CN109304432B - Single-point unbalanced protection casting device for ultrathin large-size aluminum-containing steel special-shaped blank and using method - Google Patents
Single-point unbalanced protection casting device for ultrathin large-size aluminum-containing steel special-shaped blank and using method Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/009—Continuous casting of metals, i.e. casting in indefinite lengths of work of special cross-section, e.g. I-beams, U-profiles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
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- 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
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- B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
- B22D41/18—Stopper-rods therefor
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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
- B22D41/50—Pouring-nozzles
- B22D41/58—Pouring-nozzles with gas injecting means
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Abstract
The invention discloses a single-point non-equilibrium protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank and a using method thereof, belonging to the technical field of near-net-shape continuous casting in the ferrous metallurgy industry. It includes middle package, stopper rod, the mouth of a river, the brick cup, lower mouth of a river, immersion nozzle and H parison crystallizer, stopper rod arranges middle package exit in, the middle package exit sets up the mouth of a river, and is fixed by the brick cup, the mouth of a river lower extreme is connected with lower mouth of a river, lower mouth of a river lower extreme is connected with immersion nozzle, immersion nozzle is located H parison crystallizer one side edge of a wing trigone center, still including being hollow blowing sleeve, the sleeve sets up between mouth of a river and lower mouth of a river, the mouth of a river, sleeve and lower mouth of a river form a steel stream passageway, be equipped with the inlet port on the sleeve, the quantity of inlet port be more than one, the inlet. The invention can improve the quality of the special-shaped blank products, improve the qualified rate of the casting blanks, and improve the market competitiveness of the products, and has the advantages of reasonable design and easy application.
Description
Technical Field
The invention belongs to the technical field of near net shape continuous casting in the ferrous metallurgy industry, and particularly relates to a single-point non-equilibrium protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank and a using method thereof.
Background
Continuous casting is a process of continuously cooling, solidifying and forming molten steel, and is a main steel casting mode at present. In the development process of continuous casting technology, near-net-shape continuous casting is an important achievement and sign of the development of modern continuous casting technology, and continuous casting billets with the required steel section shape or the shape close to the finished steel shape can be directly produced. The beam blank continuous casting is an important form of near-net-shape continuous casting, and the beam blank generally mainly refers to a continuous casting blank with an H-shaped section. As the H-shaped steel has the advantages of economic and reasonable section shape, large bending-resistant section modulus, convenient manufacture and the like, in order to meet the domestic requirements, the special-shaped blank continuous casting machine is built by a plurality of domestic steel companies in succession since the 90 s of the 20 th century. At present, the near net-shape beam blank continuous casting technology is applied in large scale in China, and the produced casting blank can meet the requirements of various strength grades of structural steel, weather-resistant steel, steel for an offshore oil platform, fine grain steel and the like. The special-shaped blank production and processing technology is simplified, equipment is reduced, the production flow line is shortened, the production efficiency is obviously improved, the construction investment cost and the production cost are reduced, meanwhile, the processing procedure of rolling the H-shaped blank by the special-shaped blank is reduced, the comprehensive energy consumption is low, the production cost is greatly reduced, and the yield is improved.
The casting process of molten steel is a key technology for controlling the quality of casting blanks. Compared with the conventional casting blank (square blank, plate blank and round blank), the special-shaped blank with the H-shaped section has a complex casting section shape, and the main body of the special-shaped blank is divided into a web and two flanges which are symmetrically distributed left and right. The casting process will directly affect the operability, ease and stability of the production process and ultimately the quality of the H-section cast slab. At present, the casting process of the H-shaped blank mainly comprises the following four steps:
the first process is that casting from tundish to crystallizer is carried out by two points of 'fixed diameter nozzle + semi-immersion (semi-open) funnel-shaped nozzle' in flange triangle area at each casting flow, there is no stopper system in the tundish to control flow, fixed diameter nozzle is used at the outlet of the tundish, and fixed diameter nozzle is not connected with funnel-shaped nozzle inserted in molten steel of crystallizer, so there is a certain distance.
The Chinese patent application numbers are: 201410284643.3, application date 2014.06.23 entitled "method for producing continuous casting slab by using near-net-shape beam blank continuous casting machine", which discloses a casting process method of a flange triangular area two-point semi-open type funnel-shaped nozzle of a near-net-shape beam blank continuous casting machine for producing continuous casting slab, which improves the casting success rate of a tundish and reduces the problems of steel overflow and steel leakage in the casting process.
The second process is a double-immersion type water gap full-protection casting process of each casting flow in two flange triangular areas, a pouring box water gap is connected with an immersion type water gap in a sealing mode, the immersion type water gap is in a straight cylinder shape and is provided with a side hole, the process is simple and convenient to operate, production stability is good, the service life of the immersion type water gap is long, but when the two-point full-protection casting is carried out, due to the limitation of the size of a special-shaped blank, a stopper rod flow control system cannot be arranged in a pouring box between the two points, a fixed-diameter slide block is used for controlling the flow of a pouring box outlet, the diameter of the slide block is small, and Al is easily adhered to2O3And the inclusion causes serious trepanning and can not meet the production requirements of steel grades containing aluminum and adopting an aluminum deoxidation process, so that the aluminum deoxidation can not be realized, the purity of molten steel is not high, and meanwhile, the protective casting process can not realize the production of steel grades containing higher titanium content and requiring the addition of rare earth.
The Chinese patent application numbers are: 201410350560.X and 201110254150.1, application dates 2014.07.22 and 2011.08.31 respectively, the patent literature is named as "submerged nozzle for casting a profiled blank and the arrangement thereof" and "arrangement structure of the submerged nozzle for a profiled blank crystallizer", and discloses a full-protection casting process of a flange triangle double submerged nozzle, and the internal structure and the hole opening condition of the submerged nozzle. However, during two-point casting, due to the size constraint of the beam blank, the distance between the two water gaps is too small, so that two groups of stopper rod devices cannot be placed above the water gaps.
The third process is a full-protection casting process of a single point stopper rod, a water feeding port and an immersion nozzle in the center of a web plate, and the process has the problems that the immersion nozzle in the middle of the web plate is difficult to center, the service life of the nozzle is short, the process is unstable, and the application of the process is limited especially when the size space of the ultra-thin web plate is too small.
The Chinese patent application numbers are: 200710014826.3, application No. 2007.07.17 entitled "method and apparatus for continuous casting and casting of a beam blank with a single submerged nozzle", which discloses a method and apparatus for casting a beam blank with a single submerged nozzle, that is, a circular to flat double-hole submerged nozzle is placed in the center of a web plate of a beam blank crystallizer for casting. When the ultrathin special-shaped blank is cast, the middle width of the ultrathin special-shaped blank is too small, the minimum specification is only 90mm, a water gap needs to keep a certain distance with an inner arc crystallizer copper plate and an outer arc crystallizer copper plate, and a refractory material at the outermost side of the water gap structure needs to have a certain thickness.
