A quick-change cold material frame and a method for controlling the quality of a casting blank in quick-change operation
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHU XINXING DUCTILE IRON PIPES
- Filing Date
- 2022-12-21
- Publication Date
- 2026-07-21
Smart Images
Figure CN115805296B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of continuous casting technology, specifically relating to a quick-change cold material frame and a method for controlling the quality of cast billets during quick-change operations. Background Technology
[0002] With the increasing demand for production, it is necessary and essential to develop towards continuous production to meet the stability and continuity of continuous casting production. Continuous casting quick changeover needs to shorten changeover time, increase the success rate, ensure billet quality, and improve production efficiency. Existing technologies mainly focus on how to improve the efficiency of quick changeover operations in the tundish during continuous casting production and ensure the success rate of quick changeover operations. Current tundish quick changeover technologies lack methods for controlling the quality of the center of large-section billets and reducing the contamination of molten steel in the liquid core area caused by the settling of cold material during quick changeover operations. Furthermore, currently, during continuous casting quick changeover, the solidification rate is slow after the cold material frame is placed, prolonging the quick changeover time; placing solidified cold material also makes it easy for the cold material to slide down the liquid core, thus affecting the internal quality and composition of the billet.
[0003] A search revealed that Chinese invention patent CN200910262105, published on June 9, 2010, discloses a quick-change tool for continuous production of large billets in continuous casting. This tool is a quick-change cold material basket, where the height dimension of the basket is greater than its horizontal dimension. The basket includes a horizontally positioned upper opening (2), a central hoop (5), and a lower bottom (3), as well as a main core (4) positioned along the vertical direction. Multiple main cores (4) constitute the main structure of the basket's frame, and the frame is made of reinforcing steel. However, this patent does not effectively address the aforementioned technical problems and cannot completely resolve them. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a simple and easy-to-use quick-change cold slug frame. The invention also provides a simple and convenient method for controlling billet quality during quick-change operations. By fabricating an integral cold slug frame, the invention avoids the impact of cold slug settling on the center quality of the billet, reduces waste during quick-change operations, and improves billet yield. While ensuring quick-change efficiency and improving the success rate, the invention solves the related technical problems existing in tundish quick-change operations in the prior art.
[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a quick-change cold material frame, wherein the quick-change cold material frame is an integral cold material frame, including a frame body, a steel plate, a support and wire rods, the steel plate is disposed in the middle of the frame body, the support is disposed in the upper part of the frame body above the steel plate, the steel plate and the support are both welded to the frame body, and the wire rods are connected to the support.
[0006] Furthermore, the steel plate divides the frame into upper and lower layers, and the steel plate is provided with U-shaped through grooves. The U-shaped through grooves are evenly distributed along the circumference of the steel plate, and the upper and lower layers of the frame are connected through the U-shaped through grooves.
[0007] Furthermore, the bracket has a "well" shaped structure, and the bracket is welded from threaded steel bars. Adjacent threaded steel bars are welded to each other, and the two ends of the threaded steel bars are welded to the frame.
[0008] Furthermore, the upper diameter of the frame is larger than the lower diameter of the frame. The frame is welded from threaded steel bars and shaped wire rods. The top and bottom of the frame are provided with shaped wire rods, and the threaded steel bars are welded evenly on the shaped wire rods at intervals.
[0009] Furthermore, the wire rod is a cooling wire rod used for cooling, and the wire rod is spring-shaped, folded, or hook-shaped, and the wire rod is welded to the support.
[0010] Furthermore, the upper end of the frame is provided with a handle, which is symmetrically arranged at the upper diameter of the frame and welded to the threaded steel of the frame.
