CN115178719A - Method for reducing longitudinal cracks of hypoperitectic steel continuous casting slab - Google Patents
Method for reducing longitudinal cracks of hypoperitectic steel continuous casting slab Download PDFInfo
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- CN115178719A CN115178719A CN202210292675.2A CN202210292675A CN115178719A CN 115178719 A CN115178719 A CN 115178719A CN 202210292675 A CN202210292675 A CN 202210292675A CN 115178719 A CN115178719 A CN 115178719A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 113
- 239000010959 steel Substances 0.000 title claims abstract description 113
- 238000009749 continuous casting Methods 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000007654 immersion Methods 0.000 claims abstract description 49
- 239000002893 slag Substances 0.000 claims abstract description 16
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052802 copper Inorganic materials 0.000 claims abstract description 11
- 239000010949 copper Substances 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims abstract description 10
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 112
- 229910052786 argon Inorganic materials 0.000 claims description 56
- 239000007789 gas Substances 0.000 claims description 39
- 238000005266 casting Methods 0.000 claims description 25
- 239000000498 cooling water Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000007547 defect Effects 0.000 abstract description 13
- 230000000694 effects Effects 0.000 abstract description 7
- 238000005461 lubrication Methods 0.000 abstract description 6
- 230000001681 protective effect Effects 0.000 abstract description 4
- 230000008569 process Effects 0.000 abstract description 3
- 230000002035 prolonged effect Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000003628 erosive effect Effects 0.000 description 5
- 238000012856 packing Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
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- 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
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Abstract
The invention relates to the technical field of continuous casting processes, in particular to a method for reducing longitudinal cracks of a hypoperitectic steel continuous casting slab, which comprises the following steps: pouring molten steel into a tundish, and conveying the molten steel into a crystallizer from the tundish through an immersion nozzle; placing the covering slag on the liquid level of the molten steel in the crystallizer; the immersion depth of the immersion nozzle is adjusted according to the heat of each pouring time, so that the activity of molten steel near the immersion nozzle in the crystallizer is improved, the flow speed of the surface of the molten steel is improved, the temperature is increased, the protective slag on the surface of the molten steel is melted and uniformly enters gaps between a copper plate and a blank shell of the crystallizer to play a role in heat conduction and lubrication, the uniformity of a primary blank shell is ensured, the longitudinal crack defect is avoided, the immersion depth of the immersion nozzle is adjusted, the contact position of the immersion nozzle and the liquid level of the molten steel is increased, the molten steel is prevented from always corroding one position of the immersion nozzle, and the service life is prolonged.
Description
Technical Field
The invention relates to the technical field of continuous casting processes, in particular to a method for reducing longitudinal cracks of a hypoperitectic steel continuous casting slab.
Background
In the continuous casting production, the steel is divided into ultra-low carbon steel, hypo-peritectic steel, medium carbon steel, high carbon steel and the like according to the carbon content in the steel, the hypo-peritectic steel generally refers to the steel with the carbon content of 0.08-0.12%, the shrinkage of a casting blank caused by peritectic reaction is increased rapidly, an as-grown blank shell is very fragile, the early tearing of the blank shell can be caused by the separation of the blank shell from the surface of a crystallizer and the disturbance of the blank shell from the outside, and the large-area longitudinal crack of the casting blank is formed in the crystallizer, so that the invention provides a method for reducing the longitudinal crack of the hypo-peritectic steel continuous casting blank.
Disclosure of Invention
The embodiments of the present invention are directed to solving at least one of the technical problems occurring in the prior art or the related art.
Therefore, the invention aims to provide a method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab.
In order to achieve the purpose, the technical scheme of the embodiment of the invention provides a method for reducing the longitudinal crack of a hypo-peritectic steel continuous casting slab, which comprises the following steps:
pouring molten steel into a tundish, wherein the molten steel is conveyed into a crystallizer from the tundish through a submerged nozzle;
placing the covering slag on the liquid level of the molten steel in the crystallizer;
and adjusting the immersion depth of the submerged nozzle according to the heat of each pouring.
