High-quality steel steelmaking continuous casting process and equipment thereof

Abstract

The invention relates to the technical field of steel continuous casting, and discloses a high-quality steel steelmaking continuous casting process and equipment thereof. The high-quality steel steelmaking continuous casting process comprises a steel ladle used for containing molten steel, a tundish located below the steel ladle, a crystallizer located below the tundish, a vibrator in transmission connection with the crystallizer, a spraying device, a plurality of supporting rollers and a dummy bar. The spraying device comprises a plurality of annular pipes, a plurality of nozzles, a third connecting pipe and a tubular collecting shell; the multiple annular pipes are arranged outside a steel billet in a sleeving mode and are arranged at intervals in the extending direction of the steel billet. Each annular pipe is connected with a plurality of sprayers, the sprayers are arranged at intervals in the circumferential direction of the annular pipes, the spraying directions of the sprayers all face the steel billet, and the third connecting pipe communicates with all the annular pipes; the annular pipe is fixedly sleeved with the collecting shell, the collecting shell is fixedly connected with the annular pipe, the bottom end of the collecting shell communicates with a drainage pipe used for collecting cooling water, and the top of the collecting shell communicates with a fan used for blowing away heat in the collecting shell; the problem of reasonable spraying coverage is solved.

Description

Technical Field

[0001] The present application relates to the technical field of steel continuous casting, and more particularly to a high-quality steelmaking continuous casting process and equipment thereof. Background Art

[0002] At present, China's continuous casting technology is developing rapidly, and the number of continuous casting machines and the output of continuous casting billets have ranked first in the world. During the continuous casting process, temperature is one of the most important parameters in the entire continuous casting process. In the secondary cooling zone, the billet is cooled by spraying cooling water, which has an important influence on the quality of the billet. The billet coming out of the crystallizer is not completely solidified inside, and spraying and cooling in the secondary cooling zone can effectively prevent the billet from deformation.

[0003] In the prior art, the spraying of the secondary cooling zone is generally performed by atomizing or granulating the cooling water and spraying it on the surface of the steel billet to cool it down. However, the nozzles in the existing spraying device are only distributed on the upper and lower surfaces of the steel billet. This spraying method does not fully cover the water spray on the steel billet and the design is unreasonable. Summary of the invention

[0004] On the one hand, the present application provides a high-quality steelmaking and continuous casting equipment, which aims to solve the problem of unreasonable spray coverage in the prior art.

[0005] In one embodiment, a high-quality steelmaking and continuous casting apparatus is provided, comprising:

[0006] A ladle for holding molten steel, a tundish located below the ladle, a crystallizer located below the tundish, a vibrator drivingly connected to the crystallizer, a spray device, a plurality of support rollers, and a dummy rod;

[0007] The ladle is connected to the tundish through a first connecting pipe, and the tundish is connected to the crystallizer through a second connecting pipe;

[0008] The steel billet formed in the crystallizer is pulled out by the dummy rod, and the plurality of support rollers are sequentially spaced along the extension direction of the steel billet; the steel billet is divided into a sector segment and a straight segment, the sector segment is connected to the crystallizer, and the spray device is located on the sector segment;

[0009] The spray device comprises: a plurality of annular tubes, a plurality of nozzles, a third connecting tube, and a tubular collecting shell; the plurality of annular tubes are sleeved outside the steel billet and arranged at intervals along the extending direction of the steel billet; each of the annular tubes is connected to a plurality of nozzles, and the plurality of nozzles are arranged at intervals along the circumference of the annular tube, and the spraying directions of the nozzles are all toward the steel billet, and the third connecting tube is connected to each of the annular tubes; the collecting shell is sleeved and fixed outside the annular tube and fixedly connected to the annular tube, the bottom end of the collecting shell is connected to a drain pipe for collecting cooling water, and the top of the collecting shell is connected to a fan for blowing away the heat in the collecting shell;

[0010] The crystallizer and the sector are respectively provided with a first temperature sensor and a second temperature sensor in a one-to-one correspondence.

[0011] Among them, a heater (arc heater) is arranged in the ladle, and the outer layer of the ladle and the intermediate ladle has a heat insulation layer.

[0012] The supporting rollers include an upper roller and a lower roller, which are symmetrically arranged. The two rollers are used to extrude the steel billet into shape and reduce the internal gap of the steel billet.

