CN114799140A - Tundish slag suppression control device and preparation and slag suppression control method thereof - Google Patents

Tundish slag suppression control device and preparation and slag suppression control method thereof Download PDF

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CN114799140A
CN114799140A CN202210401480.7A CN202210401480A CN114799140A CN 114799140 A CN114799140 A CN 114799140A CN 202210401480 A CN202210401480 A CN 202210401480A CN 114799140 A CN114799140 A CN 114799140A
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slag
tundish
molten steel
inhibitor
control device
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CN114799140B (en
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张敏
钟鹏
龚航
刘启龙
徐伟
尹纯锋
徐钢
徐园园
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Maanshan Iron and Steel Co Ltd
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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
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D46/00—Controlling, supervising, not restricted to casting covered by a single main group, e.g. for safety reasons
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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Abstract

The invention discloses a tundish slag suppression control device and a preparation method and a slag suppression control method thereof, and belongs to the technical field of continuous casting tundish flow control. The tundish slag inhibiting control device comprises an inverted slag inhibitor, wherein coating layers are coated on the inner surface and the outer surface of the slag inhibitor, and the slag inhibitor comprises an annular base and a baffle arm protruding downwards from the annular surface of the base; the outer ring of base has cup jointed the overlay on the week, the stopper rod has been cup jointed to the ring heart close-fitting formula of base, and the casting period can regard as sealing device, reduces the molten steel oxidation, and 3 ~ 6 that fender arm quantity generally sets up for the symmetry can be turned into the rotational kinetic energy of middle package restrainer with the molten steel of molten steel district molten steel, come the critical spin-up height of restraining middle package last phase of casting, and then restrain the formation of swirl in the middle package, reach and prevent that coating agent and the gas of coating layer from getting into the crystallizer along with the molten steel, and then solve the technical problem that keeps off the slag effect relatively poor and reduce the surplus piece of casting processing work load.

Description

Tundish slag suppression control device and preparation and slag suppression control method thereof
Technical Field
The invention belongs to the technical field of continuous casting tundish flow control, and particularly relates to a tundish slag suppression control device and a preparation method and a slag suppression control method thereof.
Background
In the continuous casting production process, the tundish is an important metallurgical reactor, plays a role in reducing pressure, stabilizing flow, purifying, shunting and other metallurgical functions, is continuously developed in function, and also has heating and refining functions. In the continuous casting process, confluence vortex is generated along with the reduction of the liquid level of the molten steel in the tundish in the later casting period. The confluence vortex is that in the drainage process of the container, liquid firstly descends vertically, when the liquid falls to a certain height, the liquid begins to converge towards the central line of the outflow port, and a concave vortex is formed on the surface of a slag layer, and the liquid level height at the moment is generally called as the critical vortex starting height. Along with the further decline of liquid level, the concave vortex is more and more obvious, can be drawn into the molten steel inside with the covering agent of liquid level, causes the entrainment of metal phase and liquid phase, even draws in the air, all will increase the secondary oxidation of molten steel, reduces the molten steel cleanliness factor, has worsened the casting blank quality. Particularly, in the final stage of casting, in order to prevent slag entrapment caused by formation of confluence vortex, the casting needs to be stopped before the liquid level reaches the critical height, so that the amount of the residual molten steel in tundish casting is large, the metal yield is reduced, and the workload of the residual block casting treatment is increased.
How to inhibit the steel slag in the tundish from entering the tundish is a difficult problem which puzzles the iron and steel metallurgy production enterprises for many years. Through patent search, there is a related technical scheme disclosed in the related patent technology of "flow control structure for preventing vortex generation in tundish" (publication number: CN102825229A, published 2012-12-29). in the technical scheme, the middle vacant part of the hollow funnel with the lower end of the stopper rod in the shape of an inverted cone covers the submerged nozzle outlet below, so as to prevent molten steel in the vertical direction from being sucked by the nozzle, and force the molten steel to enter the nozzle from the horizontal direction, so as to achieve the purpose of suppressing confluent vortex above the nozzle outlet. But the actual operation strictly requires the centering of the stopper rod center and the nozzle center so as to meet the requirement that the lower end of the stopper rod can realize good sealing with the brick cup groove, and certain difficulty exists; although the molten steel in the vertical direction is prevented from being sucked into the nozzle, the slag caught after the formation of the confluence vortex is also carried into the nozzle. The patent technology of 'a method for inhibiting the generation of vortexes at a water gap in a metallurgical process' (publication number: CN108907170A, published 2018-11-30) is characterized in that when the liquid level drops to a critical height close to the generation of a confluent vortex at the end of the pouring of a metallurgical ladle, a stopper rod in the metallurgical ladle is driven by a rotating device to rotate towards the reverse direction of the rotating direction of the vortex to be formed, so that the tangential speed of the fluid motion is reduced. However, it is difficult to provide a rotating device at the upper part of the stopper rod, and it is necessary to consider a proper starting time and set a proper rotating speed, which makes the control requirement high. The technical scheme of the patent technology of the continuous casting slag-rolling-preventing stopper rod (publication number: CN108380862A, published 2018-8-10) is that the purposes of weakening and even offsetting the generation of molten steel confluence vortexes of a tundish and reducing the risk of continuous casting slag rolling are achieved by means of the unique shape of a slag-rolling-preventing functional section of the continuous casting slag-rolling-preventing stopper rod, but the maintenance is not easy.
