CN112536425B - Molten steel solidification and casting blank simulation device for continuous casting funnel-shaped crystallizer and use method of molten steel solidification and casting blank simulation device - Google Patents
Molten steel solidification and casting blank simulation device for continuous casting funnel-shaped crystallizer and use method of molten steel solidification and casting blank simulation device Download PDFInfo
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- CN112536425B CN112536425B CN202011394267.5A CN202011394267A CN112536425B CN 112536425 B CN112536425 B CN 112536425B CN 202011394267 A CN202011394267 A CN 202011394267A CN 112536425 B CN112536425 B CN 112536425B
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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
- B22D11/14—Plants for continuous casting
- B22D11/145—Plants for continuous casting for upward casting
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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
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
- B22D11/053—Means for oscillating the moulds
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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
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
Abstract
The invention discloses a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer and a use method thereof. The invention obtains the initial solidification billet shell with the actual characteristics of the thin slab and the temperature change curve in the crystallizer by simulating the solidification process and the continuous casting process of the molten steel in the funnel-shaped crystallizer in the continuous casting production of the thin slab, and realizes the simulation research on the influence of the initial solidification behavior of the molten steel in the funnel-shaped crystallizer, the surface quality of a casting blank and the continuous casting process parameters on the initial solidification behavior of the molten steel. The invention is suitable for simulating the production of the prior steel grade and can also be used for the development and research of the continuous casting production of crack sensitive steel grade thin slabs. Compared with the actual continuous casting industrial production process of the sheet billet, the invention has the advantages of simple and convenient operation, low experimental cost and the like.
Description
Technical Field
The invention discloses a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer and a using method thereof, belonging to the technical field of ferrous metallurgy.
Background
In the nineties of the last century, after two times of oil crises and three times of financial crises, global economy is low, and the steel industry, as an industry with large energy consumption and low profit, inevitably faces structural adjustment, technical optimization and process improvement so as to improve competitiveness and ensure economic benefit. Therefore, a short-flow process represented by continuous casting and rolling of thin slabs is of particular interest to investors and manufacturers because of its low energy consumption, low cost and high efficiency. Since the first thin slab continuous casting and rolling production line-CSP process production line developed by Western Mark company in Germany in 1989, 67 thin slab continuous casting and rolling production lines are built globally until 2017, and the annual production capacity exceeds 1.24 hundred million tons. The CSP process can produce 34 products, the technology is relatively mature, and the production is stable.
As is known, the crystallizer is the "heart" of the continuous casting machine. The key point of the huge success of the continuous casting and rolling of the thin slab and the successful breakthrough of the CSP process lies in the design of the funnel-shaped crystallizer. The funnel-shaped crystallizer is characterized in that the upper opening funnel is shaped and has large area; the edge part and the lower part are a section of parallel plate, and the narrow plate interval is the thickness of the casting blank; a schematic diagram of a Continuous Casting Funnel crystallizer in actual industrial production is shown in FIG. 2 (L.C. Hibbeler, thermo-Mechanical Belovior and Steel Continuous Casting in channel Molds [ D ]. University of Illinois at Urbana-Champiaign, 2009). The design has the advantages that the area of the upper opening is large, the shearing speed of a molten steel flow field is favorably reduced at a high drawing speed, and the stability of the flow field and the smooth running of a continuous casting process are ensured; the distance between the parallel plates at the lower part is narrow, so that the thickness of a casting blank out of the crystallizer can be effectively reduced, and the production process of continuous casting of the sheet billet is well realized.
In the development of thin slab continuous casting and rolling for thirty years, there are many technical problems and fundamental researches to be carried out. For example, the defects of the casting blank are more serious compared with the defects of the traditional continuous casting, the flow field, the temperature field and the heat flow distribution in the crystallizer at high drawing speed, and the application of steel grades is expanded. However, the funnel-shaped crystallizer used in the actual industrial production is integrated, and the inside of the crystallizer is often a black box, so that the high-temperature dynamic behavior of the molten steel and the protective slag in the crystallizer cannot be observed, and the solidification behavior of the molten steel in the crystallizer cannot be researched; when the mold flux is discharged out of the crystallizer along with the casting blank, the mold flux is immediately flushed by the secondary cooling water, and a mold flux film cannot be collected, so that the dynamic behavior of the mold flux in the crystallizer cannot be researched. The most common method at present is to perform numerical calculation and simulation. However, the numerical calculation and simulation are often deviated from the actual process due to uncertainty or inaccuracy of boundary condition setting, and generally can only be used as a reference for qualitative analysis. The cost for developing research and industrial tests on an industrial continuous casting machine is huge, and safety accidents are easy to occur in the test process. This has seriously hampered the progress of basic research, optimization research, and development research of the thin slab continuous casting. The best method is to establish a crystallizer simulation system on the laboratory level, develop a physical experiment according to field process parameters, and analyze the physical experiment in combination with numerical simulation, so that the actual production effect can be well reduced to a certain extent. However, so far, there is no good design to simulate the funnel-shaped crystallizer for continuous casting of thin slabs, and the continuous casting simulation research of the funnel-shaped crystallizer is realized on the laboratory level.
