CN221063916U - Flexible production line for endless rolled strip steel - Google Patents

Abstract

The utility model discloses a flexible production line of endless rolled strip steel. The device comprises a pre-rolling unit, a tunnel furnace, a rough rolling unit, an induction heating device, a finishing mill unit, a laminar flow cooling device and a coiling unit which are sequentially arranged; the tunnel furnace is used for carrying out uniform temperature treatment on the intermediate billet I from the pre-rolling mill group; the induction heating device is used for performing induction heating temperature adjustment on the intermediate billet II from the roughing mill; the pre-rolling mill group is used for pre-rolling or emptying continuous casting billets and comprises at least 1 pre-rolling mill; the roughing mill unit comprises at least 3 roughing mills; the finishing mill group comprises 3-5 finishing mills. The production line has compact structure and reasonable arrangement, is more beneficial to the application of large-scale steel flux by additionally arranging the pre-rolling unit to pre-rolling or blank passing of the continuous casting blank, and is beneficial to controlling the temperature and blank tissues and obtaining different finished strip steel by adopting a tunnel furnace and an induction heating device as heating procedures between the pre-rolling unit and the rough rolling unit and between the rough rolling unit and the finish rolling unit.

Description

Flexible production line for endless rolled strip steel

Technical Field

The utility model relates to the technical field of steel continuous casting and rolling, in particular to a flexible production line of endless rolled strip steel.

Background

Compared with the conventional hot rolled strip steel, the headless continuous casting and rolling process flow is compact, the energy consumption is low, and the metal yield and the production rhythm are obviously improved; the continuous casting has high drawing speed and high production efficiency. The endless rolling omits the strip steel threading and tail flicking processes during single rolling, the precision and stability of the strip steel size and performance are obviously improved, the thickness specification of the strip steel which can be stably produced is as low as 0.8mm, the realization of replacing cold with heat is realized, and the production cost of the strip steel is reduced. The continuous casting and rolling technology is used as a revolutionary hot rolled strip steel production technology, has many advantages which are not possessed by conventional hot continuous rolling, and has certain requirements on steel passing quantity in order to realize endless rolling.

At present, the rolling speed and the casting blank drawing speed are limited, the endless rolling is basically impossible to realize on one line, the flexibility and the adaptability are greatly limited, different steel passing amounts often relate to a plurality of production lines, the investment is increased, and the market adaptability and the production cost are influenced.

Disclosure of utility model

According to one embodiment of the utility model, the utility model aims to provide a flexible production line of endless rolled strip steel, which is compact in structure and reasonable in arrangement, so that the flexibility and adaptability of the production line are improved.

The above object can be achieved by the following embodiments of the present invention:

According to one aspect of the utility model, there is provided a flexible line for endless rolled strip comprising: the device comprises a pre-rolling unit, a tunnel furnace, a rough rolling unit, an induction heating device, a finishing mill unit, a laminar flow cooling device and a coiling unit which are sequentially arranged; the tunnel furnace is used for carrying out uniform temperature treatment on the intermediate billet I from the pre-rolling mill group; the induction heating device is used for performing induction heating temperature adjustment on the intermediate billet II from the roughing mill; the pre-rolling mill group is used for pre-rolling or emptying continuous casting billets and comprises at least 1 pre-rolling mill arranged along the rolling direction; the roughing mill unit comprises at least 3 roughing mills arranged along the rolling direction; the finishing mill group comprises 3 to 5 finishing mills arranged along the rolling direction.

Optionally, the pre-rolling mill is a two-high mill; the roughing mill is a four-high mill, and the finishing mill is a four-high mill.

Optionally, the pre-rolling mill set comprises 1 two-roll mill arranged along the rolling direction; the roughing mill unit comprises 3 four-high mills which are sequentially arranged along the rolling direction; the finishing mill group comprises 5 four rolling mills which are sequentially arranged along the rolling direction.

Optionally, the coiling unit comprises 3 coiling machines which are sequentially arranged along the rolling direction.

