CN111113635A

CN111113635A - Combined type slab continuous casting tundish turbulence controller

Info

Publication number: CN111113635A
Application number: CN202010065262.1A
Authority: CN
Inventors: 武光君; 郭伟达; 李强笃; 宁伟; 冯启超; 张海波; 武玉利
Original assignee: Laiwu Steel Group Yinshan Section Steel Co Ltd
Current assignee: Laiwu Steel Group Yinshan Section Steel Co Ltd
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2020-05-08

Abstract

The invention relates to the technical field of continuous casting refractory material processes, in particular to a composite slab continuous casting tundish turbulence controller and a preparation method thereof, the tundish turbulence controller comprises a shell, a sleeve core and a bottom plate, the bottom plate is arranged on the bottom surface of an inner cavity of the shell, the sleeve core is arranged in the inner cavity of the shell, the longitudinal center line of the sleeve core is superposed with the longitudinal center line of the inner cavity of the shell, a joint seam is arranged between the shell and the sleeve core, the outer part of the sleeve core is a truncated cone-shaped magnesium prefabricated member, the inner part of the sleeve core is a paraboloid-shaped inner cavity, the bottom plate is a whole magnesia carbon brick, the sleeve core is sleeved in the shell of the turbulence controller, the joint seam between the shell and the sleeve core is filled with sintered magnesia, the response time and the average residence time of molten steel can be prolonged, the volume of piston flow is increased, the volume of dead zones is reduced, the turbulence energy of ladle flow injection can be effectively, and effectively solves the problem of slag entrapment caused by injection in the impact area.

Description

Combined type slab continuous casting tundish turbulence controller

Technical Field

The invention relates to the technical field of continuous casting refractory material processes, in particular to a turbulence controller for a combined slab continuous casting tundish.

Background

The turbulence controller is arranged in the tundish of the continuous casting machine, so that the running route of molten steel in the tundish can be changed, the retention time is prolonged, floating removal of impurities is promoted, the important effect on improving the quality of a casting blank is achieved, meanwhile, the scouring of a ladle pouring stream on a tundish working lining impact area can be slowed down, and the continuous casting time of the tundish is prolonged. In recent years, the production technology of the turbulence controller is developed to the metallurgy functionalization, the longevity and the cost reduction, but the tundish turbulence controller produced by the prior art cannot meet the performance requirements of the metallurgy functionalization, the longevity and the cost reduction at the same time.

CN103658577B discloses a method for preparing a continuous casting tundish composite turbulence controller, the composite turbulence controller comprises a shell, a bottom plate, a sleeve core, an expansion joint and an antioxidant coating, the shell is cast by magnesium casting material, the bottom plate is built by magnesium carbon bricks which are formed by machine pressing, the sleeve core is built by fan-shaped magnesium carbon bricks which are formed by machine pressing, the expansion joint is arranged between the shell and the bottom plate and between the shell and the sleeve core, and the antioxidant coating is coated on the outer surface of the sleeve core. However, the inner cavity of the tundish is cylindrical, the effect of inhibiting turbulent energy of ladle injection flow is poor, the improvement of the flow characteristic of molten steel in the tundish is not facilitated, and meanwhile, the sleeve core is built by fan-shaped magnesia carbon bricks, so that the tundish is poor in overall performance, easy to generate brick removal and poor in quality stability.

CN109591158A discloses a tundish current stabilizer, which is formed by integrally embedding a casing and a hollow inner cavity, wherein the shape and size of the casing are designed to be adapted to an impact area of a tundish, the center of the casing is recessed, so that the casing is in a concave shape, the casing is formed by a steel fiber aluminum-magnesium castable prefabricated member, and the steel fiber aluminum-magnesium castable prefabricated member is integrally cast and molded; the hollow inner cavity is cylindrical and is suitable for being embedded into the center of the shell, the hollow inner cavity is flush with the top of the shell, the hollow inner cavity is built by a magnesium-carbon prefabricated part, and the carbon prefabricated part is formed by isostatic pressing integral pressing; the method for manufacturing the tundish current stabilizer is characterized in that the inner cavity of the current stabilizer is improved into an integral pressing forming mode by a traditional multiple magnesia carbon brick masonry forming method, so that inner cavity brick joints which are easy to erode in the traditional current stabilizer are eliminated, the problems of steel infiltration and steel penetration of the brick joints of the inner cavity of the traditional current stabilizer are thoroughly solved, and the service life of the tundish current stabilizer is greatly prolonged. However, the preparation cost is high, and the popularization and the application are limited.

The disposable foam internal mold is prepared from polystyrene foam in the prior art, is suitable for various inner cavity shapes and specifications, is disposable, does not need to be demoulded, is simple and convenient, saves time and labor, does not deform and absorb water in the using process, and has good pressure resistance, elasticity and rigidity.

