A kind of inner fillet slow cooling crystallizer copper mould device

Abstract

The application provides a kind of inner fillet slow cooling crystallizer copper mould device, relates to crystallizer copper mould technical field, including copper mould body, the inner cavity cross section of copper mould body is square, four corners are respectively provided with inner fillet, inner fillet and square straight edge are provided with bevel transition section between, bevel transition section is connected inner fillet and straight edge respectively.The included angle between bevel transition section and straight edge presents decreasing trend from the upper end surface of copper mould body to the direction of lower end surface, and the vertical length of bevel transition section remains consistent at each cross section.Bevel transition section and straight edge are provided with thickness electroplating layer on the surface of the inner cavity of the copper mould body.The application effectively reduces the corner taper of the crystallizer copper mould by the design of bevel transition section structure and gradually decreasing included angle, reduces the friction between the inner fillet and the shell, meets the characteristics of slow shrinkage of high-quality steel, improves the corner crack defects of the casting blank;At the same time, the thickened electroplating layer significantly improves the wear resistance of the copper mould, prolongs the service life.

Description

Technical Field

[0001] This invention mainly relates to the field of copper mold technology for crystallizers, and specifically to a copper mold device for a slow-cooling crystallizer with rounded inner corners. Background Technology

[0002] This invention relates to the field of continuous casting technology for steel billets, and specifically to a copper mold device for a slow-cooling crystallizer with rounded corners used in the continuous casting production of special steel.

[0003] The copper mold is a core component of continuous casting equipment. After high-temperature molten steel is injected into the mold's cavity, it cools externally to form a solid billet shell. The mold taper is one of the key parameters in mold design, directly affecting the billet shell quality and casting speed. An ideal mold taper should accommodate the shrinkage of the solidified shell, ensuring close contact between the billet shell and the mold without interference. The taper of a square billet mold typically includes a face taper and corner tapers. In ordinary molds, the inner radius of the copper mold remains consistent across all sections along the height direction. The corner taper is determined by the face taper and is approximately 1.414 times the face taper.

[0004] With the transformation and upgrading of the steel industry from general to high-quality and from high-quality to special-grade steels, the output of high-quality and special-grade steels such as spring steel 60Si2Mn and bearing steel GCr15 has continued to increase. When producing these steels, the molten steel needs to cool and shrink slowly within the crystallizer, especially at the corners of the continuously cast billet, where a particularly good slow cooling effect is required. However, the corner taper of existing crystallizer copper molds is generally too large. For high-quality and special-grade steels with smaller shrinkage, an excessively large corner taper will increase the cooling intensity at the corners of the billet shell and accelerate corner shrinkage, making it difficult for the protective slag to enter for lubrication. Excessive friction between the inner rounded corners of the copper mold and the corners of the billet shell causes defects such as dents or cracks at the corners of the continuously cast billet. At the same time, severe wear of the corner plating directly affects the service life of the crystallizer copper mold. Summary of the Invention

[0005] 1. The technical problem that the invention aims to solve: The present invention provides a copper mold device for a slow cooling crystallizer with rounded inner corners, which solves the technical problems existing in the background art.

[0006] 2. Technical Solution: To achieve the above objectives, the technical solution provided by the present invention is as follows: a copper mold device for a slow-cooling crystallizer with rounded inner corners, comprising a copper mold body, wherein the copper mold body has an inner cavity, the cross-section of the inner cavity is square, and the four corners of the square are respectively provided with inner corner radius R. X The inner fillet R X A beveled transition section is provided between the straight edge of the square and the beveled transition section, which connects to the inner fillet R. X And the straight edge.

[0007] Furthermore, the hypotenuse transition segment and the straight side have an included angle θ. X The included angle θ X The diameter of the copper mold body decreases from the upper end to the lower end.

[0008] Furthermore, the vertical length of the inclined transition section remains consistent across all cross-sections.

[0009] Furthermore, the inner surface of the copper mold body is provided with an electroplated layer, the thickness of which is greater than 0.2 mm.

[0010] Furthermore, the electroplated layer is made of a nickel-cobalt alloy layer and a chromium layer.

[0011] Furthermore, the copper mold body is provided with a facial taper H along the height direction. X The facial taper H X The size of the copper mold body gradually decreases from the upper end face to the lower end face.