Optionally, the distance between the rough rolling unit and the finishing rolling unit is 15-50 m.

Optionally, the distance between the center line of the rolling frame of the pre-rolling mill set and the tunnel furnace mouth is 6-10 m; the distance between the outlet of the tunnel furnace and the central line of the first rolling stand of the roughing mill set is 6-10 m; the center line distance between the last finishing mill frame of the finishing mill group along the rolling direction and the first coiling machine of the coiling machine group along the rolling direction is 50-120 m.

Optionally, the production line is arranged behind the continuous casting machine, and the interval between the outlet of the continuous casting machine and the center line of the rolling frame of the pre-rolling mill set is 5-8 m.

Optionally, the interval between adjacent roughing stands of the roughing mill group is 4-5 m; the distance between the center lines of adjacent finishing mill frames of the finishing mill group is 4-5 m.

Optionally, the production line further comprises: the first high-pressure water descaling device, the second high-pressure water descaling device and the third high-pressure water descaling device are respectively arranged in front of the pre-rolling mill set, in front of the rough rolling mill set and in front of the finishing mill set.

Optionally, a pendulum shear is arranged after the pre-mill train and before the tunnel furnace; a rotary drum flying shear is arranged behind the roughing mill and in front of the induction heating device; a high-speed flying shear is arranged behind the laminar cooling device and before the crimping machine set; an ultra-fast cooling device is arranged after the finishing mill group and before the laminar cooling device.

The beneficial effects are that: according to one embodiment of the utility model, the flexible production line of the endless rolled strip steel is compact in structure and reasonable in arrangement, the production line adopts three units, a pre-rolling unit is arranged in front of a rough rolling unit, the pre-rolling unit is used for pre-rolling or emptying continuous casting blanks, the application of large-scale steel passing quantity is facilitated, and the tunnel furnace and the induction heating device are used as heating procedures between the pre-rolling unit and the rough rolling unit and between the rough rolling unit and the finish rolling unit, so that the temperature and the blank structure of the whole process can be effectively controlled, and different finished strip steel products can be obtained. The production line has the advantages of wider applicable steel flux range, wider application range for steel types, thickness and width, improved flexibility and adaptability of the production line, low cost, high productivity, high product quality and the like.

Drawings

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be described in the following preferred detail with reference to the accompanying drawings, in which:

Fig. 1 is a schematic layout view of a flexible production line of endless rolled steel strip for continuous casting of steel strip in an embodiment of the present utility model.

Reference numerals: the continuous casting machine comprises a continuous casting machine 1, a high-pressure water descaling device 2, a pre-rolling mill group 3, a pendulum shear 4, a tunnel furnace 5, a waste billet pushing and stacking device 6, a high-pressure water descaling device 7, a roughing mill group 8, a rotary drum flying shear 9, an induction heating device 10, a high-pressure water fine descaling device 11, a finishing mill group 12, an ultra-fast cooling device 13, a laminar cooling device 14, a high-speed flying shear 15, a coiling unit 16, a continuous casting billet 201, an intermediate billet I202, an intermediate billet II 203 and strip steel 204.

Detailed Description

The technical solutions of the present utility model will be clearly and completely described in conjunction with the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The flexible production line for the endless rolled strip steel for strip steel continuous casting provided by the embodiment of the utility model comprises a pre-rolling unit, a tunnel furnace, a rough rolling unit, an induction heating device, a finishing mill unit, a laminar cooling device and a coiling unit which are sequentially arranged. The tunnel furnace is used for carrying out uniform temperature treatment on the intermediate billet I from the pre-rolling mill group; the induction heating device is used for performing induction heating temperature adjustment on the intermediate billet II coming out of the roughing mill. The pre-rolling mill group is used for pre-rolling or emptying continuous casting billets and comprises at least 1 pre-rolling mill arranged along the rolling direction; the roughing mill unit comprises at least 3 roughing mills arranged along the rolling direction; the finishing mill group comprises 3 to 5 finishing mills arranged along the rolling direction. Furthermore, the coiler group comprises at least 2 coiler machines arranged in succession in the rolling direction.