The isostatic pressing forming method is a forming method in which the pug is subjected to equal hydrostatic pressure in all directions, liquid is used as a pressure transmission medium, the pug is loaded into an elastic die, and pressure is applied in a high-pressure cylinder for forming. The isostatic pressing machine consists of a high-pressure container and a high-pressure oil pump. The high pressure vessel is made of high-grade alloy steel and has a certain thickness to withstand a great pressure. The size of the container is selected according to the size of the molded article. The liquid medium in the high-pressure container can be oil, water or glycerin, generally brake oil or anhydrous glycerin, and the compressibility of the two liquids is extremely small, so that almost all pressure can be transmitted to the elastic die.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a composite plate blank continuous casting tundish turbulence controller and a preparation method thereof.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a package turbulence controller in middle of combined type slab continuous casting, includes shell, cover core and bottom plate, the bottom plate set up the bottom surface in the shell cavity, the cover core set up in the inner chamber of shell, and the longitudinal center line of cover core and the coincidence of the longitudinal center line of shell cavity are equipped with joint line, its characterized in that between shell and the cover core: the sleeve core is externally provided with a truncated cone-shaped magnesium prefabricated part, so that the thickness of the side wall of the upper part of the sleeve core is larger than that of the side wall of the lower part, the side wall of the upper part of the sleeve core is suitable for being flushed and the erosion rate of the side wall of the upper part of the sleeve core is larger than that of the side wall of the lower part, the service life synchronization of all parts of the side wall of the sleeve core is realized, the whole inner wall and the whole outer wall of the sleeve core adopt a rotating surface design, the problem of cracks caused by the thermal stress concentration of the side wall of the sleeve core is solved, the inner part of the sleeve core is internally provided with a paraboloid, the bottom plate is a whole magnesia carbon brick, the inner cavity is divided into the upper part of the inner cavity of the sleeve core and the lower part of the inner cavity of the sleeve core, the upper part of the inner cavity of the sleeve core is a rotating surface with a circular arc, the piston flow volume is increased, the dead zone volume is reduced, the turbulent energy of ladle injection flow can be effectively reduced, the molten steel flow field in the tundish is better improved, and the problem of injection flow and slag entrapment in an impact zone is effectively solved.

Preferably, the bottom of the inner cavity of the shell is provided with an inner concave cavity, the bottom plate is matched with the inner concave cavity, the bottom plate and the bottom of the inner cavity are in the same plane, and the inner concave cavity for arranging the bottom plate is reserved through embedding a forming die when the bottom of the inner cavity of the shell is poured.

Preferably, the sleeve core is a truncated cone-shaped magnesium prefabricated part formed by a disposable foam inner die and a magnesium casting material through casting, and the bottom plate is a whole magnesia carbon brick formed by isostatic pressing.

Furthermore, the diameter D1 of the upper bottom surface of the truncated cone-shaped sleeve core is 720-750 mm, and the diameter D2 of the lower bottom surface of the truncated cone is 635-665 mm; the upper part of the inner cavity of the sleeve core of the turbulence controller is in a bell mouth shape, the diameter phi of an outer opening is 480-500 mm, the radius R of an arc is 75-80 mm, and the height a of the upper part of the inner cavity of the sleeve core is 80-100 mm, and the shape design of the upper part of the inner cavity of the sleeve core in the shape is adopted, so that the turbulence energy of steel ladle injection flow is effectively reduced, the flow field of molten steel in a tundish is well improved, the scouring of the molten steel flow on the inner cavity wall can be reduced, the shape of the inner cavity wall is maintained, and the service life is prolonged;

furthermore, the lower part of the inner cavity of the sleeve core is small in upper opening and large in lower opening, the diameter d1 of the upper opening in the sleeve core is 420-440 mm, the diameter d2 of the lower opening is 460-480 mm, the height h of the lower part of the inner cavity of the sleeve core is 320-350 mm, and the shape of the lower part of the inner cavity of the special sleeve core is designed, so that the running track of steel flow is changed, the flow path is prolonged, and the average residence time of the steel liquid in the tundish is prolonged.

Preferably, the bottom surface of the bottom plate is square, the side length c is 40-60 mm larger than d2, and the thickness b is 90-110 mm, so that the bottom of the sleeve core presses the bottom plate, the bottom plate is prevented from floating, and the steel flow is prevented from impacting on a shell outside the bottom plate.

Preferably, the width of the joint seam is large at the upper part and small at the lower part, the width m of the upper part is 10-15 mm, the width n of the lower part is 5-10 mm, the density of the filler at the lower part of the joint seam can be naturally increased, and the problem of steel infiltration of the joint seam penetrating from top to bottom is effectively solved.

By adopting the tundish turbulence controller with the size, the average residence time of the molten steel in the tundish can be improved by more than 6.7 percent on the same scale, the dead zone proportion is reduced by more than 5.2 percent on the same scale, and the inclusion removal rate is improved by more than 10 percent on the same scale.

The preparation method of the tundish turbulence controller adopting the inner cavity shape comprises the following steps:

firstly, casting and molding a shell by adopting a magnesium spinel castable;

secondly, casting and molding the sleeve core by adopting a disposable foam inner die and a magnesium castable;

thirdly, preparing the bottom plate into a whole magnesia carbon brick by adopting an isostatic pressing forming method;

fourthly, coating a layer of magnesium coating material with the thickness of 25-35mm on the outer surface of the sintered magnesia;

and fifthly, sleeving the sleeve core in a shell of the turbulence controller, ensuring that the longitudinal center line of the sleeve core is superposed with the longitudinal center line of the inner cavity of the shell, filling a joint seam between the shell and the sleeve core by using sintered magnesia with the granularity of less than or equal to 1mm, and naturally maintaining for 1-2 days.

The shape and the size of the shell are designed according to the shape and the size of a continuous casting tundish working lining impact area, and the shell is prepared by casting and molding a magnesium spinel castable produced by the prior art, naturally curing and baking in a heating furnace.

The magnesium spinel castable is produced by the prior art, the MgO content is more than or equal to 71 wt%, the volume density is more than or equal to 3.03g/cm3, and the flexural strength (1500 ℃) is more than or equal to 9 Mpa.

