A thin slab continuous casting mold copper plate with a cooling structure

Abstract

The application provides a thin slab continuous casting crystallizer copper plate with a cooling structure and relates to the technical field of metallurgical continuous casting. In the two flat parts of the cooling surface, each flat part includes high-temperature zone flow guide cooling ribs, transition zone flow guide cooling ribs and low-temperature zone flow guide cooling ribs between the two adjacent cooling zones, and the height and width of the high-temperature zone flow guide cooling ribs are smaller than the height and width of the transition zone flow guide cooling ribs and the height and width of the low-temperature zone flow guide cooling ribs; the cooling water groove includes high-temperature zone cooling water grooves, transition zone cooling water grooves and low-temperature zone cooling water grooves, and the width of the high-temperature zone cooling water grooves is larger than the width of the transition zone cooling water grooves and the width of the low-temperature zone cooling water grooves. Through the optimized design of the high-temperature zone, the cooling capacity of the copper plate is improved, the temperature of the hot surface of the eddy current zone with high heat flux density is reduced, the occurrence of the copper plate crack phenomenon is improved or completely eliminated, and the service life of the copper plate is prolonged.

Description

Technical Field

[0001] This invention relates to the field of metallurgical continuous casting technology, and more specifically, to a thin slab continuous casting crystallizer copper plate with a cooling structure. Background Technology

[0002] The continuous casting crystallizer is where molten steel begins to form a primary billet shell, with the shell thickness gradually increasing. The rationality of the crystallizer's copper plate cooling structure design directly affects the service life of the copper plates, the quality of the cast iron, and the operating rate of the continuous casting machine. From bottom to top, the continuous casting crystallizer consists of a low-temperature zone, a transition zone, and a high-temperature zone. Along the width of the cooling surface, the middle section is a straight section or funnel-shaped section, with straight sections on both sides. With the development and popularization of high-efficiency continuous casting technology, the continuous casting crystallizer, as the "heart" of the continuous casting machine, is receiving increasing attention. Related technicians are constantly exploring advanced technologies to improve the heat transfer conditions of the crystallizer's copper plates. Especially when molten steel is injected into the crystallizer, a high-temperature vortex region easily forms in the upper part of the straight sections on both sides of the pouring pipe. This region has a high heat flux density, resulting in high surface temperatures on the copper plates at this location, making them prone to cracking. How to reduce surface cracks on the copper plates and extend the service life of the crystallizer has become a focus of attention in the continuous casting industry.

[0003] Designing an efficient and uniform cooling structure for the crystallizer copper plate to avoid excessively high local temperatures or large temperature gradients, which could lead to thermal stress concentration and cracks in the crystallizer copper plate, in order to meet the requirements of high drawing speed, has become an urgent problem for technicians to solve.

[0004] Patent document CN107116186B discloses an ultra-thin slab crystallizer copper plate with a composite cooling structure. The plate includes a main body with a working surface on the front and a cooling surface on the back. Multiple cooling water tanks are arranged on the lower part of the back surface, specifically in the meniscus region. Multiple cooling water holes are also arranged on the back surface, specifically in the meniscus region. The centerlines of the cooling water holes are parallel to the front surface of the copper plate, and the centerlines of the cooling water holes and the cooling water channels are equidistant from the front surface. A transverse groove connecting the cooling water holes and the cooling water tanks is provided at the junction of the cooling water holes and the cooling water tanks. The number of cooling water holes exceeds the number of cooling water tanks, and the cooling water holes are evenly spaced. This design satisfies the requirement of easy machining of the cooling water tanks while avoiding uneven cooling of molten steel in the meniscus region and the initial slab shell region.

[0005] However, in practical applications, in cooling structures with a full water tank or a water tank plus water holes, the copper plate has severe cracks in the straight section within 90-120mm downwards from the top edge and 320-460mm from the edge to the center, which is the high-temperature zone and the location of the reinforcing ribs where the pins are located, thus affecting the service life of the copper plate.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a thin slab continuous casting crystallizer copper plate with a cooling structure, thereby improving or completely eliminating copper plate cracking and extending the service life of the copper plate.

