Perforated efficient crystallizer copper pipe

Abstract

The utility model discloses an opening type efficient crystallizer copper pipe, and relates to the technical field of metallurgical steel, an inner cavity of the crystallizer copper pipe adopts double parabola conicity, namely, the angle conicity and the face conicity both adopt parabola forms, the angle adopts small conicity, and the reverse conicity is 0.9%-1.1%; the face part adopts a large taper, the reverse taper is 1.5%-2.0%, and the cooling strength of the corner part and the face part of the steel billet is controlled to be uniform and consistent through two taper curves; the angle R of the inner cavity of the crystallizer copper pipe is 8-15 degrees, so that deviation angle cracks and longitudinal recesses of the steel billet are avoided; the length of the crystallizer copper pipe is 1000 mm-1200 mm, a plurality of rows of holes are evenly machined in the upper portion and the lower portion of the 1 / 3 surface of the lower portion of the crystallizer copper pipe, each row of holes are evenly distributed at intervals, the two sides of each row of holes are arranged at the corner tangency point positions of the crystallizer copper pipe, the adjacent upper row of holes and the lower row of holes are mutually staggered, and the center of the lower row of holes is the center of the position where the adjacent upper row of holes are not provided with holes. The total hole opening area accounts for 30%-40% of the surface area of the hole opening position; according to the utility model, steel billets can be prevented from being separated and bleed out due to thin billet shells after being discharged out of the crystallizer.

Description

Technical Field

[0001] The utility model relates to the technical field of metallurgical iron and steel, and particularly relates to an open-hole type high-efficiency mold copper tube. Background Art

[0002] In the current continuous casting high drawing speed transformation in the metallurgical industry, mainly grooves are cut on the outer surface of the mold copper tube and holes are drilled in the middle of the wall thickness. The purpose is to thin the wall thickness of the local mold copper tube matrix. Thinning the mold copper tube matrix enables faster heat transfer, rapid growth of the billet shell inside the mold copper tube, increased billet shell thickness, and improved drawing speed. However, when using high drawing speed grooved and drilled mold copper tubes, breakage and leakage of molten steel often occur. Especially when only the mold and secondary cooling are transformed, quality accidents and billet quality problems are more likely to occur. High-efficiency continuous casting means achieving high drawing speed on the premise of ensuring product quality. The higher the drawing speed, the greater the output. Therefore, if the processability and worker operation are not good, it is difficult to meet the requirements. For example, after the drawing speed of a 165x165 continuous casting billet reaches 4 m / min, the billet shell thickness after the billet exits the mold must reach 10 - 12 mm or more. Otherwise, the billet shell is difficult to withstand the hydrostatic pressure and straightening force of the molten steel, resulting in breakage and leakage of molten steel. Content of the Utility Model

[0003] In view of the above technical problems, the utility model provides an open-hole type high-efficiency mold copper tube. The inner cavity of the mold copper tube adopts a double parabolic taper, that is, both the corner taper and the face taper adopt a parabolic form. The corner uses a small taper, and the reverse taper is 0.9% - 1.1% to reduce the wear of the mold copper tube and reduce the billet drawing resistance. The face uses a large taper, and the reverse taper is 1.5% - 2.0%. By two taper curves, the cooling intensity of the billet at the corner and the face of the billet is made uniform, avoiding continuous casting defects such as corner longitudinal cracks, corner cracks, square deviation, and large billet drawing resistance of the billet. The R angle of the inner cavity of the mold copper tube is 8° - 15° to avoid corner cracks and longitudinal depressions of the billet. The length of the mold copper tube is 1000 mm - 1200 mm. On the surface of the lower 1 / 3 of the mold copper tube, multiple rows of holes are evenly processed up and down. Each row of holes is evenly spaced. The two sides of each row of holes are set at the tangent point positions of the corners of the mold copper tube. The adjacent upper and lower rows of holes are staggered. The center of the lower row of holes is the center of the position where there is no hole in the adjacent upper row. The total opening area accounts for 30% - 40% of the surface area of the opening position.

