Mixed rolling production line and production method thereof

Abstract

The invention relates to a mixed rolling production line and a production method thereof. The production line comprises a production line A and a production line B which are arranged in parallel; the production line A comprises a continuous casting unit, a line A rough rolling unit, a line A hot coiling station, a finish rolling unit, a cooling device and a coiling unit which are collinearly arranged in sequence; the production line B comprises a heating furnace, a line B descaling device, a line B rough rolling unit and a line B hot rolling station; a furnace discharging roller way of the heating furnace, the line B descaling device, the line B rough rolling unit and the line B hot rolling station are collinearly arranged in sequence; the A-line hot rolling station and the B-line hot rolling station are connected through a transverse moving track, and a movable hot rolling device is movably arranged on the transverse moving track. The movable hot rolling device is switched between the A-line hot rolling station and the B-line hot rolling station, organic coupling of the two production lines is achieved, the thin slab production mode and the thick slab production mode of the mixed rolling production line share the finish rolling unit, the coiling machine and the like, and the equipment investment and the occupied area of the production line are effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical production, and particularly relates to a mixed rolling production line and a production method thereof. Background Art

[0002] Hot-rolled coil production lines primarily include conventional hot rolling and thin slab continuous casting and rolling. Currently, the most technologically advanced thin slab continuous casting and rolling lines feature a headless continuous casting and rolling production mode, also known as a headless rolling line. Conventional hot rolling lines typically use thick slabs with a thickness of more than 200mm as raw material. The thick slabs are heated in a heating furnace and then transported to the rolling line, where they are pressed and deformed to produce steel coils. In headless rolling lines, continuous casting and rolling are connected. The line uses molten steel as raw material, and after continuous casting, thin slabs less than 150mm are obtained. These slabs then enter the rolling line to produce steel coils. The headless rolling process directly produces steel coils from molten steel.

[0003] Conventional rolling production lines have the advantages of high output, wide product range, and flexible production, but the production of strip steel products below 1.5mm thickness is difficult; headless rolling production lines have the advantage of being able to stably produce thin-gauge strip steel products with a thickness of 0.7-1.5mm, but the production line has poor flexibility, the product steel grade is single, and molten steel must be used as raw material.

[0004] Competition in the current steel industry is fierce, and steel companies with a single product line have limited ability to withstand market risks. Hot-rolling mills that are capable of producing a wide range of steel grades and thicknesses typically require the construction of both conventional and endless rolling lines, which incurs high investment costs and requires significant floor space. Summary of the Invention

[0005] The present invention relates to a mixed rolling production line and a production method thereof, which can at least solve some of the defects of the prior art.

[0006] The present invention relates to a hybrid rolling production line, comprising a production line A and a production line B arranged in parallel;

[0007] The A production line includes a continuous casting unit, a line A rough rolling unit, a line A hot coil station, a finishing rolling unit, a cooling device and a coiling unit arranged in sequence on the same line;

[0008] The B production line includes a heating furnace, a B-line descaling device, a B-line roughing unit, and a B-line hot coil station. The discharge roller of the heating furnace is arranged in the same line as the B-line descaling device, the B-line roughing unit, and the B-line hot coil station.

[0009] The A-line hot coiling station and the B-line hot coiling station are connected by a transverse track, and a movable hot coiling device is movably arranged on the transverse track.

[0010] As one of the implementation modes, a line A heating device and a line A descaling device are further provided between the line A hot coil station and the finishing rolling unit, and the line A descaling device is located downstream of the line A heating device.

[0011] As one of the implementation modes, the A-line heating device adopts an induction heating furnace.

[0012] As one of the implementation modes, the A-line roughing unit includes 1 to 5 roughing mills; the finishing unit includes 3 to 8 finishing mills; and the B-line roughing unit includes at least 1 roughing mill.

[0013] As one of the implementation modes, the A-line roughing unit includes three four-high roughing mills; the finishing unit includes six four-high finishing mills; and the B-line roughing unit includes one four-high reversing mill.