[0013] The ladle is lifted from the furnace to the top of the tundish by a gantry crane. The tundish has multiple liquid outlets to achieve multiple continuous castings. The vibrator is an existing vibrator on the market used in the continuous casting process, which is used to drive the crystallizer to vibrate reciprocatingly up and down. The guide rod is also an existing equipment.

[0014] The lower section of the second connecting pipe is located below the molten steel level, and the liquid outlet of the second connecting pipe is an immersion water outlet. The spray device is fixedly connected to the support bracket of the support roller.

[0015] The first temperature sensor is a thermocouple temperature sensor, the number of the second temperature sensors is two, one is located at the top of the collection shell, and the other is located at the bottom of the collection shell, and the second temperature sensor is an infrared temperature sensor.

[0016] In one embodiment, the crystallizer includes a cooling water tank having a cooling channel and a formed tube body for circulating the molten steel; the formed tube body is detachably inserted into the cooling channel, and the outer wall of the formed tube body is in close contact with the inner wall of the cooling channel.

[0017] Specifically, the cooling water tank is cylindrical; a plurality of water inlets are provided at the lower portion of the cooling water tank, and the plurality of water inlets are distributed around the circumference of the cooling water tank, and the water inlet direction of the water inlet is at a predetermined angle to the tangent of the side of the cooling water tank, and the predetermined angle is 30 degrees; a water outlet is provided at the upper portion of the water inlet tank.

[0018] Specifically, a flange is provided on the top of the formed tube body, and the formed tube body is detachably connected to the cooling water tank via the flange.

[0019] An electromagnetic stirrer is arranged in the cooling water tank, and the electromagnetic stirrer is sleeved outside the cooling channel; electromagnetic stirrers are also arranged at the middle position and the end position of the fan-shaped segment.

[0020] The cooling water in the cooling water tank and the spraying device are both powered by the pump body.

[0021] In one embodiment, a buffer tank, a filter screen, a retaining wall, a vent and a liquid outlet are provided in the intermediate bag; the buffer tank is located directly below the first connecting pipe, the filter screen is fixedly connected to the top of the buffer tank, the retaining wall is fixedly connected to the side wall of the intermediate bag, and the bottom of the retaining wall is spaced apart from the bottom of the intermediate bag, the retaining wall is spaced apart from the buffer tank, and the retaining wall is fixedly connected to the filter screen; the vent is located at the bottom of the intermediate bag, and the vent is located on one side of the retaining wall; the liquid outlets are spaced apart on one side of the vent.

[0022] Specifically, the molten steel passes through the buffer tank, the filter screen, the retaining wall, the vent in sequence, and finally flows out from the liquid outlet.

[0023] The vent is used to connect the argon gas pipeline. The filter is a ceramic filter.

[0024] In one embodiment, a controller is further included; a heater is provided in the intermediate package, the third connecting pipe is connected to a cooling water source with a stable water pressure, and a flow regulating valve is provided on the third connecting pipe; the first temperature sensor, the second temperature sensor, the heater, the flow regulating valve, and the fan are all electrically connected to the controller.

[0025] Specifically, the cooling water source with stable water pressure is provided by the pump body, and the water pressure is: 0.4-0.9Mpa; usually 800m3 of water is supplied around the crystallizer. 3 / h. The temperature difference between inlet and outlet water does not exceed 10℃, and the outlet water temperature is controlled at 45-50℃.

[0026] The controller is a single chip microcomputer and the heater is an arc heater.

[0027] On the other hand, the present application provides a high-quality steelmaking and continuous casting process, comprising the following steps:

[0028] According to the composition of the molten steel, determining the tapping temperature, casting temperature, billet drawing speed and mold slag composition of the molten steel;

[0029] The molten steel is injected into the crystallizer, and protective slag is added when the molten steel reaches a predetermined liquid level;

[0030] The billet is pulled out of the crystallizer by the dummy bar and moves on the support rollers;

[0031] Obtaining the required heat dissipation according to the difference between the temperature value of the first temperature sensor and the casting temperature, and determining the cooling water flow rate passing through the crystallizer;

[0032] Determining the cooling water flow rate of the spray device according to the temperature value of the second temperature sensor;

[0033] According to the moving speed of the steel billet, the steel billet is cut within a predetermined time, and the cutting position is located on a straight line segment.

[0034] Specifically, the cutting method adopts flame cutting; the steel tapping temperature is the temperature of the molten steel when it flows out of the ladle.