In addition, the method for reducing the longitudinal crack of the hypo-peritectic steel continuous casting slab in the technical scheme provided by the embodiment of the invention can also have the following additional technical characteristics:
in one aspect of the embodiment of the present invention, the step of transferring the molten steel from the tundish to the mold through the submerged nozzle includes:
and inserting a stopper rod into a molten steel flow channel of the tundish, wherein air holes are formed among the stopper rod, a water feeding port of the tundish and the tundish plate, and argon is dissipated through the air holes.
In one technical solution of the embodiment of the present invention, the step of dissipating argon through the gas hole includes:
adjusting the flow of argon gas escaping from the stopper rod pore to be 1 liter/min to 3 liters/min;
adjusting the flow of argon dissipated from the air hole of the water feeding port of the tundish to be 1 liter/min to 3 liters/min;
the flow rate of argon gas escaping from the gas holes between the tundish plates was adjusted to 2 liters/minute to 5 liters/minute.
In one technical solution of the embodiment of the present invention, the step of dissipating argon through the gas hole further includes:
adjusting the pressure of argon gas escaping from the gas hole of the stopper rod to be 0.2 MPa to 0.4 MPa;
adjusting the pressure of argon gas dissipated from the air holes of the water feeding port of the tundish to be 0.2-0.4 MPa;
the pressure of argon gas escaping from the air holes between the tundish plates is adjusted to be 0.2 MPa to 0.4 MPa.
In one aspect of the embodiment of the present invention, the step of adjusting the immersion depth of the submerged nozzle according to the heat of each casting includes:
in the first heat of each pouring time, adjusting the immersion depth of the submerged nozzle to a first preset depth;
adjusting the immersion depth of the submerged nozzle to a second preset depth in a second heat to a fourth heat of each pouring heat;
and adjusting the immersion depth of the submerged nozzle to a third preset depth in the fifth heat of each casting time to the heat of replacing the submerged nozzle.
In a technical solution of the embodiment of the present invention, the first preset depth is 120 mm to 140 mm;
the second preset depth is 141 mm to 160 mm;
the third preset depth is 120 mm to 140 mm.
In one technical solution of the embodiment of the present invention, the method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab further includes:
heating or cooling the cooling water of the crystallizer so that the temperature of the cooling water is kept between 30 ℃ and 37 ℃.
In one technical solution of the embodiment of the present invention, the method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab further includes:
controlling the excessive steel amount of the crystallizer within the range of 9-10 ten thousand tons, and replacing the crystallizer when the excessive steel amount of the crystallizer is not less than 10 ten thousand tons.
In one technical scheme of the embodiment of the invention, the melting point temperature of the mold flux is 1050-1150 ℃.
In one technical solution of the embodiment of the present invention, the method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab further includes:
and monitoring the temperature information of the crystallizer copper plate and the temperature information of the casting blank in real time, and adjusting the flow of cooling water based on the monitored data information.
Compared with the prior art, the invention at least comprises the following beneficial effects:
the invention provides a method for reducing the longitudinal crack of a hypo-peritectic steel continuous casting slab, which improves the activity of molten steel near an immersion nozzle in a crystallizer by adjusting the immersion depth of the immersion nozzle according to the heat of each casting time, thereby improving the flow speed on the surface of the molten steel and the temperature, so that protective slag on the surface of the molten steel is melted and uniformly enters a gap between a copper plate and a blank shell of the crystallizer to play the roles of heat conduction and lubrication, thereby ensuring the uniformity of an initial blank shell and avoiding the longitudinal crack defect, and increasing the contact position of the immersion nozzle and the liquid level of the molten steel by adjusting the immersion depth of the immersion nozzle, preventing the molten steel from always eroding one position of the immersion nozzle and prolonging the service life.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 shows a flow chart of steps of a method for reducing longitudinal cracks in a hypo-peritectic steel continuous casting slab, according to one embodiment of the invention.
Detailed Description
The present invention is further described in detail below with reference to the drawings and examples so that those skilled in the art can practice the invention with reference to the description.
It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
The embodiment of the application provides a method for reducing longitudinal cracks of a hypo-peritectic steel continuous casting slab, the implementation process can be shown as figure 1, and the method comprises the following steps:
step S101, pouring molten steel into a tundish, and conveying the molten steel into a crystallizer from the tundish through an immersion nozzle;
s102, placing the covering slag on the liquid level of the molten steel in the crystallizer;
and step S103, adjusting the immersion depth of the submerged nozzle according to the heat of each casting time.