The fourth process is that each casting flow adopts a single submerged nozzle to carry out protective casting in a flange triangular area on one side of the section of the beam blank, so that the flow field and the temperature field of molten steel in the crystallizer are extremely asymmetric, various surface and internal quality problems of the casting blank are frequent, and steel leakage accidents can occur in severe cases.
Journal documents 'MA 345 steel smelting and beam blank continuous casting process development' and 'development of beam blank continuous casting technology from production of beam blank continuous casting machine' simply mention that the beam blank continuous casting adopts a stopper rod and a flange triangular area single submerged nozzle for protecting casting when producing high-quality steel small-section (500mm multiplied by 300mm multiplied by 120mm) casting blank, the beam blank of the beam blank can easily realize single-point protection casting from two aspects of size and flange thickness, and the beam blank adopts a fixed diameter nozzle and a semi-submerged double-nozzle semi-open casting when producing web thin and large-section (750mm multiplied by 450mm multiplied by 120mm) casting blank. During single-point casting, the distribution of a molten steel flow field and a temperature field of a crystallizer is asymmetric and uneven, the growth of a casting blank shell in the crystallizer and the melting of protective slag are uneven, so that production accidents such as steel leakage, pulling immobility and the like and the quality problem of cracks on the surface of a casting blank are easily caused; meanwhile, when the thickness of the web plate is too thin, flange single-point casting is adopted, the passing capacity of molten steel on the non-casting point side is poor when the molten steel passes through the web plate, the asymmetry and the nonuniformity of molten steel flow field and temperature field distribution of the crystallizer are further aggravated, and the molten steel has strong scouring on the web plate, so that the leakage accident of local blank shell is easily caused; if the width of the section of the casting blank is large, the asymmetry unevenness of the molten steel flow field and the temperature field distribution of the crystallizer can be further aggravated; the flow of molten steel at the single-point casting point of the flange is larger than that at the two-point casting point, and the injection flow seriously erodes the nearby shell.
The Chinese patent application No. 201210090957.0, 2012.03.30 on the application date, "a large Z-direction H-shaped steel and a preparation method thereof", discloses components of the large Z-direction H-shaped steel and a method for preparing the H-shaped steel, wherein the continuous casting process comprises the steps of tundish baking temperature of 1100 ℃, crystallizer arc alignment, nozzle alignment meeting the requirement, good cooling water effect, full-protection casting by using an immersion nozzle, the immersion nozzle is flat, weak cooling is adopted in secondary cooling, and non-sinusoidal vibration is adopted in the crystallizer. The continuous casting work of the Z-direction H-shaped steel can be completed, and qualified Z-direction H-shaped steel is produced; however, when the aluminum-containing steel is produced, the flat nozzle is easy to form the nodule, and the nozzle is easy to generate jet flow, so that the flow field is uneven.
In summary, the above patent documents and journal documents provide certain solutions to the problems faced by continuous casting of the special-shaped blank, but are not suitable for casting the aluminum-containing steel special-shaped blank with ultra-thin (such as 90mm web thickness) and large specification (such as 1024mm casting blank width).
Disclosure of Invention
1. Problems to be solved
Aiming at the problem that the prior art is difficult to safely and stably cast the ultrathin large-size aluminum-containing steel beam blank, the invention provides the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel beam blank, which can further improve the quality control level of the beam blank under the condition of solving the problems of asymmetrical and uneven distribution of a molten steel flow field and a temperature field of a crystallizer, growth of a blank shell of a casting blank in the crystallizer, uneven melting of protective slag, easy production accidents such as steel leakage, pulling and the like and the quality of cracks on the surface of the casting blank in the flange single-point unbalanced casting, and lays a foundation for realizing the large-scale safe and stable production of the beam blank of ultrathin web plates, oversized cross sections, aluminum-containing and other easily-oxidized element steel beam blanks by a beam blank continuous.
The invention also aims to provide a using method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank, which has the advantages of orderly step connection, smooth casting process and safe and reliable use.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention relates to a single-point unbalanced protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank, which comprises a tundish, a stopper rod, an upper nozzle, a brick cup, a lower nozzle, an immersed nozzle and an H-shaped blank crystallizer, wherein the stopper rod is arranged at the outlet of the tundish, the outlet of the tundish is provided with the upper nozzle and is fixed by the brick cup, the lower end of the upper nozzle is connected with the lower nozzle, the lower end of the lower nozzle is connected with the immersed nozzle, the immersed nozzle is positioned in the center of a flange triangular area on one side of the H-shaped blank crystallizer, the casting device also comprises a hollow air blowing sleeve, the air blowing sleeve is arranged between the upper nozzle and the lower nozzle, the upper nozzle, the sleeve and the lower nozzle form a steel flow channel, the sleeve is provided with more than one air.
As the preferable scheme of the invention, when the number of the air inlet holes is more than two, the included angles formed by the central lines of the two adjacent air inlet holes are equal.
As a preferable scheme of the present invention, when the air inlet is in an operating state, an inert gas with a certain pressure needs to be introduced into the connection between the upper water inlet and the lower water inlet, and the inert gas includes helium, neon, argon, krypton, xenon, or a mixture of the above gases.
As a preferable scheme of the invention, the pressure of the inert gas in the gas inlet is in the range of 0.1-0.35 MPa.
As the preferred scheme of the invention, the upper nozzle is funnel-shaped, the caliber of the contact part of the upper end and the stopper rod is large, the caliber of the connection part of the lower end and the lower nozzle is small, and the upper nozzle is nested inside the brick cup.
In a preferred embodiment of the present invention, the tundish is a T-shaped multi-flow tundish, two molten steel outlets are provided for each flow, one molten steel outlet is used for casting during casting, and the other molten steel outlet is reserved.
In a preferred embodiment of the present invention, the submerged nozzle is a straight cylinder submerged nozzle, the upper end of the straight cylinder submerged nozzle is a bowl opening, the inner diameter of the bowl opening gradually decreases from top to bottom and is connected to the lower end of the lower nozzle, the lower end of the bowl opening is a straight cylinder submerged nozzle body, the inner diameters of the straight cylinder submerged nozzle body are equal at all places, and a slag line portion is disposed at the contact position of the straight cylinder submerged nozzle and the molten steel surface in the mold.
As a preferable scheme of the invention, a casting opening is arranged at the central point of a flange triangular area at one side of the H-shaped blank crystallizer, the free end of the submerged nozzle is arranged in the casting opening for casting, and the H-shaped blank crystallizer comprises an inner arc wide-surface copper plate, an outer arc wide-surface copper plate, a narrow-surface copper plate at one side close to the casting opening and a narrow-surface copper plate at one side far away from the casting opening.