[0035] T C represents the pouring temperature, T L represents the liquidus temperature, ΔT represents the superheat of molten steel; ΔT = T L -T C The principle of determining superheat ΔT is related to product quality. The range of superheat values ​​is as follows:

[0036]

[0037]

[0038] In one solution, the required heat dissipation and the cooling water flow rate through the crystallizer satisfy the following relationship:

[0039] Where, Q: required heat dissipation; W: total amount of water passing through the crystallizer; C: specific heat capacity of water, 4.2 kj / kg×℃; △Q: temperature difference between inlet and outlet water of the crystallizer.

[0040] Specifically, the amount of cooling water passing through the crystallizer can also be calculated by the formula: Where S is the water gap area; W is the amount of cooling water passing through the crystallizer, m3 / h; V is the cooling water flow rate.

[0041] in, In the formula, Qk: unit water flow m 3 / n·m, the experience value is 100-500m 3 / n·m; take 100m 3 / n·m; a: circumference of cooling channel, 10 3 m; V: cooling water flow rate, take 6-10m / s, actually take 8m / s.

[0042] In one embodiment, the cooling water flow rate of the spray device satisfies the following formula:

[0043] W = s × v × ρ × δ, where W is the cooling water flow rate of the spray device, s is the cross-sectional area of ​​the billet, v is the billet drawing speed, ρ is the billet density, and δ is the specific water content.

[0044] Specifically, the range of specific water content is shown in the following table:

[0045] Steel type Specific water content L / kg Plain carbon steel, low alloy steel 1.0-1.2 Medium and high carbon steel, alloy steel 0.6-0.8 Crack-sensitive steel 0.4-0.6 High Speed ​​Steel 0.1-0.3

[0046] The water pressure of the third connecting pipe is 0.1-1.0MP, and the water supply of the fan section is usually 400m 3 / h.

[0047] In one embodiment, the protective slag includes: 25% to 45% CaO, 20% to 50% SiO2, 0% to 10% Al2O3, 1% to 20% Na2O, and 2% to 5% graphite.

[0048] Specifically, the thickness of the protective slag is: the liquid slag layer on the surface of the crystallizer steel liquid is maintained at 5 to 15 mm, and the melting point temperature is between 1300 degrees Celsius and 1400 degrees Celsius; when casting aluminum-containing steel or steel with a manganese content higher than 0.65%, a graphite high-aluminum nozzle is used, that is, the third connecting pipe is made of graphite high-aluminum material. Its prevention mechanism is mainly to reduce the adhesion of alumina on the nozzle wall by weakening the wettability of molten steel and the inner wall of the nozzle.

[0049] In one embodiment, when the molten steel is OCr18NI9 stainless steel, the ratio of CaO / SiO2 in the protective slag is between 0.9 and 1.1.

[0050] Specifically, OCr18NI9 stainless steel includes 18% chromium and 9% nickel.

[0051] In one embodiment, when the molten steel is high aluminum steel with an Al content of 0.5% to 3.5%, the protective slag includes: 15% to 40% CaO, 3% to 15% SiO2, and 10% to 20% Al2O3.

[0052] Specifically, when the molten steel is high aluminum steel with an Al content of 1.0% to 3.5%, the protective slag includes: 15% to 35% CaO, 10% to 25% SiO2, and 12% to 15% Al2O3.

[0053] Beneficial effects of the present application: molten steel flows from the ladle into the tundish in sequence, and then flows from the tundish into the crystallizer, where it is cooled to form a billet and pulled out by the dummy rod. The billet moves on multiple support rollers in sequence and is cut into a suitable length. A spray device is provided on the fan-shaped segment to cool the pulled billet so that the inside of the billet is completely solidified. The annular tube and the annularly distributed nozzles provided in the spray device can cover the entire circumferential surface of the billet, completely cooling the billet in all directions. The cooling is uniform and the design is reasonable.

[0054] At the same time, the collection shell is designed to collect the sprayed cooling water and treat it uniformly. A fan is arranged on the collection shell to drive the water vapor evaporated from the collection shell out of the collection shell, thereby enhancing the air flow in the collection shell and improving the cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0056] Figure 1 This is a schematic diagram of the continuous casting equipment process in one embodiment of the present application;

[0057] Figure 2 It is a schematic diagram of the structure of the intermediate package in one embodiment of the present application;

[0058] Figure 3 This is a schematic diagram of the crystallizer structure in one embodiment of the present application;

[0059] Figure 4 is a top view of a crystallizer in one embodiment of the present application;

[0060] Figure 5 It is a schematic diagram of the cross-sectional structure of a spray device in one embodiment of the present application;