Preferably, the magnesia carbon coating is a coating prepared by mixing a recycled magnesia carbon granule with the particle size of less than or equal to 1mm and less than 3mm and the particle size of less than or equal to 1mm and the particle size of less than or equal to 0.074mm with sintered magnesia fine powder, soft clay, silica powder, sodium tripolyphosphate and the like according to a certain proportion in the prior art, wherein the weight percentage of the recycled magnesia carbon granule is 60-70%.

According to the preferred preparation method, the magnesium casting material for the sleeve core is added into a mixer for dry mixing for 2-3 minutes, water accounting for 4.0-5.0% of the total weight of the material is added, wet mixing is carried out for 4-6 minutes, the mixture is placed into a sleeve core casting outer mold provided with the disposable foam inner mold after being mixed uniformly, the mixture is compacted through a vibrating rod, when no large bubbles emerge, green casting of the sleeve core is completed, the sleeve core casting outer mold is removed after solidification is carried out for 12-24 hours, natural curing is carried out for 12-24 hours, baking is carried out in a heating furnace, ① temperature is increased to 120-150 ℃ from room temperature at a temperature increasing speed of 10 ℃/h, ② temperature is kept for 11-13 hours at 120-150 ℃, ③ temperature is increased to 220-250 ℃ at a temperature increasing speed of 10 ℃/h, ④ temperature is kept for 7-9 hours at 220-250 ℃, ⑤ temperature is increased to 360-390 ℃ at a temperature increasing speed of 15 ℃/h, ⑥ ℃ is kept for 9 hours, the temperature is stopped, and is cooled to ⑦ hours, and the sleeve core is prepared after natural fire is cooled and residual foam is cleaned.

According to the invention, the bottom plate is preferably prepared by an isostatic pressing method and is prepared from the following raw materials in percentage by weight:

main materials: 76-84 wt% of sintered magnesia

Auxiliary materials: 11.5-16 wt% of flake graphite

Antioxidant: 2-5 wt% of one or a mixture of aluminum powder, silicon powder and silicon carbide powder

Binding agent: 3.5-4.0 wt% of phenolic resin.

The sintered magnesite is produced by using light-burned magnesia with the MgO content of 95 wt% as a raw material and through ball pressing, high-temperature shaft kiln calcination and other processes, wherein the MgO content is 94-95 wt%, and the sintered magnesite is prepared by mixing particles with the particle size of less than or equal to 1mm and less than or equal to 3mm, the particle size of more than 0.074mm and less than or equal to 1mm, and the particle size of less than or equal to 0.074 mm.

The purity C content of the flake graphite is more than or equal to 98 wt%, and the granularity is 100 meshes.

The Al powder has a purity AI content of more than or equal to 99 wt% and a particle size of 100 meshes.

The silicon powder has the purity Si content of more than or equal to 97 wt% and the granularity of 100 meshes.

The purity SiC content of the silicon carbide is more than or equal to 94 wt%, and the granularity of the silicon carbide is 100 meshes.

The solid content of the phenolic resin is more than or equal to 72 wt%, the residual carbon content is more than or equal to 42 wt%, and the water content is less than or equal to 5 wt%.

According to the invention, the base plate is produced by isostatic pressing, comprising the following steps:

1) preparing materials: weighing the raw materials according to the proportion;

2) mixing: preheating a mixing roll to 40-50 ℃, adding sintered magnesia with the particle size being less than or equal to 1mm and less than or equal to 3mm and the particle size being less than 0.074mm and less than 1mm at low speed, → dry mixing for 1-2 minutes, adding phenolic resin → wet mixing for 2-3 minutes, adding flake graphite → wet mixing for 2-3 minutes, adding sintered magnesia with the particle size being less than or equal to 0.074mm and antioxidant → wet mixing for 2-3 minutes → high-speed mixing for 10-15 minutes → discharging, wherein the temperature of the pug in the mixing process is less than 70 ℃;

3) green body forming: filling the mud into a mold, then removing air in the mold, pressing and molding under the pressure of 200-250 MPa by equal static pressure, and then discharging the mold, thus completing green body molding;

4) and (3) naturally drying and baking, namely naturally drying the formed green body for 8-16 hours, then putting the green body into a kiln for baking, ① continuously raising the temperature from room temperature to 140-160 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 4-8 hours, ② continuously raising the temperature from 140-160 ℃ to 200-220 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 16-24 hours, ③ stopping fire, naturally cooling to room temperature, and finishing the preparation of the base plate, wherein the compressive strength of the base plate is more than or equal to 40 MPa.

Compared with the prior art, the invention has the beneficial effects that:

(1) the composite structure design of the body shell, the sleeve core and the bottom plate simplifies the preparation process and has low preparation cost.

(2) The sleeve core of the slab continuous casting tundish turbulence controller is a circular truncated cone-shaped prefabricated member with a special inner cavity shape, which is designed based on water model experimental research and application experimental verification, and the water model experimental research result shows that the tundish turbulence controller designed by the invention is more than the continuous casting tundish composite turbulence controller described in CN 103658577B: the average residence time of the molten steel in the tundish is improved by more than 6.7 percent in the same ratio, and the dead zone ratio is reduced by more than 5.2 percent in the same ratio.