Disclosure of Invention
The invention provides a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer and a using method thereof, in order to well simulate the high-temperature dynamic behavior in the funnel-shaped crystallizer and the continuous casting process in the continuous casting process of a thin slab.
The invention provides a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer, which comprises the following main accessories: the system comprises an induction heating furnace body (a steelmaking furnace), a motor driving system (a billet puller driving motor M1 and a crystallizer vibration motor M2), a continuous casting funnel-shaped crystallizer simulation system (comprising a funnel-shaped crystallizer and a billet puller), a cooling water system (crystallizer copper mold cooling water and steelmaking furnace coil cooling water), a temperature acquisition system (a heating thermocouple), an automatic power operation system and the like; the overall schematic diagram of the device is shown in fig. 1 a.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the simulation device comprises a steel-making furnace, a blank-drawing motor, a vibration motor, a blank-drawing device and a crystallizer metal mold; the blank drawing motor is connected with a blank drawing device through a rigid connecting rod, and the blank drawing device is sleeved on the crystallizer metal mold; a cooling channel is arranged in the crystallizer metal mold; a wide surface of the crystallizer metal mold is provided with a curved surface groove, and the curved surface groove is funnel-shaped; defining the lowest end of the curved surface groove as a bottom; the distance from the bottom of the curved surface groove to the bottom of the crystallizer metal mold is more than or equal to 7 mm; the crystallizer metal mold is provided with at least 3 heat extraction couples; the first row and the second heat-extraction galvanic couples are positioned in the crystallizer metal mould opposite to the curved surface groove, and the third heat-extraction galvanic couple is not superposed with the first row and the second heat-extraction galvanic couples;
projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projections of at least 2 thermocouples fall into the projection formed by the curved surface groove; the projection of at least 1 thermocouple falls outside the projection formed by the curved surface groove and is positioned on the left side or the right side of the projection formed by the curved surface groove.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the number of any 2 heat extraction couples is equal; from the upper direction to the lower direction of the metal mold of the crystallizer, the thermocouples in the No. 1 heat-discharging couple are named as TC1-1, TC1-2, TC1-3, … … to TC 1-N; the thermocouples in the No. 2 heat-removal couple are named as TC2-1, TC2-2, TC2-3 and … … to TC 2-N; the thermocouples in the 3 rd heat-removal couple are named as TC3-1, TC3-2, TC3-3 and … … to TC 3-N; … … naming each thermocouple in the ith heat removal couple as TCi-1, TCi-2, TCi-3, … … till TCi-N; i is greater than or equal to 3;
projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projection of the P-th thermocouple in the first row of thermocouples is superposed with the projection of the P-th thermocouple in the second row of thermocouples, and P is a positive integer which is more than or equal to 1 and less than or equal to N;
when i is equal to 4; projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projection of the P-th thermocouple in the third heat discharge thermocouple is superposed with the projection of the P-th thermocouple in the fourth row, and P is a positive integer greater than or equal to 1 and less than or equal to N;
when the thermocouple is named TCx-y; when y is a fixed value, all thermocouples are positioned on one plane; x is more than or equal to 1 and less than or equal to i; and y is more than or equal to 1 and less than or equal to N.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the curved surface groove is of a symmetrical structure; the wide surface of the crystallizer metal mold is also designed symmetrically; on the vertical plane, the symmetry axis of the curved surface groove and the symmetry axis of the wide surface of the crystallizer metal mold are positioned on the same plane and are superposed;
projecting perpendicular to the wide surface of the crystallizer metal mold; the obtained projection is a symmetrical structure; the projection symmetrical axis of the projection is superposed with the projections of the first row of heat discharge couples and the second row of heat discharge couples;
when said N is equal to 4; projecting perpendicular to the wide surface of the crystallizer metal mold; the projections of the third row and the fourth row of the heat discharge couples are superposed. The minimum distance from the projection of the third row and/or the fourth heat-extraction galvanic couple to the projection frame of the wide surface of the crystallizer metal mold is equal to the distance from the projection frame of the third row and/or the fourth heat-extraction galvanic couple to the straight line A; the straight line A is as follows: on projection, making vertical lines perpendicular to projection lines obtained at the bottom of the wide surface of the mold metal die along the projection boundary formed by the curved surface groove, wherein the line with the minimum distance to a projection frame of the wide surface of the mold metal die in the vertical lines is A or A1; and the line A is the projection of the third row and/or the fourth row of heat discharging couples on the same side.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the funnel shape is 70 mm; the inclination angle of the groove is 8-10 degrees. Preferably, the invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the effective length of the funnel-shaped crystallizer metal mold is 77mm (wherein the groove part is 70mm, the flat plate part at the lower part of the groove is 7mm, the inclination angle of the groove is 8-10 degrees), the upper part is a flat plate, a cooling water tank is arranged in the copper mold, a temperature thermocouple is embedded in the copper mold, and the schematic diagram of the crystallizer device is shown in figure 1 b.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; the material of the mold is copper, preferably red copper.