[0012] Furthermore, the facial taper H X It includes a facial taper in the length direction and a facial taper in the width direction, wherein the facial taper in the length direction is equal to the facial taper in the width direction.

[0013] Furthermore, the corner taper of the area where the inner rounded corner is located is 1.414 times smaller than the facial taper of the area where the square straight edge is located.

[0014] Furthermore, the area where the inner rounded corner is located includes a apex corner portion and a side corner portion, and the side corner portion includes at least a first side corner area and a second side corner area; the distribution taper of the first side corner area is smaller than the distribution taper of the apex corner portion, the distribution taper of the apex corner portion is smaller than or equal to the distribution taper of the second side corner area, and the distribution taper of the second side corner area is not greater than the facial distribution taper of the area where the straight edge is located.

[0015] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this invention has the following advantages: This invention is rationally designed. By increasing the inner corner radius and adding a beveled transition section, it effectively increases the corner wall thickness and thermal resistance, slowing down the cooling intensity of the corner of the continuously cast billet. Simultaneously, it reduces the overall taper of the corner, significantly decreasing the friction between the copper mold and the billet shell. This adapts to the slow shrinkage characteristics of the special steel and significantly improves corner crack defects. The beveled transition section also expands the slow cooling coverage of the inner corner, ensuring good slow cooling effects for both the apex and edge corners. The taper distribution in each region satisfies CX < eX ≤ DX ≤ aX, achieving gradient slow cooling at the corners and improving cooling uniformity.

[0016] The increased thickness of the electroplating layer, utilizing the high hardness and low thermal conductivity of the nickel-cobalt alloy and chromium layer, significantly improves the wear resistance of the inner cavity of the copper mold, further increases thermal resistance, and enhances the slow cooling effect, thus significantly extending the service life of the copper mold. Moreover, only the structure of the copper mold needs to be modified, and no other parts need to be invested, making it easy to promote and apply.

[0017] It should be noted that the structures not described in this invention are not related to the design points and improvement directions of this invention, and are the same as or can be implemented using existing technologies, so they will not be elaborated here. Attached Figure Description

[0018] Figure 1 This is a side view of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of the copper mold body at any height according to the present invention; Figure 3 This is a top view of the inner wall surface of the copper mold of the present invention; Figure 4 For the present invention Figure 3 Enlarged schematic diagram of the structure at point I; Figure 5 This is an enlarged schematic diagram of the top corner portion structure of the present invention; Figure 6 This is an enlarged schematic diagram of the structure at the intersection of the apex corner portion and the first side corner region of the present invention; Figure 7 This is an enlarged schematic diagram of the structure at the intersection of the hypotenuse transition segment and the straight segment of the present invention; Figure 8 Schematic diagram of the structure for producing 160 square spring steel 60Si2Mn continuous casting billets using ordinary crystallizer copper molds. Figure 9 A schematic diagram of the structure for producing 160 cubic meter spring steel 60Si2Mn continuous casting billets for this application. Figure 10 Schematic diagram of the internal structure of 160 square spring steel 60Si2Mn continuous casting billet produced by ordinary crystallizer copper mold. Figure 11 A schematic diagram of the internal structure of a 160 cubic meter spring steel 60Si2Mn continuous casting billet produced for this application.

[0019] Figure label: 1. Copper mold body; 2. Straight edge; 3. Beveled transition section; 4. Top corner part; 5. First corner area; 6. Second corner area; 7. Electroplating layer. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more complete description of the invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., 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 this 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 limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," "provided with," and "located in" 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 according to the specific circumstances.

[0024] It should be noted that structures not described in this invention do not involve the design points and improvement directions of this invention, and can all be achieved using existing technologies known to those skilled in the art.

[0025] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0026] See attached document Figure 1-11 This embodiment uses a 160 square crystallizer copper mold as an example for illustration, but the present invention is not limited to the 160 square specification and is also applicable to square billet crystallizer copper molds of other cross-sectional sizes.

[0027] This embodiment provides a copper mold device for a slow-cooling crystallizer with rounded inner corners, including a copper mold body 1. The copper mold body 1 has an inner cavity with a square cross-section. The total height of the copper mold body 1 is 900mm, and the dimensions of the inner cavity are designed and measured every 100mm along the height direction.