[0011] This invention also relates to a method for controlling the quality of cast billets in a quick changeover operation. Based on the aforementioned quick changeover cold slub frame, the equipment used in the method for controlling the quality of cast billets in the quick changeover operation includes a ladle, a tundish, a crystallizer, and a cold slub frame. The control method includes: a. Preparatory work before quick changeover: During the final pouring of the ladle in the production scheduling, the tundish speed is reduced at the end of the pouring process; after the ladle pouring is completed, the tundish pouring is carried out at 0.1 m / min, and pouring is stopped when the liquid level in the tundish is not lower than 400 mm, and the quick changeover operation is carried out; and the amount of protective slag added is gradually reduced during the speed reduction process; b. Quick changeover operation: When the tundish pouring at the casting position is completed, the ladle baking device of the tundish to be poured is raised at the same time, and the various parameters in the main control room are finally confirmed; after the tundish is plugged, the cold slub frame is quickly placed into the crystallizer, and the cold slub frame is placed at the top of the crystallizer; after the cold slub frame solidifies, the tundish to be poured is opened to the top of the crystallizer for centering, and the tundish is lowered to the pouring position.
[0012] Furthermore, the specific operation of 'a' is as follows:
[0013] Step 1. When the steel ladle is being cast for the last time, the casting speed of the tundish is reduced at the end of the casting process. When the steel ladle has 20-30 tons of steel remaining after the last heat of steel is cast, the casting speed of the tundish is reduced. After the speed is reduced to 0.02 m / min lower than the standard casting speed of the process card, the speed reduction of the tundish is stopped until the steel ladle is finished.
[0014] Step 2. After the ladle pouring is completed, the tundish continues to reduce the casting speed by 0.02m per minute until the casting speed is reduced to 0.1m / min. Continue pouring for 3-7 minutes, and stop pouring when the liquid level in the tundish is not lower than 400mm. Then, perform a quick changeover operation.
[0015] Step 3. During the process of reducing the pulling speed, gradually reduce the amount of protective slag added to the crystallizer to ensure that the slag surface inside the crystallizer is slightly reddish and the slag layer thickness is reduced from 35-40mm to 10-15mm before quick replacement.
[0016] Step 4. Temperature measurement of the continuous casting ladle. The superheat of the molten steel in the ladle is controlled at 80-90℃ to ensure the fluidity of the molten steel and avoid excessive temperature in the tundish.
[0017] Furthermore, the specific operation of b is as follows:
[0018] Step 1. When the casting of the tundish at the casting position is completed, the ladle baking device of the tundish at the casting position is raised to ensure that the baking temperature of the tundish is ≥1100℃.
[0019] Step 2. The main control room makes a final confirmation of various parameters, adjusts the M-EMS parameter from 200A / 2Hz to 100A / 2Hz, adjusts the F-EMS parameter from 200A / 5Hz to 150A / 5Hz, and lowers the electromagnetic stirring intensity to reduce the impact on the fast solidification operation while ensuring uniform composition and temperature.
[0020] Step 3. After plugging the tundish eye, pull the billet to a position approximately 295-305mm from the top of the crystallizer. This depth facilitates the addition of the cold slug frame and ensures optimal connection between the billets from the upper and lower furnaces.
[0021] Step 4. When the ladle leaves the casting area, insert the preheated cold slug frame through the support oxygen pipe, and quickly place the cold slug frame at the top of the crystallizer. The quick-change cold slug frame must be placed upright and must not be tilted. Wait for the cold slug frame to solidify. Do not add any cold slug while waiting for the cold slug frame to solidify. The support oxygen pipe is placed at the top of the crystallizer to support the cold slug frame.
[0022] Step 5. After the cold material frame solidifies, remove the oxygen support pipe and pull the billet to a position 500mm away from the top of the crystallizer to reserve space for pouring molten steel for the next batch; when stopping pouring, stop the casting speed first, and then stop the crystallizer vibration to achieve better billet shelling;
[0023] Step 6. Sprinkle 1 kg of iron oxide scale on the edge of the billet shell to improve the solidification effect in the edge area and at the same time improve the shell removal effect in the crystallizer after quick change operation;
[0024] Step 7. Move the tundish to the top of the crystallizer for alignment, ensuring the casing is in the center of the crystallizer, and then lower the tundish to the pouring position.