The invention relates to a molten steel solidification and casting blank simulation device of a continuous casting funnel-shaped crystallizer; in the crystallizer metal mold, 4 thermocouples in the first row are positioned at the center line of the copper mold, the distribution positions are respectively 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mold, and the corresponding vertical distances from the surface of the copper mold are sequentially 4.47mm, 11.89mm, 13.68mm and 5.20 mm; the 4 thermocouples all fell on the arc of a sphere with a radius of 50 mm.
In the crystallizer metal die, the positions of the second row of 4 thermocouples are also located at the center line of the copper die and are respectively located at positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper die, and the corresponding vertical distances to the surface of the copper die are 10.73mm, 16.92mm, 18.86mm and 11.72mm in sequence; the 4 thermocouples were all located on the arcs of a sphere of 55mm radius concentric with the first row of thermocouples.
In the metal mold of the crystallizer, the distribution positions of the 4 thermocouples in the third row are positioned at the central line of the non-funnel-shaped flat plate area at the edge of the copper mold and are respectively positioned at the positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mold; the corresponding vertical distances to the surface of the copper mold are all 3 mm.
In the crystallizer metal mould, the distribution positions of the 4 thermocouples in the fourth row are also positioned at the central line of the non-funnel-shaped flat plate area at the edge of the copper mould and are respectively positioned at the positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mould; the corresponding vertical distances to the surface of the copper mold are all 8 mm.
In the invention, the purpose of arranging the first row of heat discharge couples and the second row of heat discharge couples is to calculate the heat transfer along the thickness direction at the cambered surface of the funnel-shaped crystallizer in order to facilitate the construction of unsteady heat transfer of a sphere model.
In the present invention, the third row and/or the fourth row of heat-removal couples are arranged so as to: the method is convenient for constructing a flat plate model for unsteady heat transfer inverse calculation of the heat flow change along the thickness of the copper mold at the flat plate of the funnel-shaped crystallizer.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; the method comprises the following steps:
putting 40-60 Kg of steel blocks into a steelmaking furnace, and melting the steel blocks by electromagnetic induction heating under the protective atmosphere of argon; adding 50-100 g of covering slag to the surface of the molten steel, and fishing out the covering slag floating on the surface of the molten steel after 5min so as to remove oxides floating on the surface of the molten steel and purify the molten steel; then adding 150-300 g of covering slag to the surface of the molten steel to play roles in preventing the molten steel from being oxidized and preserving heat; after 10 minutes, testing the temperature of the molten steel by using a temperature measuring gun, and correcting the superheat degree of the molten steel; then, starting a copper mold temperature measuring system in the crystallizer, and inserting the continuous casting simulation device into the molten steel through the driving of a motor, wherein the insertion depth is 70mm above the bottom of the copper mold of the crystallizer (namely the position of a meniscus shown in fig. 1 b); the molten steel and the liquid slag flow into a water-cooled crystallizer copper mold together, stay for 5-10 s, start a crystallizer vibration motor, vibrate periodically according to set vibration frequency and amplitude, and because the molten steel solidifies and can generate volume shrinkage, a gap is formed between the crystallizer and an initial solidified blank shell, and the liquid slag flows into the gap under the vibration action of the crystallizer, so that the effects of lubrication and heat transfer control are achieved; then, under the drive of a motor, the throwing device moves downwards relative to the crystallizer at a certain speed, namely, the throwing speed, and an initial solidified shell with a certain thickness is pulled out of the crystallizer; meanwhile, the molten steel is newly filled into the crystallizer for solidification, so that the simulation of the continuous casting process is realized; the downward movement time of the billet puller is 6-8 periods of the vibration of the crystallizer, then the crystallizer and the billet puller synchronously ascend to remove molten steel, a temperature measuring system is closed, and the experiment is finished; after cooling, the initial solidified shell and the covering slag film in the crystal are taken down, and the pulled casting blank is used for further analysis.