The hypo-peritectic steel is easy to generate peritectic reaction, and rapid volume shrinkage can occur at the initial solidification stage of the blank shell, so that the blank shell is separated from the crystallizer to form an air gap, and if the effective slag film is not formed in time by the protective slag, the blank shell is easy to be cooled unevenly, and then the blank shell is torn to form a longitudinal crack defect. The invention considers that the surface longitudinal crack defect of the hypo-peritectic steel continuous casting slab usually occurs at 1/2 position of the width direction, and the position corresponds to the position near the submerged nozzle, and the activity of the molten steel near the submerged nozzle is improved by adjusting the submerged depth of the submerged nozzle, particularly reducing the distance between the liquid level of the molten steel and the outlet of the submerged nozzle, thereby improving the flow speed of the surface of the molten steel and the temperature, so that the protective slag on the surface of the molten steel is melted and uniformly enters the gap between the copper plate and the shell of the crystallizer to play the roles of heat conduction and lubrication, thereby ensuring the uniformity of the primary shell and avoiding the longitudinal crack defect.
It can be understood that the immersion depth of the immersion nozzle is adjusted, the contact position of the immersion nozzle and the molten steel level is increased, the molten steel is prevented from corroding one position of the immersion nozzle all the time, and the service life of the immersion nozzle is prolonged.
It will be appreciated that the temperature of different heats of the same pour may vary, for example, the temperature of the first furnace may be lower and then the temperature of the heat may be higher. Therefore, considering the influence of temperature, in order to melt the casting powder uniformly, the immersion depth of the immersion nozzle is adjusted according to different heats, so that the primary blank shell is uniform, and the longitudinal crack defect is avoided.
In some examples, the step of transferring the molten steel from the tundish to the mold through the submerged entry nozzle comprises: and a stopper rod is inserted into a molten steel flow channel of the tundish, and air holes are formed among the stopper rod, an upper water gap of the tundish and the tundish plate and used for dissipating argon through the air holes.
It can be understood that the stopper rod is arranged in the molten steel channel of the tundish, and the flow rate of the molten steel entering the crystallizer of the tundish is adjusted by adjusting the opening degree of the stopper rod, wherein the larger the opening degree of the stopper rod is, the faster the flow rate of the molten steel is.
The gas holes are formed among the stopper rod, the water feeding port of the tundish and the tundish plate, and argon is dissipated through the gas holes, specifically, the argon is dissipated from the stopper rod and the water feeding port of the tundish to form argon disturbance, so that molten steel is ensured to flow smoothly, and the situation that a molten steel channel is blocked due to the fact that impurities in the molten steel are gathered together is avoided; argon is dissipated from the middle packing plates to block gaps among the middle packing plates to form sealing, so that the conditions of molten steel deterioration, oxidation and the like caused by air flowing into the gaps are avoided, and the quality of the molten steel is ensured.
In some examples, the step of dissipating argon through the gas vent comprises: adjusting the flow of argon gas escaping from the stopper rod pore to be 1 liter/min to 3 liters/min; adjusting the flow of argon dissipated from the air hole of the water feeding port of the tundish to be 1 liter/minute to 3 liters/minute; the flow of argon gas escaping from the gas holes between the middle packing plates was adjusted to 2L/min to 5L/min.
The argon disturbance effect at the water feeding port of the stopper rod and the tundish is ensured by adjusting the flow of argon, the molten steel is ensured to flow smoothly, and the situation that the molten steel channel is blocked due to the fact that impurities in the molten steel are gathered together is avoided; the sealing performance between the tundish plates is ensured, the conditions of molten steel deterioration, oxidation and the like caused by air flowing in from gaps are avoided, and the quality of the molten steel is ensured.
Illustratively, the stopper argon flow rate was adjusted to 1 liter/minute, the upper nozzle argon flow rate of the tundish was adjusted to 2 liters/minute, and the inter-tundish argon flow rate was adjusted to 4 liters/minute.
In some examples, the step of dissipating argon through the gas vent further comprises: adjusting the pressure of argon gas dissipated from the plug air hole to be 0.2 MPa to 0.4 MPa; adjusting the pressure of argon dissipated from the air holes of the water feeding port of the tundish to be 0.2 MPa to 0.4 MPa; the pressure of argon gas released from the pores between the intermediate packing plates was adjusted to 0.2 MPa to 0.4 MPa.