[0028] The four corners of the inner cavity of the copper mold body 1 are respectively provided with inner rounded corners, and the radius value R of the inner rounded corners is... X The height of the copper mold body 1 is consistently 8mm. A beveled transition section 3 is provided between the inner rounded corner and the square straight edge 2, connecting both the inner rounded corner and the straight edge 2. That is, in each cross-section, the arc surface of the inner rounded corner is not directly connected to the straight edge 2 through the point of tangency, but first connected to a beveled transition section 3. The end of this beveled transition section 3 then connects to the straight edge 2, thereby increasing the copper mold wall thickness at the inner rounded corner to 14.32mm, compared to R... X When the inner radius is 4mm, the wall thickness increases significantly to 12.24mm.

[0029] The vertical length of the inclined transition section 3 remains consistent across all cross-sections of the copper mold body 1; in this embodiment, it is set to 28 mm. The inclined transition section 3 and the straight side 2 form an angle θ. X The included angle gradually decreases from the upper end face of the copper mold body 1 towards the lower end face. Specifically, at a distance of X = 0 mm from the upper end face, the included angle θ0 = 1.402°; at X = 100 mm, the included angle θ 100 = 1.336°; at X = 200mm, the included angle θ 200 = 1.054°; at X = 300mm, the included angle θ 300 =0.860°; at X = 400mm, the included angle θ 400 =0.654°; at X = 500mm, the included angle θ 500 =0.466°; at X = 600mm, the included angle θ 600 =0.314°; at X = 700mm, the included angle θ 700 =0.189°; at X = 800mm, the included angle θ 800 =0.064°; at X = 900mm, the included angle θ 900 =0°.

[0030] An electroplated layer 7 is provided on the inner surface of the copper mold body 1. The electroplated layer 7 is made of a nickel-cobalt alloy layer and a chromium layer, that is, a nickel-cobalt alloy underlayer is first electroplated on the inner surface of the copper mold, and then a chromium surface layer is electroplated on top of the nickel-cobalt alloy layer. The total thickness of the electroplated layer 7 is greater than 0.2 mm, and in this embodiment, it is preferably 0.5 mm. The hardness of the nickel-cobalt alloy in the plating layer is about 300 Hv, which is equivalent to about 285 HB in Brinell hardness, and the hardness of the chromium layer is about 800 Hv, while the hardness of the copper mold body 1 material is only 85-100 HB; the thermal conductivity of the nickel-cobalt alloy is 85-87 W / (m·K), the thermal conductivity of the chromium layer is 87-89 W / (m·K), and the thermal conductivity of the copper mold body 1 material is 370-380 W / (m·K). Therefore, the hardness of the electroplated layer 7 is much higher than that of the copper mold body 1, and the wear resistance is significantly improved; at the same time, the thermal conductivity of the electroplated layer 7 is much lower than that of the copper mold body 1, and it has a good heat insulation effect.

[0031] The copper mold body 1 has a face taper H along the height direction. X Facial taper H X The taper of the face gradually decreases from the upper end face to the lower end face of the copper mold body 1. X This includes the facial taper in the length direction and the facial taper in the width direction, with the length direction facial taper being equal to the width direction facial taper. Specifically, at a distance X from the upper end face, the length dimension is denoted as A. X The width dimension is denoted as B. X And A X =B X Facial taper H X =A X -A 900 =B X -B 900 At X = 0, A0 = B0 = 165.600 mm; at X = 900, A 900 =B 900 =163.500mm. Total facial taper H0 = 165.600 - 163.500 = 2.100mm. Facial distribution taper a X This represents the change in facial taper per 100mm along the height of the copper mold. Specifically, the taper distribution 'a' within the 0-100mm range. 100 =H0-H 100 =2.100 - 1.960 = 0.140 mm; the distribution taper a in the 100-200 mm range 200 =H 100 -H 200 =1.960 - 1.461 = 0.499 mm; the distribution taper a in the 200-300 mm range 300 =H 200 -H 300=1.461 - 1.055 = 0.406 mm; the distribution taper a in the 300-400 mm range. 400 =H 300 -H 400 =1.055 - 0.734 = 0.321 mm; the distribution taper a in the 400-500 mm range 500 =H 400 -H 500 =0.734 - 0.493 = 0.241 mm; the distribution taper a in the 500-600 mm range 600 =H 500 -H 600 =0.493 - 0.311 = 0.182 mm; the distribution taper a in the 600-700 mm range 700 =H 600 -H 700 =0.311 - 0.171 = 0.140 mm; the distribution taper a in the 700-800 mm range 800 =H 700 -H 800 =0.171 - 0.053 = 0.118 mm; the distribution taper a in the 800-900 mm range 900 =H 800 -H 900 =0.053-0=0.053mm.