In specific application, the invention relates to application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; the method comprises the following steps:
And (3) putting 40-60 Kg of steel blocks into a medium-frequency induction furnace, and melting the steel blocks through electromagnetic induction heating. Argon is introduced in the whole heating process for atmosphere protection, so that molten steel is prevented from being oxidized.
Adding 50-100 g of prepared covering slag to the surface of molten steel, wherein the covering slag can be melted by the high-temperature molten steel and floats on the surface of the molten steel to absorb impurities; and fishing out the casting powder floating on the surface of the molten steel after 5min, so as to remove oxides floating on the surface of the molten steel and purify the molten steel.
And adding 150-300 g of the covering slag to the surface of the molten steel again, wherein the covering slag can be melted by the high-temperature molten steel, and a layer of liquid slag layer is formed on the surface of the molten steel, so that the effects of preventing the molten steel from being oxidized and preserving heat can be achieved.
Step 4
And testing the temperature of the molten steel by using a temperature measuring gun after 10min, correcting the superheat degree of the molten steel, and preparing to start a continuous casting crystallizer simulation experiment.
And starting the crystallizer copper mold cooling water system and the temperature measuring system, synchronously starting the lifting motor, inserting the continuous casting simulation device into the molten steel, submerging the continuous casting simulation device into the molten steel, stopping deepening, enabling the molten steel and the liquid slag to flow into the water-cooled crystallizer together, and starting solidification under the action of cooling water.
Step 6
Stopping for 5-10 s, and starting a crystallizer vibration motor (periodically vibrating according to the set vibration frequency and amplitude); because the molten steel is solidified and can produce volume contraction, a gap is formed between the crystallizer and the initial solidified blank shell, and under the vibration action of the crystallizer, the liquid slag can flow into the gap to play roles in lubricating and controlling heat transfer.
Step 7
And then, starting the lifting motor again to enable the blank puller to move downwards relative to the crystallizer at a certain speed (namely the pulling speed), pulling out an initial solidified blank shell with a certain thickness from the crystallizer, and simultaneously filling molten steel into the crystallizer again to be solidified to form the blank shell, thereby realizing the simulation of the continuous casting process.
Step 8
And stopping the downward movement of the throwing device after the throwing device moves downwards for six cycles of the vibration of the crystallizer, closing a crystallizer vibration motor to stop the vibration of the crystallizer, and finishing the throwing experiment.
Step 9
After the drawing experiment is finished, the lifting motor lifts the crystallizer and the drawing device from the molten steel to move out of the molten steel, and the temperature measuring system is closed to store data.
Turning off the power supply of the induction heating furnace; but not shut down the cooling water. And (5) after the molten steel in the furnace is cooled to the room temperature, closing the cooling water and all control power supplies. The experiment was ended.
Step 11
And cooling to room temperature, detaching the blank puller, detaching the copper mold of the crystallizer, and taking out the initial solidified blank shell and the covering slag film of the crystallizer and the pulled solidified blank shell for further analysis.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; in said application, the steel blocks have dimensions of 50 × 50 × 50 mm.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; in the said application; the test molten steel temperature and the superheat degree of correction molten steel, this superheat degree and actual production keep unanimous or carry out experiment and data acquisition according to the superheat degree of design, so, utilize this equipment to carry out experimental study to the variable of designing the superheat degree.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; in the said application; the amplitude and the frequency of the vibration of the crystallizer are consistent with the actual production or the experiment and the data acquisition are carried out according to the design values. Thus, the invention can carry out systematic research on the amplitude and the frequency of the crystallizer vibration as variables.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; in the said application; the downward moving speed of the throwing device, namely the drawing speed, is consistent with the actual production or is subjected to experiment and data acquisition according to design values. Thus, the present invention can carry out systematic research on the pulling speed as a variable.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; in the said application; and (3) inversely calculating the heat flow distribution to the funnel-shaped area and the non-funnel-shaped area through the unsteady heat transfer of the sphere model and the unsteady heat transfer of the flat plate model according to the temperature data acquired by the thermocouple. In a specific application; the temperature data collected by the thermocouple stored in step 9 can be used for obtaining heat flow data through back calculation.