The utility model provides a technological path of pre-rolling, rough rolling and finish rolling three-stage rolling, and adds a pre-rolling unit, so that the production of continuous casting billets with two or more than two billet thicknesses can be realized in a tunnel furnace and subsequent rolling, continuous casting continuous rolling endless rolling of strip steel with the steel passing variable range of 3-10 t/min on one production line can be realized, namely, the endless rolling strip steel flexible production line with wide steel passing capacity is provided, the application range of steel types, thickness and width is wider, and the production is more flexible. When the production line is adopted for rolling production, whether the pre-rolling mill group participates in the preparation of large-range steel flux change can be realized, and the temperature and the structure of the whole process are controlled by combining the heating procedure, so that the control of the material structure under the optimal supercooling degree and temperature combination condition is realized. During rolling production, whether the pre-rolling mill set is pre-rolled or not can be determined according to the steel passing amount, and also can be determined according to the thickness of the continuous casting billet. For example, when the steel flux is more than or equal to 6.0t/min, a pre-rolling unit is adopted to pre-roll the continuous casting billet, and the rolling reduction can be 20-40 mm; and when the steel flux is less than 6.0t/min, the pre-rolling unit performs blank treatment on the continuous casting billet. For example, the pre-rolling is performed when the thickness of the continuous casting billet is greater than 120 mm; and (5) carrying out blank passing at a speed of less than or equal to 120 mm.

In addition, a tunnel furnace is arranged between the pre-rolling and the rough rolling, and the temperature of the pre-rolled intermediate billet I is supplemented by the tunnel furnace, so that the uniform temperature treatment of the pre-rolled intermediate billet I is realized, the temperature and the billet structure of the whole process can be effectively controlled, and different finished strip steels can be obtained more easily.

In an alternative embodiment, the roughing mill train and finishing mill train spacing is controlled to 15 to 45m. The space can enable 5-15s of dynamic recovery and recrystallization time before finish rolling, thereby obtaining a more compact and uniform austenite structure and providing structure preparation for further controlling the shape, the dimensional accuracy and the rolling stability. In addition, the interval between the outlet of the continuous casting machine and the center line of the rolling frame of the pre-rolling mill group is 5-8 m. The distance between the center line of the rolling frame of the pre-rolling mill set and the tunnel furnace mouth is 6-10 m. The distance between the outlet of the tunnel furnace and the central line of the first rolling stand of the roughing mill set is 6-10 m. The distance between the adjacent roughing stands of the roughing mill set is 4-5 m. The distance between the center lines of adjacent finishing frames of the finishing mill group is 4-5 m. The center line distance between the last finishing mill frame of the finishing mill group along the rolling direction and the first coiling machine of the coiling machine group along the rolling direction is 50-120 m.

In an alternative embodiment, before the pre-rolling mill set and before the rough rolling stand, the high-pressure water descaling devices are respectively arranged in front of the finish rolling stand, so that primary descaling, secondary descaling and tertiary descaling operations are respectively carried out before rolling, and the defect of residual iron oxide scale on the surface of the finished strip steel caused by pressing the iron oxide scale into the strip steel in the rolling stage can be avoided through tertiary high-pressure water descaling treatment, and the surface quality of the strip steel can be obviously improved. In the actual rolling production process, the required effect can be achieved by adjusting the descaling pressures of the first high-pressure water descaling device, the second high-pressure water descaling device and the third high-pressure water descaling device.

In addition, an induction heating device is arranged between the rough rolling and the finish rolling, so that the intermediate billet II after the rough rolling adjusts the heating temperature by induction heating. In the actual rolling production process, a temperature system can be flexibly formulated according to the needs, different steel grades have different temperature control requirements, particularly, the temperature switching required by austenite rolling and ferrite rolling can be formulated according to the tissue types of rolling products, such as austenite, ferrite and the like, and the dynamic recovery and recrystallization time, such as 5-25 s and the like, before finish rolling of blanks for a certain time can be ensured based on the interval between a roughing mill group and a finishing mill group in the production line, so that the rolling production line adopts a headless mode to finish rolling to produce various multi-specification strip steel with the rolling thickness of 0.7-25.4 mm.