(3) The sleeve core of the slab continuous casting tundish turbulence controller is formed by casting the disposable foam inner die and the magnesium castable, and the bottom plate is a whole magnesium carbon brick formed by isostatic pressing, so that the casting forming quality is improved, the integral performance is improved, the problems of poor integral performance, easiness in brick removal, poor quality stability and the like of the continuous casting tundish composite turbulence controller disclosed by CN103658577B are effectively solved, and the sleeve core is used for a uniflow slab continuous casting tundish and has the service life of more than 17-21 hours.

(4) The sleeve core of the slab continuous casting tundish turbulence controller is molded by casting through the disposable foam inner die, meets the design requirement of the inner die with a special inner cavity shape, does not need to be demoulded, simplifies the preparation process flow, shortens the preparation period by 8-24 hours on the same scale, realizes synchronous mass production, and solves the problem that the mass production is limited by the number of steel films.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a front view of the combined slab continuous casting tundish turbulence controller of the present invention;

FIG. 2 is a top view of the composite slab continuous casting tundish turbulence controller of the present invention;

FIG. 3 is a schematic diagram of the core of the turbulence controller for the continuous casting of the composite slab tundish of the present invention being poured with a disposable foam inner mold.

In the figure, 1. a housing; 2. sleeving a core; 3. a joint seam; 4. the upper part of the inner cavity of the sleeve core; 5. the lower part of the inner cavity of the sleeve core; 6. a base plate; 7. a disposable foam inner mold; 8. and (5) casting an outer die by the sleeve core.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments, and the magnesium castable and the magnesium coating used in the embodiments are all produced by using the prior art.

Referring to figures 1-3 of the drawings,

example 1:

as shown in fig. 1, fig. 2 and fig. 3, a turbulence controller for a composite slab continuous casting tundish comprises a casing 1, a sleeve core 2 and a bottom plate 6, wherein the bottom plate 6 is arranged on the bottom surface of an inner cavity of the casing 1, the sleeve core 2 is arranged in the inner cavity of the casing 1, a longitudinal center line of the sleeve core 2 is overlapped with a longitudinal center line of the inner cavity of the casing 1, and a joint seam 3 is arranged between the casing 1 and the sleeve core 2, and the turbulence controller is characterized in that: the outer part of the sleeve core 2 is a truncated cone-shaped magnesium prefabricated part, the inner part of the sleeve core 2 is a paraboloid-shaped inner cavity, the bottom plate 6 is a whole piece of magnesia carbon brick, the inner cavity is divided into a sleeve core inner cavity upper part 4 and a sleeve core inner cavity lower part 5, the sleeve core inner cavity upper part 4 is a rotating surface with a circular arc cross section, the sleeve core inner cavity lower part 5 is an inwards concave rotating paraboloid, the bottom of the sleeve core inner cavity is provided with an opening, the inner cavity with the shape is adopted, the flowing state of molten steel in the middle has direct influence, the response time and the average residence time of the molten steel are prolonged, the piston flow volume is increased, the dead zone volume is reduced, the turbulent energy of ladle pouring flow can be effectively reduced, the molten steel flow field in the tundish is better improved, and the problem of slag entrapment in a pouring area is effectively.

Preferably, the bottom of the inner cavity of the shell 1 is provided with an inner concave cavity, the bottom plate 6 is matched with the inner concave cavity, the bottom plate 6 and the bottom of the inner cavity are in the same plane, and the inner concave cavity for arranging the bottom plate 6 is reserved through embedding a forming die when the bottom of the inner cavity of the shell 1 is poured.

Preferably, the sleeve core 2 is a truncated cone-shaped magnesium prefabricated part cast by a disposable foam inner die 7 and a magnesium casting material, and the bottom plate 6 is a whole magnesium carbon brick molded by isostatic pressing.

The sleeve core 2 of the turbulence controller is in a circular truncated cone shape with a large upper bottom surface and a small lower bottom surface, preferably, the diameter D1 of the upper bottom surface of the circular truncated cone is 720mm, and the diameter D2 of the lower bottom surface of the circular truncated cone is 635 mm; the upper part 4 of the hollow inner cavity of the sleeve core 2 of the turbulence controller is in a bell mouth shape, the diameter phi of an outer opening is 480mm, the radius R of an arc is 75mm, and the height a of the upper part 4 of the inner cavity of the sleeve core is 80 mm; the lower part 5 of the inner cavity of the sleeve core is in a round drum shape with a small upper opening and a large lower opening, the diameter d1 of the upper opening is 420mm, the diameter d2 of the lower opening is 460mm, and the height h of the lower part 5 of the inner cavity of the sleeve core is 320 mm.

The bottom surface of the bottom plate 6 is square, the side length c is 500mm, and the thickness b is 90 mm.

The upper part of the width of the joint seam 3 is large, the lower part is small, the width m of the upper part is 10mm, and the width n of the lower part is 5 mm.

The shape and the size of the shell 1 are designed according to the shape and the size of a continuous casting tundish working lining impact area, and the shell is prepared by casting and molding a magnesium castable produced by the prior art, naturally curing and baking in a heating furnace.