The invention relates to the application of a continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; the solidified shell and slag film in the crystallizer and the pulled casting blank are used for electron microscope analysis, and the correlation of steel grade, continuous casting process parameters, covering slag behavior, heat flow distribution, molten steel meniscus initial solidification and casting blank surface quality can be obtained. In a specific application; and (4) analyzing the solidified blank shell, the slag film and the casting blank taken out in the step (11) by using an electron microscope to obtain the correlation among steel grade, continuous casting process parameters, protective slag behavior, heat flow distribution, initial solidification of a meniscus of molten steel and surface quality of the casting blank.
Major advantages
The molten steel solidification and casting blank simulation device of the continuous casting funnel-shaped crystallizer and the using method thereof have the following advantages that:
(1) the crystallizer is called as a black box in industry, and the states of the molten steel and the covering slag in the crystallizer cannot be obtained, so that the high-temperature dynamic behaviors of the molten steel and the covering slag in the crystallizer cannot be effectively observed and detected. The funnel crystallizer designed by the invention can obtain an initial solidified blank shell formed in the funnel crystallizer and a covering slag film in a gap between a copper mold of the crystallizer and the initial solidified blank shell; through the analysis of the initial solidification blank shell and the covering slag film, the initial solidification of the reducing molten steel and the high-temperature dynamic behavior of the covering slag in the crystallizer can be realized.
(2) The distribution of the temperature field in the crystallizer can be obtained based on the temperature data measured by the thermocouple buried in the crystallizer; and through the reasonable arrangement of thermocouples in the crystallizer, the heat flow distribution at the funnel-shaped cambered surface of the crystallizer can be calculated reversely by utilizing the unsteady heat transfer of the spherical model, and the heat flow distribution in the non-funnel-shaped area of the crystallizer can be calculated by utilizing the unsteady heat transfer of the flat model.
(4) The continuous casting funnel-shaped crystallizer simulator which is skillfully designed by the invention can obtain a set of complete information of continuous casting process parameters, covering slag films, distribution of temperature and heat flow in the crystallizer, solidification behavior of molten steel in the molten steel crystallizer, surface quality of casting blanks and the like, thereby effectively establishing the mutual relation of steel grade-continuous casting process parameters-covering slag behavior-heat flow distribution-initial solidification of meniscus of molten steel-surface quality of casting blanks and being beneficial to scientific research and guidance of industrial actual production.
In conclusion, the continuous casting funnel-shaped crystallizer simulation device designed by the invention refers to the shape of a crystallizer used in the actual thin slab continuous casting production, is effectively improved on the basis, and is matched with a special thermocouple arrangement mode, so that the actual thin slab continuous casting production process can be simulated, initial solidified blank shells, covering slag films and the like in the funnel-shaped crystallizer which are difficult to obtain in the actual production can be obtained, and the influence of continuous casting process parameters (covering slag, pulling speed, superheat degree, vibration frequency, amplitude and the like) on the initial solidification of molten steel and the quality of casting blanks can be researched at lower cost.
Drawings
FIG. 1 is a diagram of a simulation apparatus of a continuous casting funnel-shaped crystallizer designed according to the present invention;
FIG. 2 is a schematic view showing the structure of a Continuous Casting Funnel-shaped crystallizer in actual industrial production (L.C. Hibbeler, thermo-Mechanical Behavior during Steel Continuous Casting in channel Molds [ D ]. University of Illinois at Urbana-Champiaign, 2009);
FIG. 3 shows the initial solidified shell obtained in the experiment of the example.