In summary, in the prior art, although many experiments and researches are made on the slag blocking of the tundish, the tundish is difficult to popularize on a large scale, and the reasons are two: (1) the cost of the slag stopping device is too high, and the slag stopping device is not easy to maintain when the continuous casting site is at a high temperature; (2) the slag blocking effect is not ideal, and even new harm can be caused, so that the loss is avoided. How to realize good slag stopping effect in the tundish tapping process and further remove impurities in molten steel to realize the smelting target of high-purity steel is a difficult problem which troubles steel metallurgy production enterprises for many years.
Disclosure of Invention
1. Problems to be solved
Aiming at the problems of poor slag stopping effect of a continuous casting tundish and large workload of casting residue block treatment in the prior art, the invention provides a tundish slag inhibiting control device and a preparation method and a slag inhibiting control method thereof, which can inhibit the formation of vortex in the tundish to prevent a coating agent and gas from entering a crystallizer along with molten steel, thereby achieving the purposes of stopping slag and reducing the workload of casting residue block treatment.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention discloses a tundish slag suppression control device, which comprises an inverted slag suppressor, wherein the inner surface and the outer surface of the slag suppressor are coated with coating layers, and the slag suppressor comprises an annular base and a baffle arm protruding downwards from the annular surface of the base; the outer ring of base has cup jointed the overlay on the periphery, and the stopper rod has been cup jointed to the ring core tight fit formula of base, and the casting period can regard as sealing device, reduces the molten steel oxidation, and 3 ~ 6 that fender arm quantity generally sets up for the symmetry can be turned into the kinetic energy of the rotation of middle package restrainer of molten steel district molten steel, come the critical spin-up height of restraining middle package casting final stage, and then restrain the formation of swirl in the middle package, reach and prevent that coating agent and the gas of coating layer from getting into the crystallizer along with the molten steel, and then reach the technological effect that keeps off the sediment and reduce the surplus piece of casting processing work load.
Preferably, the stopper rod pushing mechanism is used for releasing the stopper rod into the molten steel area from the top of the stopper rod and plays a role of pushing the blocking arm to the molten steel area along with the stopper rod.
Preferably, the overall diameter and the ring center diameter of the base are respectively 1.15D-1.16 times and 1.04-1.05 times of the diameter of the stopper rod, so that the cover plate can be conveniently sleeved outside and the stopper rod is tightly matched inside.
Preferably, the specific gravity of the whole device is 4.1-4.9 g/cm 3 (ii) a The density of the molten steel is generally 7g/cm 3 Left and right to achieve the purpose that the baffle arm is under and the whole semi-floats in the molten steel area.
The inner layer of the slag inhibitor is made of cast iron; the apparent porosity of the outer coating layer is 20-26%, the coating layer has strong adsorbability and high additional porosity, has a good effect of adsorbing impurities at the later stage, and has a specific gravity of 2.2-2.8 g/cm 3 (ii) a So as to balance the specific gravity of the whole slag inhibitor; the wall surface roughness is 2-4 mu m, when conveniently cup jointing with the covering plate, the slag inhibitor converts the kinetic energy of the molten steel into the rotational kinetic energy of the slag inhibitor, and then dissipates under the action of the friction force generated by the roughness 2-4 mu m, so that the formation of confluence vortex can be effectively inhibited, the friction force is insufficient when the roughness is too small, and the slag is hung when the roughness is too large.
