CN117245068A - Quick-change process for slab high-quality carbon steel tundish - Google Patents
Quick-change process for slab high-quality carbon steel tundish Download PDFInfo
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- CN117245068A CN117245068A CN202311397936.8A CN202311397936A CN117245068A CN 117245068 A CN117245068 A CN 117245068A CN 202311397936 A CN202311397936 A CN 202311397936A CN 117245068 A CN117245068 A CN 117245068A
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- 238000000034 method Methods 0.000 title claims abstract description 57
- 230000008569 process Effects 0.000 title claims abstract description 48
- 229910000975 Carbon steel Inorganic materials 0.000 title claims abstract description 29
- 239000010962 carbon steel Substances 0.000 title claims abstract description 29
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 110
- 239000010959 steel Substances 0.000 claims abstract description 110
- 238000005266 casting Methods 0.000 claims abstract description 62
- 239000002893 slag Substances 0.000 claims description 68
- 239000007788 liquid Substances 0.000 claims description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 230000008859 change Effects 0.000 claims description 33
- 238000003825 pressing Methods 0.000 claims description 17
- 238000010079 rubber tapping Methods 0.000 claims description 11
- 230000009467 reduction Effects 0.000 claims description 10
- 230000000903 blocking effect Effects 0.000 claims description 2
- 238000004806 packaging method and process Methods 0.000 claims 2
- 229920002148 Gellan gum Polymers 0.000 claims 1
- 229910000677 High-carbon steel Inorganic materials 0.000 claims 1
- 230000003068 static effect Effects 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000005272 metallurgy Methods 0.000 abstract description 2
- 238000002360 preparation method Methods 0.000 description 15
- 238000007689 inspection Methods 0.000 description 6
- 238000009749 continuous casting Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000012858 packaging process Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000005499 meniscus Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- RQMIWLMVTCKXAQ-UHFFFAOYSA-N [AlH3].[C] Chemical compound [AlH3].[C] RQMIWLMVTCKXAQ-UHFFFAOYSA-N 0.000 description 1
- OTCHGXYCWNXDOA-UHFFFAOYSA-N [C].[Zr] Chemical compound [C].[Zr] OTCHGXYCWNXDOA-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/005—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with heating or cooling means
- B22D41/01—Heating means
- B22D41/015—Heating means with external heating, i.e. the heat source not being a part of the ladle
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
The invention discloses a quick-changing process of a plate blank high-quality carbon steel tundish, which belongs to the technical field of metallurgy and comprises the following steps of: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; finally, after the molten steel in the first furnace is poured, the pulling speed of the casting blank is adjusted, and when the stopping weight is reached, the old tundish clamping rod pushes the blind plate, meanwhile, the pulling speed of the new tundish is reduced, and the ladle receiving is completed. By using the process technology, the slab casting machine realizes quick replacement of the high-quality carbon steel tundish, has the characteristics of simple operation and high success rate of quick replacement of the tundish, and is suitable for quick replacement of the high-quality carbon steel tundish in slab production.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a quick-change process for a plate blank high-quality carbon steel tundish.
Background
In the existing metallurgical enterprises of continuous casting, the improvement of productivity of a slab continuous casting machine mainly depends on the implementation of ladle receiving production, and the ladle quick-change technology in continuous casting is a method for reducing the casting stop and production preparation times of the casting machine, improving the slab productivity and improving the operation rate of the casting machine. The ordinary carbon steel is steel with carbon content of 0.08-0.45%, and the optimal carbon steel with carbon content of 0.45-0.75%, and is steel with higher carbon content. Because the excellent carbon steel has high temperature characteristic and solidification characteristic, in the continuous casting process, the solidification shrinkage rate of molten steel in a crystallizer is large, the strength and the plasticity are low, cracks are very easy to generate in the cooling process, and risks such as casting blank fracture and the like can be caused by temperature stress even in an air cooling state. At present, under the condition that a proper quick-change tundish process control method is not found, tundish quick-change operation is not adopted when a slab caster produces excellent carbon steel, only about 15 furnaces can be produced in the original single casting time, and after casting is stopped, dummy ingot is sent again to do production preparation work for at least 1 hour, so that the slab caster efficiency and yield are greatly influenced, and a large amount of head and tail billets and cutting scraps are produced, so that the caster yield is influenced.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a quick-change process for a plate blank high-quality carbon steel tundish.