As a preferable scheme of the invention, the use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving a single-point unbalanced protection casting device of the ultrathin large-specification aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle of the device into a crystallizer from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap and the lower water gap by using the air inlet hole from outside to inside, and starting casting;
D. when the tundish is replaced, the blind hole drainage port (namely the drainage port without the hole) is replaced by using the hydraulic cylinder for blocking, and the step A, the step B and the step C are repeated.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention relates to a single-point unbalanced protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank, which adopts the matching of a stopper rod, an upper nozzle, a blowing sleeve, a lower nozzle and a straight cylinder type immersion nozzle, a blowing sleeve is added between the upper water gap and the lower water gap to blow inert gas with certain pressure into the steel flow, the impact force of the steel flowing into the crystallizer is reduced by the upward floating of the bubble group, the production operation safety can be improved, but also reduces the asymmetry of the distribution of the molten steel flow field and the temperature field during the flange single-point unbalanced casting, and stabilizes the fluctuation of the liquid level of the crystallizer, not only realizes the full-protection casting of the molten steel from the tundish to the crystallizer, has simple realization and low cost, meanwhile, the method has strong operability, is safe and reliable, can be used for producing aluminum-containing steel, and can be popularized to the production of other high-grade special-shaped blank steel grades containing easily-oxidizable elements and the like;
(2) according to the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank, when the number of the air inlet holes in the sleeve is more than two, included angles formed by the central lines of two adjacent air inlet holes are equal, the uniformity of air inlet can be ensured, and the stress of steel flow in the sleeve is balanced;
(3) according to the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank, the pressure range of inert gas in the air inlet of the sleeve is 0.1-0.35MPa, steel flow can smoothly flow down in the pressure range, the steel flow cannot be blocked, the atmosphere environment of the steel flow can be ensured in the pressure range, and the oxidation of aluminum is reduced;
(4) the invention relates to a single-point unbalanced protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank, wherein an upper water gap of the casting device is funnel-shaped, the caliber of the contact part of the upper end and a stopper rod is large, the caliber of the connection part of the lower end and a lower water gap is small, and the upper water gap is nested inside a brick cup; the straight cylinder type water gap with large inner diameter has large molten steel flow.
Drawings
The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for illustrative purposes only and thus do not limit the scope of the present invention. Furthermore, unless otherwise indicated, the drawings are intended to be illustrative of the structural configurations described herein and are not necessarily drawn to scale.
FIG. 1 is a cross-sectional structural dimension (mm) of an H-shaped beam blank according to an embodiment of the present invention;
FIG. 2 is a schematic view of a flange single-point unbalanced casting process device for an ultrathin large-specification aluminum-containing steel special-shaped blank of the invention;
FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;
FIG. 4 is a top view of a beam blank flange single-point unbalanced casting crystallizer.
In the drawings:
1. a tundish; 2. a stopper rod; 3. a water feeding port; 4. brick setting; 5. a water outlet; 6. an immersion nozzle; 7. a crystallizer; 8. a sleeve; 9. and (4) air inlet holes.
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
The process method for continuously casting the ultrathin large-size aluminum-containing steel special-shaped blank mainly comprises a single-point unbalanced protection casting device and a using method of the ultrathin large-size aluminum-containing steel special-shaped blank, which are used for casting the molten steel from a tundish 1 to a crystallizer 7, a safe production operation method matched with the unbalanced protection casting device and the using method, an adaptive process parameter range, an asymmetric crystallizer cooling process and an asymmetric mold flux multi-point distribution process.
(1) A single-point unbalanced protection casting device for an ultrathin large-size aluminum-containing steel special-shaped blank and a using method thereof are used for casting molten steel from a tundish 1 to a crystallizer 7.
As shown in fig. 2, the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises a tundish 1, a stopper rod 2, an upper nozzle 3, a brick cup 4, a lower nozzle 5, an immersion nozzle 6, an H-shaped blank crystallizer 7, a sleeve 8 and an air inlet 9; the stopper 2 is arranged in the interior exit of tundish 1, 2 lower extremes of stopper are equipped with brick cup 4, it is connected with tundish 1 to go up mouth of a river 3, and it is fixed with brick cup 4, it is connected with down mouth of a river 5 to go up 3 lower extremes of mouth of a river, it is equipped with sleeve 8 with lower mouth of a river 5 junction to go up mouth of a river 3, be equipped with inlet port 9 in the middle of the sleeve 8, the quantity of inlet port 9 is more than one, and inside the junction of going up mouth of a river 3 and lower mouth of a river 5 by sleeve 8 outside, lower mouth of a river 5 lower extreme is connected with immersion nozzle 6, it forms a steel stream channel to go. The submerged nozzle 6 is positioned in the center of a flange triangle on one side of the H-shaped parison crystallizer 7.
The tundish 1 is a T-shaped multi-flow tundish 1 of a special-shaped blank, each flow is provided with two molten steel outlets, the distance between the two outlets is determined according to the section of the special-shaped blank at the lower part, only one molten steel outlet is used for casting during single-point casting of each flow, and the other molten steel outlet is reserved for standby application; the multi-stream simultaneous continuous casting can be realized, the molten steel outlet on one side is broken or damaged, the molten steel outlet on the other side of the same stream can be replaced for casting, the continuous casting is not influenced, and the production is convenient. The stopper rod 2 is arranged at an inner outlet of the tundish 1, the control of the flow of molten steel from the outlet of the tundish 1 to the crystallizer 7 is realized by controlling the opening degree of the stopper rod 2, the automatic flow control of the flow of the molten steel can be realized by automatically regulating and controlling the stopper rod 2, and the method is convenient, simple, safe and easy to implement.
The upper nozzle 3 is funnel-shaped, the caliber of the contact part of the upper end and the stopper rod 2 is larger, the caliber of the connection part of the lower end and the lower nozzle 5 is smaller, and the upper nozzle 3 is nested inside the brick cup 4; the brick cup 4 is used for fixing the upper nozzle 3. Compared with a two-point casting method at the flange, the method has the advantages that the water flow of cast steel is large under the non-equilibrium protection of a single point at the flange, the flow cannot be blocked by using simple tools such as a blocking cone and the like under the out-of-control states such as rod breakage, turning around and the like of the stopper rod 2, and the large production hidden trouble exists. For this purpose, a sleeve 8 and a lower nozzle 5 are provided below the upper nozzle 3. Air inlet holes 9 are formed in the sleeve 8, and when the number of the air inlet holes 9 is more than two, included angles formed by the central lines of the two adjacent air inlet holes 9 are equal; the sleeve 8 not only plays a role in fixing and sealing the upper water gap 3 and the lower water gap 5, but also introduces inert gas (such as argon) with certain pressure into the air inlet 9, and reduces the impact force of molten steel through the floating of the bubble group.