It can be understood that, as argon gas between the stopper rod, the water feeding port and the plates is blown in, argon gas enters the crystallizer along with molten steel to form argon gas bubbles which float to the surface of the molten steel in the crystallizer, when the flow of the argon gas is too large, a large amount of argon gas bubbles float to the surface of the molten steel in the crystallizer, and a primary blank shell is stirred, so that the primary blank shell is not uniform in thickness in the initial solidification stage, and is torn to form longitudinal crack defects.
The argon gas disturbance effect at the water feeding port of the stopper rod and the tundish is ensured by adjusting the pressure of the argon gas, the molten steel is ensured to flow smoothly, and the situation that the molten steel channel is blocked due to the fact that impurities in the molten steel are gathered together is avoided, and meanwhile, the situation that the flow of the argon gas is too large is avoided; the sealing performance between the tundish plates is ensured, the conditions of molten steel deterioration, oxidation and the like caused by air flowing in from gaps are avoided, and the quality of the molten steel is ensured.
Illustratively, the flow pressure of the argon gas in the stopper rod is adjusted to 0.2 MPa, the pressure of the argon gas in the upper nozzle of the tundish is adjusted to 0.3 MPa, and the pressure of the argon gas between plates of the tundish is adjusted to 0.4 MPa.
In some examples, the step of adjusting the immersion depth of the submerged entry nozzle according to the heat of each casting includes: in the first heat of each pouring time, the immersion depth of the submerged nozzle is adjusted to a first preset depth; adjusting the immersion depth of the submerged nozzle to a second preset depth in a second heat to a fourth heat of each pouring time; and adjusting the immersion depth of the submerged nozzle to a third preset depth from the fifth heat of each casting time to the heat of replacing the submerged nozzle.
It will be appreciated that the temperature of different heats of the same heat may vary, for example the temperature of the first furnace may be lower and the temperature of the subsequent heat may be higher. Therefore, considering the influence of temperature on the casting powder, in order to ensure that the melted casting powder uniformly enters the gaps between the copper plate and the blank shell of the crystallizer to play roles of heat conduction and lubrication, thereby ensuring the uniformity of the primary blank shell and avoiding the defect of longitudinal cracking, the immersion depth of the immersion nozzle needs to be adjusted according to different heats.
Since the submerged entry nozzle needs to be immersed into molten steel, the service life of the submerged entry nozzle is affected by the erosion of the molten steel, and in order to ensure the production stability, the submerged entry nozzle is usually replaced after the sixth furnace use.
In some examples, the first preset depth is 120 millimeters to 140 millimeters; the second preset depth is 141 mm to 160 mm; the third predetermined depth is 120 mm to 140 mm.
It can be understood that, because the temperature of the first heat is lower, the temperature on the surface of the molten steel cannot enable the covering slag to be melted uniformly, the first preset depth of the submerged nozzle is set to be shallow, so that the activity of the molten steel near the submerged nozzle is improved, the flow speed on the surface of the molten steel is improved, the temperature is increased, the covering slag on the surface of the molten steel is melted and uniformly enters a gap between a crystallizer copper plate and a blank shell to play a role in heat conduction and lubrication, the uniformity of a primary blank shell is ensured, and the longitudinal crack defect is avoided, and the situation that the longitudinal crack defect is caused due to the fact that the submerged nozzle is inserted too shallow and is disturbed strongly on the liquid level of the molten steel is avoided being generated because the first preset depth is set to be 120 mm to 140 mm.
It can be understood that, the temperature rises after the second heat, the covering slag is melted more easily, the second preset depth of the submerged nozzle can be set to be deeper, the setting is 141 mm to 160 mm, the covering slag is melted uniformly, the disturbance to the liquid level of the molten steel is reduced, the occurrence of longitudinal crack defects is reduced, the position of the submerged nozzle is adjusted, the continuous erosion of the molten steel to the same position of the submerged nozzle is avoided, the service life of the submerged nozzle is prolonged, and the stability in use is improved.