The invention solves the technical problems by adopting the following technical scheme.
The invention provides a quick-change process for a plate blank high-quality carbon steel tundish, which comprises the following steps of: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; finally, after the molten steel in the first furnace is poured, the pulling speed of the casting blank is adjusted, and when the stopping weight is reached, the old tundish clamping rod pushes the blind plate, meanwhile, the pulling speed of the new tundish is reduced, and the ladle receiving is completed.
The invention has the following beneficial effects:
the invention provides a quick-change process for a plate blank high-quality carbon steel tundish, which comprises the following steps of: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; finally, after the molten steel in the first furnace is poured, the pulling speed of the casting blank is adjusted, and when the stopping weight is reached, the old tundish clamping rod pushes the blind plate, meanwhile, the pulling speed of the new tundish is reduced, and the ladle receiving is completed. The invention adopts a mode of not stopping pulling speed, and reduces the pulling speed to replace a new tundish while the old tundish clamping rod pushes a blind plate. The method can realize quick replacement of the plate blank high-quality carbon steel tundish.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a quick change of a ladle in a slab carbon steel;
fig. 2 is a drawing speed curve of a new and old tundish quick-change tundish.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The quick-change process of the plate blank high-quality carbon steel tundish provided by the embodiment of the invention is specifically described below.
Aiming at the defect that the tundish of the prior-stage slab casting machine cannot be quickly replaced by the high-quality carbon steel, the embodiment of the invention provides a tundish quick-replacing process for the high-quality carbon steel of the slab casting machine. The quick-change process for the medium ladle of the slab high-quality carbon steel, with reference to FIG. 1, comprises the following steps:
the operation steps of the quick-change tundish are as follows:
preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4-5 h, the baking temperature of the tundish is 1050-1150 ℃, the baking time of the immersed water inlet is 50-90min, and the baking temperature of the tundish is 1000-1100 ℃.
Controlling the temperature of molten steel: the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish is controlled according to the upper limit of the casting furnace time +5deg.C (1550-1560deg.C), the ladle type is controlled according to A, B type ladle (in order to prevent the lower ladle temperature in the ladle receiving process, the cold steel is blocked in the casting process, the risks of poor ladle receiving mark and the like are increased, the temperature of the front and rear furnace times of the quick-change tundish is improved, the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish is controlled according to the upper limit of the casting furnace time +5deg.C (1550-1560deg.C), and the ladle type is controlled according to A, B type ladle).
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap. Old operation method: dynamic soft pressure L2 is used in the whole process, and the tension leveler is pressed by 4.5Mpa. And finally, closing the ladle sliding gate after pouring the ladle of the 1 furnace ladle, and lifting the fork arm of the rotary table to the highest position. After the new ladle is placed, the rotary table is rotated to the pouring position, and meanwhile, the fork arm is kept to be lifted to the highest position. The dynamic soft pressure L2 is used in the whole process of the old operation, and the tension leveler is pressed by 4.5Mpa. In the quick-change packaging process, the liquid core is contracted at 8-9 sections in the 270mm thickness packaging process, and the liquid core is contracted at 7-8 sections in the 220mm thickness packaging process. The casting blank is short in ladle receiving and speed reducing time, so that shrinkage is insufficient (the casting blank is not shrunk to a straightening section), a casting blank at the solidification end has slight bulging, the casting blank is high in blank drawing resistance and is not pulled to be in ladle receiving failure, particularly, a 12-section roller is easy to top dead of the casting blank at a 12-section position, by adopting the scheme provided by the embodiment of the invention, the liquid core is shrunk at 7-8 sections in a 270mm thick ladle receiving process, the liquid core is shrunk at 6-7 sections in a 220mm thick ladle receiving process, and after the 12-section roller gap is raised by 20mm, the casting blank passes through each sector section smoothly.