The hydraulic cylinder is adopted for replacing the drain 5, when the stopper rod 2 is out of control, the hydraulic cylinder is used for replacing the blind hole drain 5 for blocking, and the production operation safety is greatly improved. The submerged nozzle 6 is a straight cylinder type submerged nozzle, the upper end of the straight cylinder type submerged nozzle is a bowl opening part, the inner diameter of the bowl opening part is gradually reduced from top to bottom and is connected with the lower end of the lower nozzle 5, the lower end of the bowl opening part is a straight cylinder type submerged nozzle body, the inner diameter of the straight cylinder type submerged nozzle body is equal everywhere, and a slag line part is arranged at the contact part of the straight cylinder type submerged nozzle and the surface of molten steel in the crystallizer 7; the design is simple, the cost is low, but the impact depth of the steel flow is large, and the sleeve 8 with the air inlet hole 9 is increased, so that the impact depth of the steel flow can be just reduced.
Along with the increase of the pressure of the air inlet of the sleeve 8, the impact depth is obviously reduced, but the fluctuation of the liquid level of the crystallizer 7 is also increased, so that the number of the air inlet holes 9 is more than one, and when the number of the air inlet holes 9 is more than two, the included angles formed by the central lines of the two adjacent air inlet holes 9 are equal, especially aiming at the single-point casting of the ultrathin large-size beam blank and the straight-tube water gap by combining with the field experiment. When the air inlet 9 is in a working state, inert gas with a certain pressure needs to be introduced into the connection part of the upper water gap 3 and the lower water gap 5, and the gas pressure range is 0.1-0.35 MPa.
The use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle 6 of the device into a crystallizer 7 from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod 2 according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap 3 and the lower water gap 5 by using the gas inlet hole 9 from outside to inside, and starting casting;
D. and (4) when the tundish 1 is replaced, replacing the blind hole lower nozzle 5 by using the hydraulic cylinder to perform flow blocking, and repeating the step A, the step B and the step C.
(2) Matched safe production operation method
Considering that the single-point unbalanced casting of the ultrathin large-section aluminum-containing steel special-shaped blank may have a greater safety risk, design optimization is also performed on a production operation method, and the method specifically comprises preparation and baking of a stopper rod 2 tundish 1, a casting starting method and a full-protection casting production accident plan of the stopper rod 2 tundish 1.
Preparation of stopper 2 tundish 1: checking the use condition of a working layer, wherein the working surface is not cracked or fallen, and an overflow port of a tundish 1 cannot be blocked; checking the installation condition of the stopper rod 2, wherein a fastening nut between the stopper rod 2 and a connecting screw rod must be tightened and cannot be loosened, the stopper rod 2 and the screw rod have no deformation and distortion, the stopper rod 2 has no crack and no dropping piece, and the head part of the rod must be smooth; and thirdly, the joint of the stopper rod 2 and the screw rod is sealed by the refractory clay.
Baking the tundish 1 of the stopper rod 2 for at least 3.5 hours, baking the tundish 1 with medium fire for at least 0.5 hours and baking the tundish 1 with big fire for at least 2.5 hours before casting; baking the submerged nozzle 6 for at least 1.0 hour before casting, and baking the upper nozzle 3 by air draft, wherein the temperature of a tundish working layer is more than or equal to 1000 ℃ before casting, and the tundish 1, a nozzle bowl opening and a nozzle are ensured to have good baking effect.
The casting method comprises the following steps: firstly, 1 minute after the pouring of the big ladle, a plurality of casting flows of the tundish 1 start casting at the same time, the seedling emergence time is controlled to be 40-50 seconds, the opening degree of the stopper rod 2 is manually controlled, the liquid level of molten steel in the crystallizer 7 is ensured to be stable (the liquid level is stable, namely the fluctuation of the liquid level is less than 5mm), and the molten steel slowly rises, so that the liquid level of the molten steel in the crystallizer 7 is prevented from rising too fast, and meanwhile, the stopper rod 2 is prevented from being closed to cause no flow due to frozen eyes (the molten steel cannot flow into the crystallizer 7.
Secondly, when the liquid level of the molten steel in the crystallizer 7 is over the bottom of the submerged nozzle 6, adding the casting powder into the crystallizer 7, wherein the casting powder is required to well cover the liquid level of the molten steel in the crystallizer 7 in the casting process, the thickness of the casting powder slag layer is required to be controlled within the range of 40-55mm, and the thickness of the casting powder slag layer is required to be controlled within the range of 6-8 mm.
And thirdly, starting the pulling speed to be 0.4m/min, slowly raising the pulling speed to be 0.6-0.7m/min after the liquid level is stable, starting to install the electric cylinder (the electric cylinder provides power for vibration demoulding of the crystallizer 7), and adjusting the set liquid level to be in an automatic control state when the set liquid level is adjusted to be equal to the actual liquid level after the electric cylinder is confirmed to be firmly installed. When the temperature of the molten steel in the crystallizer 7 is proper and the liquid slag layer meets the requirement, the pulling speed is increased to the final stable pulling speed range. The pulling rate is increased according to the pulling rate of 0.2m/min per minute in the lifting process. Before the pulling speed is increased, the large slag strips must be cleaned up, and the pulling speed is slowly increased under the conditions of ensuring the stable liquid level of molten steel in the crystallizer 7 and the like.
The full protection casting production accident plan of the stopper 2 tundish 1 comprises the following steps: firstly, when the stopper rod 2 is out of control, the submerged nozzle 6 is quickly taken down, the flow is blocked by using a blocking cone, the pouring basket 1 is immediately stopped to pour away the pouring basket 1 when the ball and the aluminum strip are blocked and the blockage cannot occur.
And secondly, when the casting device leaks steel, the continuous casting device is switched from the automatic control state to the manual control state, the stopper rod 2 is closed, and the casting is stopped by the continuous casting device.
Thirdly, when the casting blank is not pulled in the casting process, the flow-drawing steel worker immediately places the casting blank in a groove for processing, if the casting blank is recovered to be normal within 2min, the casting is continued, and if not, the flow is stopped immediately.
When the submerged nozzle 6 is sleeved with the hole, the stopper rod 2 control device needs to control the stopper rod 2 in a manual control state, the pulling speed is determined according to the liquid level condition in the crystallizer 7, the liquid level in the crystallizer 7 is kept stable, if the pulling speed is reduced to 0.8m/min, the liquid level is not stable, the nozzle changing treatment is adopted, if the water changing port is invalid, the pulling speed is reduced to 0.7m/min, and the pouring is stopped immediately if the liquid level in the crystallizer 7 is not stable within 10 min.
And fifthly, when the liquid level of the crystallizer 7 is out of control, the stopper rod 2 control device immediately turns to a manual control state, adjusts the opening degree of the stopper rod 2, slowly adjusts the liquid level, timely picks out large slag strips and pays attention to the pulling condition of the casting blank.
When a blank shell of the crystallizer 7 is bonded, immediately turning a manual control state of a continuous casting device, closing the stopper rod 2, returning the pulling speed to zero, slowly feeding the pulling speed to 0.4m/min, observing whether the casting blank can be pulled, if the casting blank can be pulled, keeping the pulling speed for 2 minutes, and after the liquid level and the liquid slag layer are normal, increasing the pulling speed to the normal pulling speed; if the strand cannot be pulled after 2 minutes, the flow stops.