[0004] Furthermore, the hardness HB of the mold copper tube ≥ 90. The hardness of the mold copper tube can only be increased by extrusion to prevent heat deformation.

[0005] Furthermore, the inner cavity of the mold copper tube adopts a composite coating Ni + Cr - Cr, and the coating thickness is 0.1 mm - 0.13 mm to increase the coating bonding force and improve the wear resistance of the coating.

[0006] Furthermore, the material of the crystallizer copper tube is silver copper or chromium zirconium copper to increase the recrystallization temperature and prevent high-temperature deformation.

[0007] Furthermore, the thickness of the crystallizer copper tube is 8-10% of the crystallizer copper tube specification.

[0008] The beneficial effects of the present utility model compared with the prior art are as follows: (1) By lengthening the crystallizer copper tube, the opening part of the assembled crystallizer copper tube is outside the crystallizer, replacing the foot roll device, and avoiding square deviation and steel leakage of the billet due to the thin billet shell after the billet exits the crystallizer; (2) By evenly processing multiple rows of holes on the surface of the lower 1 / 3 of the crystallizer copper tube up and down, the billet exiting the crystallizer can be effectively cooled strongly at the opening position and the billet shell can be protected. The cooling water is directly injected into the billet surface through the openings at the lower end of the crystallizer copper tube, realizing front cooling, greatly increasing the cooling intensity of the billet, increasing the billet shell thickness, and at the same time protecting the primary billet shell to further protect the billet shell shape and increase the billet shell growth thickness in the lengthened part, realizing efficient continuous casting and solving the problems of square deviation and steel leakage due to the thin billet shell; (3) Through the two taper curves in the inner cavity of the crystallizer copper tube, the present utility model can control the cooling intensity of the billet at the corner and face of the billet to be uniform, avoiding continuous casting defects such as longitudinal corner crack, corner crack, square deviation, and large drawing resistance of the billet. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the structure of the crystallizer copper tube of the present utility model Figure 1 。

[0010] Figure 2 For the present utility model Figure 1 Cross-sectional view along the M-M direction in

[0011] Figure 3 For the present utility model Figure 1 Cross-sectional view along the K-K direction in

[0012] Figure 4 For the present utility model Figure 1 Cross-sectional view along the W-W direction in

[0013] Figure 5 Schematic diagram of the structure of the crystallizer copper tube of the present utility model Figure 2 。

[0014] Figure 6 Schematic diagram of the cooling process of the crystallizer assembly of the present utility model.

[0015] Figure 7 For the present utility model Figure 6 Cross-sectional view along the A-A direction in

[0016] Figure 8For the present utility model Figure 6 is a sectional view along the B-B direction in the present utility model.

[0017] Reference numerals in the drawings: 1 - crystallizer water outlet annular cavity; 2 - crystallizer water jacket; 3 - crystallizer water inlet annular cavity; 4 - crystallizer water inlet pipe; 5 - perforated copper tube water inlet pipe; 6 - spray ring; 7 - crystallizer water outlet pipe; 8 - perforated copper tube spray riser; 9 - nozzle. Specific embodiments

[0018] The present utility model will be further described below in conjunction with specific embodiments. The schematic embodiments and descriptions of this utility model are used to explain the present utility model, but do not limit the present utility model.