[0061] Figure 6 This is a schematic diagram of a control flow in an embodiment of the present application;

[0062] Reference numerals in the figures:

[0063] 1. Ladle; 11. First connecting pipe; 2. Tundish; 21. Second connecting pipe; 22. Buffer tank; 23. Filter screen; 24. Retaining wall; 25. Vent; 26. Liquid outlet; 27. Heater; 3. Crystallizer; 31. Cooling water tank; 32. Cooling channel; 33. Forming tube body; 34. Electromagnetic stirrer; 35. Water inlet; 36. Water outlet; 37. Flange; 4. Vibrator; 5. Spraying device; 51. Annular pipe; 52. Nozzle; 53. Third connecting pipe; 54. Collecting shell; 55. Drain pipe; 56. Fan; 6. Support roller; 61. Support bracket; 7. Draw bar; 8. Billet; 81. Sector segment; 82. Straight segment; 9. Controller; 91. First temperature sensor; 92. Second temperature sensor; 93. Flow regulating valve. DETAILED DESCRIPTION

[0064] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0066] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0069] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0070] The present application makes improvements and innovations and proposes the following embodiments.

[0071] In some embodiments, see Figure 1-Figure 6 , provides a high-quality steelmaking and continuous casting equipment, including:

[0072] A ladle 1 for holding molten steel, a tundish 2 located below the ladle 1, a crystallizer 3 located below the tundish 2, a vibrator 4 drivingly connected to the crystallizer 3, a spray device 5, a plurality of support rollers 6, and a dummy rod 7;

[0073] The ladle 1 is connected to the tundish 2 through the first connecting pipe 11, and the tundish 2 is connected to the crystallizer 3 through the second connecting pipe 21;

[0074] The steel billet 8 formed in the crystallizer 3 is pulled out by the dummy rod 7, and a plurality of support rollers 6 are sequentially spaced and distributed along the extending direction of the steel billet 8; the steel billet 8 is divided into a sector segment 81 and a straight segment 82, the sector segment 81 is connected to the crystallizer 3, and the spray device 5 is located on the sector segment 81;

[0075] The spray device 5 includes: a plurality of annular tubes 51, a plurality of nozzles 52, a third connecting tube 53, and a tubular collecting shell 54; the plurality of annular tubes 51 are sleeved outside the steel billet 8 and arranged at intervals along the extension direction of the steel billet 8; each annular tube 51 is connected to a plurality of nozzles 52, and the plurality of nozzles 52 are arranged at intervals along the circumference of the annular tube 51, and the spraying direction of the nozzles 52 is toward the steel billet 8, and the third connecting tube 53 is connected to each annular tube 51; the collecting shell 54 is sleeved and fixed outside the annular tube 51 and is fixedly connected to the annular tube 51, the bottom end of the collecting shell 54 is connected to a drain pipe 55 for collecting cooling water, and the top of the collecting shell 54 is connected to a fan 56 for blowing away the heat in the collecting shell 54;

[0076] The crystallizer 3 and the sector segment 81 are respectively provided with a first temperature sensor 91 and a second temperature sensor 92 in a one-to-one correspondence.

[0077] The ladle 1 is provided with a heater 27 (arc heater), and the outer layers of the ladle 1 and the tundish 2 have a heat insulation layer. The heater 27 can ensure that the molten steel maintains a stable temperature during the transportation process, ensuring that the subsequent casting proceeds smoothly.

[0078] The support roller 6 includes an upper roller and a lower roller, and is symmetrically arranged. The two rollers are used to extrude the steel billet 8 into shape and reduce the internal gap of the steel billet 8.

[0079] The ladle 1 is lifted from the furnace to the top of the tundish 2 by a gantry crane. The tundish 2 has multiple liquid outlets 26 to achieve multiple continuous castings. The vibrator 4 is an existing vibrator 4 used in the continuous casting process on the market, which is used to drive the crystallizer 3 to vibrate reciprocatingly up and down. The ingot guide rod 7 is also an existing equipment.

[0080] The lower section of the second connecting pipe 21 is located below the molten steel surface, and the liquid outlet 26 of the second connecting pipe 21 is an immersion water outlet. The spray device 5 is fixedly connected to the support bracket 61 of the support roller 6.

[0081] The first temperature sensor 91 is a thermocouple temperature sensor, and the number of the second temperature sensors 92 is two, one located at the top of the collection shell 54 and the other located at the bottom of the collection shell 54. The second temperature sensor 92 is an infrared temperature sensor. The temperature sensor can continuously detect the temperature of the molten steel and the billet 8 and provide real-time feedback on the temperature status.