FIG. 1 consists of FIGS. 1(a), 1(b), 1(c), wherein FIG. 1(a) is a schematic view of a continuous casting funnel mold simulator in its entirety; FIG. 1(b) is a three-dimensional view of a copper mold of a crystallizer; FIG. 1(c) is a schematic diagram showing distribution of temperature thermocouples. In fig. 1a, the continuous casting funnel-shaped crystallizer simulation device comprises an electromagnetic induction steel furnace, a drawing motor M1, a vibration motor M2, a drawing device and a funnel-shaped crystallizer with a cooling water channel. In FIG. 1b, the total length of the funnel-shaped crystallizer design is 340mm (Z-axis direction), the width is 100mm (Y-axis direction), and the thickness is 30mm (X-axis direction); wherein the effective part has a length of 77mm, and comprises a funnel-shaped area with a length of 70mm and a lower flat plate area with a length of 7 mm; the side parts are provided with temperature thermocouple slots; the upper part of the effective part is a flat plate cooling channel and a billet puller extended length. In fig. 1c, the active area of the funnel-shaped crystallizer is shown in front view, with the first and third rows visible, and the second and fourth rows coinciding with the first and third rows in the Y-axis and Z-axis, respectively, and in side view and in thermocouple distribution position; from the side view, the complete 16 thermocouple arrangement is seen, with three-dimensional coordinates CH1-1(4.47,50,70), CH1-2(11.89,50,45), CH1-3(13.68,50,25), CH1-4(5.20,50, 5); CH2-1(10.73,50,70), CH2-2(16.92,50,45), CH2-3(18.86,50,25), CH2-4(11.72,50, 5); CH3-1(3,90,70), CH3-2(3,90,45), CH3-3(3,90,25), CH3-4(3,90, 5); CH4-1(8,90,70), CH4-2(8,90,45), CH4-3(8,90,25), CH4-4(8,90, 5). The basic structure of the continuous casting funnel-shaped mold simulator designed according to the present invention and the manner of arrangement of the thermocouples can be seen in fig. 1.
FIG. 2 is composed of FIGS. 2(a) and 2(b), in which FIG. 2(a) is a sectional view of a continuous casting funnel mold in actual industrial production; FIG. 2(b) is a top view of a funnel-shaped crystallizer; the basic structure of a funnel-shaped crystallizer in a prior art practical production process can be seen in fig. 2.
The morphology of the initial solidified shell obtained by the example experiment can be seen in fig. 3.
Detailed Description
The embodiments described in the embodiments of the present invention are merely representative of some embodiments of the present invention, and not all embodiments. All other embodiments based on the embodiments of the present invention without any inventive work are within the scope of the present invention.
Example 1
The apparatus used in this example is shown in figure 1.
In the embodiment, the molten steel solidification and casting blank simulation method of the continuous casting funnel-shaped crystallizer comprises the following steps:
1) 50Kg of experimental steel block with the size of 50 multiplied by 50mm is put into an induction steelmaking furnace, under the condition of argon protection, induction heating is started to heat molten steel to 1500 ℃, and the temperature is kept for 20min until the molten steel is completely melted.
2) And adding 100g of casting powder particles to the surface of the molten steel, melting the casting powder particles to be in a liquid state by the high-temperature molten steel, covering the molten steel surface with the casting powder particles, absorbing inclusions floating up on the molten steel surface, and fishing out the casting powder with the inclusion absorbed on the molten steel surface after 5 min.
3) Adding 200g of covering slag particles into the molten steel again, standing for 10min, testing the temperature of the molten steel by using a temperature measuring gun, and calibrating the temperature of the molten steel; the induction heating program is turned off.
4) At the same time, positioning is carried out with the positioning rod so that the funnel-shaped crystallizer is inserted 70mm below the liquid level of the steel (i.e. the meniscus is in the position of red line in fig. 1 b); in addition, setting vibration motor parameters (amplitude is 6mm, vibration frequency is 4Hz), and setting the descending speed of the throwing motor (namely the pulling speed is 4 m/min); and introducing cooling water into the copper mould of the crystallizer and starting a temperature measuring program.
5) After all the settings and the temperature calibration are finished, starting an automatic blank drawing program, inserting the crystallizer and the blank drawing device into the molten steel together in a descending manner until the molten steel is immersed into the position of 70mm of the funnel-shaped crystallizer, stopping the insertion and staying for 5 s; starting a vibration motor to enable the funnel-shaped crystallizer to perform sinusoidal vibration according to the amplitude of 6mm and the vibration frequency of 4 Hz;
6) starting a blank drawing motor to enable a blank drawing device to move downwards at a drawing speed of 4m/min, wherein the blank drawing time is 6 crystallizer vibration cycles;
7) and after the drawing is finished, synchronously removing molten steel from the crystallizer and the drawing device, closing the temperature measuring system, and finishing the experiment.