[0025] Furthermore, since the cold slug frame serves as the medium for connecting the upper and lower ladles of molten steel, the selection of the cold slug frame must be for an integral type with a partition in the middle, and its manufacturing process must meet the standardized requirements for the manufacture of quick-change cold slug frames in continuous casting:
[0026] a. Use wire rods to pre-fabricate the upper and lower diameters of the cold material frame on the model; after prefabrication, manually adjust the final dimensions;
[0027] b. Place the rebar on a cutting machine and cut it to the required length;
[0028] c. The steel plate is a circular partition, the diameter of the steel plate is 420mm, and the length of the U-shaped through groove on the steel plate is 155±2mm and the width is 15±2mm;
[0029] d. At the lower diameter, the rebar is evenly distributed according to the lower diameter with a distribution gap of 20-25mm; at the upper diameter, the rebar is evenly distributed according to the upper diameter with a distribution gap of 30-35mm.
[0030] e. Weld a support frame with threaded steel to the center of the cold material frame, and weld wire rods onto the support frame. The wire rods need to be made into spring shape, folded shape or barb shape. The weight of the wire rods used is 20-30kg.
[0031] The advantages of using the technical solution of this invention are:
[0032] 1. This invention avoids the impact of cold material sinking on the center quality of the billet by making an integral cold material frame, reduces the amount of waste thrown during the quick change operation, and improves the billet yield. Under the premise of ensuring quick change efficiency and improving quick change success rate, it solves the relevant technical problems existing in the quick change operation of the tundish in the prior art.
[0033] 2. This invention mainly includes the control of the casting process before quick changeover, the fabrication of the cold material frame during quick changeover, and the control of process parameters during quick changeover. By adopting the above process, the quality of the billet center can be controlled. By using an integral cold material frame, the "floating" process of the cold material in the liquid core of the billet is avoided, reducing the impact of uncertainty on the quality of the billet core, improving the quality of the billet product, and reducing the waste length of the single-flow tail billet from 10m to 5m, thereby increasing the tail furnace capacity by 44 tons (calculated based on a reduction of 5 meters of tail billet per flow for 4 flows, the tail furnace of 600mm round billets can reduce waste by 44 tons). Standardized operation requirements, combined with the cold material frame, achieve a 100% success rate in quick changeover operations. By using iron oxide scale to improve the demolding effect between the billet shell and the crystallizer, the wear of the inner wall of the crystallizer is reduced, and the appearance quality of the billet is improved, thus achieving stable control of the production process and quality during the quick changeover of large round billets. Attached Figure Description
[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:
[0035] Figure 1 This is a front view schematic diagram of the quick-change cold material frame of the present invention;
[0036] Figure 2 This is a top view of the quick-change cold material frame of the present invention;
[0037] Figure 3 This is a side view of the quick-change cold material frame of the present invention.
[0038] The markings in the above figure are as follows: 1. Frame; 11. Threaded steel bar; 12. Shaped wire rod; 2. Steel plate; 21. U-shaped through groove; 3. Support; 5. Wire rod I; 6. Handle. Detailed Implementation
[0039] In this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "planar direction," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.
[0040] like Figure 1 As shown, a quick-change cold slug frame is an integral cold slug frame, comprising a frame body 1, a steel plate 2, a support 3, and wire rods 5. The steel plate 2 is located in the middle of the frame body 1, and the support 3 is located on the upper part of the frame body 1 above the steel plate 2. Both the steel plate 2 and the support 3 are welded to the frame body 1, and the wire rods 5 are connected to the support 3. This invention, by manufacturing an integral cold slug frame, avoids the impact of cold slug settling on the center quality of the cast billet, reduces the amount of waste thrown during the quick-change operation, and improves the yield of the cast billet. While ensuring quick-change efficiency and improving the success rate of quick-change, it solves the related technical problems existing in the quick-change operation of the tundish in the prior art.