[0032] The longest diagonal distance on each cross section is denoted as E. X In this embodiment, the corner taper of the area containing the inner rounded corner is less than 1.414 times the facial taper of the area containing the square straight edge 2. Specifically, the total corner taper F X =E X -E 900 At X=0, E0=226.208mm, E 900 =224.597mm, the total taper of the corner F0 = 226.208 - 224.597 = 1.611mm. The total taper of the face H0 = 2.100mm, H0 × 1.414 = 2.969mm, obviously 1.611mm < 2.969mm.

[0033] The area containing the inner rounded corner includes the vertex portion 4 and the side corner portion. The side corner portion is the area where the hypotenuse transition segment 3 is located, and the side corner portion further includes the first side corner area 5 and the second side corner area 6. The vertex portion 4 is the area where the inner rounded corner arc surface is located; the first side corner area 5 is the half of the hypotenuse transition segment 3 closest to the vertex portion 4; the second side corner area 6 is the half of the hypotenuse transition segment 3 closest to the straight side 2. The taper of the vertex portion 4 is denoted as e. X The taper of the first corner region 5 is denoted as C. X CX From the unilateral contraction value c X Multiply by 2 to get the taper of the second corner region 6, denoted as D. X D X From the unilateral contraction value d X Multiply by 2 to get the facial tapering of the region containing straight edge 2, denoted as a. X On each cross-section of the copper mold body 1, the distribution taper C of the first corner area 5 is... X The distribution taper e is less than the apex portion 4. X The distribution taper e of the apex portion 4 X The distribution taper D of the second corner region 6 is less than or equal to 6. X And the distribution taper D of the second corner region 6 X The facial distribution taper a in the region where the straight side 2 is located is not greater than 2. X That is, the relationship C is satisfied between the various distribution tapers. X <e X ≤D X ≤a X Specifically, in this embodiment, the total taper F0 of the apex portion 4 is 1.611 mm, and the distributed taper e of the apex portion 4 is... 100 =F0-F 100 =1.611-1.476=0.135mm,e 200 =F 100 -F 200 =1.476-1.040=0.436mm,e 300 =F 200 -F 300 =1.040-0.652=0.388mm,e 400 =F 300 -F 400 =0.652-0.398=0.254mm,e 500 =F 400 -F 500 =0.398-0.240=0.158mm, e 600 =F 500 -F 600 =0.240-0.131=0.109mm,e 700 =F 600 -F 700 =0.131-0.055=0.076mm,e 800 =F 700 -F 800 =0.055-0.011=0.044mm,e 900 =F 800 -F 900 =0.011-0=0.011mm.

[0034] First corner area 5 distribution taper C 100 =0.098mm, C 200 =0.316mm, C 300 =0.280mm, C 400 =0.182mm, C 500 =0.114mm, C 600 =0.078mm, C 700 =0.054mm, C 800 =0.032mm, C 900 =0.008mm. The taper DX of the second corner area is equal to the taper aX of the face, that is, D100 = a100 = 0.140mm, D200 = a200 = 0.499mm, D300 = a300 = 0.406mm, D400 = a400 = 0.321mm, D500 = a500 = 0.241mm, D600 = a600 = 0.182mm, D700 = a700 = 0.140mm, D800 = a800 = 0.118mm, D900 = a900 = 0.053mm. Therefore, C X The relationship <eX < aX = DX holds true on all cross sections.