New and old tundish quick change:
and after the pouring basket molten steel is left for 14-17t, ending baking of the standby pouring basket, before the old pouring basket molten steel is closed for about 3min, switching the crystallizer liquid level control to manual control, rotating the crystallizer liquid level sensor to the rear position, checking and accepting the standby pouring basket, closing a water gap baking gas and a pouring basket baking device, immediately lifting the old pouring basket and moving the pouring basket to the position above a slag plate after a blocking rod pushes a blind plate, fishing out slag strips around a shell of the crystallizer, performing black slag operation on the crystallizer, and controlling the thickness of a protective slag layer to be 60-70mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the tundish while pouring a large ladle, lowering a submerged nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, and when the tundish nozzle is poured with the large ladle, slightly moving the tundish to be below the submerged nozzle side hole to be below the molten steel liquid level of the crystallizer for pouring, pressing a large steel flow to open the tundish, starting the ladle, using a wooden strip to move the liquid level of the crystallizer near the tundish nozzle, observing the condition of no-quenching steel or blank shell without demoulding, picking out large slag skin around the crystallizer, and preventing the incompletely solidified molten steel from capturing slag skin to generate joint steel leakage.
The control curve of the packet receiving pulling speed in the quick change process of the new and old tundish is shown in fig. 2, and the specific pulling speed is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the new middle ladle is pressed and the stopper rod is opened for casting, the pulling speed is manually lifted to 0.2m/min for 2min, and then the pulling speed is lifted to 0.3m/min, and the pulling speed is gradually lifted to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the ladle receiving time is less than or equal to 110S, and the casting blank thickness is 270mm and less than or equal to 150S. Whereas the old operation operates as follows: and (3) manually reducing the pulling speed to 0.80m/min within 2min after pouring of the ladle molten steel is finished, keeping the pulling speed at 0.80m/min for at least 3min, pushing the blind plate by the old ladle clamping rod when the pouring stopping weight is reached, simultaneously pressing a stop button of the withdrawal and straightening machine, and automatically returning the pulling speed to zero, wherein the liquid level of the crystallizer steel is at or slightly lower than the position of the meniscus. And (3) after the pouring ladle is pressed and the stopper is opened by the old operation, manually lifting the pulling speed to 0.5m/min for 1 minute, and gradually lifting the pulling speed to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The liquid core of the casting blank is lifted by the pulling speed to be prolonged, the contraction is insufficient (the casting blank is not contracted to the straightening section) due to short ladle receiving and reducing time, and the casting blank at the solidification end has slight bulging, so that the drawing resistance is large and the casting blank is not moved. By improving operation, the scheme provided by the embodiment of the invention can reduce the ladle receiving time, prevent the blank shell in the crystallizer from shrinking too fast in the ladle receiving process, break the water inlet by collision of the blank shell, reduce the pulling speed to 0.03m/min for quick-changing the tundish by adopting a mode without stopping the pulling speed, and improve the success rate of quick-changing the tundish.
The features and capabilities of the present invention are described in further detail below in connection with the examples.
Example 1
The quick-change process for the slab high-quality carbon steel tundish comprises the following steps of referring to fig. 1 in a flow chart:
preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4-5 h, the baking temperature of the tundish is 1050-1150 ℃, the baking time of the immersed water inlet is 50-90min, and the baking temperature of the tundish is 1000-1100 ℃.
Controlling the temperature of molten steel: the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish is controlled according to the upper limit of the casting furnace time +5deg.C (1550-1560 deg.C), and the ladle class is controlled according to A, B class.
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap.