And when the liquid level suddenly rises or falls or fluctuates too much, immediately reducing the pulling speed to 0.4m/min, observing whether the casting blank can be pulled, timely picking slag strips, adding protective slag, slowly adjusting the liquid level to a set height, and slowly adjusting the pulling speed to the set pulling speed.
(3) Optimum technological parameter range of matched pulling speed, superheat degree, inner diameter of submerged nozzle 6 and insertion depth
By means of numerical simulation and water model experiment methods, the flow (flow field and liquid level fluctuation) and heat transfer and solidification behaviors of the special-shaped blank crystallizer 7 under different process parameters are researched in a combined manner, impact depth, vortex center height, response time of injection molten steel whirling to reach the liquid level and an outlet, slag rolling conditions, temperature distribution uniformity, uniformity of production of a solidified blank shell and the like under different process parameters are contrastively analyzed from obtained data of flow fields, temperature fields, solidified blank shells, fluctuation conditions of the liquid level of the crystallizer 7, tracer agent stimulation response curves of characteristic points of the liquid level and characteristic points of an outlet of the crystallizer 7 and the like, so that the quality of the flow fields and the temperature fields of the crystallizer 7 is evaluated, and the process parameter range is determined: the immersion type water gap 6 is inserted with the depth of 55-65mm, the superheat degree is 15-30 ℃, the final stable casting speed of a casting blank is 0.85-0.9m/min, the inner diameter of the immersion type water gap 6 is 35-45mm, and the outer diameter of the immersion type water gap 6 is 75-85 mm.
(4) Asymmetric crystallizer cooling process
According to the characteristics of single-point unbalanced protection casting of the ultrathin large-size aluminum-containing steel special-shaped blank, equipment and process characteristics of a full-arc crystallizer and the reason that the existing crystallizer cooling process cannot adapt to single-point unbalanced protection casting, the crystallizer cooling process is designed again to optimize the crystallizer cooling process and adapt to production. In the actual casting process, when a single nozzle is used for casting in a triangular area at one side edge of a special-shaped blank, the casting flow seriously erodes the narrow-surface and wide-surface outer arc blank shell close to one side of the casting nozzle, so that the local blank shell is thin, and the production accidents such as steel leakage and the like are easily caused. In order to cope with the above situation, it is necessary to enhance cooling of the narrow-face mold on the side close to the casting gate and also enhance cooling of the wide-face outer arc as required.
In order to enhance the cooling of the blank shell of the narrow surface and the wide surface outer arc close to one side of the casting opening, the four copper plates of the crystallizer 7 are cooled separately through reasonable analysis and calculation, and the cooling requirements of the copper plates on different surfaces of the crystallizer copper plate are changed. Because use the special parison crystallizer of full arc among the casting process, the special parison crystallizer of full arc comprises four copper boards, and four copper boards are inner arc broad face copper board, outer arc broad face copper board respectively, are close to sprue gate one side leptoprosopy copper board, keep away from sprue gate one side leptoprosopy copper board, and the cooling water yield that four faces let in is respectively: the cooling water amount of the outer arc wide-surface copper plate is 2500-. In order to conveniently know the cooling condition of the copper plate of the crystallizer, temperature detection devices are respectively arranged at the cooling water inlets and outlets of the four surfaces of the crystallizer 7, and the temperature detection devices can adopt temperature sensors or thermocouples for detecting the water temperatures at the cooling water inlets and outlets; meanwhile, in order to ensure the cooling effect of the crystallizer 7, the copper plates on four surfaces of the crystallizer 7 are effectively transferred, and the water temperature difference between the cooling water outlet and the cooling water inlet on the same surface of the crystallizer 7 is kept between 5.5 and 6.5 ℃. The water inlet temperature of the crystallizer 7 is controlled between 35 ℃ and 40 ℃, and the water inlet temperature is ensured by automatic temperature control equipment.
(5) Asymmetric casting powder multi-point distributing process
The casting powder used in the crystallizer 7 has great influence on the uniform growth of a flow field, a temperature field and a solidified shell in the crystallizer 7, and the casting powder of the crystallizer is influenced according to the single-point unbalanced casting process of the aluminum-containing steel and the ultrathin large-size special-shaped blank. In the crystallizer 7, the consumption of the covering slag is uneven due to the uneven temperature field and flow field in the crystallizer 7, the covering slag at the casting point is slowly consumed, the covering slag at the non-casting point is quickly consumed, and the thickness of the liquid slag layer of the covering slag layer is different due to the different consumption of the covering slag at different parts, so that the continuous, even and stable condensation of the blank shell is not facilitated.
In order to reduce the influence of non-uniform flow field and temperature field of a crystallizer on the thickness and consumption of liquid slag of the casting powder during single-point non-equilibrium casting protection, the process for multi-point distribution of the asymmetric casting powder, which is suitable for aluminum-containing steel and ultrathin large-size special-shaped blanks, is provided: the thickness of a normal casting powder slag layer is generally 40-50mm, when a flange single-point unbalanced casting device 'stopper rod 2+ upper nozzle 3+ blowing sleeve 8+ lower nozzle 5+ straight cylinder type immersion nozzle 6' is adopted, the molten steel temperature is low at non-casting point parts, the slag surface is easy to crust, the thickness of the casting powder slag layer is controlled within the range of 55-65mm, the casting point parts are used for accelerating the consumption of casting powder, the thickness of the casting powder slag layer is controlled within the range of 35-45mm, and the thickness of the liquid slag layer is controlled within the range of 6-8 mm.
Example 1
The continuous casting machine in the embodiment is an H-shaped section beam blank, three machines are used for three flows, the size of the section of the cast H-shaped beam blank is 1024mm multiplied by 390mm multiplied by 90mm, and the specific structure is shown in figure 1; the beam blank web plate thickness 90mm is the beam blank with the thinnest web plate thickness in China at present, the width 1024mm belongs to a large-section beam blank, the section with the very large width-thickness ratio is very complex, simultaneously, the C345 series steel containing aluminum (0.015% -0.060%) for oil and gas factory projects is cast, and under the conditions that the double water ports are opened, the protection casting cannot be realized, and the single-nozzle casting of the center of the web plate which is too thin is impossible, the single-point unbalanced casting device and the single-point unbalanced casting method for the triangular area at one side of the beam blank flange are adopted, so that the continuous casting machine can safely and stably produce the ultrathin large-section beam blank with qualified quality in batches. As shown in fig. 4, the crystallizer 7 used for producing the beam blank by continuous casting is a full arc crystallizer 7, a casting opening is left on a flange on one side of the full arc crystallizer, and single-point unbalanced protection casting is performed on the beam blank.