The preparation method of the sleeve core 2 by adopting the disposable foam inner die and the magnesium castable casting molding comprises the following steps of adding the magnesium castable for the sleeve core 2 into a mixer for dry mixing for 2 minutes, adding water accounting for 4.0% of the total weight of the materials, wet mixing for 6 minutes, uniformly mixing, putting into a sleeve core casting outer die 8 provided with the disposable foam inner die 7, compacting by using a vibrating rod, completing casting of a green body of the sleeve core 2 when no large bubbles emerge, solidifying for 12 hours, removing the sleeve core casting outer die 8, naturally curing for 12 hours, baking in a heating furnace, heating ① from room temperature at a heating speed of 10 ℃/h to 120 ℃, insulating ② at 120 ℃ for 11 hours, heating ③ from the heating speed of 10 ℃/h to 220 ℃, insulating ④ at 220 ℃ for 7 hours, heating ⑤ from 15 ℃/h to 360 ℃, insulating ⑥ at 360 ℃ for 7 hours, naturally cooling ⑦, cooling to normal temperature, cleaning the disposable foam inner die 7 residues, and completing preparation of the sleeve core 2.

The bottom plate 6 is prepared by an isostatic pressing forming method and is prepared from the following raw materials in percentage by weight:

main materials: 84 wt% of sintered magnesite

Auxiliary materials: flake graphite 10.5 wt%

Antioxidant: 2.0 wt% of aluminum powder

Binding agent: 3.5 wt% of phenolic resin.

The bottom plate 6 is prepared by an isostatic pressing forming method, and comprises the following steps:

1) preparing materials: weighing the raw materials according to the proportion;

2) mixing: preheating a mixing roll to 40 ℃, adding sintered magnesia with the granularity being less than or equal to 1mm and less than or equal to 3mm and the granularity being less than or equal to 1mm and 0.074mm at low speed → dry mixing for 1 minute, adding phenolic resin → wet mixing for 3 minutes, adding flake graphite → wet mixing for 2 minutes, adding sintered magnesia with the granularity being less than or equal to 0.074mm and antioxidant → wet mixing for 3 minutes → high-speed mixing for 10 minutes → discharging, wherein the temperature of the pug is less than 70 ℃ in the mixing process;

3) green body forming: filling the mud into a mold, then removing air in the mold, pressing and molding under the pressure of 200MPa by equal static pressure, and then discharging the mold, thus completing green body molding;

4) and (3) naturally drying and baking, namely naturally drying the formed green body for 8 hours, then putting the green body into a kiln for baking, ① continuously raising the temperature from room temperature to 140 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 8 hours, ② continuously raising the temperature from 140 ℃ to 200 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 24 hours, ③ stopping heating, naturally cooling to room temperature, and finishing the preparation of the base plate, wherein the compressive strength of the base plate is more than or equal to 40 MPa.

A preparation method of a combined continuous casting tundish turbulence controller comprises the following steps: the sleeve core 2 is sleeved in the shell 1 of the turbulence controller, the longitudinal center line of the sleeve core 2 is ensured to be coincident with the longitudinal center line of the inner cavity of the shell 1, the joint seam 3 between the shell 1 and the sleeve core 2 is filled by sintered magnesia with the granularity of less than or equal to 1mm, a layer of regenerated magnesia carbon coating material with the thickness of 25mm is coated on the outer surface of the sintered magnesia carbon coating material, natural curing is carried out for 1 day, and the preparation of the composite slab continuous casting tundish turbulence controller is completed.

The magnesia-carbon coating is prepared from a regenerated magnesia-carbon particle material with the particle size of less than or equal to 1mm and less than or equal to 3mm and the particle size of less than or equal to 0.074mm, which are processed and processed by adopting waste magnesia-carbon bricks, and sintered magnesia fine powder, soft clay, silica powder, sodium tripolyphosphate and the like with the particle size of less than or equal to 0.074mm according to a certain proportion, wherein the regenerated magnesia-carbon particle material accounts for 60-70 wt%, the MgO content is more than or equal to 65 wt%, and the bulk density is more than or equal to 1.87g/cm 3.

Example 2

As described in example 1, except that:

in the sleeve core 2 of the turbulence controller, the diameter D1 of the upper bottom surface of the circular truncated cone is 750mm, and the diameter D2 of the lower bottom surface of the circular truncated cone is 665 mm; the upper part 4 of the hollow inner cavity of the sleeve core 2 of the turbulence controller is in a bell mouth shape, the diameter phi of an outer opening is 500mm, the radius R of an arc is 80mm, and the height a of the upper part 4 of the inner cavity of the sleeve core is 100 mm; the diameter d1 of the upper opening of the lower part 5 of the inner cavity of the sleeve core is 440mm, the diameter d2 of the lower opening is 480mm, and the height h of the lower part 5 of the inner cavity of the sleeve core is 350 mm.

The bottom surface of the bottom plate 6 is square, the side length c is 520mm, and the thickness b is 110 mm.

The upper part of the width of the joint seam 3 is large, the lower part of the width of the joint seam is small, the width m of the upper part is 15mm, and the width n of the lower part is 10 mm.

The preparation method of the sleeve core 2 by adopting the disposable foam inner die and the magnesium casting material casting molding comprises the following steps of adding the magnesium casting material for the sleeve core 2 into a mixer for dry mixing for 3 minutes, adding water accounting for 5.0% of the total weight of the materials, wet mixing for 6 minutes, uniformly mixing, putting the mixture into a sleeve core casting outer die 8 provided with the disposable foam inner die 7, compacting by using a vibrating rod, completing casting of a green body of the sleeve core 2 when no large bubbles emerge, solidifying for 24 hours, removing the sleeve core casting outer die 8, naturally curing for 24 hours, baking in a heating furnace, heating ① from room temperature at a heating speed of 10 ℃/h to 150 ℃, insulating ② at 150 ℃ for 13 hours, heating ③ from the heating speed of 10 ℃/h to 250 ℃, insulating ④ at 250 ℃ for 9 hours, heating ⑤ at a heating speed of 15 ℃/h, heating to 390 ℃, insulating ⑥ at 390 ℃ for 9 hours, naturally cooling ⑦, cooling to normal temperature, cleaning the residue of the disposable foam inner die, and completing preparation of the sleeve core 2.

main materials: 76 wt% of sintered magnesite

Auxiliary materials: 16 wt% of flake graphite

Antioxidant: 2 wt% of silicon powder and 2 wt% of silicon carbide powder

Binding agent: 4.0 wt% of phenolic resin.