New and old tundish quick change:
and after the steel ladle remains for 14-17t and the spare tundish is baked, before the old tundish is closed for about 3min, the crystallizer liquid level control is switched to manual control, the crystallizer liquid level sensor rotates to the rear position, the new tundish is checked and accepted, the new water inlet baking gas and the new tundish baking device are closed, the old tundish clamping rod pushes the blind plate, the old tundish is immediately lifted and moved to the position above the slag pan, slag strips around the shell of the crystallizer are fished out, the black slag operation of the crystallizer is carried out, and the thickness of a covering slag layer is controlled to be 60-70mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening the pouring ladle, lowering the immersed water nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, and when the ladle is opened to pour the tundish molten steel for about 4.3t, tapping the tundish to be lowered to the side hole of the immersed water nozzle to be below the molten steel liquid level of the crystallizer, opening the pouring ladle by pressing a first bar, tapping the molten steel by pressing a wooden strip, using the mold liquid level near the tundish nozzle in the ladle tapping process, observing the condition of no-junction cold steel or blank shell without demoulding, picking out large slag skin around the crystallizer, and preventing the incompletely solidified molten steel from capturing slag skin to generate joint steel leakage.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the middle ladle is pressed to open the stopper rod for casting, the pulling speed is manually increased to 0.2m/min for 2min, and then the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the ladle receiving time is less than or equal to 110S, and the casting blank thickness is 270mm and less than or equal to 150S.
Example 2
Preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4 hours, the baking temperature of the tundish is 1060 ℃, the baking time of the immersed water inlet is 55 minutes, and the baking temperature of the tundish is 1015 ℃.
Controlling the temperature of molten steel: the ladle of the fast-changing tundish front furnace is a B-type ladle, the outlet temperature of molten steel is 1550 ℃, the ladle receiving furnace time ladle is an A-type ladle, and the outlet temperature of molten steel is 1560 ℃.
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap.
New and old tundish quick change:
and after the old tundish molten steel is left for 17t, ending baking of the standby tundish, before the old tundish molten steel is closed for about 3min, switching the crystallizer liquid level control to manual control, rotating the crystallizer liquid level sensor to a rear position, checking and accepting the new tundish, closing a new water port baking gas and a new tundish baking device, immediately lifting the old tundish and moving the old tundish to a position above a slag pan after the old tundish clamping bars push blind plates, fishing out slag strips around a crystallizer blank shell, performing crystallizer black slag operation, and controlling the thickness of a protecting slag layer to be 66mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening the pouring ladle, lowering the immersed water nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, and when the ladle is opened to pour the tundish molten steel for about 4.9t, tapping the tundish to be lowered to the side hole of the immersed water nozzle to be below the molten steel liquid level of the crystallizer, opening the pouring ladle by pressing a first bar, tapping the molten steel by pressing a wooden strip, using the mold liquid level near the tundish nozzle in the ladle tapping process, observing the condition of no-junction cold steel or blank shell without demoulding, picking out large slag skin around the crystallizer, and preventing the incompletely solidified molten steel from capturing slag skin to generate joint steel leakage.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the middle ladle is pressed to open the stopper rod for casting, the pulling speed is manually increased to 0.2m/min for 2min, and then the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the package receiving time is 65S, and the casting blank thickness is 270mm, and the package receiving time is 120S.
Example 3
Preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4.2 hours, the baking temperature of the tundish is 1085 ℃, the baking time of the immersed water inlet is 70 minutes, and the baking temperature of the tundish is 1050 ℃.
Controlling the temperature of molten steel: the ladle of the fast-changing tundish front furnace is a class A ladle, the outlet temperature of molten steel is 1560 ℃, the ladle receiving furnace time ladle is a class B ladle, and the outlet temperature of molten steel is 1558 ℃.
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap.