As shown in fig. 2 and 3, the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises a tundish 1, a stopper rod 2, an upper nozzle 3, a brick cup 4, a lower nozzle 5, an immersion nozzle 6 and an H-shaped blank crystallizer 7, wherein the stopper rod 2 is arranged at an inner outlet of the tundish 1, the brick cup 4 is arranged at the lower end of the stopper rod 2, the upper nozzle 3 is connected with the tundish 1 and is fixed by the brick cup 4, the lower end of the upper nozzle 3 is connected with the lower nozzle 5, the lower end of the lower nozzle 5 is connected with the immersion nozzle 6, the device further comprises a hollow sleeve 8, the sleeve 8 is arranged between the upper nozzle 3 and the lower nozzle 5, the upper nozzle 3, the sleeve 8 and the lower nozzle 5 form a steel flow channel, 4 air inlets 9 are uniformly distributed on the sleeve 8, and the air inlets. When the air inlet 9 is in a working state, 0.2MPa of inert gas needs to be introduced into the steel flow channel. The submerged nozzle 6 is positioned in the center of a flange triangle on one side of the H-shaped parison crystallizer 7.
The use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle 6 of the device into a crystallizer 7 from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod 2 according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap 3 and the lower water gap 5 by using the gas inlet hole 9 from outside to inside, and starting casting;
D. and (4) when the tundish 1 is replaced, replacing the blind hole water outlet by using the hydraulic cylinder to perform flow blocking, and repeating the step A, the step B and the step C.
The continuous casting production method of the ultrathin large-size aluminum-containing steel special-shaped blank based on the device and the method for protecting the single-point unbalanced protection casting comprises the following steps:
a. checking whether the stopper rod 2 and the tundish 1 meet the working requirements, and determining the process parameters: the insertion depth of the straight cylinder type submerged nozzle is 60mm, the slag line part of the submerged nozzle 6 is arranged at a position 60mm away from the bottom of the submerged nozzle 6, the superheat degree is 25 ℃, the final stable casting blank pulling speed is 0.87m/min, the inner diameter of the submerged nozzle 6 is 40mm, and the outer diameter of the submerged nozzle 6 is 80 mm; and specifying the associated production incident protocol.
b. Baking the stopper rod 2 and the tundish 1 for 3.5 hours before casting, wherein the tundish 1 is baked with medium fire for 0.5 hour and with big fire for 3.0 hours, the submerged nozzle 6 is baked for 1.0 hour, and the water feeding nozzle 3 is baked with air draft, and the temperature of the working layer of the tundish 1 is 1100 ℃ before casting; after baking is finished, the unbalanced protection casting device is connected, and the submerged nozzle 6 is inserted into the casting opening of the crystallizer 7.
c. The pouring of the large ladle is started for 1 minute, the pouring of a plurality of casting flows of the tundish 1 is started simultaneously, the opening degree of the stopper rod 2 is adjusted, the seedling emergence time is 45 seconds, and the casting blank starting pulling speed is 0.4 m/s.
d. Cooling water is respectively introduced into four surfaces of the crystallizer 7 for cooling, and the cooling water amount of the four surfaces is respectively as follows: the cooling water amount of the outer arc wide-surface copper plate is 2600L/min, the cooling water amount of the inner arc wide-surface copper plate is 2100L/min, the cooling water amount of the narrow-surface copper plate at the side close to the casting opening is 1200L/min, and the cooling water amount of the narrow-surface copper plate at the side far away from the casting opening is 900L/min; the water inlet temperature of the crystallizer is 37 ℃; the water temperature difference between the cooling water outlet and the cooling water inlet on the same surface of the crystallizer is kept at 6.0 ℃.
e. When the liquid level of the molten steel in the crystallizer 7 is over the bottom of the submerged nozzle 6, adding the casting powder into the crystallizer 7 through an asymmetric multipoint material distribution process; the thickness of the covering slag layer at the non-casting point part is 60mm, and the thickness of the covering slag layer at the casting point part is 40 mm; the thickness of the liquid slag layer of the protective slag in the crystallizer 7 is required to be 7 mm.
f. And when the fluctuation of the liquid level in the crystallizer 7 is less than 5mm, the casting blank pulling speed is increased to 0.65m/min, an electric cylinder is installed, when the set liquid level is equal to the actual liquid level, the control of the liquid level of the crystallizer 7 is converted into an automatic control state, and the pulling speed is increased to the final stable pulling speed value of the casting blank.
The single-point unbalanced casting device and the single-point unbalanced casting method in the embodiment are used for carrying out 98 times of batch production on a continuous casting site, the total volume is 1.2 ten thousand tons, the production process is controlled stably, production accidents such as steel leakage and the like do not occur, the rolled material quality is normal, the performance detection is good, and the requirements of the quality and the performance of steel for oil and gas plant projects are met.
Example 2
This example is identical to the apparatus of example 1 in construction and method of use and in the method of continuous casting, except that the invention is illustrated and based upon the selection of different values.
The utility model provides a single-point unbalance protection casting device of ultra-thin big specification aluminium-containing steel special-shaped blank, including middle package 1, stopper rod 2, upper nozzle 3, brick cup 4, lower nozzle 5, immersion nozzle 6 and H parison crystallizer 7, stopper rod 2 is arranged in middle package 1, 2 lower extremes of stopper rod are equipped with brick cup 4, upper nozzle 3 is connected with middle package 1, and fixed by brick cup 4, upper nozzle 3 lower extreme is connected with lower nozzle 5, lower nozzle 5 lower extreme is connected with immersion nozzle 6, still include and be hollow sleeve 8, sleeve 8 sets up between upper nozzle 3 and lower nozzle 5, upper nozzle 3, sleeve 8 and lower nozzle 5 form a steel stream channel, the equipartition has 39 on the sleeve 8, inlet port 9 and steel stream channel inlet port intercommunication. When the air inlet 9 is in a working state, 0.1MPa of argon gas needs to be introduced into the steel flow channel. The submerged nozzle 6 is positioned in the center of a flange triangle on one side of the H-shaped parison crystallizer 7.
The use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle 6 of the device into a crystallizer 7 from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod 2 according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap 3 and the lower water gap 5 by using the gas inlet hole 9 from outside to inside, and starting casting;
D. and (4) when the tundish 1 is replaced, replacing the blind hole water outlet by using the hydraulic cylinder to perform flow blocking, and repeating the step A, the step B and the step C.