[0082] The molten steel flows from the ladle 1 to the tundish 2 in sequence, and then flows from the tundish 2 to the crystallizer 3. The molten steel is cooled in the crystallizer 3 to form a billet 8 and is pulled out by the dummy rod 7. The billet 8 moves on multiple support rollers 6 in sequence and is cut into a suitable length. A spray device 5 is provided on the sector 81 to cool the pulled billet 8 so that the inside of the billet 8 is completely solidified. The annular tube 51 and the annularly distributed nozzles 52 provided in the spray device 5 can cover the entire circumferential surface of the billet 8, and completely cool the billet 8 in all directions. The cooling is uniform and the design is reasonable.

[0083] The collecting shell 54 is designed to collect the cooling water sprayed out and to process it uniformly. A fan 56 is arranged on the collecting shell 54 to drive the water vapor evaporated from the collecting shell 54 out of the collecting shell 54, thereby enhancing the air flow in the collecting shell 54 and improving the cooling efficiency.

[0084] In some embodiments, the crystallizer 3 includes a cooling water tank 31 having a cooling channel 32 and a formed tube body 33 for circulating molten steel; the formed tube body 33 is detachably inserted into the cooling channel 32, and the outer wall of the formed tube body 33 is in close contact with the inner wall of the cooling channel 32. The detachable formed tube body 33 is convenient for later replacement and maintenance, and it is convenient to replace the formed tube body 33 of different sizes to ensure that the size of the drawn steel billet 8 meets the production requirements.

[0085] Specifically, the cooling water tank 31 is cylindrical; a plurality of water inlets 35 are provided at the lower part of the cooling water tank 31, and the plurality of water inlets 35 are distributed around the circumference of the cooling water tank 31, and the water inlet direction of the water inlet 35 forms a predetermined angle with the tangent of the side of the cooling water tank 31, and the predetermined angle is 30 degrees; a water outlet 36 is provided at the upper part of the water inlet tank. The water flows into the cooling water tank 31 at an angle of 30 degrees, so that the water flow forms a vortex, so that the cold and hot water can be fully mixed, and the cooling efficiency is improved.

[0086] Specifically, a flange 37 is provided on the top of the formed tube body 33, and the formed tube body 33 is detachably connected to the cooling water tank 31 through the flange 37. Through the connection of the flange 37, the structure is simple and the design is reasonable.

[0087] An electromagnetic stirrer 34 is provided in the cooling water tank 31, and the electromagnetic stirrer 34 is sleeved outside the cooling channel 32; electromagnetic stirrers 34 are also provided at the middle position and the end position of the sector 81. The electromagnetic stirrer 34 is provided to strengthen the flow of molten steel in the ingot by utilizing the electromagnetic force generated by the electromagnetic stirrer 34, thereby improving the flow, heat transfer and mass transfer conditions during the solidification process of the molten steel, so as to improve the quality of the continuous casting ingot.

[0088] The cooling water of the cooling water tank 31 and the spray device 5 flows and is powered by the pump body. The pump body is electrically connected to the controller 9 so that the controller can control the power of the pump body and keep the water pressure stable.

[0089] In some embodiments, a buffer tank 22, a filter screen 23, a retaining wall 24, a vent 25, and a liquid outlet 26 are provided in the tundish 2; the buffer tank 22 is located directly below the first connecting pipe 11, the filter screen 23 is fixedly connected to the top of the buffer tank 22, the retaining wall 24 is fixedly connected to the side wall of the tundish 2, and the bottom of the retaining wall 24 is spaced apart from the bottom of the tundish 2, the retaining wall 24 is spaced apart from the buffer tank 22, and the retaining wall 24 is fixedly connected to the filter screen 23; the vent 25 is located at the bottom of the tundish 2, and the vent 25 is located on one side of the retaining wall 24; the liquid outlet 26 is spaced apart on one side of the vent 25. The buffer tank 22, the filter screen 23, the retaining wall 24, and the vent 25 are mainly used to sequentially reduce the fluidity of the molten steel to help the impurities float up, so as to obtain pure molten steel.

[0090] Specifically, the molten steel passes through the buffer tank 22 , the filter screen 23 , the retaining wall 24 , the vent 25 , and finally flows out from the liquid outlet 26 .