New and old tundish quick change:
and after the old tundish molten steel is left for 15t, finishing baking of the standby tundish, before the old tundish molten steel is closed for about 3min, switching the crystallizer liquid level control to manual control, rotating the crystallizer liquid level sensor to a rear position, checking and accepting the new tundish, closing a new water port baking gas and a new tundish baking device, immediately lifting the old tundish and moving the old tundish to a position above a slag pan after the old tundish clamping bars push blind plates, fishing out slag strips around a crystallizer blank shell, performing crystallizer black slag operation, and controlling the thickness of a protective slag layer to be 61mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening the pouring ladle, lowering the immersed water nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, and when the ladle is opened to pour the tundish molten steel for about 4.5t, tapping the tundish to be lowered to the side hole of the immersed water nozzle to be below the molten steel liquid level of the crystallizer, opening the pouring ladle by pressing a first bar, tapping the molten steel by pressing a wooden strip, using the mold liquid level near the tundish nozzle in the ladle tapping process, observing the condition of no-junction cold steel or blank shell without demoulding, picking out large slag skin around the crystallizer, and preventing the incompletely solidified molten steel from capturing slag skin to generate joint steel leakage.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the middle ladle is pressed to open the stopper rod for casting, the pulling speed is manually increased to 0.2m/min for 2min, and then the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the package receiving time is 100S, and the casting blank thickness is 270mm, and the package receiving time is 130S.
Example 4
Preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4.5 hours, the baking temperature of the tundish is 1123 ℃, the baking time of the immersed water inlet is 80 minutes, and the baking temperature of the tundish is 1092 ℃.
Controlling the temperature of molten steel: the ladle of the fast-changing tundish front furnace is a type A ladle, the outlet temperature of molten steel is 1555 ℃, the ladle receiving furnace time ladle is a type B ladle, and the outlet temperature of molten steel is 1553 ℃.
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap.
New and old tundish quick change:
and after the steel ladle is subjected to molten steel remaining for 14.3t, finishing baking of the standby tundish, before the old tundish is closed for about 3min, switching the crystallizer liquid level control to manual control, rotating the crystallizer liquid level sensor to a rear position, checking and accepting the new tundish, closing a new water port baking gas and a new tundish baking device, immediately lifting the old tundish and moving the old tundish to a slag pan, fishing out slag strips around a crystallizer blank shell, performing crystallizer black slag operation, and controlling the thickness of a covering slag layer to be 68mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and (3) opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening the pouring ladle, lowering the immersed water nozzle to be above the molten steel liquid level of the crystallizer, performing fine adjustment centering on the tundish nozzle, slightly moving the tundish to be opened until the immersed water nozzle side hole is lowered to be below the molten steel liquid level of the crystallizer for about 5t, opening the pouring ladle by pressing a first bar, opening the pouring by pressing a large steel flow, starting the pouring by pressing a wooden bar, using the mold liquid level near the tundish nozzle, observing the condition of no-demoulding of the cold steel or the blank shell, picking out large slag skin around the crystallizer, and preventing the incompletely solidified molten steel from capturing slag skin to generate joint steel leakage.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the middle ladle is pressed to open the stopper rod for casting, the pulling speed is manually increased to 0.2m/min for 2min, and then the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the package receiving time is 105S, and the casting blank thickness is 270mm, and the package receiving time is 136S.
Example 5
Preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 4.8 hours, the baking temperature of the tundish is 1130 ℃, the baking time of the immersed water inlet is 85 minutes, and the baking temperature of the tundish is 1095 ℃.
Controlling the temperature of molten steel: the ladle of the fast-changing tundish front furnace is a B-type ladle, the outlet temperature of molten steel is 1554 ℃, the ladle of the receiving furnace is an A-type ladle, and the outlet temperature of molten steel is 1558 ℃.
Tool preparation and inspection before pack change: tools used for preparing to change packages: splash guards, slag scooping bars, battens and the like; checking whether the lifting of the standby middle ladle roaster is normal or not and whether the lifting and the walking of the standby middle ladle are normal or not; and (5) removing sundries on the running track of the tundish car, and ensuring smooth running of the tundish car.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: finally, pouring the ladle in the furnace 1 is controlled by a dynamic soft reduction L2 control-static roll gap L1, and the tension leveler roll pressure is increased from 4.5Mpa to 6Mpa. After the pulling speed is reduced to 0.5m/min, the 12-section roll gap is lifted by 20mm, and the pulling speed of the connected bag is lifted to 0.5m/min to gradually recover the 12-section roll gap.