[0014] The present invention also relates to a production method of the above-mentioned mixed rolling production line, which comprises:

[0015] According to production requirements, the hybrid rolling production line is operated in thin slab production mode or thick slab production mode.

[0016] (1) In the thin slab production mode:

[0017] The continuous casting unit casts a thin-gauge continuous casting slab, which enters the rough rolling unit of line A to be rolled to obtain a first intermediate bar, which enters the coiling unit for coiling after finish rolling and cooling;

[0018] (2) In the thick slab production mode:

[0019] The thick-gauge slab is heated to a target temperature by the heating furnace and then enters the rough rolling unit of line B to obtain a second intermediate slab;

[0020] The mobile hot coiling device moves to the hot coiling station of line B to coil the second intermediate billet into an intermediate hot coil, and then moves to the hot coiling station of line A to uncoil the intermediate hot coil into a single intermediate billet;

[0021] The single intermediate billet is finished rolled and cooled before entering the coiling unit for coiling.

[0022] As one of the embodiments, in the thin slab production mode, the mobile hot coil device moves to the B-line hot coil station, and before the first intermediate billet enters the finishing rolling unit, the first intermediate billet is heated to 1050°C-1150°C by the A-line heating device arranged between the A-line hot coil station and the finishing rolling unit.

[0023] As one of the embodiments, in the thin slab production mode, the mobile hot coiling device moves to the A-line hot coiling station, and the mobile hot coiling device coils and uncoils the first intermediate billet, and the first intermediate billet is supplemented with heat by the A-line heating device arranged between the A-line hot coiling station and the finishing rolling unit.

[0024] As one of the embodiments, in the thick slab production mode, after the mobile hot coil device moves to the A-line hot coil station, the single intermediate slab is supplementally heated by the A-line heating device arranged between the A-line hot coil station and the finishing rolling unit.

[0025] The present invention has at least the following beneficial effects:

[0026] In the present invention, by setting a transverse track between production line A and production line B, the mobile hot coil device can switch between the hot coil station of line A and the hot coil station of line B, realizing the organic coupling of the two production lines, so that the thin slab production mode and the thick slab production mode of the mixed rolling production line share the finishing unit and coiler, etc., effectively reducing equipment investment and production line floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of the layout of a hybrid rolling production line provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] Example 1: Figure 1 , an embodiment of the present invention provides a hybrid rolling production line, comprising a production line A and a production line B arranged in parallel;

[0031] The A production line includes a continuous casting unit 101, a line A rough rolling unit 102, a line A hot coil station 109, a finishing rolling unit 105, a cooling device 106 and a coiling unit 108, which are arranged in sequence on the same line;

[0032] The B production line includes a heating furnace 201, a B-line descaling device 202, a B-line roughing unit 203, and a B-line hot coil station 204. The discharge roller of the heating furnace 201 is arranged in the same line as the B-line descaling device 202, the B-line roughing unit 203, and the B-line hot coil station 204.

[0033] The A-line hot coiling station 109 and the B-line hot coiling station 204 are connected via a transverse track, and a movable hot coiling device is movably arranged on the transverse track.

[0034] Preferably, the continuous casting unit 101 is used to continuously cast molten steel into thin-gauge continuous casting slabs; optionally, the slab thickness is 80-130 mm, and the slab production speed is 4.5-5.5 m / min.

[0035] The A-line roughing unit 102 is used to roll thin-gauge continuously cast slabs into first intermediate bars. Optionally, the thickness of the first intermediate bar is 10-20 mm. In one embodiment, the A-line roughing unit 102 includes one to five roughing mills; optionally, the A-line roughing unit 102 includes three four-high roughing mills, which can better meet the roughing process requirements for thin-gauge continuously cast slabs.

[0036] The heating furnace 201 is used to heat thick slabs. Optionally, the outlet temperature of the heating furnace 201 is 1150-1200°C.

[0037] The above-mentioned B-line descaling device 202 is used to remove iron oxide scale on the surface of thick-gauge slabs. Preferably, the B-line descaling device 202 uses high-pressure water for descaling, and the descaling pressure is 25~30MPa.

[0038] Optionally, the thick-gauge slab has a thickness of 200-400 mm.