The continuous casting production method of the ultrathin large-size aluminum-containing steel special-shaped blank based on the device and the method for protecting the single-point unbalanced protection casting comprises the following steps:
a. checking whether the stopper rod 2 and the tundish 1 meet the working requirements, and determining the process parameters: the insertion depth of the straight cylinder type submerged nozzle is 55mm, the slag line part of the submerged nozzle 6 is arranged at a position 55mm away from the bottom of the submerged nozzle 6, the superheat degree is 15 ℃, the final stable casting blank pulling speed is 0.85m/min, the inner diameter of the submerged nozzle 6 is 35mm, and the outer diameter of the submerged nozzle 6 is 75 mm; and specifying the associated production incident protocol.
b. Baking the stopper rod 2 and the tundish 1 for 4 hours before casting, wherein the tundish 1 is baked with medium fire for 1.0 hour and with big fire for 3.0 hours, the submerged nozzle 6 is baked for 1.5 hours, and the upper nozzle 3 is baked with air draft, and the temperature of a working layer of the tundish 1 is 1150 ℃ before casting; after baking is finished, the unbalanced protection casting device is connected, and the submerged nozzle 6 is inserted into the casting opening of the crystallizer 7.
c. The pouring of the large ladle is started for 1 minute, the pouring of a plurality of casting flows of the tundish 1 is started simultaneously, the opening degree of the stopper rod 2 is adjusted, the seedling emergence time is 50 seconds, and the casting blank starting pulling speed is 0.4 m/s.
d. Cooling water is respectively introduced into four surfaces of the crystallizer 7 for cooling, and the cooling water amount of the four surfaces is respectively as follows: the cooling water amount of the outer arc wide-surface copper plate is 2500L/min, the cooling water amount of the inner arc wide-surface copper plate is 2000L/min, the cooling water amount of the narrow-surface copper plate close to the casting opening is 1100L/min, and the cooling water amount of the narrow-surface copper plate far away from the casting opening is 850L/min; the water inlet temperature of the crystallizer is 35 ℃; the water temperature difference between the cooling water outlet and the cooling water inlet on the same surface of the crystallizer is kept at 5.5 ℃.
e. When the liquid level of the molten steel in the crystallizer 7 is over the bottom of the submerged nozzle 6, adding the casting powder into the crystallizer 7 through an asymmetric multipoint material distribution process; the thickness of the casting powder slag layer at the non-casting point part is 55mm, and the thickness of the casting powder slag layer at the casting point part is 35 mm; the thickness of the liquid slag layer of the protective slag in the crystallizer 7 is required to be 6 mm.
f. And when the fluctuation of the liquid level in the crystallizer 7 is less than 5mm, the casting blank pulling speed is increased to 0.60m/min, an electric cylinder is installed, when the set liquid level is equal to the actual liquid level, the control of the liquid level of the crystallizer 7 is converted into an automatic control state, and the pulling speed is increased to the final stable pulling speed value of the casting blank.
Example 3
This example is identical to the apparatus of example 1 in construction and method of use and in the method of continuous casting, except that the invention is illustrated and based upon the selection of different values.
The utility model provides a single-point unbalance protection casting device of ultra-thin big specification aluminium-containing steel special-shaped blank, including middle package 1, stopper rod 2, upper nozzle 3, brick cup 4, lower nozzle 5, immersion nozzle 6 and H parison crystallizer 7, stopper rod 2 is arranged in middle package 1, 2 lower extremes of stopper rod are equipped with brick cup 4, upper nozzle 3 is connected with middle package 1, and fixed by brick cup 4, upper nozzle 3 lower extreme is connected with lower nozzle 5, lower nozzle 5 lower extreme is connected with immersion nozzle 6, still include and be hollow sleeve 8, sleeve 8 sets up between upper nozzle 3 and lower nozzle 5, upper nozzle 3, sleeve 8 and lower nozzle 5 form a steel stream channel, the symmetry is equipped with 2 on the sleeve 8 and is equipped with 2, inlet port 9 and steel stream channel inlet port intercommunication. When the air inlet 9 is in a working state, helium and argon with the volume ratio of 1:1 of 0.35MPa need to be introduced into the steel flow channel. The submerged nozzle 6 is positioned in the center of a flange triangle on one side of the H-shaped parison crystallizer 7.
The use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank comprises the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle 6 of the device into a crystallizer 7 from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod 2 according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap 3 and the lower water gap 5 by using the gas inlet hole 9 from outside to inside, and starting casting;
D. and (4) when the tundish 1 is replaced, replacing the blind hole water outlet by using the hydraulic cylinder to perform flow blocking, and repeating the step A, the step B and the step C.
The continuous casting production method of the ultrathin large-size aluminum-containing steel special-shaped blank based on the device and the method for protecting the single-point unbalanced protection casting comprises the following steps:
a. checking whether the stopper rod 2 and the tundish 1 meet the working requirements, and determining the process parameters: the insertion depth of the straight cylinder type submerged nozzle is 65mm, the slag line part of the submerged nozzle 6 is arranged at a position 65mm away from the bottom of the submerged nozzle 6, the superheat degree is 30 ℃, the final stable casting blank pulling speed is 0.90m/min, the inner diameter of the submerged nozzle 6 is 45mm, and the outer diameter of the submerged nozzle 6 is 85 mm; and specifying the associated production incident protocol.
b. Baking the stopper rod 2 and the tundish 1 for 4.5 hours before casting, wherein the tundish 1 is baked with medium fire for 1.0 hour and with big fire for 3.5 hours, the submerged nozzle 6 is baked for 1.5 hours, and the water feeding nozzle 3 is baked with air draft, and the temperature of the working layer of the tundish 1 is 1180 ℃ before casting; after baking is finished, the unbalanced protection casting device is connected, and the submerged nozzle 6 is inserted into the casting opening of the crystallizer 7.
c. The pouring of the large ladle is started for 1 minute, the pouring of a plurality of casting flows of the tundish 1 is started simultaneously, the opening degree of the stopper rod 2 is adjusted, the seedling emergence time is 40 seconds, and the casting blank starting pulling speed is 0.4 m/s.
d. Cooling water is respectively introduced into four surfaces of the crystallizer 7 for cooling, and the cooling water amount of the four surfaces is respectively as follows: the cooling water amount of the outer arc wide-surface copper plate is 2700L/min, the cooling water amount of the inner arc wide-surface copper plate is 2200L/min, the cooling water amount of the narrow-surface copper plate at one side close to the casting opening is 1300L/min, and the cooling water amount of the narrow-surface copper plate at one side far away from the casting opening is 950L/min; the water inlet temperature of the crystallizer is 40 ℃; the water temperature difference between the cooling water outlet and the cooling water inlet on the same surface of the crystallizer is kept at 6.5 ℃.
e. When the liquid level of the molten steel in the crystallizer 7 is over the bottom of the submerged nozzle 6, adding the casting powder into the crystallizer 7 through an asymmetric multipoint material distribution process; the thickness of the casting powder slag layer at the non-casting point part is 65mm, and the thickness of the casting powder slag layer at the casting point part is 45 mm; the thickness of the liquid slag layer of the protective slag in the crystallizer 7 is required to be 8 mm.
f. And when the fluctuation of the liquid level in the crystallizer 7 is less than 5mm, the casting blank pulling speed is increased to 0.70m/min, an electric cylinder is installed, when the set liquid level is equal to the actual liquid level, the control of the liquid level of the crystallizer 7 is converted into an automatic control state, and the pulling speed is increased to the final stable pulling speed value of the casting blank.