New and old tundish quick change:
and after the molten steel of the tundish remains 16.3t, finishing baking of the standby tundish, before the old tundish is closed for about 3min, switching the crystallizer liquid level control to manual control, rotating the crystallizer liquid level sensor to a rear position, checking and accepting the new tundish, closing a new water port baking gas and a new tundish baking device, immediately lifting the old tundish and moving the old tundish to a position above a slag pan after the old tundish is clamped by a rod to push a blind plate, fishing out slag strips around a shell of the crystallizer, operating the black slag of the crystallizer, and controlling the thickness of a covering slag layer to be 64mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and (3) opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening the pouring ladle, lowering the immersed water nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, slightly moving the tundish to be opened until the immersed water nozzle side hole is lowered to be below the molten steel liquid level of the crystallizer for about 4t, opening the pouring ladle by pressing a first bar, opening the pouring by pressing a large steel flow, starting the pouring by pressing a wooden bar, using the mold liquid level near the tundish nozzle in the pouring ladle, observing the condition of no-quenching steel or blank shell non-demoulding, picking out large slag skin around the crystallizer, and preventing the slag skin from being caught by incompletely solidified molten steel to generate joint steel leakage.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
the pulling speed is manually reduced to 0.20m/min (15-20 seconds is taken as a step every 0.02 m/min), the pulling speed is kept within 0.2m/min for 1-2min, the liquid core is received within 8 sections, the old middle ladle clamping rod pushes the blind plate, meanwhile, the pulling speed is reduced to 0.03m/min, the middle ladle is replaced, after the middle ladle is pressed to open the stopper rod for casting, the pulling speed is manually increased to 0.2m/min for 2min, and then the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer. The casting blank thickness is 220mm, the ladle receiving time is less than or equal to 110S, and the casting blank thickness is 270mm and less than or equal to 150S.
Comparative example 1
Similar to the procedure of example 1, the only difference is that: and the old operation method results in the failure of the quick change of the middle packet.
Preparation before quick replacement:
baking of tundish and submerged nozzle: the baking time of the standby tundish is 6 hours, the baking temperature of the tundish is 1210 ℃, the baking time of the immersed water inlet is 180 minutes, and the baking temperature of the tundish is 1200 ℃.
Controlling the temperature of molten steel: and controlling the temperature of the molten steel discharged from the furnace at the front and rear times of the quick-change tundish according to the upper limit of the continuous casting standard.
Controlling the roller gap of the sector section and controlling the roller tension of the tension leveler: the roll gap of the sector section is controlled by dynamic soft reduction L2, and the tension leveler roll pressure is 4.5Mpa.
New and old tundish quick change:
after the old tundish molten steel is closed, the standby tundish baking is finished, the new tundish is checked and accepted, the old tundish is immediately lifted and moved above a slag pan, slag strips around a crystallizer blank shell are fished out, the crystallizer black slag operation is performed, and the thickness of a casting powder slag layer is controlled to be 60-70mm. At the same time, a new tundish to be replaced at the slag pan position is opened to the pouring position.
Pouring in a new tundish: and (3) opening a new tundish to be replaced at the slag pan position to a pouring position, centering a tundish nozzle, lowering the new tundish, simultaneously opening a large ladle for pouring, lowering a submerged nozzle to be above the molten steel liquid level of the crystallizer, fine-tuning and centering the tundish nozzle, and when the large ladle is opened for pouring the tundish molten steel for about 4-5t, tapping the tundish to be lowered to a side hole of the submerged nozzle to be below the molten steel liquid level of the crystallizer for pouring.