Preferably, the coating layer comprises the following components in percentage by mass: 78.5-85.5% MgO, 5-15% FC + SiC, 2-3.5% Al 2 O 3 、0～3.5％SiO 2 、0～0.05％FeO、0～0.1％Fe 2 O 3 、1.8～2.7％ZrO 2 The balance of water and negligible impurities and elements, belonging to a high-magnesium coating, having strong adsorbability and adsorbing Al 2 O 3 The particles react and have a higher melting point than the molten steel, preventing melting in the molten steel.
A preparation method of a tundish slag-inhibiting control device comprises the following steps:
step one, preparation of a cast iron block: preparing a matched sand mold cavity according to the shape of the slag inhibitor, and injecting molten iron by adopting a sand mold casting process to obtain an inner layer of the cast iron slag inhibitor;
step two, preparation of coating layer materials: weighing the components according to the component requirements of the coating layer, uniformly mixing the components, adding water, and stirring to form a pasty mixture;
step three, a coating process: polishing the surface of the slag inhibitor in the first step to be rough, and then coating the coating material in the second step on the outer side of the cast iron block to form the overall shape of the slag inhibitor;
step four, maintaining and drying: and (4) standing the slag inhibitor in the step three, demolding, naturally curing the slag inhibitor at normal temperature, putting the naturally cured slag inhibitor into a baking furnace, and taking the slag inhibitor out of the furnace after baking and naturally cooling.
The further preparation method comprises the steps of forming lines on the inner surface of the sand mould cavity in the step one; the water content of the muddy mixture obtained in the second step is 8-13%; the weight ratio of the coating layer material to the slag inhibitor cast iron block in the third step is 2: 1, reducing the specific gravity of the whole slag inhibitor; and step four, integrally standing the slag inhibitor in the step three for 1 hour, then demolding, naturally curing the slag inhibitor for 9-13 hours at normal temperature, and putting the naturally cured slag inhibitor into a baking furnace: baking at 60 deg.C or below for 1 hr; the baking temperature is raised to 100-180 ℃, and the baking time is 1.5 hours; the baking temperature is raised to 300-350 ℃, and the baking time is 1.5 hours; and (4) raising the baking temperature to 450-600 ℃, baking for 1 hour, and discharging from the furnace for natural cooling after baking.
A slag suppression control method is characterized in that the slag suppression control device of the tundish is fixed on a tundish cover during installation; before the residual casting, the stopper is pushed down by a stopper rod pushing mechanism to slowly release the slag inhibitor onto a molten steel area of the tundish along the stopper rod, and the baffle arm is immersed into the molten steel area.
The slag inhibiting device is placed at the bottom of a tundish before casting, floats upwards in a molten steel area along with the increase of molten steel in the early stage and floats on a steel slag interface, so that the slag inhibiting device can inhibit slag while casting and stopping casting.
The further slag inhibiting control method comprises the following steps: al in molten steel zone 2 O 3 The following chemical reaction occurs when the particles contact the magnesium wall covering the plate:
MgO(s)+Al 2 O 3 (s)＝MgAl 2 O 4 (s)，△Gθ＝H-TS＝-23604-5.91T(J/mol)，
where Δ G θ is Gibbs free energy, H is enthalpy, S is entropy, and T is temperature. From this reaction Gibbs white, it is clear that the reaction proceeds more easily as the temperature is higher. MgAl is generally formed at 1150 deg.C 2 O 4 The speed of (2) is faster. When pouring, the temperature of molten steel is 1550-1600 ℃, and MgAl is easily generated 2 O 4 The inclusions are absorbed and attached to the wall surface of the coating layer, and another part of the inclusions are separated from the wall surface of the coating layer after forming large clusters, and the other part of the inclusions are removed by floating in the movement of the molten steel in the tundish.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) in the technical scheme of the invention, only one slag inhibitor is needed to be added, and other modifications are not needed, so the slag inhibitor is easy to manufacture, low in cost and convenient to operate;
(2) due to the action of the baffle arm, the kinetic energy of the molten steel is converted into the rotational kinetic energy of the slag inhibitor and then dissipated under the action of friction force, so that the formation of confluence vortex can be effectively inhibited;
(3) because the refractory material is high in Mg quality and high in porosity, later-stage impurities can be effectively adsorbed, and the cleanliness of molten steel in the crystallizer is improved;
(4) the invention can effectively inhibit the formation of confluence vortex and prevent slag from entering the nozzle, thereby reducing the casting allowance of the tundish molten steel, improving the metal yield and simultaneously reducing the workload of treating the tundish casting residual block;
(4) the invention has the characteristics of easy manufacture, low cost and convenient operation, and can effectively inhibit confluent vortex and prevent slag from entering the water inlet.