Fig. 1 schematically illustrates a flexible production line for endless rolled strip steel for strip steel continuous casting, which is provided in an embodiment of the present utility model, and as shown in fig. 1, the production line is arranged behind a continuous casting machine 1 and comprises a high-pressure water descaling device i2→a pre-rolling mill group 3→a pendulum shear 4→a tunnel furnace 5→a waste billet pushing and stacking device 6→a high-pressure water descaling device ii 7→a roughing mill group 8→a rotary drum flying shear 9→an induction heating device 10→a high-pressure water descaling device iii 11→a finishing mill group 12→an ultra-fast cooling device 13→a laminar cooling device 14→a high-speed flying shear 15→a coiling unit 16, which are sequentially arranged.

Wherein, the pre-rolling unit 3 includes 1 two-roll mill that sets up along the rolling direction, and the roughing unit 8 includes 3 four-roll mill that set gradually along the rolling direction, and the finishing mill unit 12 includes 5 four-roll mill that set gradually along the rolling direction, and the coiling unit 16 includes 3 recoilers that set gradually along the rolling direction.

Further, in this example, the roughing mill train and finishing mill train spacing was 25.5m. The distance between the outlet of the continuous casting machine and the center line of the rolling frame of the pre-rolling mill set is 6.9m. The distance between the center line of the mill frame of the pre-rolling mill set and the tunnel furnace mouth is 8.9m. The distance between the outlet of the tunnel furnace and the center line of the first rolling stand of the roughing mill set is 8.65m. The spacing between adjacent roughing stands of the roughing mill train is 5m. The distances between the central lines of adjacent finishing frames of the finishing mill group are 5m,4.8m and 4.8m in sequence. The center line distance between the last finishing mill frame of the finishing mill group along the rolling direction and the first coiling machine of the coiling machine group along the rolling direction is 83.95m.

The rolling production process of the endless rolled strip steel flexible production line adopting the continuous casting of strip steel in the embodiment of the utility model is as follows, and the rolling whole line adopts continuous endless rolling.

1) Pre-rolling or blank passing: the continuous casting billet 201 with the thickness of 140-160 mm from the outlet of the continuous casting machine is firstly subjected to preliminary descaling by adopting a first high-pressure water descaling device in front of a pre-rolling unit, and the descaling pressure is 3-10 bar; then, the intermediate blank I202 is obtained by pre-rolling or blank passing through a pre-rolling mill group consisting of 1 two-roll mills along the rolling direction. Wherein, when pre-rolling, the rolling mill rolling reduction is 20-40 mm, and the intermediate blank I with the thickness of 110-120 mm is obtained. The continuous casting speed of the continuous casting machine can be 5.5-6 m/min, the continuous casting outlet temperature is 1030+/-30 ℃, and the thickness of a continuous casting billet coming out of the outlet of the continuous casting machine is 140-160 mm.

2) Homogenizing and rough rolling: after the intermediate billet I is subjected to temperature compensation by a tunnel furnace, a second high-pressure water descaling device in front of a roughing stand is adopted to perform secondary descaling, the descaling pressure is 380bar, and the intermediate billet II203 with the thickness of 5-35 mm is continuously rolled by a roughing mill group consisting of 3 or more four-roller rolling mills which are sequentially arranged along the rolling direction. When the tunnel furnace is adopted to perform uniform temperature treatment on the blank, the temperature difference of the intermediate blank I before rolling can be controlled to be +/-15 ℃ by controlling the temperature of the tunnel furnace, the uniform temperature time in the transportation process is 8-15 min, the structure state is in an austenite region, and the temperature of the intermediate blank I at the inlet of a rough rolling machine frame is ensured to be not lower than 970 ℃; when the roughing mill is used for rolling, a large reduction is adopted, for example, the first pass of roughing is not less than 40mm, the second pass is not less than 30mm and the third pass is not less than 16mm, an as-cast structure is crushed, and the preparation of a structure state and a uniform temperature state can be finished for further rolling; and the composition segregation in the solidification process is eliminated, and particularly, the chemical composition of the high-strength steel with high alloy composition is fully homogenized before rolling, so that single-phase austenite with uniform composition is obtained, and the production of the high-strength steel, the dual-phase steel and part of excellent steel is facilitated.