[0041] Steel plate 2 divides frame 1 into upper and lower layers. U-shaped through grooves 21 are provided on steel plate 2. The U-shaped through grooves 21 are evenly distributed along the circumference of steel plate 2. The upper and lower layers of frame 1 are connected through the U-shaped through grooves 21. Support 3 has a "well" shaped structure. Support 3 is welded from threaded steel bars. Adjacent threaded steel bars are welded to each other, and the two ends of the threaded steel bars are welded to frame 1.
[0042] The upper diameter of frame 1 is larger than the lower diameter of frame 1. Frame 1 is welded from threaded steel bars 11 and shaped wire rods 12. Shaped wire rods 12 are provided on both the top and bottom of frame 1. The threaded steel bars 11 are welded evenly at intervals onto the shaped wire rods 12. Wire rods 5 are cooling wire rods used for cooling. Wire rods 5 are spring-shaped, folded, or hook-shaped, and are welded to the support 3. In this invention, cooling wire rods and shaped wire rods are essentially the same type of wire rod, used in different places for different functions. The distinction between "shaped" and "cooling" is to indicate their respective functions in different applications and to differentiate between the two types of wire rods, avoiding the use of the same name.
[0043] To facilitate the handling of cold material frames, handles 6 are provided at the upper end of the frame 1. The handles 6 are symmetrically arranged at the upper diameter of the frame 1 and are welded to the threaded steel 11 of the frame 1.
[0044] Based on the aforementioned quick-change cold charge frame, this invention also relates to a method for controlling the quality of cast billets in quick-change operations. The equipment used in this method includes a ladle, tundish, crystallizer, and cold charge frame. The ladle, as a molten steel container, is used to receive molten steel and perform casting operations before the electric furnace or converter. The tundish is a refractory material container that first receives the molten steel poured from the ladle, and then distributes it to various crystallizers through the tundish nozzle. The crystallizer is a continuous casting equipment that receives the molten steel poured from the tundish and solidifies it into a solid billet shell according to a specified cross-sectional shape. This method for controlling the quality of cast billets in quick-change operations is primarily designed for casting methods using ladles, tundishes, and crystallizers. The control method mainly includes: a. Preparatory work before quick changeover: When the steel ladle is being cast for the last time during the production schedule, the tundish speed is reduced at the end of the casting process; after the steel ladle casting is completed, the tundish is cast at 0.1 m / min, and casting is stopped when the liquid level in the tundish is not lower than 400 mm, and quick changeover operation is carried out; and the amount of protective slag added is gradually reduced during the process of reducing the casting speed.
[0045] b. Quick changeover operation: When the casting of the tundish at the casting position is completed, the ladle baking device of the tundish at the waiting casting position is raised at the same time, and the various parameters in the main control room are finally confirmed; after the tundish is plugged, the cold material frame is quickly placed into the crystallizer and the cold material frame is placed at the top of the crystallizer; after the cold material frame solidifies, the tundish at the waiting casting position is opened to the top of the crystallizer for centering operation, and the tundish is lowered to the casting position.
[0046] a. The specific procedures for preparing for a quick change are as follows:
[0047] Step 1. During the final pouring of the steel ladle, reduce the casting speed of the tundish at the end of the casting process. When the remaining steel in the ladle is 20-30 tons, start reducing the continuous casting machine speed in the tundish. After reducing it to 0.02 m / min lower than the standard speed of the process card, stop reducing the tundish speed until the steel ladle is completely filled. For example, the normal casting speed for 45# steel is 0.28 m / min. When there are 20-30 tons of steel remaining in the ladle, reduce the speed to 0.26 m / min to reduce the liquid core length of the billet.