[0008] This invention is implemented as follows:

[0009] This invention provides a thin slab continuous casting crystallizer copper plate with a cooling structure, comprising a copper plate body with a working surface on the front and a cooling surface on the back. Along the flow direction of the coolant on the cooling surface, from bottom to top, there are a low-temperature zone, a transition zone, and a high-temperature zone. In the width direction of the cooling surface, the middle part of the cooling surface is a straight section or a funnel section, and the two sides are straight sections. The periphery of the cooling surface is a sealing surface. Several pin bolt holes connected to a water supply container are arranged in rows on the sealing surface. Each row of pin bolt holes is connected by reinforcing ribs, and the reinforcing ribs are at the same height as the sealing surface. Each pair of adjacent rows of pin bolt holes is a relatively independent cooling zone. Multiple flow guiding cooling ribs are set in each cooling zone, dividing each cooling zone into multiple cooling water tanks.

[0010] On both sides of the straight section of the cooling surface, the two adjacent cooling zones on each side of the straight section include a high-temperature zone cooling fin, a transition zone cooling fin, and a low-temperature zone cooling fin. The height and width of the high-temperature zone cooling fin are smaller than the height and width of the transition zone cooling fin, and the height and width of the high-temperature zone cooling fin are smaller than the height and width of the low-temperature zone cooling fin.

[0011] The cooling water tank includes a high-temperature zone cooling water tank, a transition zone cooling water tank, and a low-temperature zone cooling water tank. The width of the high-temperature zone cooling water tank is greater than the width of the transition zone cooling water tank, and the width of the high-temperature zone cooling water tank is greater than the width of the low-temperature zone cooling water tank.

[0012] Through long-term practice and exploration, the inventors discovered that by optimizing the design of the high-temperature region where molten steel is injected into the crystallizer to form a vortex, the copper plate can maintain a high heat exchange efficiency in the region with high heat flux density, thereby improving the cooling capacity of the copper plate, reducing the hot surface temperature of the vortex region with high heat flux density, and thus helping to improve or completely eliminate the occurrence of copper plate cracks, while extending the service life of the copper plate.

[0013] Specifically, by widening the cooling water tanks in the high-temperature zones of the straight sections on both sides, the contact area between the copper plate and the coolant is increased, improving the cooling efficiency of the copper plate and enhancing its cooling matching capacity in this area. This effectively prevents localized overheating and cracking of the copper plate caused by excessive local heat flux density and high hot surface temperature due to the eddy currents of the continuously cast molten steel. In a true sense, the cooling capacity of the copper plate is better matched with the heat load, and the phenomenon of copper plate cracking disappears or is reduced, thereby improving the service life of the crystallizer copper plate.

[0014] In a preferred embodiment of the present invention, the height and width of the cooling fins in the transition zone decrease from the low temperature zone to the high temperature zone, and the depth of the cooling water tank in the transition zone decreases from deep to shallow.

[0015] The gradient arrangement of the cooling fins and cooling water tank in the transition zone helps to match the heat flux density of the copper plate in the transition zone with the corresponding cooling capacity requirements, and also helps to reduce the stress on the copper plate, thereby avoiding cracking and improving the service life of the crystallizer copper plate.

[0016] The height and width of the cooling fins and the depth of the cooling water tank gradually change from the transition zone. That is, the cooling water tank in the transition zone forms an "eight" shape towards the high temperature zone, and the corresponding cooling fins form an "eight" shape towards the low temperature zone. This makes the water flow cross-section change smoothly, which can effectively avoid drastic temperature changes on the hot surface of the copper plate in the crystallizer, prevent stress concentration on the copper plate in the crystallizer, and prevent copper plate cracks from occurring.

[0017] In one alternative embodiment, the cooling ribs in the transition zone and the high-temperature zone are milled. Milling is performed from the sealing surface towards the working surface, so that the height and width of the cooling ribs in the transition zone gradually decrease from the low-temperature zone to the high-temperature zone, reaching their minimum in the high-temperature zone.

[0018] The depth of the cooling water tank in the transition zone gradually decreases from the low temperature zone to the high temperature zone. From the perspective of the cooling surface, as the cooling water tank in the transition zone develops from the low temperature zone to the high temperature zone, the width of the transition cross section gradually expands in a figure-eight shape. The corresponding transition zone guide cooling fins also expand in a figure-eight shape as they develop from the high temperature zone to the low temperature zone.

[0019] In a preferred embodiment of the present invention, in the high-temperature zone of the straight portion, a diversion boss is provided around the periphery of the bolt hole, and the diversion boss is provided on one or both sides of the reinforcing rib.

[0020] The diversion boss serves to divert the flow, preventing excessively high local flow density and making the flow more uniform.