[0091] The vent 25 is used to connect the argon pipeline. The filter 23 is a ceramic filter 23. When the argon is introduced, the argon will form a gas wall to reduce the flow of molten steel. The vent 25 is provided with a gas separation net to divide the argon into fine bubbles, improve the blocking effect, and help the impurities float. The filter 23 is a ceramic filter 23, which will not be melted by the molten steel.

[0092] In some embodiments, a controller 9 is further included; a heater 27 is provided in the tundish 2, the third connecting pipe 53 is connected to a cooling water source with a stable water pressure, and a flow regulating valve 93 is provided on the third connecting pipe 53; the first temperature sensor 91, the second temperature sensor 92, the heater 27, the flow regulating valve 93, and the fan 56 are all electrically connected to the controller 9. The controller 9 controls the opening of the flow regulating valve 93 according to the temperature signals transmitted by the first temperature sensor 91 and the second temperature sensor 92, thereby changing the flow of cooling water, ensuring the cooling effect, and improving the automation and precision of the cooling process.

[0093] Specifically, the cooling water source with stable water pressure is provided by the pump body, and the water pressure is: 0.4-0.9Mpa; the cooling water flow rate around the crystallizer 3 is 800m 3 / h. The temperature difference between inlet and outlet water does not exceed 10℃, and the outlet water temperature is controlled at 45-50℃.

[0094] The controller 9 is a single chip microcomputer, and the heater 27 is an arc heater.

[0095] On the other hand, the present application provides a high-quality steelmaking and continuous casting process, comprising the following steps:

[0096] According to the composition of the molten steel, the tapping temperature of the molten steel, the casting temperature, the drawing speed of the steel billet 8 and the composition of the protective slag are determined;

[0097] The molten steel is poured into the crystallizer 3, and when the molten steel reaches the predetermined liquid level, the protective slag is added;

[0098] The billet 8 is pulled out of the crystallizer 3 by the dummy bar 7 and moves on the support rollers 6;

[0099] Obtain the required heat dissipation according to the difference between the temperature value of the first temperature sensor 91 and the casting temperature, and determine the cooling water flow rate passing through the crystallizer 3;

[0100] Determine the cooling water flow rate of the spray device 5 according to the temperature value of the second temperature sensor 92;

[0101] According to the moving speed of the steel billet 8 , the steel billet 8 is cut within a predetermined time, and the cutting position is located on the straight line segment 82 .

[0102] According to the two temperature sensors, the cooling water flow through the crystallizer 3 and the cooling water flow through the spray device 5 are obtained respectively, thereby facilitating the staff to control the cooling water flow, reducing the difficulty of cooling and ensuring the quality of the billet 8.

[0103] Specifically, the cutting method adopts flame cutting; the steel tapping temperature is the temperature of the molten steel when it flows out of the ladle 1.

[0104] represents the pouring temperature, represents the liquidus temperature, and represents the superheat of molten steel; ΔT = T L -T C The principle of determining superheat is related to product quality. The range of superheat values ​​is as follows:

[0105] Casting steel Slabs, blooms Billet High carbon steel, high manganese steel +10℃ +15～20℃ Alloy structural steel +5～10℃ +15～20℃ Aluminum killed steel, low alloy steel +15～20℃ +25～30℃ Stainless steel +15～20℃ +20～30℃ Silicon Steel +10℃ +15～20℃

[0106] Based on the corresponding superheat and liquidus temperature, the staff can quickly determine the casting temperature and then adjust the corresponding parameters, such as the control of cooling water volume.

[0107] In some embodiments, the required heat dissipation and the cooling water flow rate through the crystallizer 3 satisfy the following relationship:

[0108] In the formula, Q: required heat dissipation; W: cooling water volume passing through the crystallizer 3; C: specific heat capacity of water, 4.2 kj / kg×℃; △Q: temperature difference between the inlet and outlet water volume of the crystallizer 3. The required heat dissipation is determined by the type of billet 8 and the drawing speed in the early stage. The temperature difference between the inlet and outlet water volume of the crystallizer 3 is in the range of 6 to 10℃. When the temperature difference between the inlet and outlet water volume of the crystallizer 3 is determined, the cooling water volume passing through the crystallizer 3 can be easily obtained, and the control is flexible and convenient.

[0109] The water inlet 35 and the water outlet 36 of the crystallizer 3 are both provided with temperature sensors for detecting the inlet and outlet water temperatures.

[0110] Specifically, the amount of cooling water passing through the crystallizer 3 can also be expressed by the formula: Where S is the water gap area; W is the amount of cooling water passing through the crystallizer 3, m 3 / h; V is the cooling water flow rate.