1) preparing materials: weighing the raw materials according to the proportion;

2) mixing: preheating a mixing roll to 50 ℃, adding sintered magnesia with the granularity being less than or equal to 1mm and less than or equal to 3mm and the granularity being less than or equal to 0.074mm and less than 1mm at low speed → dry mixing for 2 minutes, adding phenolic resin → wet mixing for 2 minutes, adding flake graphite → wet mixing for 3 minutes, adding sintered magnesia with the granularity being less than or equal to 0.074mm and antioxidant → wet mixing for 2 minutes → high-speed mixing for 15 minutes → discharging, wherein the temperature of the pug is less than 70 ℃ in the mixing process;

3) green body forming: filling the mud into a mold, then removing air in the mold, pressing and molding under 250MPa by isostatic pressure, and then discharging the mold, thus completing green body molding;

4) and (3) naturally drying and baking, namely naturally drying the formed green body for 16 hours, then putting the green body into a kiln for baking, ① continuously raising the temperature from room temperature to 160 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 4 hours, ② continuously raising the temperature from 160 ℃ to 220 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 16 hours, ③ stopping heating, naturally cooling to room temperature, and finishing the preparation of the bottom plate 6, wherein the compressive strength of the bottom plate is more than or equal to 40 MPa.

A preparation method of a composite plate blank continuous casting tundish turbulence controller comprises the following steps: the sleeve core 2 is sleeved in the shell 1 of the turbulence controller, the longitudinal center line of the sleeve core 2 is ensured to be coincident with the longitudinal center line of the inner cavity of the shell 1, the joint seam 3 between the shell 1 and the sleeve core 2 is filled by adopting a sintered magnesia slab with the granularity of less than or equal to 1mm, a layer of magnesia coating material with the thickness of 35mm is coated on the outer surface of the sintered magnesia slab, the natural curing is carried out for 2 days, and the preparation of the composite continuous casting tundish turbulence controller is completed.

Example 3

As described in example 1, except that:

in the sleeve core 2 of the turbulence controller, the diameter D1 of the upper bottom surface of the circular truncated cone is 730mm, and the diameter D2 of the lower bottom surface of the circular truncated cone is 650 mm; the upper part 4 of the hollow inner cavity of the sleeve core 2 of the turbulence controller is in a bell mouth shape, the diameter phi of an outer opening is 490mm, the radius R of an arc is 77mm, and the height a of the upper part 4 of the inner cavity of the sleeve core is 90 mm; the diameter d1 of the upper opening of the lower part 5 of the inner cavity of the sleeve core is 430mm, the diameter d2 of the lower opening is 470mm, and the height h of the lower part 5 of the inner cavity of the sleeve core is 330 mm.

The bottom surface of the bottom plate 6 is square, the side length c is 510mm, and the thickness b is 100 mm.

The upper part of the width of the joint seam 3 is large, the lower part is small, the width m of the upper part is 12mm, and the width n of the lower part is 7 mm.

The preparation method of the sleeve core 2 by adopting the disposable foam inner die and the magnesium casting material for casting molding comprises the following steps of adding the magnesium casting material for the sleeve core 2 into a mixer for dry mixing for 2 minutes, adding water accounting for 4.5% of the total weight of the materials, wet mixing for 5 minutes, uniformly mixing, putting the mixture into a sleeve core casting outer die 8 provided with the disposable foam inner die 7, compacting by using a vibrating rod, completing casting of a green body of the sleeve core 2 when no large bubbles emerge, solidifying for 16 hours, removing the sleeve core casting outer die 8, naturally curing for 16 hours, baking in a heating furnace, wherein ① is heated to 135 ℃ from room temperature at a heating rate of 10 ℃/h, ② is kept at 135 ℃ for 12 hours, ③ is heated to 235 ℃ from a heating rate of 10 ℃/h, ④ is kept at 235 ℃ for 8 hours, ⑤ is heated to 375 ℃ at a heating rate of 15 ℃/h, ⑥ is kept at 375 ℃ for 8 hours, ⑦ is naturally cooled, and after cooling to normal temperature, the disposable foam inner die 7 residue is cleaned, and the preparation of the sleeve core 2 is completed.

main materials: 79 wt% of sintered magnesite

Auxiliary materials: flake graphite 14 wt%

Antioxidant: 3.3 wt% of silicon powder

Binding agent: 3.7 wt% of phenolic resin.