The packet receiving pulling speed in the quick change process of the new and old tundish is controlled as follows:
and (3) manually reducing the pulling speed to 0.80m/min within 2min after pouring of the ladle molten steel is finished, keeping the pulling speed at 0.80m/min for at least 3min, pushing the blind plate by the middle Bao Kabang when the pouring stopping weight is reached, simultaneously pressing a stop button of the withdrawal and straightening machine, and automatically returning the pulling speed to zero, wherein the liquid level of the crystallizer steel is at or slightly lower than the position of the meniscus. After the tundish pressing stopper opening rod is opened, the pulling speed is manually increased to 0.5m/min for 1 minute, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer.
Comparative example 2
Similar to the procedure of example 1, the only difference is that: and finally, the roll gap of the large ladle casting sector section of the furnace 1 is controlled by dynamic soft reduction L2, the tension leveler roll pressure is 4.5Mpa, and the tension leveler roll pressure is too small due to the overlarge roll gap reduction of the sector section, so that the blank pulling resistance in the ladle receiving process is easily caused to be large, and the success rate of quick change of the tundish is reduced.
Comparative example 3
Similar to the procedure of example 1, the only difference is that: the baking temperature of the new tundish is 1210 ℃, the baking time of the tundish is long, when the over-baking temperature is more than or equal to 1200 ℃, the oxidation melting loss of the stopper rod, the melting loss deformation loosening of the stopper rod core and the cross arm, the falling of the melting loss deformation resistant material of the steel structure of the ladle cover, the collapse of the working layer, the bonding of the stopper rod head to the bowl part of the water inlet and the like are caused, so that the success rate of quick replacement of the tundish is reduced.
Comparative example 4
Similar to the procedure of example 1, the only difference is that: the immersed water inlet is baked for 180min, when the baking time and the baking temperature are higher to the temperature of the water inlet 1168 ℃, the aluminum carbon or zirconium carbon water inlet is oxidized and decarbonized, the strength and the service life are reduced, and the whole service life of the tundish is influenced.
From the above, it can be seen that: the temperature of the front furnace and the rear furnace of the quick-change tundish is improved, so that risks of cold steel clamping, poor splicing mark of the tundish and the like caused by low ladle temperature and casting start in the ladle splicing process can be effectively prevented; the casting blank resistance in the ladle receiving process can be effectively reduced by increasing the tension-leveled roller pressure from 4.5Mpa to 6Mpa and raising the 12-section roller gap by 20mm after the tension-leveled roller pressure is reduced to 0.5 m/min; by adopting a mode of not stopping the pulling speed, the pulling speed is reduced to 0.03m/min for quick changing of the middle ladle, the ladle receiving time can be effectively reduced, and the blank shell in the crystallizer is prevented from shrinking too fast in the ladle receiving process, so that the blank shell bumps into the water inlet.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The quick-change process for the plate blank high-quality carbon steel tundish is characterized by comprising the following steps of: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; finally, after the molten steel in the first furnace is poured, the pulling speed of the casting blank is adjusted, and when the stopping weight is reached, the old tundish clamping rod pushes the blind plate, meanwhile, the pulling speed of the new tundish is reduced, and the ladle receiving is completed.
2. The slab high-quality carbon steel tundish quick-change process according to claim 1, comprising the following steps: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; and (3) flameout a baking burner of the new tundish in preheating standby, lifting the roaster, checking and accepting the new tundish, lifting the new tundish to a high position, opening the new tundish to a slag pan position for waiting, starting the new tundish, simultaneously pouring an old tundish clamping rod to push a blind plate, simultaneously reducing a pulling blank to quickly replace the new tundish, and completing the ladle receiving.