[0111] in, Wherein, Qk: unit water flow rate m / n·m, the value range is 100-500m / n·m; a: circumference of cooling channel 32, 10m; V: cooling water flow rate, the value range is 6-10m / s.

[0112] This method is used to obtain the amount of cooling water passing through the crystallizer 3. As long as a flow rate detector is set at the water inlet 35, the flow rate can be determined within a suitable range, and the cooling of different steel billets 8 can be handled. The design is simple, and fewer sensors are used. Even after determining the cooling water flow rate, the sensor can be removed. As long as the cooling water flow rate is kept constant, the cooling amount can be kept within a suitable range, and the cooling effect on the steel billet 8 can still meet the requirements.

[0113] In some embodiments, the cooling water flow rate of the spray device 5 satisfies the following formula:

[0114] , where W is the cooling water flow rate of the spray device 5, s is the cross-sectional area of ​​the billet 8, v is the drawing speed of the billet 8, is the density of the billet 8, and is the specific water volume.

[0115] Specifically, the range of specific water content is shown in the following table:

[0116] Steel type Specific water content L / kg Plain carbon steel, low alloy steel 1.0-1.2 Medium and high carbon steel, alloy steel 0.6-0.8 Crack-sensitive steel 0.4-0.6 High Speed ​​Steel 0.1-0.3

[0117] The water pressure of the third connecting pipe 53 is 0.1-1.0MP, and the fan-shaped section 81 usually supplies 400m 3 / h.

[0118] The density of the steel billet 8 is obtained by sampling and measuring by the staff and is a constant. According to the above formula, the cooling water flow rate of the spray device 5 can be easily obtained to ensure the cooling effect.

[0119] In some embodiments, the mold slag includes: 25% to 45% CaO, 20% to 50% SiO2, 0% to 10% Al2O3, 1% to 20% Na2O, and 2% to 5% graphite. The mold slag within this range can reduce the contact between molten steel and oxygen, and has a suitable viscosity to facilitate continuous casting of the steel billet 8.

[0120] Specifically, the thickness of the protective slag is 5-15 mm on the surface of the molten steel in the crystallizer 3, and the melting point is 1300 to 1400 degrees Celsius. When casting aluminum-containing steel or steel with a manganese content higher than 0.65%, a graphite high-aluminum nozzle is used, that is, the third connecting pipe 53 is made of graphite high-aluminum material. The prevention mechanism is mainly to reduce the adhesion of aluminum oxide on the nozzle wall by weakening the wettability of the molten steel and the inner wall of the nozzle.

[0121] In some embodiments, when the molten steel is OCr18NI9 stainless steel, the ratio of CaO / SiO2 in the protective slag is between 0.9 and 1.1. Under this ratio, the protective slag has good thermal conductivity, which is beneficial to the cooling and forming of the stainless steel.

[0122] Specifically, OCr18NI9 stainless steel includes 18% chromium and 9% nickel.

[0123] In some embodiments, when the molten steel is a high aluminum steel with an Al content of 0.5% to 3.5%, the protective slag includes: 15% to 40% CaO, 3% to 15% SiO2, and 10% to 20% Al2O3. During the casting process, the liquid level of the crystallizer 3 is in good condition, the protective slag performance is stable, and the surface and subcutaneous quality of the produced ingot are good.

[0124] Specifically, when the molten steel is a high aluminum steel with an Al content of 1.0% to 3.5%, the protective slag includes: 15% to 35% CaO, 10% to 25% SiO2, and 12% to 15% Al2O3. The protective slag has a good liquid level in the crystallizer 3 during the casting of high-quality steel, the protective slag has stable performance, and the surface and subcutaneous quality of the produced ingot is good.

[0125] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A high-quality steelmaking and continuous casting equipment, characterized in that: include: A ladle for holding molten steel, a tundish located below the ladle, a crystallizer located below the tundish, a vibrator drivingly connected to the crystallizer, a spray device, a plurality of support rollers, and a dummy rod; The ladle is connected to the tundish through a first connecting pipe, and the tundish is connected to the crystallizer through a second connecting pipe; The steel billet formed in the crystallizer is pulled out by the dummy rod, and the plurality of support rollers are sequentially spaced along the extension direction of the steel billet; the steel billet is divided into a sector segment and a straight segment, the sector segment is connected to the crystallizer, and the spray device is located on the sector segment; The spray device comprises: a plurality of annular tubes, a plurality of nozzles, a third connecting tube, and a tubular collecting shell; the plurality of annular tubes are sleeved outside the steel billet and arranged at intervals along the extending direction of the steel billet; each of the annular tubes is connected to a plurality of nozzles, and the plurality of nozzles are arranged at intervals along the circumference of the annular tube, and the spraying directions of the nozzles are all toward the steel billet, and the third connecting tube is connected to each of the annular tubes; the collecting shell is sleeved and fixed outside the annular tube and fixedly connected to the annular tube, the bottom end of the collecting shell is connected to a drain pipe for collecting cooling water, and the top of the collecting shell is connected to a fan for blowing away the heat in the collecting shell; The crystallizer and the sector are respectively provided with a first temperature sensor and a second temperature sensor in a one-to-one correspondence.