3) Induction heating and finish rolling: the intermediate blank II is subjected to temperature regulation by using an induction heating device, and is subjected to three times of descaling by using a third high-pressure water descaling device in front of a finish rolling frame after the temperature regulation, wherein the descaling pressure is 380bar, and then the intermediate blank II enters a finish rolling unit consisting of 3-5 four-roller rolling mills which are sequentially arranged along the rolling direction to continuously roll finished strip steel with the thickness of 0.7-25.4 mm; and finally, carrying out controlled cooling on the finished strip steel sequentially by an ultra-fast cooling device and a laminar flow cooling device, and collecting the cooled finished strip steel into rolls by a coiling machine through high-speed fly shearing. For example, the induction heating device heats the intermediate billet II to control the temperature, realizes the temperature switching required by austenite rolling and ferrite rolling, and ensures the dynamic recovery and recrystallization time before finish rolling of 5-15 s. The intermediate blank II is rolled in the finish rolling stage, at least 3 continuous finish rolling frames are required to be rolled in austenite temperature, or at least 3 continuous finish rolling frames are required to be rolled in ferrite temperature, when the austenite rolling is carried out, the inlet temperature of the intermediate blank II is 980+/-15 ℃, the outlet temperature of the finish rolling frames is 840+/-15 ℃, and the coiling temperature of the strip steel is 350-700 ℃. When ferrite rolling is carried out, the temperature of the intermediate blank II at the inlet of a finish rolling frame is 900+/-15 ℃, the temperature of the strip steel at the outlet of the finish rolling frame is 770+/-15 ℃, and the coiling temperature of the strip steel is 650-750 ℃.

In addition, based on the production line, a complete continuous casting and rolling casting secondary production process without head comprises the following steps: the full-line equipment is ready for casting, pre-rolling, rough rolling, finish rolling and coiling, the pre-swinging roll gap is in place, the continuous casting machine 1 is started for casting, when the dummy bar head passes through the last segment of the sector section, the hydraulic cylinder of the dummy bar removing device acts, the head of the dummy bar is lifted, the casting blank is separated from the dummy bar, and the dummy bar rapidly runs and is stored on the storage rack. When the casting blank is conveyed to the pendulum shear, the blank head is cut, and then the pendulum shear carries out automatic cutting with fixed length, multiple length cutting or a headless mode according to the process requirements. And (5) conveying the casting blank with the fixed length, the multiple length or the headless mode after being cut by the pendulum shear to a tunnel kiln through a conveying roller way. The strip steel sequentially passes through a high-pressure water descaling device I2, a pre-rolling mill group (R0), a pendulum shear 4, a tunnel furnace 5, a high-pressure water descaling device II 7, a rough rolling mill group 8 (R1, R2 and R3), a rotary drum flying shear 9, an induction heating device 10, a high-pressure water descaling device III 11, a finishing mill group 12 (F1, F2, F3, F4 and F5), an ultra-fast cooling device 13, a laminar cooling device 14, a high-speed flying shear 15 and a coiling unit 16, and after rolling parameters are adjusted by 2-3 fixed-length billets (the fixed length is 23.9 m), the strip steel starts endless rolling; after the current coil weight reaches the standard, shearing by a high-speed flying shear 15, and finishing the threading switching of different coiling machines of the next coil of strip steel by a quick switching device of a coiling unit 16; during endless rolling, the strip steel is produced according to the principle that the thickness of the strip steel is reduced from thickness to thickness and then reduced from thickness to thickness, and the strip rolling process involves dynamic specification change of a rolling mill and strip-carrying channeling of a roller. The roll replacement of the finishing mill can occur for 1-3 times at the same casting time, the swing shear carries out fixed-length shearing on the rough rolled intermediate billet I and sends the intermediate billet I to the tunnel furnace for soaking, at the moment, the continuous casting pulling speed is controlled to be 3.0-3.5 m/min, the advancing speed of the tunnel furnace is controlled to be 3.5m/min, three-end two-branch fixed-length billets are usually adopted, the roll replacement process is completed, and the whole process is about 8-10 minutes. Until the casting end is approached, the rolled piece continues to finish rolling, and the casting is finished.