[0035] In this embodiment, the inner rounded corner slow-cooling crystallizer copper mold device is used such that molten steel is injected from above into the inner cavity of the copper mold body 1. Cooling water enters from the lower cavity of the outer shell into the 4mm water gap between the water guide kit and the copper mold body 1, flowing at high speed from bottom to top across the outer wall of the copper mold body 1, carrying away heat. The high-temperature molten steel gradually cools in the inner cavity of the copper mold body 1 to form a solid shell, with the shell thickness gradually increasing from top to bottom. Because the inner rounded corner radius is increased to R in this embodiment... X =8mm, the copper mold wall thickness at the inner rounded corners increased to 14.32mm, compared to R X With an inner radius of 4mm, the wall thickness increases significantly to 12.24mm, leading to increased thermal resistance and reduced cooling intensity in the corner area. Simultaneously, the electroplating layer 7, at 0.5mm thickness, significantly exceeds the conventional 0.2mm thickness, further mitigating heat transfer from the corner of the blank to the copper mold body 1 due to its insulating effect. Because of the beveled transition section 3, the total corner taper in this embodiment is only 1.611mm, far less than the 2.969mm corner taper of a typical crystallizer copper mold. Furthermore, the distribution taper C of the first corner area 5... X This is the minimum value across all regions, significantly reducing the friction between the inner rounded corner area and the corner of the billet shell. Please refer to [reference needed]. Figures 8-11 When using this embodiment to produce special alloy steels such as spring steel 60Si2Mn or bearing steel GCr15, no dents or cracks appeared at the corners of the continuously cast billets, and the surface quality was good.

[0036] In actual production, when producing spring steel 60Si2Mn using a conventional crystallizer copper mold, obvious cracks appear at the corners of the continuously cast billets. With a steel throughput of only 2000 tons, the wear height of the electroplated layer 7 inside the inner rounded corner reaches 320 mm. However, when using the inner rounded corner slow-cooling crystallizer copper mold device of this embodiment to produce the same steel grade, no cracks appear at the corners of the continuously cast billets. With a steel throughput of 5000 tons, the wear height of the electroplated layer 7 inside the inner rounded corner is only 110 mm, significantly extending the service life of the copper mold.

[0037] The above-described embodiments are merely illustrative of certain implementations of the present invention, and are described in a relatively specific and detailed manner. However, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A copper mold device for a slow-cooling crystallizer with rounded inner corners, characterized in that: The application relates to a copper mold body (1) having an inner cavity, the cross section of the inner cavity being square, four corners of the square being respectively provided with inner fillets R X , and a bevel transition section (3) being arranged between the inner fillets R X and the straight side (2) of the square, the bevel transition section (3) connecting the inner fillets R X and the straight side (2) respectively.

2. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 1, characterized in that: The bevel transition section (3) has an included angle θ with the straight edge (2) X , the included angle θ X Decreases from the upper end surface to the lower end surface of the copper mold body (1).

3. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 1, characterized in that: The vertical length of the inclined transition section (3) remains consistent at each cross section.

4. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 1, characterized in that: The inner surface of the copper mold body (1) is provided with an electroplated layer (7), the thickness of which is greater than 0.2 mm.

5. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 4, characterized in that: The electroplated layer (7) is made of a nickel-cobalt alloy layer and a chromium layer.

6. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 1, characterized in that: The copper mold body (1) is provided with a face taper H in the height direction X , the face taper H X gradually decreases from the upper end surface to the lower end surface of the copper mold body (1).

7. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 6, characterized in that: The facial taper H X It includes a facial taper in the length direction and a facial taper in the width direction, wherein the facial taper in the length direction is equal to the facial taper in the width direction.

8. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 6, characterized in that: The corner taper of the area where the inner rounded corner is located is 1.414 times smaller than the facial taper of the area where the square straight edge (2) is located.

9. The copper mold device for a slow-cooling crystallizer with rounded inner corners according to claim 8, characterized in that: The area where the inner rounded corner is located includes a top corner portion (4) and a side corner portion. The side corner portion includes at least a first side corner area (5) and a second side corner area (6). The distribution taper of the first side corner area (5) is smaller than the distribution taper of the top corner portion (4). The distribution taper of the top corner portion (4) is smaller than or equal to the distribution taper of the second side corner area (6). The distribution taper of the second side corner area (6) is not greater than the facial distribution taper of the area where the straight edge (2) is located.

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