Drawings
FIG. 1 is a schematic diagram of the internal structure of a tundish slag suppression control device after half-section;
FIG. 2 is a top view of the tundish slag suppression control device of the present invention;
FIG. 3 is a perspective view of a slag inhibitor of the present invention;
fig. 4 is a side view of fig. 1.
In the figure: 1. a slag inhibitor; 3. a stopper rod downward pushing mechanism; 4. a stopper rod; 5. a cover plate; 6. a molten steel zone; 11. a catch arm; 12. a base.
Detailed Description
The invention is further described with reference to specific examples.
Example 1
The tundish slag-inhibiting control device of the embodiment comprises an inverted slag inhibitor 1, wherein the inner surface and the outer surface of the slag inhibitor 1 are coated with coating layers, and the tundish slag-inhibiting control device comprises an annular base 12 and a baffle arm 11 which protrudes downwards from the surface of the base 12; the cladding plate 5 of foam material has been cup jointed on the outer ring of base 12 week, stopper rod 4 has been cup jointed to the centre of a ring close-fitting formula of base 12, the casting period can be as sealing device, reduce the molten steel oxidation, 3 ~ 6 that fender arm 11 quantity generally sets up for the symmetry, can turn into the kinetic energy of 6 molten steel in molten steel district into the rotatory kinetic energy of pouring basket restrainer 1 in the middle of, come to restrain the critical spin-up height of pouring basket at last stage, and then restrain the formation of swirl in the pouring basket, reach and prevent that coating agent and the gas of coating layer from getting into the crystallizer along with the molten steel, and then reach the technological effect that keeps off the sediment and reduce surplus piece treatment work load of casting.
Example 2
The basic structure of the tundish slag-inhibiting control device of the embodiment is the same as that of the embodiment 1, and the differences or improvements are that: as shown in fig. 3, the number of the catch arms 11 is 4 symmetrically arranged; the whole device also comprises a stopper rod pushing mechanism 3 which releases the stopper rod 4 to the molten steel area 6 from the top of the stopper rod 4 and plays a role of pushing the baffle arm 11 to the molten steel area 6 along with the stopper rod 4. The overall diameter and the ring center diameter of the base 12 are respectively 1.15D-1.16 times and 1.04-1.05 times of the diameter of the stopper 4, so that the cover plate 5 is sleeved outside conveniently, the stopper 4 is tightly matched inside, and after the 4 baffle arms 11 are matched, the molten steel can inhibit the formation effect of the confluence vortex to be optimal, and the confluence vortex is not formed in the production process, so that the combination effect is good.
Example 3
The basic structure of the tundish slag-inhibiting control device of the embodiment is the same as that of the embodiment 2, and the differences or improvements are as follows: the inner layer of the slag inhibitor 1 is made of cast iron; the coating layer of the outer layer comprises the following components in percentage by mass: 78.5-85.5% MgO, 5-15% FC + SiC, 2-3.5% Al 2 O 3 、0～3.5％SiO 2 、0～0.05％FeO、0～0.1％Fe 2 O 3 、1.8～2.7％ZrO 2 The balance of water and negligible impurities and elements, belonging to a high-magnesium coating, having strong adsorbability and adsorbing Al 2 O 3 The particles react and have a higher melting point than the molten steel, preventing melting in the molten steel. The prepared coating layer has the apparent porosity of 20-26%, strong adsorbability and high porosity, has a good effect of adsorbing impurities at the later stage, and has the specific gravity of 2.2-2.8 g/cm 3 (ii) a So as to balance the specific gravity of the whole slag suppressor 1; the wall surface roughness is required to be 2-4 mu m, the slag inhibitor 1 can be conveniently sleeved with the covering plate 5, and the kinetic energy of the molten steel is converted into the rotating kinetic energy of the slag inhibitor and then dissipated under the action of the friction force generated by the roughness of 2-4 mu m,therefore, the formation of confluent vortices can be effectively inhibited, and when the confluent vortices are too small, the frictional force is insufficient, and when the confluent vortices are too large, slag adhering is generated. The specific gravity of the whole device is 4.1-4.9 g/cm 3 (ii) a The specific gravity is preferably 4.27-4.62 g/cm 3 The density of the molten steel is generally 7.0g/cm 3 About 56.4% of the volume of the whole device is in molten steel, so that the purpose that the baffle arm 11 is arranged below and the whole device is semi-floated on the molten steel area 6 is achieved.