8) The initial solidified shell obtained after the experiment is shown in fig. 3.
Claims (7)
1. A continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device; the method is characterized in that: the simulation device comprises a steel-making furnace, a blank-drawing motor, a vibration motor, a blank-drawing device and a crystallizer metal mold; the blank drawing motor is connected with a blank drawing device through a rigid connecting rod, and the blank drawing device is sleeved on the crystallizer metal mold; a cooling channel is arranged in the crystallizer metal mold; a wide surface of the crystallizer metal mold is provided with a curved surface groove, and the curved surface groove is funnel-shaped; defining the lowest end of the curved surface groove as a bottom; the distance from the bottom of the curved surface groove to the bottom of the crystallizer metal mold is more than or equal to 7 mm; the crystallizer metal mold is provided with at least 3 heat extraction couples; the first row and the second heat-extraction galvanic couples are positioned in the crystallizer metal mould opposite to the curved surface groove, and the third heat-extraction galvanic couple is not superposed with the first row and the second heat-extraction galvanic couples;
projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projections of at least 2 thermocouples fall into the projection formed by the curved surface groove; the projection of at least 1 thermocouple falls outside the projection formed by the curved surface groove and is positioned on the left side or the right side of the projection formed by the curved surface groove;
the number of any 2 heat extraction couples is equal; from the upper direction to the lower direction of the metal mold of the crystallizer, the thermocouples in the No. 1 heat-discharging couple are named as TC1-1, TC1-2, TC1-3, … … to TC 1-N; the thermocouples in the No. 2 heat-removal couple are named as TC2-1, TC2-2, TC2-3 and … … to TC 2-N; the thermocouples in the 3 rd heat-removal couple are named as TC3-1, TC3-2, TC3-3 and … … to TC 3-N; … … naming each thermocouple in the ith heat removal couple as TCi-1, TCi-2, TCi-3, … … till TCi-N; i is greater than or equal to 3;
projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projection of the P-th thermocouple in the first row of thermocouples is superposed with the projection of the P-th thermocouple in the second row of thermocouples, and P is a positive integer which is more than or equal to 1 and less than or equal to N;
when i is equal to 4; projecting perpendicular to the wide surface of the crystallizer metal mold, wherein the projection of the P-th thermocouple in the third heat discharge thermocouple is superposed with the projection of the P-th thermocouple in the fourth row, and P is a positive integer greater than or equal to 1 and less than or equal to N;
when the thermocouple is named TCx-y; when y is a fixed value, all thermocouples are positioned on one plane; x is more than or equal to 1 and less than or equal to i; y is greater than or equal to 1 and less than or equal to N;
the curved surface groove is of a symmetrical structure; the wide surface of the crystallizer metal mold is also designed symmetrically; on the vertical plane, the symmetry axis of the curved surface groove and the symmetry axis of the wide surface of the crystallizer metal mold are positioned on the same plane and are superposed;
projecting perpendicular to the wide surface of the crystallizer metal mold; the obtained projection is a symmetrical structure; the projection symmetrical axis of the projection is superposed with the projections of the first row of heat discharge couples and the second row of heat discharge couples;
when said N is equal to 4; projecting perpendicular to the wide surface of the crystallizer metal mold; the projections of the third row of the thermocouple and the fourth row of the thermocouple are overlapped; the minimum distance from the projection of the third row and/or the fourth heat-extraction galvanic couple to the projection frame of the wide surface of the crystallizer metal mold is equal to the distance from the projection frame of the third row and/or the fourth heat-extraction galvanic couple to the straight line A; the straight line A is as follows: on projection, making vertical lines perpendicular to projection lines obtained at the bottom of the wide surface of the mold metal die along the projection boundary formed by the curved surface groove, wherein the line with the minimum distance to a projection frame of the wide surface of the mold metal die in the vertical lines is A or A1; the line on the same side as the projection of the third row and/or the fourth row of heat discharging couples is A;
the length of the funnel shape is 70 mm; the inclination angle of the groove is 8-10 degrees.
2. The continuous casting funnel-shaped molten steel solidification and casting blank simulation device of the crystallizer of claim 1; the method is characterized in that: the crystallizer metal mold is made of red copper.