[0048] Step 2. After the ladle pouring is completed, the casting speed in the tundish continues to decrease by 0.02 m / min until it reaches 0.1 m / min. For example, for 45# steel, the casting speed is 0.26 m / min after the ladle pouring is completed, and it is decreased by 0.02 m / min until it reaches 0.1 m / min for further pouring. This reduces the liquid core length of the billet, providing conditions for quick billet changeover. After the casting speed is reduced to 0.1 m / min, pouring continues for 3-7 minutes, and pouring is stopped when the liquid level in the tundish is not lower than 400 mm. Quick billet changeover is then performed.
[0049] Step 3. During the production process, the protective slag plays a role in heat insulation, air isolation, prevention of secondary oxidation of molten steel, purification of the steel-slag interface, adsorption of inclusions in the molten steel, lubrication of the billet shell, and improvement of solidification heat transfer. However, the adhesion of a large amount of protective slag is not conducive to the bonding of the billet before and after the quick change process, which can easily lead to leakage and breakage during the quick change operation. Therefore, during the process of reducing the casting speed, the amount of protective slag added to the crystallizer is gradually reduced to ensure that the slag surface inside the crystallizer is slightly reddish, and the slag layer thickness is reduced from 35-40mm to 10-15mm before the quick change.
[0050] Step 4. Temperature measurement of the continuous casting ladle. The superheat of the molten steel in the ladle is controlled at 80-90℃ to ensure the fluidity of the molten steel and avoid excessive temperature in the tundish.
[0051] b. The specific operation of quick-change is as follows:
[0052] Step 1. When the tundish casting at the casting position is completed, simultaneously raise the ladle baking device of the tundish to be cast, ensuring that the tundish baking temperature is ≥1100℃; confirm that the sleeve suction effect is good, that is, the sleeve is red-hot and the end temperature is >800℃; confirm that the rock wool insulation wrapping effect is good, that is, the rock wool completely wraps the sleeve, reducing the heat loss of the sleeve; the stopper rod is a refractory material rod installed in the tundish that controls the opening and closing of the nozzle and the flow of molten steel by lifting and displacement. The personnel on duty need to quickly press and check the mechanism to confirm that the mechanism and the stopper rod are working properly.
[0053] Step 2. The main control room conducts a final confirmation of various parameters, adjusting the M-EMS parameters from 200A / 2Hz to 100A / 2Hz. M-EMS, or electromagnetic stirring in the crystallizer, causes the molten steel to move, which can clean the surface and subsurface of the solidified shell, removing bubbles and inclusions, thus improving the surface and subsurface quality of the billet. It also helps reduce superheat, allowing for a more appropriate increase in the superheat of the molten steel, which is beneficial for removing inclusions and improving the cleanliness of the billet. Simultaneously, it breaks up dendrites, increases equiaxed crystal nuclei, and improves the internal structure of the billet. Frequent renewal of the steel-slag interface in the crystallizer helps the protective slag absorb floating inclusions. However, excessively strong stirring parameters can easily lead to instability in the quick-change process, insufficient core cooling causing cold material to sink and contaminate the lower molten steel. Therefore, relevant process parameters need to be lowered during quick-change operations.
[0054] The F-EMS parameters were adjusted from 200A / 5Hz to 150A / 5Hz. F-EMS, or end-effector electromagnetic stirring, acts on the solidification end zone. Under the action of electromagnetic force, the moving molten steel generates electromagnetic force inside the casting, causing the unsolidified molten steel to begin rotating. The high-temperature molten steel in the center rotates around the dendrites, causing the dendrite roots to melt and fall off, becoming the solidification nuclei and making the structure denser. In addition, the mechanical force generated breaks the regrowth of dendrites, increases equiaxed crystals, and the crystal nuclei promote the convection of high-concentration molten steel through stirring, eliminating inter-crystal bridging and eliminating the uneven concentration of various components in the molten steel caused by selective crystallization. This reduces center segregation and central porosity in the casting, expands the equiaxed crystal region, eliminates V-shaped segregation in the casting, and thus improves the actual quality of the casting. However, if the F-EMS parameters are too high, it will lead to the downward movement of cold charge and instability of the core molten steel during the quick change process, which is not conducive to the control of the core quality of the billet in the previous heat before the quick change operation.