[0021] In a preferred embodiment of the present invention, the flow-dividing boss and the bolt hole are not on the same horizontal line, and the flow-dividing boss sandwiched between the two cooling zones is at the same height as the high-temperature zone guide cooling rib.

[0022] In a preferred embodiment of the present invention, a flow-dividing cooling groove is provided between the bolt hole and the flow-dividing boss, and the flow-dividing cooling groove reduces the thickness of the reinforcing rib.

[0023] In a preferred embodiment of the present invention, the diversion cooling tank is a diversion flower water tank.

[0024] The design of the diversion water tank effectively enhances the cooling capacity of the reinforcing ribs in the straight section of the high-temperature zone, eliminating the hot surface cracking phenomenon in this area and improving the service life of the crystallizer copper plate.

[0025] In a preferred embodiment of the present invention, a fixing screw hole is provided on the diversion boss.

[0026] In a preferred embodiment of the present invention, a cover plate matching the cooling zone is provided in the high-temperature zone and transition zone of the flat section, and the cover plate is fixed to the fixing screw hole by a fastener.

[0027] In a preferred embodiment of the present invention, the fastener includes, but is not limited to, screws, bolts, or bolt blocks.

[0028] In a preferred embodiment of the present invention, the cross-sectional area of ​​the channel space formed by the cover plate and the high-temperature cooling water tank is S1, and the cross-sectional area of ​​the channel space formed by the cover plate and the low-temperature cooling water tank is S2, where S1:S2 = 0.8-1:1.

[0029] The inventors discovered that within the above ratio range, although the spatial cross-sectional area is reduced, the effective heat exchange cross-sectional area increases, and it helps to increase the flow rate of water in the high-temperature zone water tank, thereby increasing the heat exchange capacity.

[0030] In an alternative implementation, the ratio is 0.8:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, 0.86:1, 0.87:1, 0.88:1, 0.89:1, 0.9:1, 0.91:1, 0.92:1, 0.93:1, 0.94:1, 0.95:1, 0.96:1, 0.97:1, 0.98:1, or 0.99:1.

[0031] In a preferred embodiment, the ratio is 0.85-0.95:1.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] This invention optimizes the design of the high-temperature region where molten steel is injected into the crystallizer to form a vortex, thereby enabling the copper plate to maintain a high heat exchange efficiency in the region with high heat flux density. This improves the cooling capacity of the copper plate, reduces the hot surface temperature of the vortex region with high heat flux density, and thus helps to improve or completely eliminate the occurrence of copper plate cracks, while extending the service life of the copper plate.

[0034] Furthermore, this invention only adjusts the depth and layout of the water tank, while the position and depth of the bolt holes and the position and depth of the thermocouples remain unchanged. The back plate and the overall assembly structure remain unchanged. For steel companies, the existing back plate can be fully utilized without the need to purchase new ones, which helps to save costs. In addition, the continuous casting process parameters do not need to be significantly adjusted, which has good application prospects. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the overall structure of the copper plate cooling structure of the crystallizer after the cover plate is added, according to an embodiment of the present invention.

[0037] Figure 2 This is a partial schematic diagram of the copper plate cooling structure of the crystallizer in an embodiment of the present invention without a cover plate;

[0038] Figure 3 This is a schematic cross-sectional view of the copper plate of the crystallizer according to an embodiment of the present invention;

[0039] Figure 4 This is a partial longitudinal section schematic diagram of the water tank structure according to an embodiment of the present invention;

[0040] Figure 5 This is a partial longitudinal cross-sectional schematic diagram of the flow-guiding cooling fins changing from the low-temperature zone to the high-temperature zone in an embodiment of the present invention.

[0041] Icons: 1-Sealing surface; 2-Cooling water tank; 3-Pin bolt hole; 4-Reinforcing rib; 41-Thinning reinforcing rib; 5-Guiding cooling rib; 51-High temperature zone guiding cooling rib; 52-Transition zone guiding cooling rib; 53-Low temperature zone guiding cooling rib; 6-Cover plate; 7-Diffusion boss; 8-Fixing bolt hole; 9-Cooling water tank a; 91-High temperature zone cooling water tank a; 92-Transition zone cooling water tank a; 93-Low temperature zone cooling water tank a; 10-Working surface; 11-Cooling surface; 12-Diffusion water tank; L-Coolant flow direction. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. These terms are used only for the convenience of describing the invention and for 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 limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Example 1

[0049] Please see Figure 1 and Figure 2 As shown, this embodiment provides a thin slab continuous casting mold copper plate with a cooling structure. It includes a mold copper plate body with a working surface 10 on the front and a cooling surface 11 on the back.