1) preparing materials: weighing the raw materials according to the proportion;

2) mixing: preheating a mixing roll to 45 ℃, adding sintered magnesia with the granularity being less than or equal to 1mm and less than or equal to 3mm and the granularity being less than or equal to 1mm and 0.075mm at low speed → dry mixing for 1 minute, adding phenolic resin → wet mixing for 3 minutes, adding flake graphite → wet mixing for 3 minutes, adding sintered magnesia with the granularity being less than or equal to 0.075mm and antioxidant → wet mixing for 2 minutes → high-speed mixing for 10 minutes → discharging, wherein the temperature of the pug is less than 70 ℃ in the mixing process;

3) green body forming: filling the mud into a mold, then removing air in the mold, pressing and molding under 220MPa by isostatic pressure, and then discharging the mold, thus completing green body molding;

4) and (3) naturally drying and baking, namely after the green body is formed and naturally dried for 12 hours, putting the green body into a kiln for baking ①, continuously heating the green body from room temperature to 150 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 6 hours, continuously heating the green body from ② to 210 ℃ at a heating rate of 10 ℃/h, keeping the temperature for 20 hours, stopping ③, naturally cooling the green body to room temperature, and finishing the preparation of the bottom plate 6, wherein the compressive strength of the bottom plate is more than or equal to 40 MPa.

A preparation method of a composite plate blank continuous casting tundish turbulence controller comprises the following steps: the sleeve core 2 is sleeved in the shell 1 of the turbulence controller, the longitudinal center line of the sleeve core 2 is ensured to be coincident with the longitudinal center line of the inner cavity of the shell 1, the joint seam 3 between the shell 1 and the sleeve core 2 is filled by sintered magnesia with the granularity of less than or equal to 1mm, a layer of magnesia coating material with the thickness of 30mm is coated on the outer surface of the sintered magnesia coating material, the magnesium coating material is naturally maintained for 2 days, and the preparation of the composite continuous casting tundish turbulence controller is completed.

Comparative example: CN201244677B discloses a method for preparing a continuous casting tundish composite turbulence controller, which comprises a shell, a bottom plate, a sleeve core, an expansion joint and an antioxidant coating, wherein the shell is cast and molded by adopting a magnesium casting material, the bottom plate is built by adopting magnesium carbon bricks which are molded by machine pressing, the sleeve core is built by adopting fan-shaped magnesium carbon bricks which are molded by machine pressing, the expansion joint is arranged between the shell and the bottom plate and between the shell and the sleeve core, and the antioxidant coating is coated on the outer surface of the sleeve core.

Examples 1 to 3 of the present invention and a reference CN201244677B disclose a method for preparing a continuous casting tundish composite turbulence controller) were all set up in a similar ratio of 1:2, and the experimental results and comparative analysis conditions of the water mold were as shown in table 1 below:

TABLE 1

Compared with the comparative example, the invention improves the equivalent ratio by more than 6.7 percent, increases the equivalent ratio by more than 9.0 percent, and reduces the equivalent ratio by more than 5.2 percent

By comparison of the data in table 1 above, the tundish turbulence controller designed by the present invention is more suitable than the continuous casting tundish composite turbulence controller described in CN 103658577B: the average residence time of the molten steel in the tundish is improved by more than 6.7 percent on the same scale, and the dead zone proportion is reduced by more than 5.2 percent on the same scale. Examples 1 to 3 of the present invention and a reference CN201244677B disclose a method for preparing a continuous casting tundish composite turbulence controller), the service life, and the total oxygen content in molten steel in a crystallizer (comparative test steel type SPHC) were compared in slab continuous casting tundish applications of the leuw iron group yinshan type steel limited company, as shown in table 2 below:

TABLE 2

Compared with the comparative example, the invention simplifies the preparation process flow, shortens the preparation period, improves the casting molding quality, improves the overall performance by over 4 hours and reduces the overall performance by 12.6 percent

Through the comparison of the data in the table 2, the service life of the novel long-life continuous casting tundish turbulence controller prepared by the invention is improved by more than 4 hours compared with the composite turbulence controller produced by the prior patent technology CN103658577B, and the total oxygen content in the molten steel in the crystallizer is reduced by more than 12 percent compared with the total oxygen content in the molten steel

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides a package turbulence controller in middle of combined type slab continuous casting, includes shell (1), cover core (2) and bottom plate (6), bottom plate (6) set up the bottom surface at shell (1) inner chamber, cover core (2) set up in the inner chamber of shell (1), and the longitudinal center line coincidence of the longitudinal center line of cover core (2) and shell (1) inner chamber, be equipped with joint line (3) between shell (1) and cover core (2), its characterized in that: the sleeve core (2) is a truncated cone-shaped magnesium prefabricated part formed by casting a disposable foam inner die (7) and a magnesium casting material, the bottom plate (6) is a whole magnesium carbon brick formed by isostatic pressing, the inner part of the sleeve core (2) is a paraboloid-shaped inner cavity which is divided into an upper part (4) of the sleeve core inner cavity and a lower part (5) of the sleeve core inner cavity, the upper part (4) of the sleeve core inner cavity is a rotating surface with a circular arc-shaped cross section, and the lower part (5) of the sleeve core inner cavity is an inwards concave rotating paraboloid.

2. The composite slab continuous casting tundish turbulence controller of claim 1, wherein: the bottom of the inner cavity of the shell (1) is provided with an inner concave cavity, the bottom plate (6) is matched with the inner concave cavity, and the bottom plate (6) and the bottom of the inner cavity are in the same plane.

3. The composite slab continuous casting tundish turbulence controller of claim 2, wherein: the diameter D1 of the upper bottom surface of the truncated cone-shaped sleeve core (2) is 720-750 mm, and the diameter D2 of the lower bottom surface of the truncated cone is 635-665 mm.