[0055] Reduce the intensity of electromagnetic stirring to minimize the impact on rapid solidification operations while ensuring uniform composition and temperature.
[0056] Step 3. After plugging the tundish, pull the billet to a distance of about 295-305mm from the top of the crystallizer; this depth facilitates the addition of the cold material frame and can achieve the best connection between the billets of the upper and lower furnaces.
[0057] Step 4. When the ladle car leaves the casting area, the heated cold material frame is quickly placed at the top of the crystallizer via the supporting oxygen pipe. This cold material frame serves as the medium for connecting the molten steel in the upper and lower ladles. The cold material frame must be an integral type with a partition in the middle, and its manufacturing process must meet the standardized requirements for continuous casting quick-change cold material frames. The central area wire rod needs to be made into a spring-like or folded shape to quickly cool the core molten steel in the crystallizer and withstand the impact of the next batch of molten steel during the quick-change operation. The weight of the wire rod should be 20-30 kg. The two sides of the wire rod need to be spot-welded to prevent detachment during the initial casting process. The quick-change cold material frame must be placed upright and not tilted. Wait for the cold material frame to solidify. During the solidification process, no cold material should be added to avoid it shifting downwards and causing inclusions in the core of the cast billet. The supporting oxygen pipe is placed at the top of the crystallizer to support the cold material frame.
[0058] Step 5. After the cold material frame solidifies, remove the supporting oxygen pipe and pull the billet to a position 500mm away from the top of the crystallizer to reduce the resistance during the quick change process and reserve space for the molten steel to be poured into the next batch. When stopping casting, stop the casting speed first and then stop the crystallizer vibration to achieve better billet shelling.
[0059] Step 6. Sprinkle 1 kg of iron oxide scale on the edge of the billet shell to improve the solidification effect in the edge area and at the same time improve the shell removal effect in the crystallizer after quick change operation;
[0060] Step 7. Move the tundish to the top of the crystallizer for alignment, ensuring the casing is in the center of the crystallizer, and then lower the tundish to the pouring position.
[0061] Step 8. The ladle is transferred from the receiving position to the pouring position to start the ladle pouring operation. The liquid level in the tundish is ≥12 tons. The pouring is organized and the order is from the edge to the center. After 10 minutes of continuous casting, the M-EMS parameters and F-EMS parameters are adjusted according to the process parameters.
[0062] As the medium connecting the upper and lower ladles of molten steel, the cold slug frame must be an integral type with a partition in the middle, and its manufacturing process must meet the standardized requirements for the manufacture of quick-change cold slug frames in continuous casting.
[0063] a. Use wire rods to pre-fabricate the upper and lower diameters of the cold material frame on the model; after prefabrication, manually adjust the final dimensions;
[0064] b. Place the rebar on a cutting machine and cut it to the required length;
[0065] c. Steel plate 2 is a circular partition, steel plate 2 has a diameter of 420mm, and the length of the U-shaped through groove 21 on steel plate 2 is 155±2mm and the width is 15±2mm;
[0066] d. At the lower diameter, the rebar is evenly distributed according to the lower diameter with a distribution gap of 20-25mm; at the upper diameter, the rebar is evenly distributed according to the upper diameter with a distribution gap of 30-35mm.
[0067] e. Weld a support 3 with threaded steel to the center of the cold material frame, and weld wire rods onto the support 3. The wire rods need to be made into spring shape, folded shape or barb shape. The weight of the wire rods used is 20-30kg.