The preparation method of the tundish slag-inhibiting control device comprises the following steps:
step one, preparation of a cast iron block: preparing a matched sand mold cavity according to the shape of the slag inhibitor 1, and injecting molten iron by adopting a sand mold casting process to obtain an inner layer of the cast iron slag inhibitor 1;
step two, preparation of coating layer materials: weighing the components according to the component requirements of the coating layer, uniformly mixing the components, adding water, and stirring to form a pasty mixture;
step three, a coating process: polishing the surface of the slag inhibitor 1 in the first step to be rough, and then coating the coating material in the second step on the outer side of the cast iron block to form the overall shape of the slag inhibitor 1;
step four, maintaining and drying: and (3) standing the slag inhibitor 1 obtained in the step three, demolding, naturally curing the slag inhibitor 1 at normal temperature, putting the naturally cured slag inhibitor 1 into a baking furnace, and taking the slag inhibitor out of the furnace after baking is finished and naturally cooling the slag inhibitor.
The middle package of this embodiment restraines sediment controlling means, because resistant material belongs to high Mg matter, and the porosity is high, can effectively adsorb the later stage and mix with, improves the cleanliness factor of molten steel in the crystallizer, in the application, can effectively restrain the formation of vortex of converging, and prevents that the sediment from getting into the mouth of a river, consequently can reduce middle package molten steel and cast the surplus, improves the metal yield, reduces middle package casting surplus piece processing work volume simultaneously.
Example 4
The preparation method of the tundish slag-inhibiting control device of the embodiment has the same basic steps as the embodiment 3, and is different from or improved in that: forming lines on the inner surface of the sand mold cavity in the first step; the water content of the muddy mixture obtained in the second step is 8-13%; the weight ratio of the coating layer material in the third step to the cast iron block of the slag inhibitor 1 is 2: 1, reducing the specific gravity of the whole slag inhibitor 1; in the fourth step, the slag inhibitor 1 in the third step is wholly kept still for 1 hour and then is demoulded, the slag inhibitor 1 is naturally maintained for 9-13 hours at normal temperature, and the slag inhibitor 1 after natural maintenance is placed into a baking furnace: baking at 60 deg.C or below for 1 hr; the baking temperature is raised to 100-180 ℃, and the baking time is 1.5 hours; the baking temperature is raised to 300-350 ℃, and the baking time is 1.5 hours; and (4) raising the baking temperature to 450-600 ℃, baking for 1 hour, and discharging from the furnace for natural cooling after baking.
Example 5
The basic structure of the tundish slag-inhibiting control device and the preparation method thereof of the embodiment is the same as that of the embodiment 3, and the preparation steps are the same as that of the embodiment 4, and the differences or improvements are that:
4 rivets are welded on the inner cast iron block of the slag inhibitor 1, so that an outer refractory coating layer can be fixed in a reinforced mode;
the preparation method of the tundish slag suppression control device of the embodiment is as follows:
step one, preparation of a cast iron block:
preparing a sand mold cavity according to the structure of the tundish slag suppression control device, forming grains on the inner surface of the sand mold cavity, and then injecting molten iron by adopting a sand mold casting process to obtain an iron casting block; in the embodiment, the lines are arranged on the inner surface of the sand mould cavity so as to ensure that the subsequent coating layer can be tightly attached to the outer part of the cast iron block;
step two, preparation of coating layer materials:
weighing the components according to the component requirements of the coating layer, wherein the coating layer material comprises the following components in percentage by mass: the coating layer comprises the following components in percentage by mass: 82% MgO, 10% FC + SiC, 1.5% SiO 2 、3％Al 2 O 3 、0.02％FeO、0.05％Fe 2 O 3 、2.3％ZrO 2 Mixing the above components uniformly, adding water, and stirring into paste, wherein the water content of the paste mixture is 8-13% (by mass), the water content of the embodiment is 9%, and the density is 4.5g/cm 3 ；
Step three, a coating process:
polishing the surface of the cast iron block in the first step to be rough, and then uniformly coating the coating material in the second step on the outer side of the cast iron block, wherein the weight ratio of the coating material to the cast iron block is 2: 1;
step four, maintaining and drying
Standing the whole tundish slag suppression control device in the third step for 1 hour, then demoulding, naturally curing the tundish slag suppression control device for 9-13 hours at normal temperature, and putting the tundish slag suppression control device after natural curing into a baking oven: baking at 60 deg.C or below for 1 hr; the baking temperature is raised to 100-180 ℃, preferably 150 ℃, and the baking is carried out for 1.5 hours; the baking temperature is raised to 300-350 ℃, the preferred temperature is 330 ℃, and the baking time is 1.5 hours; the baking temperature is raised to 450-600 ℃, preferably 500 ℃, the baking is carried out for 1 hour, the coating is taken out of the furnace and naturally cooled after the baking is finished, and the apparent porosity of the coating is 24 percent at the moment, and the bulk density is 2.5g/cm 3 。
The coating layer prepared by the method can be stably attached to the outer part of the cast iron block, so that the tundish slag suppression control device is stable in performance.
