Detailed implementation method

[0082] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0083] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, rather than physical diagrams, and should not be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0084] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0085] Please refer to Figures 1 to 3 , the rolling line I is parallel to the center line II of the tunnel furnace, and the axis III is perpendicular to the rolling line I.

[0086] This embodiment describes a production line that combines the traditional single slab production mode of hot continuous rolling and the semi-endless continuous rolling mode of long slabs.

[0087] The exemplary production line consists of a multi-strand continuous caster and a single rolling line. Usually, a 4-5 strand continuous caster is selected to match a single rolling line, and the center line of at least one strand of the continuous caster coincides with the rolling line I.

[0088] Starting from the continuous casting exit section 1, the equipment arranged downstream includes but is not limited to a slab cutting machine 11, a continuous casting exit conveying roller table 21, an induction heating device 10, a conveying roller table 22, a steel turning device 4, a roller table in front of the furnace 23, a slab feeding device into the furnace 91, a gas heating furnace 8, a slab feeding device out of the furnace 92, a billet transporting trolley 6, a tunnel furnace exit roller table 24, a tunnel furnace 5, and a rough descaling machine 7.

[0089] Downstream of the rough descaling machine 7, there are arranged the rough rolling mill 12, finish rolling mill 14, post-rolling cooling device 15 and coiler 18 contained in the conventional hot rolling. Meanwhile, after the finish rolling mill 14, there are also arranged a strip cutting device 16 and a coiling switching device 17 for the strip after the rolling of the semi-endless long slab 32.

[0090] Both the rough rolling mill 12 and the finish rolling mill 14 are in-line continuous rolling mills and do not perform forward and reverse rolling.

[0091] Before the finish rolling mill 14, there are arranged a crop shear 20 and a finish descaling device 19.

[0092] Considering the problem of large temperature difference between the head and tail of the finish rolling due to the long intermediate slab during semi-endless rolling, between the rough rolling mill 12 and the finish rolling mill 14, there is also equipped with a heat preservation cover 13 and / or an intermediate slab reheating device 101. Among them, the reheating device 101 performs temperature compensation on the intermediate slab after rough rolling according to the temperature detection result by region according to the control model, so as to reduce the temperature difference in the length direction of the intermediate slab and ensure the consistency of the finish rolling temperature of the intermediate slab.

[0093] The example production line can achieve multiple production modes.

[0094] 1) Single slab production

[0095] When performing the production of a single conventional hot rolling slab, the induction heating device 10 and the tunnel furnace 5 are placed outside the rolling line I, and the billet transfer car 6 is placed on the rolling line I. The single slab 31 is produced by the following steps:

[0096] a) After the slab comes out of the continuous casting exit section 1 and reaches the predetermined length, it is cut into a single slab 31 by the slab cutting machine 11;

[0097] b) The single slab 31 is transported to the entrance of the designated gas furnace 8 through the continuous casting exit conveying roller table 21, steel turning device 4, conveying roller table 22 and furnace front roller table 23;

[0098] c) The single slab 31 is charged into the gas furnace 8 through the furnace charging billet feeding device 91;

[0099] d) The slab is heated to the predetermined temperature in the gas furnace 8 according to the heating process requirements;

[0100] e) When the billet transfer car 6 is needed, the billet transfer car 6 locks in advance the position at the exit of the designated gas heating furnace 8. The heated single slab 31 is transported out through the furnace discharging billet feeding device 92 and placed on the billet transfer car 6, and then the billet transfer car 6 transports the single slab 31 to the downstream; when the billet transfer car 6 is not needed, the single slab 31 is transported to the downstream by the cooperation of the furnace discharging billet feeding device 92 and the tunnel furnace exit roller table 24.

[0101] f) The single slab 31 successively passes through the rough descaling machine 7 and the rough rolling mill unit 12, finishing mill unit 14, post-rolling cooling device 15, coiler 18, etc. downstream thereof, and finally winds off in a coil.