3. The slab high-quality carbon steel tundish quick-change process according to claim 2, comprising the following steps: baking the new tundish, lifting the temperature of the molten steel discharged from the front and rear furnace times of the quick-change tundish, and adjusting the roll gap of the sector section and the tension-leveler roll to perform final molten steel pouring; 3min before closing the old tundish molten steel, switching the crystallizer liquid level control to manual control, rotating a crystallizer liquid level sensor to a rear position, checking and accepting a new tundish, closing a water gap baking gas and baking device of the new tundish, immediately lifting the old tundish and moving the old tundish above a slag pan after a blocking rod of the old tundish pushes a blind plate, fishing out slag strips around a crystallizer blank shell, performing black slag operation on the crystallizer, controlling the thickness of a protecting slag layer to be 60-70mm, simultaneously opening the new tundish to be replaced at the slag pan position to a pouring position, centering the water gap of the new tundish, lowering the water inlet of the new tundish to be above the molten steel liquid level of the crystallizer, performing fine adjustment centering on the water inlet of the new tundish, and when the water gap of the new tundish is opened to 4-5t, tapping the new tundish to be below the molten steel liquid level of the crystallizer, and pressing a large steel flow opening side hole of the first rod;
preferably, in the ladle receiving process, a wooden strip is used for inching the liquid level of a crystallizer near a tundish nozzle, whether the gellan steel exists or not or whether the blank shell is not demoulded is observed, and large slag skin around the crystallizer is selected, so that the slag skin is prevented from being captured by incompletely solidified molten steel, and joint steel leakage is prevented.
4. A slab excellent carbon steel tundish quick change process according to claim 3, wherein the sector section comprises 1-12 sections, and the steps of adjusting the roll gap of the sector section and the tension-leveled roll to perform final molten steel pouring comprise the following steps: finally, the control mode of the roll gap of the large ladle casting sector section of the furnace 1 is changed from a dynamic soft reduction L2 control mode to a static roll gap L1 control mode, the tension-leveled roll pressure is increased from 4.5Mpa to 6Mpa, after the tension speed is reduced to 0.5m/min, the roll gap of 12 sections is lifted by 20mm, and after the ladle receiving is completed, the tension speed is increased to 0.5m/min to gradually restore the roll gap of 12 sections.
5. A slab excellent carbon steel tundish quick-change process according to claim 3, characterized in that the ladle pulling rate is controlled as follows: and finally, the pulling speed is manually reduced to 0.20m/min after the molten steel in the furnace is poured, the pulling speed is kept at 1-2min at 0.2m/min for 15-20 seconds by taking each 0.02m/min as a step, the liquid core shrinkage is controlled within 8 sections, the old tundish clamping rod pushes the blind plate, the pulling speed is reduced to 0.03m/min, a new tundish is replaced, after the new tundish is pressed and the stopper rod is opened, the pulling speed is manually increased to 0.2m/min for 2 minutes, the pulling speed is increased to 0.3m/min, and the pulling speed is gradually increased to the target pulling speed after the interface part of the casting blank is out of the crystallizer.
6. A slab excellent carbon steel tundish quick-change process according to claim 3, characterized in that the ladle receiving time is controlled as follows: the casting blank thickness is 220mm, the ladle receiving time is less than or equal to 110S, and the casting blank thickness is 270mm and less than or equal to 150S.
7. A slab excellent carbon steel tundish quick-change process according to claim 3, characterized in that the liquid core shrinkage in the ladle receiving process is controlled as follows: the shrinkage of the liquid core in the process of receiving and packaging with the thickness of 270mm is controlled between 7 sections and 8 sections, and the shrinkage of the liquid core in the process of receiving and packaging with the thickness of 220mm is controlled between 6 sections and 7 sections.
8. A slab high carbon steel tundish quick change process according to claim 3, characterized in that the baking of the new tundish comprises: the baking temperature of the new tundish is controlled to be 1050-1150 ℃, the baking time is controlled to be 4-5 h, the baking temperature of the immersed water inlet is controlled to be 1000-1100 ℃, and the baking time is controlled to be 50-90min.
9. The slab high-quality carbon steel tundish quick-change process according to claim 8, further comprising: and baking the new tundish, and ending the baking of the new tundish when the molten steel of the old tundish remains for 14-17 t.
10. A slab excellent carbon steel tundish quick change process according to claim 3, wherein raising the temperature of the molten steel at the front and rear heat outlets of the quick change tundish comprises: and (5) controlling the temperature of the molten steel discharged from the furnace after the quick-change tundish according to the upper limit of the casting furnace at +5 ℃.
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