[0039] The B-line roughing unit 203 is used to roll thick slabs into second intermediate bars. Optionally, the thickness of the second intermediate bar is 25-40 mm. At the exit of the B-line roughing unit 203, the temperature of the second intermediate bar is 850-1100°C. In one embodiment, the B-line roughing unit 203 includes at least one roughing mill; optionally, the B-line roughing unit 203 includes a four-high reversing mill, which can better meet the roughing process requirements for the thick slabs.

[0040] The above-mentioned mobile hot coil device preferably adopts a mobile hot coil box, which can move horizontally on a horizontal track, so as to be able to switch between the line A hot coil station 109 and the line B hot coil station 204, including but not limited to using a moving method such as configuring a horizontal moving wheel and a horizontal moving drive motor at the bottom of the hot coil box.

[0041] Optionally, the temperature of the intermediate billet coiled by the mobile hot coiling device is 800~1100℃.

[0042] Preferably, the above-mentioned transverse track extends beyond the A production line, that is, extends to the side of the A line hot coil station 109 away from the B line hot coil station 204, and a movable roller is also provided on the transverse track. Along the direction from the A line hot coil station 109 to the B line hot coil station 204, the movable roller and the movable hot coil device are arranged in sequence; when the continuous casting unit 101 and the A line rough rolling unit 102 are put into production, and the movable hot coil device is transversely moved to the B line hot coil station 204, the movable roller can be transversely moved to the A line hot coil station 109 to better connect the upstream and downstream equipment of the A line hot coil station 109.

[0043] In one embodiment, Figure 1 A line A heating device 103 and a line A descaling device 104 are further provided between the line A hot coiling station 109 and the finishing rolling unit 105. The line A descaling device 104 is located downstream of the line A heating device 103. The line A heating device 103 is used to heat the intermediate bar, and can be used to heat the first intermediate bar or the second intermediate bar. Preferably, the line A heating device 103 employs an induction heating furnace 201, which can rapidly heat the intermediate bar.

[0044] The A-line descaling device is used to remove the iron oxide scale on the surface of the intermediate billet. Preferably, the B-line descaling device 202 uses high-pressure water for descaling, and the descaling pressure is 35~40MPa.

[0045] The finishing unit 105 is used to perform finish rolling on the intermediate billet. In one embodiment, the finishing unit 105 includes 3 to 8 finishing mills; optionally, the finishing unit 105 includes 6 four-roll finishing mills, which can better meet the finishing process requirements of the first intermediate billet and the second intermediate billet.

[0046] In one embodiment, the cooling device 106 has a segmented cooling function and can adjust the cooling position and cooling capacity according to production process requirements. Preferably, the cooling device 106 is a laminar cooling device 106.

[0047] In one embodiment, a shearing device 107 is provided between the cooling device 106 and the coiling unit 108, which can shear and segment the steel plate transported at a relatively high speed. Preferably, the shearing device 107 is a high-speed flying shear.

[0048] Preferably, the coiling unit 108 includes at least two coilers, some of which are thin-gauge strip coilers and the others are high-power coilers. In one embodiment, three coilers are provided, two of which are thin-gauge strip coilers capable of coiling a minimum steel plate thickness of 0.6 mm, and one is a high-power coiler capable of coiling a maximum steel plate thickness of 32 mm.

[0049] Embodiment 2: This embodiment of the present invention relates to a production method of the hybrid rolling production line in the above embodiment 1, and the production method comprises:

[0050] According to production requirements, the hybrid rolling production line is operated in thin slab production mode or thick slab production mode.

[0051] (1) In the thin slab production mode:

[0052] The continuous casting unit 101 casts a thin continuous casting slab, which enters the A-line rough rolling unit 102 to be rolled to obtain a first intermediate bar, which enters the coiling unit 108 for coiling after finish rolling and cooling.

[0053] (2) In the thick slab production mode:

[0054] The thick slab is heated to the target temperature by the heating furnace 201 and then enters the B-line rough rolling unit 203 to be rolled to obtain the second intermediate slab;

[0055] The mobile hot coiling device moves to the B-line hot coiling station 204 to coil the second intermediate billet into an intermediate hot coil, and then moves to the A-line hot coiling station 109 to uncoil the intermediate hot coil into a single intermediate billet.