3. The continuous casting funnel-shaped molten steel solidification and casting blank simulation device of the crystallizer of claim 1; the method is characterized in that:
in the crystallizer metal mold, 4 thermocouples in the first row are positioned at the center line of the copper mold, the distribution positions are respectively 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mold, and the corresponding vertical distances from the surface of the copper mold are sequentially 4.47mm, 11.89mm, 13.68mm and 5.20 mm;
in the crystallizer metal die, the positions of the second row of 4 thermocouples are also located at the center line of the copper die and are respectively located at positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper die, and the corresponding vertical distances to the surface of the copper die are 10.73mm, 16.92mm, 18.86mm and 11.72mm in sequence;
in the metal mold of the crystallizer, the distribution positions of the 4 thermocouples in the third row are positioned at the central line of the non-funnel-shaped flat plate area at the edge of the copper mold and are respectively positioned at the positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mold; the corresponding vertical distances from the surface of the copper mold are all 3 mm;
in the crystallizer metal mould, the distribution positions of the 4 thermocouples in the fourth row are also positioned at the central line of the non-funnel-shaped flat plate area at the edge of the copper mould and are respectively positioned at the positions 70mm, 45mm, 25mm and 5mm away from the bottom of the copper mould; the corresponding vertical distances to the surface of the copper mold are all 8 mm.
4. Use of a continuous casting funnel-shaped molten steel solidification and strand simulation device according to any one of claims 1 to 3; it is characterized in that; the method comprises the following steps:
putting 40-60 Kg of steel blocks into a steelmaking furnace, and melting the steel blocks by electromagnetic induction heating under the protective atmosphere of argon; adding 50-100 g of covering slag to the surface of the molten steel, and fishing out the covering slag floating on the surface of the molten steel after 5min so as to remove oxides floating on the surface of the molten steel and purify the molten steel; then adding 150-300 g of covering slag to the surface of the molten steel to play roles in preventing the molten steel from being oxidized and preserving heat; after 10 minutes, testing the temperature of the molten steel by using a temperature measuring gun, and correcting the superheat degree of the molten steel; then, starting a copper mold temperature measuring system in the crystallizer, inserting the continuous casting simulation device into the molten steel through the driving of a motor, and stopping deepening after the continuous casting simulation device is completely immersed; the molten steel and the liquid slag flow into a water-cooled crystallizer copper mold together, stay for 5-10 s, start a crystallizer vibration motor, vibrate periodically according to set vibration frequency and amplitude, and because the molten steel solidifies and can generate volume shrinkage, a gap is formed between the crystallizer and an initial solidified blank shell, and the liquid slag flows into the gap under the vibration action of the crystallizer, so that the effects of lubrication and heat transfer control are achieved; then, under the drive of a motor, the throwing device moves downwards relative to the crystallizer at a certain speed, namely, the throwing speed, and an initial solidified shell with a certain thickness is pulled out of the crystallizer; meanwhile, the molten steel is newly filled into the crystallizer for solidification, so that the simulation of the continuous casting process is realized; the downward movement time of the billet puller is 6-8 periods of the vibration of the crystallizer, then the crystallizer and the billet puller synchronously ascend to remove molten steel, a temperature measuring system is closed, and the experiment is finished; after cooling, the initial solidified shell and the covering slag film in the crystal are taken down, and the pulled casting blank is used for further analysis.
5. The application of the continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device as claimed in claim 4 is characterized in that:
in the application, the size of the steel block is 50 multiplied by 50 mm;
in the said application; testing the temperature of the molten steel and correcting the superheat degree of the molten steel, wherein the superheat degree is consistent with the actual production or experiment and data acquisition are carried out according to the designed superheat degree;
in the said application; keeping the amplitude and the vibration frequency of the vibration of the crystallizer consistent with the actual production or carrying out experiment and data acquisition according to design values;
in the said application; the downward moving speed of the throwing device, namely the drawing speed, is consistent with the actual production or is subjected to experiment and data acquisition according to design values.
6. The application of the continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device as claimed in claim 4 is characterized in that:
in the said application; and (3) inversely calculating the heat flow distribution to the funnel-shaped area and the non-funnel-shaped area through the unsteady heat transfer of the sphere model and the unsteady heat transfer of the flat plate model according to the temperature data acquired by the thermocouple.
7. The application of the continuous casting funnel-shaped crystallizer molten steel solidification and casting blank simulation device as claimed in claim 4 is characterized in that: the solidified shell and slag film in the crystallizer and the pulled casting blank are used for electron microscope analysis, and the correlation of steel grade, continuous casting process parameters, covering slag behavior, heat flow distribution, molten steel meniscus initial solidification and casting blank surface quality can be obtained.
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