[0068] This invention mainly includes the control of the casting process before quick changeover, the fabrication of the cold material frame during quick changeover, and the control of process parameters during quick changeover. By adopting the above process, the quality of the billet center can be controlled. By using an integral cold material frame, the "floating" process of the cold material in the liquid core of the billet is avoided, reducing the impact of uncertainty on the quality of the billet core, improving the quality of the billet product, and reducing the waste length of the single-flow tail billet from 10m to 5m, thereby increasing the tail furnace capacity by 44 tons (calculated based on a reduction of 5 meters of tail billet per flow for 4 flows, the tail furnace of 600mm round billet can reduce waste by 44 tons). Standardized operation requirements, combined with the cold material frame, achieve a 100% success rate in quick changeover operations. By using iron oxide scale to improve the demolding effect between the billet shell and the crystallizer, the wear of the inner wall of the crystallizer is reduced, and the appearance quality of the billet is improved, thus achieving stable control of the production process and quality during the quick changeover of large round billets.
[0069] This invention can be used for the fabrication and utilization of a quick-change integral cold material frame for large round billets. By controlling the M-EMS and F-EMS parameters during the casting process, the impact on core quality is reduced, and the iron oxide scale is used to improve the billet descraping effect, reduce damage to the inner wall of the crystallizer, and improve the surface quality of the billet.
[0070] Standardization of continuous casting quick-change cold material frame manufacturing
[0071] I. Material Preparation for Continuous Casting Quick-Change Cold Material Frame
[0072]
[0073] II. Requirements for the Fabrication of Quick-Change Cold Material Frames in Casting 2.
[0074] (1) Dimensional requirements of each component of the cold packing frame
[0075]
[0076]
[0077] (2) Technical requirements for cold material frame manufacturing
[0078]
[0079] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A method for controlling the quality of cast billets in a quick changeover operation, characterized in that: The equipment used in the billet quality control method of the quick change operation includes a ladle, tundish, crystallizer, and cold slug frame; the control method includes: a. Preparations before quick change: When the ladle is being cast for the last time during production scheduling, the tundish speed is reduced at the end of the casting process; after the ladle casting is completed, the tundish is cast at 0.1 m / min, and casting is stopped when the liquid level in the tundish is not lower than 400 mm, and the quick change operation is carried out; and the amount of protective slag added is gradually reduced during the speed reduction process; b. Quick change operation: When the casting of the tundish at the casting position is completed, the ladle baking device of the tundish at the casting position is raised at the same time, and the various parameters in the main control room are finally confirmed; after the tundish is plugged, the cold slug frame is quickly placed into the crystallizer, and the cold slug frame is placed at the top of the crystallizer; after the cold slug frame solidifies, the tundish at the casting position is opened to the top of the crystallizer for centering, and the tundish is lowered to the casting position; The specific operation of 'a' is as follows: Step 1. When the steel ladle is being cast for the last time, the casting speed of the tundish is reduced at the end of the casting process. When the steel ladle has 20-30 tons of steel remaining after the last heat is cast, the casting speed of the tundish is reduced to 0.02 m / min lower than the standard casting speed of the process card. The reduction of the tundish casting speed is then stopped until the steel ladle is completely cast. Step 2. After the ladle pouring is completed, the tundish continues to reduce the casting speed by 0.02m / min until the casting speed is reduced to 0.1m / min. Continue pouring for 3-7 minutes, and stop pouring when the liquid level in the tundish is not lower than 400mm. Then, perform a quick changeover operation. Step 3. During the process of reducing the pulling speed, gradually reduce the amount of protective slag added to the crystallizer to ensure that the slag surface inside the crystallizer is slightly reddish and the slag layer thickness is reduced from 35-40mm to 10-15mm before quick replacement. Step 4. Temperature measurement of the continuous casting ladle, controlling the superheat of the molten steel inside the ladle at 80-90℃; The specific operation of b is as follows: Step 1. When the casting of the tundish