In addition, the production line of the embodiment can also carry out accident handling. For endless rolling production, the rolling piece steel piling or breaking accidents easily occur in the finish rolling process, so that the accident treatment of the production line is considered in time, the continuous casting of the current ladle molten steel is ensured as much as possible, and the loss is reduced.

In the production line of the embodiment, pendulum shears are arranged on a rolling production line between a pre-rolling stand and a tunnel furnace, billet pushing and stacking devices are arranged on the rolling production line between the tunnel furnace and a rough rolling stand, and rotary drum flying shears are arranged between the rough rolling stand and an induction heating device and used for accident treatment and head and tail shearing.

When accidents occur in the working procedures of finish rolling and post-finish rolling, a finishing mill frame is lifted to form a roll gap, continuous casting is carried out, a fixed-length billet with the length of 23.9m is sheared by a swinging shear, the scrap steel is removed after the rolled piece between the swinging shear and the accident shear is broken, the fixed-length shear is carried out on the intermediate billet I after rough rolling by the swinging shear and is sent to a tunnel furnace for soaking, at the moment, the continuous casting pulling speed is controlled to be 3.0-3.5 m/min, the advancing speed of the tunnel furnace is controlled to be 3.5m/min, and the strip threading rolling is carried out again after the accident treatment is completed. In addition, when the treatment time is long, the waste blank is transported to the area of the blank pushing and stacking device 5, the waste blank is pushed out of the rolling line, and the casting is completed.

The following describes in detail the application examples of the flexible production line of endless rolled strip steel for continuous casting of strip steel provided by the utility model to produce strip steel with different thickness.

Application example 1

The strip 204 was produced by rolling with a continuous casting thickness of 150 mm. Rolling by a pre-rolling mill set.

The steel strip comprises the following chemical components in percentage by mass: less than or equal to 0.045% of C, less than or equal to 0.15% of Mn, less than or equal to 0.035% of Si, less than or equal to 0.020% of P, less than or equal to 0.005% of S, less than or equal to 0.08% of Nb+Ti, less than or equal to 0.05% of Als, and the balance of Fe and impurities.

Molten steel is cast into a continuous casting blank with the thickness of 150mm through a high-speed continuous casting process, the continuous casting drawing speed is controlled to be 5.5m/min, and the surface temperature of a continuous casting blank at a continuous casting outlet is 1030+/-30 ℃. After scale on the surface of a casting blank is removed by high-pressure water, the casting blank is rolled by a 1-frame pre-rolling mill set (R0) to obtain an intermediate blank I with the thickness of 120 mm. At this time, the temperature was reduced to 950.+ -. 40 ℃.

And (5) adopting a tunnel furnace to supplement the temperature to 1005+/-10 ℃. And then removing scale on the surface of the casting blank by high-pressure water, wherein the temperature is about 1000+/-10 ℃ when rough rolling is carried out, and the thickness of the intermediate blank II is changed into 10mm after rolling by 3 rough rolling frames (R1, R2 and R3). The large rolling reduction is adopted to crush the cast structure, so as to prepare the structure state and the uniform temperature state for further rolling. And the component segregation in the solidification process is effectively eliminated, and particularly, the chemical cost of the high-strength steel with high alloy components is sufficiently homogenized before rolling, so that the single-phase austenite with uniform components is obtained. At this time, the temperature was slightly lowered to 980.+ -. 10 ℃.