[0019] Embodiment: As Figures 1 - 5 shown: The present utility model proposes a perforated high-efficiency crystallizer copper tube. The inner cavity of the crystallizer copper tube adopts a double-parabola taper, that is, both the corner taper and the face taper adopt a parabolic form. The corner part adopts a small taper, and the reverse taper is 0.9% - 1.1% to reduce the wear of the crystallizer copper tube and reduce the billet drawing resistance; the face part adopts a large taper, and the reverse taper is 1.5% - 2.0%. The cooling intensity of the billet corner and face is controlled uniformly by two taper curves to avoid continuous casting defects such as corner longitudinal cracks, corner cracks, square-off, and large billet drawing resistance of the billet; the R angle of the inner cavity of the crystallizer copper tube is 8° - 15° to avoid corner cracks and longitudinal depressions of the billet; the length of the crystallizer copper tube is 1000 mm - 1200 mm. Multiple rows of holes are evenly machined on the surface of the lower 1 / 3 of the crystallizer copper tube. Each row of holes is evenly spaced. The two sides of each row of holes are set at the tangent point positions of the corners of the crystallizer copper tube. The adjacent upper and lower rows of holes are staggered. The center of the lower row of holes is the center of the position where there is no hole in the adjacent upper row. The total area of the holes accounts for 30% - 40% of the surface area of the hole-opening position.

[0020] The hardness HB of the crystallizer copper tube ≥ 90. The hardness of the crystallizer copper tube can only be increased by extrusion to prevent thermal deformation; the inner cavity of the crystallizer copper tube adopts a composite coating Ni + Cr - Cr, and the coating thickness is 0.1 mm - 0.13 mm to increase the coating bonding force and improve the wear resistance of the coating; the material of the crystallizer copper tube adopts silver copper or chromium zirconium copper to increase the recrystallization temperature and prevent high-temperature deformation; the thickness of the crystallizer copper tube is 8 - 10% of the crystallizer copper tube specification, and generally the lower limit is selected. The purpose is that the thin wall of the crystallizer copper tube has fast heat transfer.

[0021] In this embodiment, taking the example of evenly machining multiple rows of long strip holes on the surface of the lower 1 / 3 of the crystallizer copper tube for illustration, as Figures 1 - 5 shown:

[0022] For the existing mold copper tubes with a length of 700 - 900 mm, problems such as steel leakage, square deviation, and low drawing speed often occur. The mold copper tubes are lengthened to 1000 - 1200 mm (lengthened according to the actual position), and holes are drilled in the lengthened part to enhance cooling and increase the drawing speed.

[0023] The upper half of the mold copper tube is the main area for forming the billet shell. When the steel billet reaches the grooved position, the billet shell has already formed a certain thickness and can fully bear the hydrostatic pressure of the molten steel. Therefore, the lower 1 / 3 position of the mold copper tube is selected for grooving to directly cool the steel billet, enabling the billet shell to grow rapidly. After the steel billet exits the mold, the billet shell reaches the required thickness, and the steel billet will not bulge or deform, thus enabling a high drawing speed. Processing long strip holes increases the cooling area and enhances the cooling area of the billet shell. Horizontally opening long strip holes is to maintain the strength of the mold copper tube matrix. The external chamfer of the long strip holes is mainly to ensure that the sprayed atomized water fully hits the surface of the steel billet for cooling. At the same time, the wall thickness of the mold copper tube is thinned to strengthen the cooling. The distance between the holes should be as small as possible, but the strength of the mold copper tube must be ensured. The positions between the upper and lower rows are evenly arranged, and the cooling gradually weakens from the middle to both sides. The two sides of each row of holes must be at the tangent point positions of the corners of the mold copper tube, and the internal R of the corners is not allowed to be occupied.