[0050] Along the coolant flow direction L on the cooling surface 11, from bottom to top, the zones are low temperature zone, transition zone, and high temperature zone, according to the heating conditions.

[0051] Typically, the high-temperature zone refers to the area from the first horizontal row of bolts at the top of the copper plate to within 200mm of the top of the copper plate, such as 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, or any value in between. The transition zone refers to the area from the lower end of the high-temperature zone to 300mm ± 50mm from the top of the copper plate; the low-temperature zone refers to the area below the transition zone.

[0052] In the width direction of the cooling surface 11, the middle part is a straight section or a funnel section, and the two sides are straight sections. Figure 1 The copper plate shown in the crystallizer is a funnel-shaped copper plate, that is, the middle part is a funnel and the two sides are straight parts.

[0053] The cooling surface 11 is surrounded by a sealing surface 1. Several pin bolt holes 3 connected to the water tank are arranged in a row in the sealing surface 1. Each row of pin bolt holes 3 is connected by a reinforcing rib 4. The reinforcing rib 4 is at the same height as the sealing surface 1. Each pair of adjacent rows of pin bolt holes 3 is a relatively independent cooling zone. Multiple flow guiding cooling ribs 5 are set in each cooling zone to divide the corresponding multiple cooling water tanks 2.

[0054] The two adjacent cooling zones on each side of the straight section include a high-temperature zone cooling rib 51, a transition zone cooling rib 52, and a low-temperature zone cooling rib 53.

[0055] The cooling water tank 2 includes a high-temperature zone cooling water tank 2, a transition zone cooling water tank 2, and a low-temperature zone cooling water tank 2.

[0056] In this embodiment, Figure 2 and Figure 5 As shown, in the high-temperature zone of the flat section on both sides, in the four adjacent cooling zones on each side, the height and width of the high-temperature zone guiding cooling rib 51 are less than the height and width of the corresponding transition zone guiding cooling rib 52 and the low-temperature zone guiding cooling rib 53. The width of the high-temperature zone cooling water tank a91 is greater than the width of its corresponding transition zone cooling water tank a92 and the low-temperature zone cooling water tank a93.

[0057] In the straight sections on both sides, the height and width of the cooling ribs 52 in the transition zone decrease from the low temperature zone to the high temperature zone, and the depth of the cooling water tank 2 in the transition zone changes from deep to shallow.

[0058] In this embodiment, the transition zone cooling rib 52 and the high-temperature zone cooling rib 51 are manufactured by milling. Specifically, milling is performed from the sealing surface 1 towards the working surface, so that the height and width of the transition zone cooling rib 52 gradually decrease as it progresses from the low-temperature zone to the high-temperature zone, reaching their minimum in the high-temperature zone; and the depth of the transition zone cooling water tank a92 gradually decreases as it progresses from the low-temperature zone to the high-temperature zone. From the cooling surface, the width transition section of the transition zone cooling water tank a92 gradually expands in a figure-eight shape as it progresses from the low-temperature zone to the high-temperature zone, and the corresponding transition zone cooling rib 52 expands in a figure-eight shape as it progresses from the high-temperature zone to the low-temperature zone.

[0059] In the high-temperature zone of the flat sections on both sides, a diversion boss 7 is provided on one or both sides of the reinforcing rib 4 around the periphery of the bolt hole 3. The diversion boss 7 and the bolt hole 3 are not on the same horizontal line. A diversion cooling groove, also known as a diversion flower water groove 12, is provided between the bolt hole 3 and the diversion boss 7. The diversion flower water groove 12 reduces the thickness of the reinforcing rib 4 (i.e., reduces the thickness of the reinforcing rib 41) and forms a smooth diversion flower water groove 12. The diversion boss 7 sandwiched between the two cooling zones is at the same height as the corresponding high-temperature zone guiding cooling rib 51. A fixing screw hole 8 is provided on the diversion boss 7.

[0060] like Figure 1 , Figure 3 , Figure 4 As shown, in the high-temperature zone of the flat sections on both sides, a cover plate 6 matching the cooling zone is installed and fixed to the fixing screw hole 8 with screws.