The intermediate transportation channel has 10-12 s of dynamic recovery and recrystallization time, so as to obtain more compact and uniform austenite structure. The inlet temperature of the induction heating device is reduced to 920+/-10 ℃, the temperature is regulated to 950+/-10 ℃ by the induction heating device, and then the steel is descaled by the high-pressure water descaling device and then enters the finishing mill group 12 for rolling. Passing through 5 finishing mill groups (F1, F2, F3, F4 and F5), wherein the temperature at the inlet of a first finishing mill frame F1 is 950+/-10 ℃, the finish rolling is changed into strip steel 204 with the thickness of 0.8mm, the speed of the strip steel 204 at the finish rolling outlet is 13.55m/s, and the temperature at the finish rolling outlet is 900+/-10 ℃. Finally, the temperature of the strip steel 204 at the inlet of the coiling machine is 700+/-10 ℃ through the control of ultra-fast cooling after rolling and laminar cooling, and the strip steel curling and bundling are completed.

Application example 2

The strip steel 204 was produced by rolling with a continuous casting thickness of 120 mm. The pre-rolling mill is emptied.

The strip steel of a certain continuous casting and rolling production line comprises the following chemical components in percentage by mass: c is less than or equal to 0.15%, si is less than or equal to 0.03%, mn is less than or equal to 0.15%, P is less than or equal to 0.015%, S is less than or equal to 0.008%, als is less than or equal to 0.04%, and the balance is Fe and impurities.

The molten steel is cast into a continuous casting blank 201 with the thickness of 120mm through a high-speed continuous casting process, the continuous casting drawing speed is controlled to be 5.5m/min, the surface temperature of the continuous casting blank at a continuous casting outlet is 1030+/-10 ℃, the intermediate blank I is cooled to 920+/-40 ℃ after being subjected to descaling through high-pressure water and then being rolled through 1 pre-rolling mill sets (R0).

And (5) adopting a tunnel furnace to supplement the temperature to 955+/-10 ℃. The intermediate billet I with the thickness of 20mm is rolled by 3 roughing stands (R1, R2 and R3) at the rough rolling temperature of 950+/-10 ℃ after the descaling by high-pressure water, and the cast structure is crushed by adopting large rolling reduction, so that the preparation of the structure state and the uniform temperature state is finished for further rolling. And the component segregation in the solidification process is effectively eliminated, and particularly, the chemical cost of the high-strength steel with high alloy components is sufficiently homogenized before rolling, so that the single-phase austenite with uniform components is obtained. At this point the temperature was slightly reduced to 900 ℃ ± 10 ℃.

The intermediate transportation channel has 10-15s of dynamic recovery and recrystallization time, so that a more compact and uniform austenite structure is obtained, the inlet temperature of the induction heating device is reduced to 920+/-10 ℃, the temperature is regulated to 950+/-10 ℃ by the induction heating device, and the austenite structure enters a finishing mill group for rolling after descaling by the high-pressure water descaling device. Rolling by 5 finishing mill groups 12 (F1, F2, F3, F4 and F5), wherein the temperature at the inlet of a first finishing mill frame F1 is 950+/-10 ℃, the finish rolling is finished to obtain strip steel 204 with the thickness of 3.5mm, the speed of the finish rolling outlet strip steel 204 is 8.0m/s, the finish rolling outlet temperature is 770+/-10 ℃, and finally the temperature of the strip steel 204 at the inlet of a coiling machine is 650+/-10 ℃ by controlling ultra-fast cooling and laminar cooling after rolling, so that the strip steel is coiled and bundled.