[0056] After finishing rolling and cooling, the single intermediate billet enters the coiling unit 108 for coiling.

[0057] Among them, the relevant process parameters of the thin slab production mode (including the thickness of the thin-gauge continuous casting slab, the thickness of the first intermediate slab, etc.) and the relevant process parameters of the thick slab production mode (including the thickness of the thin-gauge continuous casting slab, the thickness of the second intermediate slab, etc.) have been described in the above-mentioned embodiment 1 and will not be repeated here.

[0058] In one embodiment, in the thin slab production mode, the mobile hot coiling device moves to the B-line hot coiling station 204. Before the first intermediate bar enters the finishing rolling unit 105, it is heated to 1050°C-1150°C by the A-line heating device 103, which is arranged between the A-line hot coiling station 109 and the finishing rolling unit 105. Rapidly heating the thin slab before finishing rolling can enhance the finishing rolling effect and improve the strip quality.

[0059] In one embodiment, in the thin slab production mode, the mobile hot coiling device moves to the A-line hot coiling station 109, and the mobile hot coiling device coils and uncoils the first intermediate billet, and the first intermediate billet is supplementally heated by the A-line heating device 103 arranged between the A-line hot coiling station 109 and the finishing rolling unit 105. For this case, a shearing device can be provided between the continuous casting unit 101 and the A-line rough rolling unit 102 or between the A-line rough rolling unit 102 and the A-line hot coiling station 109 to cut the continuous thin-gauge continuous casting billet / continuous first intermediate billet into a single piece of thin-gauge slab / single piece of first intermediate billet, and the mobile hot coiling device coils and uncoils the single piece of first intermediate billet. In this solution, the hot coiling device and the A-line heating device 103 can be combined to heat the first intermediate billet, which has at least the following beneficial effects:

[0060] The buffering effect of the hot coil device can improve the flexibility and rhythm stability of the thin slab production mode, including but not limited to the reliable processing of high-value-added steel grades such as silicon steel and high-strength steel in the thin slab production mode, and the reliable response to emergency conditions such as emergency conditions in the thin slab production mode.

[0061] Among them, the hot coil device evens out the temperature during the coiling-uncoiling process, so that the head and tail of the first intermediate billet are exchanged to improve the temperature uniformity, thereby improving the subsequent finishing quality; the A-line heating device 103 can further even out the heat and / or supplement the heat of the first intermediate billet, and in particular, can specifically compensate for the temperature loss of the head and tail of the first intermediate billet that occurs in the hot coil device (which may be in the range of ±20~30℃), effectively improve the temperature uniformity of the first intermediate billet (the temperature difference can be controlled within ±5℃), thereby improving the finishing quality, which is particularly beneficial for the production of temperature-sensitive steel grades such as high-strength steel and silicon steel.

[0062] In one embodiment, in the thick slab production mode, the mobile hot coil unit moves to the A-line hot coil station 109 and then uncoils the slab into a single intermediate slab. Depending on the process requirements for the steel grade being produced, the A-line heating device 103 between the A-line hot coil station 109 and the finishing rolling unit 105 can be operated or inoperative. For some plain carbon steels, the single intermediate slab can pass directly through the inoperative A-line heating device 103. For high-value-added steel grades such as high-strength steel and silicon steel, the single intermediate slab can be supplementally heated by the A-line heating device 103. Therefore, in this solution, the hot coil unit and the A-line heating device 103 can also be combined to heat the second intermediate slab. The effects of this combination are as described above and will not be elaborated on here.

[0063] In addition to the aforementioned effects, the rapid heating function of the A-line heating device 103, especially the induction heating device, can reduce the insulation pressure and energy loss of the hot coil device, and reduce the negative impact of the production rhythm caused by the lateral movement of the hot coil device.