In the slag suppression control method of the tundish slag suppression control device of the embodiment, the tundish slag suppression control device is fixed on a tundish cover during installation; before the casting is remained, the stopper rod pushing mechanism 3 is used for slowly releasing the slag inhibitor 1 to the tundish molten steel area 6 along the stopper rod 4, the baffle arm 11 is immersed in the molten steel area 6, after the molten steel liquid level in the tundish drops to a certain height, the molten steel starts to generate vortex, the kinetic energy of the molten steel is converted into the rotating kinetic energy of the slag inhibitor under the action of the 4 baffle arms, and then the kinetic energy is dissipated under the action of friction force, so that the formation of confluence vortex can be effectively inhibited, the slag is prevented from entering a water gap, the casting allowance of the tundish molten steel can be reduced, the metal yield is improved, and the processing workload of the tundish casting residual block is reduced. Due to the specific structure of the baffle arm 11, the tundish slag-inhibiting control device can not completely block the water gap, so that molten steel can continuously flow in the slit without slag, the slag-off amount of the steel tundish can be well controlled, and the yield of the molten steel is further improved.
Further, the tundish slag-restraining control device of the present embodiment, whichThe coating layer not only has high temperature resistance and erosion resistance, but also has the function of adsorbing and removing impurities in molten steel, and by using the tundish slag inhibiting control device of the embodiment, the coating layer can effectively remove Al in the molten steel in the process of contacting with the molten steel 2 O 3 Inclusions to achieve the smelting goal of high purity steel, Al in molten steel 2 O 3 The following chemical reactions occur when the particles contact the magnesium wall:
MgOs+Al 2 O 3 (s)＝MgAl 2 O 4 (s) Δ G θ -H-TS-23604-5.91T (J/mol); it is composed of
Middle Δ G θ is Gibbs free energy, H is enthalpy, S is entropy, and T is temperature.
From the Gibbs white reaction, it is clear that the reaction proceeds more easily as the temperature is higher. MgAl is generally formed at 1150 deg.C 2 O 4 The speed of(s) is fast. When pouring, the temperature of molten steel is 1550-1600 ℃, and MgAl is easily generated 2 O 4 (s) the inclusion is absorbed and attached to the wall surface of the coating layer, and the other part of the inclusion is separated from the wall surface of the coating layer after forming a large cluster, and the part is removed by floating in the molten steel movement of the tundish, so that the tundish slag suppression control device of the embodiment skillfully realizes the effect of removing the inclusion.
The maximum pressure resistance of the tundish slag suppression control device of the embodiment at a temperature of 110 ℃ is 50 MPa. In order to test the high-temperature volume stability of the coating layer in the tundish slag-inhibiting control device of the embodiment, a heating permanent line change rate index is selected for evaluation, and the heating permanent line change rate is an important physical index for evaluating the quality of the refractory material. During measurement, a rectangular prism sample with the measured length, which is made of the material of the coating layer in the embodiment, is placed in a furnace in an oxidizing atmosphere, heated to the test temperature, then kept at the test temperature for a certain time, cooled to room temperature, and then the length of the rectangular prism sample is measured, so that the heating permanent line change rate can be calculated. The formula for the rate of change of the heating permanent line is:
△L＝(L1-L0)/L0×100％
wherein: Δ L is the rate of change of the sample heating permanent line,%; l1 is the length of the sample after heating, mm; l0 is the length of the sample before heating, mm; the coating layer of this example was measured to have a rate of change of heating permanent line of + 0.03% by the above method, and to have a small thermal deformation.