[0102] 2) Production of semi-endless long slab

[0103] When producing a semi-endless long slab, the tunnel furnace 5 is placed on rolling line I, the billet transfer car 6 is placed outside rolling line I, and the heat preservation cover 13 and / or the intermediate billet reheating device 101 on the conveying roller table between rough rolling and finishing should be in working condition. The semi-endless long slab 32 is produced by the following steps:

[0104] a) After the long slab 32 comes out of the continuous casting outlet 1, it enters the downstream tunnel furnace 5 to continue heating or heat preservation to the specified temperature; according to the continuous casting speed, slab size, heating capacity of the tunnel furnace, furnace inlet temperature, and the distance between the continuous casting outlet and the tunnel furnace, etc., comprehensively evaluate the temperature drop degree of the slab, and then decide whether to supplement the temperature through the induction heating device 10 between the continuous casting outlet 1 and the tunnel furnace 5. If necessary, the induction heating device 10 is placed in advance on rolling line I and starts to supplement the temperature. If not, it is bypassed or the induction heating device 10 is removed from the rolling line in advance;

[0105] b) After the long slab 32 comes out of the tunnel furnace 5, it successively passes through the tunnel furnace outlet roller table 24, rough descaling machine 7, and rough rolling mill unit 12, and is reduced in thickness to an intermediate billet by rough rolling;

[0106] c) The intermediate billet successively passes through the heat preservation cover 13 and / or the intermediate billet reheating device 21 (the reheating device is preferably induction heating), is cut by the crop shear 20, then the scale is removed by the finishing descaling device 19, and then enters the finishing mill unit 14 to be rolled into thin strip steel;

[0107] d) The thin strip steel is cooled to the target process temperature by post-rolling cooling 15;

[0108] e) The long thin strip steel formed after finishing rolling is coiled into a coil on the coiler 18. When the predetermined coil weight is reached, it is cut by the strip steel splitting device 16 downstream of the post-rolling cooling 15, and then the coiling is switched on different coilers 18 through the coiling switching device 17.

[0109] The process length of the long slab 32 along rolling line I can be comprehensively considered and calculated according to the slab thickness, continuous casting drawing speed, conveying temperature drop, tunnel furnace length, etc., but it should at least have a length of 3 times the single slab 31 and is cut by the slab cutting machine 11. After cutting, the downstream slab should be accelerated for conveying to reduce the air cooling temperature drop of the slab, and thus reduce the heating energy consumption in the tunnel furnace.

[0110] 3) Cross production

[0111] When semi-endless production is carried out, since the rolling speed is much higher than the continuous casting speed, as shown in Table 1, the semi-endless rolling gap time is relatively long. To avoid the rolling mill waiting and affecting production capacity, a cross-production mode is adopted. That is, during the semi-endless rolling gap period, a single slab 31 is taken out from the gas heating furnace 8 that can discharge molten steel without interfering with the tunnel furnace 5 for rolling production, as shown in Table 2.

[0112] Table 1 Production rhythm table of billets and strip steel

[0113] Item Unit Continuous casting billet Finished rolling strip steel Thickness mm 180 1.2 Speed m / min 1.5 900 Length m 30 4500 Production time min 20 5

[0114] Table 2 Cross-production rhythm table

[0115]

[0116]