In summary, the production line is a flexible production line of endless rolled strip steel with wide steel flux applicability, and when the production line comprising the pre-rolling unit is used for rolling, the wide steel flux variation can be regulated by adjusting whether the pre-rolling unit participates in rolling, and the material structure can be controlled under the optimal supercooling degree and temperature combination condition through the control of the whole flow temperature and structure. In some application embodiments, the production line can be suitable for the steel passing variable change range of 3-10 t/min, and can realize continuous endless rolling of finished strip steel with the thickness of 0.7-25.4 mm, the application range of steel grade, thickness and width is wider, the production is more flexible, and the production line has the advantages of low cost, high production rate, high product quality and the like, and is a current technical development trend and market demand.

The description of the present utility model has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the utility model in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the utility model and the practical application, and to enable others of ordinary skill in the art to understand the utility model for various embodiments with various modifications as are suited to the particular use contemplated.

Claims (10)

1. A endless rolled strip flexible production line, comprising: the device comprises a pre-rolling unit, a tunnel furnace, a rough rolling unit, an induction heating device, a finishing mill unit, a laminar flow cooling device and a coiling unit which are sequentially arranged; wherein,

The tunnel furnace is used for carrying out uniform temperature treatment on the intermediate billet I from the pre-rolling mill group; the induction heating device is used for performing induction heating temperature adjustment on the intermediate billet II from the roughing mill;

The pre-rolling mill group is used for pre-rolling or emptying continuous casting billets and comprises at least 1 pre-rolling mill arranged along the rolling direction; the roughing mill unit comprises at least 3 roughing mills arranged along the rolling direction; the finishing mill group comprises 3 to 5 finishing mills arranged along the rolling direction.

2. The endless rolled strip flexible production line of claim 1, wherein the pre-rolling mill is a two-roll mill; the roughing mill is a four-high mill, and the finishing mill is a four-high mill.

3. The flexible endless rolled strip production line of claim 2, wherein the pre-rolling train comprises 1 two-roll mill arranged in a rolling direction; the roughing mill unit comprises 3 four-high mills which are sequentially arranged along the rolling direction; the finishing mill group comprises 5 four rolling mills which are sequentially arranged along the rolling direction.

4. A flexible endless rolled strip production line as claimed in claim 3 wherein the coiler group comprises 3 coiler machines arranged in sequence in the rolling direction.

5. A flexible endless rolled strip production line as claimed in claim 3 wherein the roughing mill train is spaced from the finishing mill train by 15 to 50m.

6. The endless rolled steel strip flexible production line of claim 5, wherein,

The distance between the center line of the rolling frame of the pre-rolling mill set and the tunnel furnace mouth is 6-10 m;

the distance between the outlet of the tunnel furnace and the central line of the first rolling stand of the roughing mill set is 6-10 m;

The center line distance between the last finishing mill frame of the finishing mill group along the rolling direction and the first coiling machine of the coiling machine group along the rolling direction is 50-120 m.

7. The flexible endless rolled strip production line of claim 6, wherein the production line is disposed after a continuous caster and the distance between the caster outlet and the centerline of the pre-mill train roll stand is 5-8 m.

8. The flexible production line of endless rolled steel strip of claim 6, wherein the pitch between adjacent roughing stands of the roughing train is 4-5 m; the distance between the center lines of adjacent finishing mill frames of the finishing mill group is 4-5 m.

9. The endless rolled steel strip flexible production line of claim 1, further comprising: the first high-pressure water descaling device, the second high-pressure water descaling device and the third high-pressure water descaling device are respectively arranged in front of the pre-rolling mill set, in front of the rough rolling mill set and in front of the finishing mill set.

10. The endless rolled steel strip flexible production line of claim 2, characterized in that a pendulum shear is arranged after the pre-mill train and before the tunnel furnace; a rotary drum flying shear is arranged behind the roughing stand machine and in front of the induction heating device; a high-speed flying shear is arranged behind the laminar cooling device and before the crimping machine set; an ultra-fast cooling device is arranged after the finishing mill group and before the laminar cooling device.