Example 6
The basic structure and the preparation steps of the tundish slag suppression control device and the preparation method thereof of the embodiment are the same as those of the embodiment 5, and the differences or improvements are that: the tundish slag-inhibiting control device of the embodiment has 6 baffle arms, the apparent porosity of the coating layer is 21%, and the coating layer comprises the following components in percentage by mass: 84% MgO, 8% FC + SiC, 2.5% Al 2 O 3 、0.02％FeO、0.05％Fe 2 O 3 、2.1％ZrO 2 And the like. The weight ratio of the coating layer material to the cast iron block of the slag suppression device of the embodiment is 1.5: 1, adding water to stir the mixture into a paste, and the specific gravity (namely the bulk density) of the paste is 5.0g/cm 3 。
The slag restraining control method of the tundish slag restraining control device of the embodiment is characterized in that the slag restraining device 1 is placed at the bottom of a tundish before casting, floats upwards in a molten steel area 6 along with the increase of molten steel in the early stage and floats on a steel slag interface to restrain slag while casting and stopping, so that the yield of molten steel is improved, in addition, a coating layer of the slag restraining control device has high temperature resistance and erosion resistance and also has the function of adsorbing impurities in the molten steel, and by using the tundish slag restraining control device of the embodiment, Al in the molten steel can be effectively removed in the process of contacting with the molten steel 2 O 3 And the impurities are removed while the slag is stopped, so that the smelting target of high-purity steel is realized. The coating layer of this example was measured to have a permanent line change rate of 0.05% in heating by the method of example 5, and was not largely deformed in heat.
The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.

Claims (10)

1. The utility model provides a middle package presses down sediment controlling means which characterized in that: the slag inhibitor comprises an inverted slag inhibitor (1), wherein coating layers are coated on the inner surface and the outer surface of the slag inhibitor (1), and the slag inhibitor comprises an annular base (12) and a blocking arm (11) which protrudes downwards from the annular surface of the base (12); the outer circumference of the base (12) is sleeved with a covering plate (5), and the ring center of the base (12) is sleeved with a stopper rod (4) in a close fit manner.
2. The tundish slag-restraining control device according to claim 1, characterized in that: the stopper rod pushing mechanism (3) is used for releasing the stopper rod (4) to the molten steel area (6) from the top of the stopper rod (4).
3. The tundish slag-restraining control device according to claim 1, characterized in that: the overall diameter and the ring center diameter of the base (12) are respectively 1.15D-1.16 times and 1.04-1.05 times of the diameter of the stopper rod (4).
4. The tundish slag-restraining control device according to claim 1, characterized in that: the specific gravity is 4.1-4.9 g/cm 3 (ii) a The slag inhibitor (1) is made of cast iron; the apparent porosity of the coating layer is 20-26%, and the specific gravity of the coating layer is 2.2-2.8 g/cm 3 (ii) a The wall surface roughness is 2-4 μm.
5. The tundish slag-restraining control device according to claim 1, characterized in that: the coating layer comprises the following components in percentage by mass: 78.5-85.5% MgO, 5-15% FC + SiC, 2-3.5% Al 2 O 3 、0～3.5％SiO 2 、0～0.05％FeO、0～0.1％Fe 2 O 3 、1.8～2.7％ZrO 2 The balance being moisture and negligible impurities and elements.
6. A method for manufacturing the tundish slag-restraining control device according to any one of claims 1 to 5, characterized in that: the method comprises the following steps:
step one, preparation of a cast iron block: preparing a matched sand mold cavity according to the shape of the slag inhibitor (1), and injecting molten iron by adopting a sand mold casting process to obtain the cast iron slag inhibitor (1);
step two, preparation of coating layer materials: weighing the components according to the component requirements of the coating layer, uniformly mixing the components, adding water, and stirring to form a pasty mixture;
step three, a coating process: polishing the surface of the slag inhibitor (1) in the first step to be rough, and then coating the coating material in the second step on the outer side of the cast iron block;
step four, maintaining and drying: and (3) demolding the tundish slag inhibitor (1) in the third step, naturally curing the slag inhibitor (1) at normal temperature, putting the naturally cured middle slag inhibitor (1) into a baking furnace, and taking the middle slag inhibitor out of the furnace after baking and naturally cooling.