It can be understood that, after the submerged nozzle is used three times at the second predetermined depth, in order to prevent the molten steel from continuously eroding the same position, the submerged nozzle is adjusted to the third predetermined depth from the fifth heat until the submerged nozzle is replaced, and the third predetermined depth is set to 120 mm to 140 mm, so that the molten steel is prevented from eroding more places toward the submerged nozzle.
In some examples, the method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab further comprises the following steps: and heating or cooling the cooling water of the crystallizer so that the temperature of the cooling water is kept between 30 and 37 ℃.
It can be understood that the crystallizer is provided with cooling device, cool off the copper, so that the molten steel shaping in the copper, detect the temperature of cooling water among the cooling device before casting, and heat or cool off the cooling water of crystallizer, make the temperature of cooling water keep between 30 degrees centigrade to 37 degrees centigrade, avoid the cooling water temperature too high not to reach refrigerated effect, the too low condition of production efficiency takes place, avoid the cooling water temperature too low simultaneously, lead to the blank shell to grow too fast, peritectic reaction shrinkage rate is local too fast, lead to the blank shell inhomogeneous, produce the rip defect.
In some examples, the method for reducing longitudinal cracks of the hypo-peritectic steel continuous casting slab further comprises: controlling the excessive steel amount of the crystallizer within the range of 9-10 ten thousand tons, and replacing the crystallizer when the excessive steel amount of the crystallizer is not less than 10 ten thousand tons.
It can be understood that the crystallizer is always in a high-temperature state when working, which is easy to damage, and needs to be replaced after being used for a period of time in order to avoid accidents, and the crystallizer is replaced by controlling the steel passing amount of the crystallizer within the range of 9-10 ten thousand tons, and when the steel passing amount exceeds 10 ten thousand tons, so that the production safety is ensured, and the risk is reduced.
In some examples, the melting point temperature of the mold flux is 1050 to 1150 degrees celsius. So set up, reduced the solidification temperature of covering slag to this guarantees to have the liquid slag film of abundant thickness to the lubrication of casting blank, thereby reduces the production of indulging the split.
In some examples, the method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab further comprises the following steps: and monitoring the temperature information of the crystallizer copper plate and the temperature information of the casting blank in real time, and adjusting the flow of cooling water based on the monitored data information.
It can be understood that the temperature of the copper plate of the crystallizer and the temperature of the casting blank are monitored in real time so as to determine whether the production is normally carried out, if the temperature is abnormal, the flow rate of the cooling water can be adjusted so as to ensure that the hypo-peritectic steel can be normally formed, and the longitudinal crack defect on the surface is less.
Illustratively, in one casting pass, the immersion depth of the submerged entry nozzle of the first furnace was fixed to 120 mm, the immersion depth of the submerged entry nozzles of the second to fourth furnaces was fixed to 150 mm, and the immersion depth of the submerged entry nozzles of the fifth and sixth furnaces was fixed to 120 mm. Adjusting the argon flow of the stopper to 2 liters/minute, adjusting the pressure value to 0.4 MPa, adjusting the argon flow of a water feeding port of the tundish to 2 liters/minute, adjusting the pressure value to 0.3 MPa, adjusting the argon flow between tundish plates to 3 liters/minute, adjusting the pressure value to 0.3 MPa, and adjusting the temperature of cooling water of the crystallizer to 35 ℃ before casting. And when the excessive steel amount of the crystallizer is 10 ten thousand tons, the crystallizer is replaced.
Illustratively, in one casting pass, the immersion depth of the submerged entry nozzle of the first furnace was fixed at 125 mm, the immersion depth of the submerged entry nozzles of the second to fourth furnaces was fixed at 145 mm, and the immersion depth of the submerged entry nozzles of the fifth and sixth furnaces was fixed at 125 mm. The argon flow of the stopper is adjusted to 1 liter/minute, the pressure value is adjusted to 0.4 MPa, the argon flow of the upper water port of the tundish is adjusted to 1 liter/minute, the pressure value is adjusted to 0.3 MPa, the argon flow between tundish plates is adjusted to 2 liters/minute, the pressure value is adjusted to 0.3 MPa, and the temperature of cooling water of the crystallizer is adjusted to 32 ℃ before casting. When the excessive steel amount of the crystallizer is 10 ten thousand tons, the crystallizer is replaced.