2. The high-quality steelmaking and continuous casting equipment according to claim 1 is characterized in that: The crystallizer comprises a cooling water tank with a cooling channel and a formed tube body for circulating the molten steel; the formed tube body is detachably inserted in the cooling channel, and the outer wall of the formed tube body is in close contact with the inner wall of the cooling channel.

3. The high-quality steelmaking and continuous casting equipment according to claim 1 is characterized in that: A buffer tank, a filter screen, a retaining wall, an air vent and a liquid outlet are provided in the intermediate bag; the buffer tank is located directly below the first connecting pipe, the filter screen is fixedly connected to the top of the buffer tank, the retaining wall is fixedly connected to the side wall of the intermediate bag, and the bottom of the retaining wall is spaced apart from the bottom of the intermediate bag, the retaining wall is spaced apart from the buffer tank, and the retaining wall is fixedly connected to the filter screen; the air vent is located at the bottom of the intermediate bag, and the air vent is located on one side of the retaining wall; the liquid outlets are spaced apart on one side of the air vent.

4. The high-quality steelmaking and continuous casting equipment according to claim 1, characterized in that: It also includes a controller; a heater is provided in the intermediate package, the third connecting pipe is connected to a cooling water source with a stable water pressure, and a flow regulating valve is provided on the third connecting pipe; the first temperature sensor, the second temperature sensor, the heater, the flow regulating valve, and the fan are all electrically connected to the controller.

5. A high-quality steelmaking and continuous casting process, using any high-quality steelmaking and continuous casting equipment according to any one of claims 1 to 4, characterized in that: The steps include: According to the composition of the molten steel, determining the tapping temperature, casting temperature, billet drawing speed and mold slag composition of the molten steel; The molten steel is injected into the crystallizer, and protective slag is added when the molten steel reaches a predetermined liquid level; The billet is pulled out of the crystallizer by the dummy bar and moves on the support rollers; Obtaining the required heat dissipation according to the difference between the temperature value of the first temperature sensor and the casting temperature, and determining the cooling water flow rate passing through the crystallizer; Determining the cooling water flow rate of the spray device according to the temperature value of the second temperature sensor; According to the moving speed of the steel billet, the steel billet is cut within a predetermined time, and the cutting position is located on a straight line segment.

6. The high-quality steelmaking and continuous casting process according to claim 5, characterized in that: The required heat dissipation and the cooling water flow rate through the crystallizer satisfy the following relationship: Where, Q: required heat dissipation; W: total water volume passing through the crystallizer, L / min; C: specific heat capacity of water, 4.2 kj / kg×℃; △Q: temperature difference between inlet and outlet water of crystallizer.

7. The high-quality steelmaking and continuous casting process according to claim 5, characterized in that: The cooling water flow rate of the spray device satisfies the following formula: W = s × v × ρ × δ, where W is the cooling water flow rate of the spray device, s is the cross-sectional area of ​​the billet, v is the billet drawing speed, ρ is the billet density, and δ is the specific water content.

8. The high-quality steelmaking and continuous casting process according to claim 5, characterized in that: The protective slag includes: 25% to 45% CaO, 20% to 50% SiO2, 0% to 10% Al2O3, 1% to 20% Na2O, and 2% to 5% graphite.

9. The high-quality steelmaking and continuous casting process according to claim 8, characterized in that: When the molten steel is OCr18NI9 stainless steel, the ratio of CaO / SiO2 in the protective slag is between 0.9 and 1.

1.

10. The high-quality steelmaking and continuous casting process according to claim 8, characterized in that: When the molten steel is high aluminum steel with an Al content of 0.5% to 3.5%, the protective slag includes: 15% to 40% CaO, 3% to 15% SiO2, and 10% to 20% Al2O3.

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