4. The composite slab continuous casting tundish turbulence controller of claim 3, wherein: the cover core inner chamber upper portion (4) of cover core (2) be horn mouth shape, outer mouthful diameter phi is 480 ~ 500mm, circular arc radius R is 75 ~ 80mm, the height an of cover core inner chamber upper portion (4) is 80 ~ 100 mm.

5. The composite slab continuous casting tundish turbulence controller of claim 4, wherein: the upper opening of the lower part (5) of the inner cavity of the sleeve core is small, the lower opening of the lower part (5) of the inner cavity of the sleeve core is large, the diameter d1 of the upper opening of the lower part (5) of the inner cavity of the sleeve core is 420-440 mm, the diameter d2 of the lower opening of the inner cavity of the sleeve core is 460-480 mm, and the height h of the lower part (5) of the inner cavity of the sleeve core is 320-.

6. The composite continuous slab casting tundish turbulence controller of any one of claims 1-5, wherein: the bottom surface of the bottom plate (6) is square, the side length c is 40-60 mm larger than d2, and the thickness b is 90-110 mm.

7. The composite continuous slab casting tundish turbulence controller of any one of claims 1-5, wherein: the width of the joint seam (3) is large at the upper part and small at the lower part, the width m of the upper part is 10-15 mm, and the width n of the lower part is 5-10 mm.

8. The method for manufacturing the turbulence controller for the continuous casting of the composite slab for the tundish according to any one of claims 1 to 7, comprising the steps of:

firstly, a shell (1) is cast and molded by adopting a magnesium spinel castable, the shape and the size of the shell (1) are designed according to the shape and the size of a continuous casting tundish working lining impact area, the magnesium spinel castable produced by the prior art is cast and molded, and the magnesium spinel castable is prepared by natural curing and baking in a heating furnace; the magnesium spinel castable is produced by the prior art, the MgO content is more than or equal to 71 wt%, the volume density is more than or equal to 3.03g/cm3, and the flexural strength (1500 ℃) is more than or equal to 9 Mpa;

secondly, casting and molding the sleeve core (2) by using a disposable foam inner die (7) and a magnesium casting material, and casting and molding the sleeve core (2) by using a disposable foam inner die (7) and a magnesium casting material, wherein the preparation method comprises the following steps of adding the magnesium casting material for the sleeve core (2) into a mixer for dry mixing for 2-3 minutes, adding water accounting for 4.0-5.0% of the total weight of the materials, wet mixing for 4-6 minutes, uniformly mixing, putting into a sleeve core casting outer die (8) provided with the disposable foam inner die (7), compacting by using a vibrating bar, pouring a green blank of the sleeve core (2) when no large bubbles emerge, solidifying for 12-24 hours, removing the sleeve core casting outer die (8), naturally curing for 12-24 hours, baking in a heating furnace, wherein ① is heated from room temperature to 120-150 ℃ at a heating speed of 10 ℃/h, ② is heated to 120-150 ℃ for 11-13 hours, ③ is heated to 220-250 ℃ at a heating speed of 10 ℃/h, is heated to 397, is cooled again at a heating speed of 397-397 ℃ and is heated to 360-390 ℃ after natural heat preservation, and heat preservation is carried out, and the temperature is carried out, the sleeve core is carried out, and the temperature is carried out after the temperature is carried out, the temperature;

thirdly, preparing the bottom plate (6) into a whole magnesia carbon brick by adopting an isostatic pressing method, wherein the bottom plate (6) is prepared by adopting the isostatic pressing method and is prepared from the following raw materials in percentage by weight:

main materials: 76-84 wt% of sintered magnesia

Auxiliary materials: 11.5-16 wt% of flake graphite

Binding agent: 3.5-4.0 wt% of phenolic resin.

According to the invention, the base plate (6) is produced by isostatic pressing, comprising the following steps:

1) preparing materials: weighing the raw materials according to the proportion;

4) naturally drying and baking, namely, naturally drying the formed green body for 8-16 hours, and then putting the green body into a kiln for baking, wherein ① is heated continuously from room temperature to 140-160 ℃ at a heating rate of 10 ℃/h, and is subjected to heat preservation for 4-8 hours, ② is heated continuously from 140-160 ℃ to 200-220 ℃ at a heating rate of 10 ℃/h, and is subjected to heat preservation for 16-24 hours, ③ is stopped, the green body is naturally cooled to room temperature, the preparation of the bottom plate (6) is completed, and the compressive strength of the green body is more than or equal to 40 MPa;

fourthly, coating a layer of magnesia coating material with the thickness of 25-35mm on the outer surface of the sintered magnesia, wherein the magnesia carbon coating material is a coating material prepared by adopting regenerated magnesia carbon clay with the granularity of 1mm less than or equal to 3mm and the granularity of more than 1mm and regenerated magnesia carbon clay with the granularity of 0.074mm in the prior art and sintered magnesia fine powder, soft silica powder, sodium tripolyphosphate and the like according to a certain proportion, and the weight percentage of the regenerated magnesia carbon particle material is 60-70%;

fifthly, the sleeve core (2) is sleeved in the shell (1) of the turbulence controller, the longitudinal center line of the sleeve core (2) is enabled to be coincident with the longitudinal center line of the inner cavity of the shell (1), a joint seam (3) between the shell (1) and the sleeve core (2) is filled with sintered magnesia with the granularity of less than or equal to 1mm, natural maintenance is carried out for 1-2 days, and the preparation of the composite continuous casting tundish turbulence controller is completed.