Illustratively, in one casting pass, the immersion depth of the submerged entry nozzle of the first furnace was fixed at 130 mm, the immersion depth of the submerged entry nozzles of the second to fourth furnaces was fixed at 150 mm, and the immersion depth of the submerged entry nozzles of the fifth and sixth furnaces was fixed at 130 mm. Adjusting the argon flow of the stopper to 2 liters/minute, adjusting the pressure value to 0.3 MPa, adjusting the argon flow of a water feeding port of the tundish to 2 liters/minute, adjusting the pressure value to 0.3 MPa, adjusting the argon flow between the tundish plates to 4 liters/minute, adjusting the pressure value to 0.3 MPa, and adjusting the temperature of cooling water of the crystallizer to 34 ℃ before casting. And when the excessive steel amount of the crystallizer is 10 ten thousand tons, the crystallizer is replaced.
In the description of the present invention, the terms "plurality" or "a plurality" refer to two or more, and unless otherwise specifically limited, the terms "upper", "lower", and the like indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and simplification of the description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present invention; the terms "connected," "mounted," "secured," and the like are to be construed broadly and include, for example, fixed connections, removable connections, or integral connections; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description of the present invention, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for reducing longitudinal cracks of a hypo-peritectic steel continuous casting slab is characterized by comprising the following steps:
pouring molten steel into a tundish, wherein the molten steel is conveyed into a crystallizer from the tundish through a submerged nozzle;
placing the covering slag on the liquid level of the molten steel in the crystallizer;
and adjusting the immersion depth of the submerged nozzle according to the heat of each pouring time.
2. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 1, wherein the step of transferring the molten steel from the tundish to the mold through a submerged entry nozzle comprises:
and a stopper rod is inserted into the molten steel flow channel of the tundish, and air holes are formed among the stopper rod, the water feeding port of the tundish and the tundish plate, so that argon is dissipated through the air holes.
3. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 2, wherein the step of dissipating argon gas through the gas holes comprises:
adjusting the flow of argon escaping from the stopper rod gas hole to be 1 liter/minute to 3 liters/minute;
adjusting the flow of argon dissipated from the air hole of the water feeding port of the tundish to be 1 liter/min to 3 liters/min;
the flow rate of argon gas escaping from the gas holes between the tundish plates was adjusted to 2 liters/minute to 5 liters/minute.
4. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 2, wherein the step of dissipating argon gas through the gas holes further comprises:
adjusting the pressure of argon gas escaping from the stopper rod air hole to be 0.2 MPa to 0.4 MPa;
adjusting the pressure of argon gas dissipated from the air hole of the water feeding port of the tundish to be 0.2 MPa to 0.4 MPa;
the pressure of argon gas escaping from the air holes between the tundish plates is adjusted to be 0.2 MPa to 0.4 MPa.
5. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab according to claim 1, wherein the step of adjusting the immersion depth of the submerged nozzle according to the heat of each casting includes:
in the first heat of each pouring time, adjusting the immersion depth of the submerged nozzle to a first preset depth;
adjusting the immersion depth of the submerged nozzle to a second preset depth in a second heat to a fourth heat of each pouring heat;
and adjusting the immersion depth of the submerged nozzle to a third preset depth in the fifth heat of each casting time to the heat of replacing the submerged nozzle.
6. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab according to claim 5,
the first preset depth is 120 mm to 140 mm;
the second preset depth is 141 mm to 160 mm;
the third preset depth is 120 mm to 140 mm.
7. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 1, further comprising:
heating or cooling the cooling water of the crystallizer so that the temperature of the cooling water is kept between 30 ℃ and 37 ℃.
8. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 1, further comprising:
controlling the excessive steel amount of the crystallizer within the range of 9-10 ten thousand tons, and replacing the crystallizer when the excessive steel amount of the crystallizer is not less than 10 ten thousand tons.
9. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 1,
and the melting point temperature of the covering slag is 1050-1150 ℃.
10. The method for reducing the longitudinal cracks of the hypo-peritectic steel continuous casting slab as claimed in claim 1, further comprising:
and monitoring the temperature information of the crystallizer copper plate and the temperature information of the casting blank in real time, and adjusting the flow of cooling water based on the monitored data information.
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