at the casting position is completed, simultaneously lift the ladle baking device of the tundish at the casting position to ensure that the tundish baking temperature is ≥1100℃; Step 2. The main control room makes a final confirmation of various parameters, adjusts the M-EMS parameter from 200A / 2Hz to 100A / 2Hz, adjusts the F-EMS parameter from 200A / 5Hz to 150A / 5Hz, and lowers the electromagnetic stirring intensity. Step 3. After plugging the tundish eye, pull the billet to a position 295-305mm from the top of the crystallizer; Step 4. When the ladle car leaves the casting area, it passes through the oxygen support pipe into the baked cold material frame and quickly places the cold material frame on the top of the crystallizer. The quick-change cold material frame must be placed upright and must not be tilted. Wait for the cold material frame to solidify. During the waiting period for the cold material frame to solidify, it is strictly forbidden to put in any cold material. Step 5. After the cold material frame solidifies, remove the oxygen support pipe and pull the billet to a position 500mm from the top of the crystallizer to reserve space for pouring molten steel for the next batch; when stopping pouring, first stop the casting speed, then stop the crystallizer vibration; Step 6. Sprinkle 1 kg of iron oxide scale onto the edge of the billet shell; Step 7. Move the tundish to the top of the crystallizer for alignment, ensuring the casing is in the center of the crystallizer, and then lower the tundish to the pouring position. The cold material frame is an integral cold material frame, including a frame body (1), a steel plate (2), a support (3), and wire rods (5). The steel plate (2) is located in the middle of the frame body (1), and the support (3) is located on the upper part of the frame body (1) above the steel plate (2). The steel plate (2) and the support (3) are both welded to the frame body (1), and the wire rods (5) are connected to the support (3). The steel plate (2) divides the frame body (1) into upper and lower layers. The steel plate (2) is provided with a U-shaped through groove (21), which is evenly distributed along the circumference of the steel plate (2). The upper and lower layers of the frame (1) are connected by a U-shaped through groove (21); the support (3) is a "well" shaped structure, the support (3) is welded from threaded steel bars, adjacent threaded steel bars are welded to each other, and the two ends of the threaded steel bars are welded to the frame (1); the upper diameter of the frame (1) is larger than the lower diameter of the frame (1), the frame (1) is welded from threaded steel bars (11) and shaped wire rods (12), and shaped wire rods (12) are provided on the top and the top of the frame (1), and the threaded steel bars (11) are welded evenly on the shaped wire rods (12) at intervals.
2. The method for controlling the quality of cast billets in a quick changeover operation as described in claim 1, characterized in that: The wire rod (5) is a cooling wire rod used for cooling. The wire rod (5) is spring-shaped, folded, or hook-shaped. The wire rod (5) is welded to the bracket (3).
3. The method for controlling the quality of cast billets in a quick changeover operation as described in claim 2, characterized in that: The upper end of the frame (1) is provided with a handle (6), which is symmetrically arranged at the upper diameter of the frame (1). The handle (6) is welded to the threaded steel (11) of the frame (1).
4. The method for controlling the quality of cast billets in a quick changeover operation as described in claim 1, characterized in that: The cold slug frame serves as the medium for connecting the upper and lower ladles of molten steel. The selection of the cold slug frame must be for an integral type with a partition in the middle, and its manufacturing process must comply with the standardized requirements for the manufacture of quick-change cold slug frames in continuous casting. a. Use wire rod to pre-fabricate the upper and lower diameters of the cold material frame on the model; after prefabrication, manually adjust the final dimensions; b. Place the rebar on a cutting machine and cut it to the required length; c. The steel plate (2) is a circular partition, the diameter of the steel plate (2) is 420mm, and the length of the U-shaped through groove (21) on the steel plate (2) is 155±2mm and the width is 15±2mm; d. At the lower diameter, the rebar is evenly distributed according to the lower diameter with a distribution gap of 20-25mm; at the upper diameter, the rebar is evenly distributed according to the upper diameter with a distribution gap of 30-35mm. e. Weld a support (3) with threaded steel to the center of the cold material frame, and weld wire rods on the support (3). The wire rods need to be made into spring shape, folded shape or barb shape. The weight of the wire rods used is 20-30kg.