7. The manufacturing method of the tundish slag-inhibiting control device according to claim 6, characterized in that: forming lines on the inner surface of the sand mold cavity in the first step; the water content of the muddy mixture obtained in the second step is 8-13%; the weight ratio of the coating layer material in the third step to the cast iron blocks in the inner layer of the slag inhibitor (1) is 2: 1; in the fourth step, the tundish slag inhibiting control device in the third step is integrally stood for 1 hour and then is demoulded, the slag inhibiting device (1) is naturally maintained for 9-13 hours at normal temperature, and the naturally maintained slag inhibiting device (1) is placed into a baking furnace: baking at 60 deg.C or below for 1 hr; the baking temperature is raised to 100-180 ℃, and the baking time is 1.5 hours; the baking temperature is raised to 300-350 ℃, and the baking time is 1.5 hours; and (4) raising the baking temperature to 450-600 ℃, baking for 1 hour, and discharging from the furnace for natural cooling after baking.
8. A slag suppression control method is characterized by comprising the following steps: when in installation, the tundish slag suppression control device according to any one of claims 1 to 7 is fixed on a tundish cover; before the residual casting, the slag inhibitor (1) is slowly released to a molten steel area (6) of a tundish along a stopper rod (4) by using a stopper rod lower jacking mechanism (3), and a baffle arm (11) is immersed in the molten steel area (6).
9. A slag suppression control method is characterized by comprising the following steps: when the slag inhibitor (1) of any one of claims 1 to 7 is installed, the slag inhibitor is placed at the bottom of a tundish before casting, floats upwards in a molten steel area (6) along with the increase of molten steel in the early stage, floats on a steel slag interface, and inhibits slag while casting is started and stopped.
10. The slag suppression control method according to claim 8 or 9. The method is characterized in that: al in molten steel zone (6) 2 O 3 The following chemical reactions occur when the particles contact the magnesium wall covering the plate (5):
MgO(s)+Al 2 O 3 (s)＝MgAl 2 O 4 (s)，△Gθ＝H-TS＝-23604-5.91T(J/mol)，
where Δ G θ is Gibbs free energy, H is enthalpy, S is entropy, and T is temperature.
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JPH0570750U (en) * 1992-02-26 1993-09-24 新日本製鐵株式会社 Tundish stopper refractory for continuous casting
US5382003A (en) * 1992-12-08 1995-01-17 Sankaranarayanan; Ramani Flow control device for the suppression of vortices
EP0974801A1 (en) * 1998-07-24 2000-01-26 MANNESMANN Aktiengesellschaft Method and apparatus for slag-free tapping
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US20110186602A1 (en) * 2007-12-11 2011-08-04 Tetron, Inc. Vortex inhibitor
CN203578742U (en) * 2013-10-08 2014-05-07 濮阳濮耐高温材料（集团）股份有限公司 Continuous casting tundish confluent vortex suppressor and continuous casting tundish
CN104707986A (en) * 2013-09-27 2015-06-17 安徽工业大学 Method for preparing steel ladle slag suppressing device
CN204842955U (en) * 2015-04-21 2015-12-09 宝山钢铁股份有限公司 Excellent pushing off slag of long -life stopper circle subassembly
CN216096378U (en) * 2021-10-28 2022-03-22 马鞍山钢铁股份有限公司 Continuous casting tundish stopper device capable of preventing slag from being rolled

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0570750U (en) * 1992-02-26 1993-09-24 新日本製鐵株式会社 Tundish stopper refractory for continuous casting
US5382003A (en) * 1992-12-08 1995-01-17 Sankaranarayanan; Ramani Flow control device for the suppression of vortices
EP0974801A1 (en) * 1998-07-24 2000-01-26 MANNESMANN Aktiengesellschaft Method and apparatus for slag-free tapping
CN2603718Y (en) * 2003-01-27 2004-02-18 宝山钢铁股份有限公司 Slag-shielding ring of bakie water mouth
US20110186602A1 (en) * 2007-12-11 2011-08-04 Tetron, Inc. Vortex inhibitor
CN104707986A (en) * 2013-09-27 2015-06-17 安徽工业大学 Method for preparing steel ladle slag suppressing device
CN203578742U (en) * 2013-10-08 2014-05-07 濮阳濮耐高温材料（集团）股份有限公司 Continuous casting tundish confluent vortex suppressor and continuous casting tundish
CN204842955U (en) * 2015-04-21 2015-12-09 宝山钢铁股份有限公司 Excellent pushing off slag of long -life stopper circle subassembly
CN216096378U (en) * 2021-10-28 2022-03-22 马鞍山钢铁股份有限公司 Continuous casting tundish stopper device capable of preventing slag from being rolled

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