[0061] In a preferred embodiment, such as Figure 2 and Figure 4 As shown, in the straight sections on both sides, from the low-temperature zone to the high-temperature zone, the width of some cooling fins 5 decreases from 10.2mm to 3mm, and the width of others decreases from 16mm to 4mm. The width of the cooling water tank 2 increases from 6mm to 16mm, and the height of the tank gradually decreases from 25mm in the low-temperature zone to 9mm in the high-temperature zone. According to this scheme, the cross-sectional area of ​​the cooling water tank a9 in the high-temperature zone is reduced by 12% compared to the low-temperature zone, and the flow velocity increases from 12.85m / s to 14.4m / s in the straight sections on both sides.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A copper plate of thin slab continuous casting crystallizer with cooling structure, comprising a copper plate body with a working face as a front face and a cooling face as a back face, wherein along the flow direction of coolant, from bottom to top, the cooling face is sequentially provided with a low temperature zone, a transition zone and a high temperature zone, in the width direction of the cooling face, the middle of the cooling face is a flat portion or a funnel portion, both sides of the cooling face are flat portions, and the periphery of the cooling face is a sealing face, a plurality of pin bolt holes connected with water supply containers are arranged in rows on the sealing face, each row of pin bolt holes is connected by a reinforcing rib, the reinforcing rib is at the same height as the sealing face, each adjacent two rows of pin bolt holes are a relatively independent cooling interval, a plurality of flow guide cooling ribs are arranged in each cooling interval to divide each cooling interval into a plurality of cooling water grooves, characterized in that, in the flat portion on both sides of the cooling face, the immediately adjacent two cooling intervals on each side of the flat portion comprise high temperature zone flow guide cooling ribs, transition zone flow guide cooling ribs and low temperature zone flow guide cooling ribs, and the height and width of the high temperature zone flow guide cooling ribs are smaller than the height and width of the transition zone flow guide cooling ribs, and the height and width of the high temperature zone flow guide cooling ribs are smaller than the height and width of the low temperature zone flow guide cooling ribs; the cooling water grooves comprise high temperature zone cooling water grooves, transition zone cooling water grooves and low temperature zone cooling water grooves, the width of the high temperature zone cooling water grooves is greater than the width of the transition zone cooling water grooves, and the width of the high temperature zone cooling water grooves is greater than the width of the low temperature zone cooling water grooves. Along the direction from the low temperature zone to the high temperature zone, the height and width of the transition zone flow guide cooling ribs decrease, and the depth of the transition zone cooling water grooves changes from deep to shallow. In the high temperature zone of the flat portion, a flow distribution boss is arranged around the periphery of the pin bolt hole, and the flow distribution boss is arranged on one side or both sides of the reinforcing rib.

2. The thin slab continuous casting mold copper plate with a cooling structure according to claim 1, characterized by, The flow distribution boss is not at the same horizontal line as the pin bolt hole, and the flow distribution boss and the high temperature zone flow guide cooling rib are at the same height.

3. The thin slab continuous casting mold copper plate with a cooling structure according to claim 1 or 2, characterized in that, A flow distribution cooling groove is arranged between the pin bolt hole and the flow distribution boss, and the thickness of the reinforcing rib is reduced.

4. The thin slab continuous casting mold copper plate with a cooling structure according to claim 3, characterized by, A fixing hole is arranged on the flow distribution boss.

5. The thin slab continuous casting mold copper plate with a cooling structure according to claim 4, characterized by, In the high temperature zone and the transition zone of the flat portion, a cover plate matched with the cooling interval is further arranged.

6. The thin slab continuous casting mold copper plate with a cooling structure according to claim 5, characterized by, The cover plate is fixed on the fixing hole by a fixing member.

7. The thin slab continuous casting mold copper plate with a cooling structure according to claim 6, characterized by, The fixing member is a screw, a screw rod or a screw block.

8. The thin slab continuous casting mold copper plate with a cooling structure according to claim 7, characterized by, The cross-sectional area of the channel space formed by the cover plate and the high temperature zone cooling water groove is S1, the cross-sectional area of the channel space formed by the cover plate and the low temperature zone cooling water groove is S2, and S1:S2 = 0.8-1:

1.

9. The thin slab continuous casting mold copper plate with cooling structure according to claim 8, characterized by, ​ 10. The thin slab continuous casting mold copper plate with cooling structure according to claim 8, characterized by, ​

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