[0117] The multi-mode hot strip mill production line described above retains the production mode of traditional hot strip mills and also has the conditions for semi-endless production. When producing in the semi-endless mode, it can effectively reduce the threading and tail throwing during single-roll rolling. Only the first roll needs threading and the last roll needs tail throwing, which is beneficial to high-proportion production of 1.2-mm thin strip steel on traditional hot strip mills, and even to break through the lower thickness limit of 1.2 mm, realizing the stable coiling production of hot strip mill thin strip steel.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A multi-mode hot rolling production line, characterized in that: include: A multi-strand continuous casting machine (1), wherein the center line of at least one of the continuous casting strands coincides with the center line of the rolling strand (I); A temperature compensation device (5, 10) is arranged downstream of the continuous casting machine (1), the temperature compensation device is arranged along the center line (I) of the rolling line, and is used to continuously heat or keep the long slab (32); A gas-fired heating furnace (8) is arranged perpendicular to the center line (I) of the rolling line, connected to the continuous casting machine (1) through a steel transfer device (4) and conveyor rollers (21, 22, 23), and used for heating a single slab (31); A movable billet transport trolley (6) is arranged at the center line (I) of the rolling line or moved out of the rolling line, and is used to transport a single slab (31) output from the gas heating furnace (8) to a downstream process in a single-piece production mode; A rough descaling machine (7) is arranged downstream of the temperature compensation device (5, 10) and the gas heating furnace (8); A series roughing mill group (12) and a finishing mill group (14) are sequentially arranged downstream of the rough descaling machine (7); A post-rolling cooling device (15), a slitting device (16), a coiling switching device (17) and a coiler (18) are arranged downstream of the finishing mill group (14); A heat preservation cover (13) and / or an intermediate billet heating device (101) are arranged on a conveying roller table between a rough rolling mill group (12) and a finishing rolling mill group (14); A space is reserved between the temperature compensation device (5, 10) and the rough descaling machine (7), allowing a single slab (31) output from the gas heating furnace (8) to enter the rolling line via the slab transport trolley (6).

2. The multi-mode hot rolling production line according to claim 1, characterized in that: The temperature compensation device comprises a tunnel furnace (5) and / or an electric induction heating device (10).

3. The multi-mode hot rolling production line according to claim 2, characterized in that: The tunnel furnace (5) is arranged to move in a direction perpendicular to the rolling line, and the electric induction heating device (10) is arranged to move in or out along the center line (I) of the rolling line.

4. The multi-mode hot rolling production line according to claim 1, characterized in that: The billet transport trolley (6) is provided with a driving roller, the gap between which matches the bearing beam of the billet discharge device (92) of the gas heating furnace (8), and is used to seamlessly receive a single slab (31).

5. The multi-mode hot rolling production line according to claim 1, characterized in that: A steel transfer device (4) is provided between the continuous casting machine (1) and the gas-fired heating furnace (8) for adjusting the conveying direction of a single slab (31).

6. A multi-mode hot rolling production process, based on the production line described in any one of claims 1 to 5, characterized in that: The following steps are involved: Single block production mode: a) the cast billet outputted from the continuous casting machine (1) is cut into individual slabs (31) by a cutting machine (11); b) transporting a single slab (31) to a gas-fired heating furnace (8) for heating via a conveying system (21, 22, 23, 4); c) the heated single slab (31) is transported by a slab transporting trolley (6) to a rough descaling machine (7), a rough rolling mill group (12), a finishing rolling mill group (14), and a post-rolling cooling device (15), and finally coiled by a coiler (18); Semi-headless production mode: a) the long slab (32) outputted from the continuous casting machine (1) is continuously heated by the heating devices (5, 10) and then directly enters the rough descaling machine (7); b) the long slab (32) is rolled into thin strip steel in sequence through a rough rolling mill (12), an intermediate slab heating device (101), and a finishing rolling mill (14); c) after the thin steel strip is cut by the slitting device (16), it is alternately coiled on a plurality of coilers (18) through a coiling switching device (17); Cross-production mode: In the semi-headless rolling gap, the gas-fired heating furnace (8) outputs a single slab (31) for rolling, thereby avoiding the rolling mill to be idle.

7. The production process according to claim 6, characterized in that: In the semi-headless production mode, the length of the long slab (32) is at least twice that of a single slab (31), and the heating temperature of the temperature compensation device (5, 10) is dynamically adjusted through the model to match the continuous casting speed and the rolling speed.

8. The production process according to claim 6, characterized in that: In the single-block production mode, the temperature compensation devices (5, 10) are moved out of the rolling line center line (I), and the billet transport trolley (6) occupies the position of the rolling line center line (I).

9. A hot rolling cross production control method, based on the production process described in any one of claims 6 to 8, characterized in that: include: Real-time monitoring of the gap time of semi-endless rolling; When the gap time exceeds a threshold value, the gas heating furnace (8) is triggered to output a single slab (31); The single slab (31) is transported to the rolling line by a slab transporting trolley (6) to complete the single slab rolling process; After the single block rolling is completed, the semi-headless production mode is restored.

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