[0064] In particular, when hot coil boxes coil high-strength steel, problems such as loose coils and insufficient slab flatness after uncoiling are prone to occur. By combining an induction heating device to quickly heat the head, tail or edges of the intermediate slab, the overall deformation resistance of the intermediate slab is made consistent and the stress is evenly distributed during uncoiling. This can improve the flatness of the intermediate slab after uncoiling, avoid defects such as local bending, and thus improve the quality of finishing rolling.

[0065] In one embodiment, based on the aforementioned coupling scheme between the hot coil unit and the A-line heating unit 103 (induction heating unit), the induction heating unit monitors the temperature of the intermediate billet at its inlet in real time and dynamically adjusts its heating power. Simultaneously, this temperature data is fed back to a central control console, which adjusts the back tension of the hot coil unit's uncoiler based on the temperature data. The back tension is reduced in areas with high intermediate billet temperatures and increased in areas with low intermediate billet temperatures. This solution can prevent poor sheet shape caused by localized overtension or slack.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mixed rolling production line, characterized in that: It includes production line A and production line B arranged in parallel; The A production line includes a continuous casting unit, a line A rough rolling unit, a line A hot coil station, a finishing rolling unit, a cooling device and a coiling unit arranged in sequence on the same line; The B production line includes a heating furnace, a B-line descaling device, a B-line roughing unit, and a B-line hot coil station. The discharge roller of the heating furnace is arranged in the same line as the B-line descaling device, the B-line roughing unit, and the B-line hot coil station. The A-line hot coiling station and the B-line hot coiling station are connected by a transverse track, and a movable hot coiling device is movably arranged on the transverse track.

2. The hybrid rolling production line according to claim 1, characterized in that: A line A heating device and a line A descaling device are further provided between the line A hot coil station and the finishing rolling unit, and the line A descaling device is located downstream of the line A heating device.

3. The hybrid rolling production line according to claim 2, characterized in that: The A-line heating device adopts an induction heating furnace.

4. The hybrid rolling production line according to claim 1, characterized in that: The A-line roughing unit includes 1 to 5 roughing mills; the finishing unit includes 3 to 8 finishing mills; and the B-line roughing unit includes at least 1 roughing mill.

5. The hybrid rolling production line according to claim 4, characterized in that: The A-line roughing unit includes three four-high roughing mills; the finishing unit includes six four-high finishing mills; and the B-line roughing unit includes one four-high reversing mill.

6. The production method of the hybrid rolling production line according to any one of claims 1 to 5, characterized in that: According to production requirements, the hybrid rolling production line is operated in thin slab production mode or thick slab production mode. (1) In the thin slab production mode: The continuous casting unit casts a thin-gauge continuous casting slab, which enters the rough rolling unit of line A to be rolled to obtain a first intermediate bar, which enters the coiling unit for coiling after finish rolling and cooling; (2) In the thick slab production mode: The thick-gauge slab is heated to a target temperature by the heating furnace and then enters the rough rolling unit of line B to obtain a second intermediate slab; The mobile hot coiling device moves to the hot coiling station of line B to coil the second intermediate billet into an intermediate hot coil, and then moves to the hot coiling station of line A to uncoil the intermediate hot coil into a single intermediate billet; The single intermediate billet is finished rolled and cooled before entering the coiling unit for coiling.

7. The production method according to claim 6, characterized in that In the thin slab production mode, the mobile hot coil device moves to the B-line hot coil station. Before the first intermediate billet enters the finishing rolling unit, the first intermediate billet is heated to 1050℃-1150℃ by the A-line heating device arranged between the A-line hot coil station and the finishing rolling unit.

8. The production method according to claim 6, characterized in that In the thin slab production mode, the mobile hot coiling device moves to the A-line hot coiling station, and the mobile hot coiling device coils and uncoils the first intermediate billet, and the first intermediate billet is supplemented with heat by the A-line heating device arranged between the A-line hot coiling station and the finishing rolling unit.

9. The production method according to claim 6, wherein In the thick slab production mode, after the mobile hot coil device moves to the A-line hot coil station, the single intermediate slab is supplementarily heated by the A-line heating device arranged between the A-line hot coil station and the finishing rolling unit.

Images