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 (7)
1. The utility model provides a single-point unbalanced protection casting device of ultra-thin big specification aluminium-containing steel special-shaped blank, includes tundish (1), stopper stick (2), goes up mouth of a river (3), brick cup (4), lower mouth of a river (5) and immersion nozzle (6), stopper stick (2) arrange in tundish (1), stopper stick (2) lower extreme is equipped with brick cup (4), last mouth of a river (3) be connected with tundish (1), and fixed by brick cup (4), it is connected with lower mouth of a river (5) to go up mouth of a river (3) lower extreme, lower mouth of a river (5) lower extreme is connected with immersion nozzle (6), its characterized in that: the device is characterized by further comprising a hollow sleeve (8), wherein the sleeve (8) is arranged between the upper water gap (3) and the lower water gap (5), the upper water gap (3), the sleeve (8) and the lower water gap (5) form a steel flow channel, the sleeve (8) is provided with more than one air inlet hole (9), and the air inlet holes (9) are communicated with the steel flow channel; a sleeve (8) is added between the upper water gap (3) and the lower water gap (5), inert gas with certain air pressure is blown into the steel flow, and the impact force of the steel flow into the crystallizer is relieved by the floating of the bubble group; the submerged nozzle (6) is a straight cylinder type submerged nozzle, the upper end of the straight cylinder type submerged nozzle is a bowl opening part, the inner diameter of the bowl opening part is gradually reduced from top to bottom and is connected with the lower end of the lower nozzle (5), the lower end of the bowl opening part is a straight cylinder type submerged nozzle body, the inner diameter of the straight cylinder type submerged nozzle body is equal in all places, and a slag line part is arranged at the contact part of the straight cylinder type submerged nozzle and the surface of molten steel in the crystallizer (7); crystallizer (7) one side edge of a wing central point department be equipped with the casting gate, immersion nozzle (6) free end put in the casting gate and cast, crystallizer (7) include inner arc broad face copper, outer arc broad face copper, be close to casting gate one side leptoprosopy copper, keep away from casting gate one side leptoprosopy copper.
2. The single-point unbalanced protection casting device for the ultra-thin large-size aluminum-containing steel special-shaped blank according to claim 1, wherein: when the number of the air inlet holes (9) is more than two, the included angles formed by the central lines of the two adjacent air inlet holes (9) are equal.
3. The single-point unbalanced protection casting device for the ultra-thin large-size aluminum-containing steel special-shaped blank according to claim 1 or 2, wherein: when the air inlet hole (9) is in a working state, inert gas with certain pressure needs to be introduced into the connection part of the upper water gap (3) and the lower water gap (5).
4. The single-point unbalanced protection casting device for the ultra-thin large-size aluminum-containing steel special-shaped blank according to claim 3, wherein: the pressure range of the inert gas in the gas inlet hole (9) is 0.1-0.35 MPa.
5. The single-point unbalanced protection casting device for the ultra-thin large-size aluminum-containing steel special-shaped blank according to claim 1, wherein: the upper nozzle (3) is funnel-shaped, the caliber of the contact part of the upper end and the stopper rod (2) is large, the caliber of the connection part of the lower end and the lower nozzle (5) is small, and the upper nozzle (3) is embedded inside the brick cup (4).
6. The single-point unbalanced protection casting device for the ultra-thin large-size aluminum-containing steel special-shaped blank according to claim 1, wherein: the tundish (1) is a T-shaped multi-flow tundish, each flow is provided with two molten steel outlets, one molten steel outlet is used for casting during casting, and the other molten steel outlet is reserved.
7. The use method of the single-point unbalanced protection casting device for the ultrathin large-size aluminum-containing steel special-shaped blank as claimed in any one of claims 1 or 2 or 4 to 6 is characterized by comprising the following steps:
A. connecting and assembling the single-point unbalanced protection casting device of the ultrathin large-size aluminum-containing steel special-shaped blank;
B. moving the single-point non-equilibrium protection casting device of the ultrathin large-specification aluminum-containing steel special-shaped blank, and inserting the free end of a submerged nozzle (6) of the device into a crystallizer (7) from the upper end of a casting opening;
C. adjusting the opening degree of the stopper rod (2) according to the flow and production requirements, simultaneously introducing inert gas into the joint of the upper water gap (3) and the lower water gap (5) from outside to inside by using the air inlet hole (9), and starting casting;
D. and (3) when the tundish (1) is replaced, replacing the blind hole water outlet by using the hydraulic cylinder to perform flow blocking, and repeating the step A, the step B and the step C.
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| CN110548848B (en) * | 2019-09-02 | 2020-12-25 | 柳州钢铁股份有限公司 | Method for preventing longitudinal crack generation and bonding breakout of slab caster |
| CN110935872B (en) * | 2019-11-18 | 2021-07-30 | 柳州钢铁股份有限公司 | Blocking cone for tundish nozzle and nozzle blocking method |
| CN115301911B (en) * | 2022-08-15 | 2024-04-12 | 广西钢铁集团有限公司 | Pulling speed control method in billet casting operation |
| CN115283657B (en) * | 2022-08-19 | 2023-12-19 | 山东钢铁股份有限公司 | Tundish device for unbalanced casting and application method |
| CN117340204B (en) * | 2023-12-05 | 2024-02-13 | 山西宝隆科技有限公司 | Separation judgment method for ingot mould and steel ingot |
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| JPH0616920B2 (en) * | 1985-07-01 | 1994-03-09 | 川崎製鉄株式会社 | Beam blank continuous casting method |
| JPH0422538A (en) * | 1990-05-17 | 1992-01-27 | Nkk Corp | Method for continuously casting beam blank |
| JPH05146858A (en) * | 1991-11-28 | 1993-06-15 | Kawasaki Steel Corp | Method for adjusting discharging quantity of molten steel by using nozzle gas in beam blank continuous casting |
| JP3089608B2 (en) * | 1992-06-22 | 2000-09-18 | 川崎製鉄株式会社 | Continuous casting method of beam blank |
| JPH08168857A (en) * | 1994-12-19 | 1996-07-02 | Nippon Steel Corp | Method for blowing gas from refractory-made nozzle and gas blowing nozzle |
| JPH115144A (en) * | 1997-06-17 | 1999-01-12 | Nkk Corp | Continuous casting of beam blank |
| JP2001259800A (en) * | 2000-03-21 | 2001-09-25 | Kawasaki Steel Corp | Continuous casting method of beam blank |
| JP4595186B2 (en) * | 2000-10-06 | 2010-12-08 | Ｊｆｅスチール株式会社 | Continuous casting method |
| CN101091982A (en) * | 2007-07-17 | 2007-12-26 | 莱芜钢铁集团有限公司 | Method and device for carrying out protected casting for shaped blank continuous casting by using single immersed nozzle |
| KR101159930B1 (en) * | 2009-12-24 | 2012-06-25 | 현대제철 주식회사 | Continuous casting method of impact guarantee beam blank |
| CN102294454A (en) * | 2011-08-31 | 2011-12-28 | 中冶南方工程技术有限公司 | Arrangement structure of immerged water inlets for special blank crystallizer |
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