[0024] Produce mold copper tubes with a length of 1000 - 1200 mm according to the specifications by normal processes, and machine installation positioning grooves. The upper part of the mold copper tube ensures that the molten steel solidifies into a billet shell and reaches a certain strength, while the lower part enhances the cooling intensity to achieve a high drawing speed. Take 1 / 3 of the distance from the lower part of the mold copper tube and machine long strip holes on the surface, leaving a 1 - mm installation positioning distance at the lower end. The total area of the long strip holes accounts for 30 - 40% of the surface area of the hole - opening position. The specific hole - opening requirements are as follows: The long strip holes are all horizontal. The upper and lower rows of holes are cross - designed, and the hole size is determined according to the left - right distance. The intervals can be the same or different. The length a of the long strip hole is not more than 50 mm; the width b is not more than 10 mm; the two ends of the long strip hole are rounded with R. The distance between the upper and lower long strip holes is 2 times the hole width b. Design the number of long strip holes according to the tangent length distance at the corners. It can be evenly distributed or not, but the middle one must be the longest and symmetrically distributed left and right. The upper and lower arrangements of the long strip holes must be staggered. The center of the second row of holes must be at the center of the position where the upper row has no holes. With one less long strip hole, the area of the middle holes can be maximized, the areas on both sides are small, and the large - area cooling is strong. The outer side of the long strip hole is an open hole, forming an angle β with the reference hole edge line. The outer open hole mainly ensures that the cooling water can fully spray into the long strip hole for strong cooling. For the round - billet mold copper tube, the holes in the upper and lower rows are only staggered from each other, and the number of holes is the same.

[0025] During cooling, such as Figures 6 - 8As shown: The lower part of the mold copper tube is designed with transverse cooling holes, and the external cooling water is directly sprayed onto the surface of the billet and the mold copper tube, achieving zero-distance rapid cooling of the billet to increase the thickness of the billet shell, enhance the strength of the billet, increase the drawing speed, and increase the output. The perforated high-efficiency mold copper tube is installed on the mold assembly. The upper part of the mold assembly uses a circulating cooling water structure to form the billet shell, and the lower part uses a spraying method for direct cooling.

[0026] The upper part of the mold copper tube is cooled inside the mold to ensure the normal formation of the billet shell. The water flow enters the mold water inlet ring cavity 3 from the mold water inlet pipe 4 along the F direction, enters the water gap between the mold copper tube and the mold water jacket 2 through the gap at the lower end of the mold water jacket 2, and flows into the mold water outlet ring cavity 1 from the gap at the upper end of the mold water jacket 2; the cooling water forms a high flow rate between the water gaps, flows from the mold water outlet ring cavity 1 into the mold water outlet pipe 7, and then into the recovery pipeline, realizing the cooling process of the billet shell inside the mold.

[0027] The opening at the lower part of the mold copper tube replaces the supporting and guiding functions of the foot rolls, and directly uses the holes in the mold copper tube to improve the cooling of the billet and protect the re-growth of the billet shell. Through the holes, the cooling intensity of the billet can be more effectively increased and the problems of square billet breakout and leakage can be avoided, realizing the rapid cooling process at a high drawing speed. The cooling water enters the spray ring 6 from the H direction along the perforated copper tube water inlet pipe 5. The spray ring 6 uses a high cooling intensity, and the water ratio is greater than 3L / Kg. It flows from the spray ring 6 into the perforated copper tube spray riser 8. A plurality of nozzles 9 are evenly spaced on the perforated copper tube spray riser 8. The nozzles 9 directly inject the atomized cooling water directly into the billet through the holes in the mold copper tube, achieving rapid strong cooling, increasing the cooling of the billet shell, and at the same time cooling the matrix of the mold copper tube.

Claims

1. Open-hole high-efficiency crystallizer copper tube, characterized in that: The inner cavity of the crystallizer copper tube adopts a double parabolic taper, that is, the corner taper and the face taper are both in the form of a parabola, the corner adopts a small taper, and the inverted taper is 0.9%-1.1% to reduce the wear of the crystallizer copper tube and reduce the resistance to billet drawing; the face adopts a large taper, and the inverted taper is 1.5%~2.0%, and the cooling strength of the billet corner and face is controlled to be uniform and consistent through two taper curves; the R angle of the inner cavity of the crystallizer copper tube is 8°-15° to avoid angular cracks and longitudinal depressions of the billet; the length of the crystallizer copper tube is 1000mm-1200mm, and multiple rows of holes are evenly processed on the upper and lower surfaces of the lower 1 / 3 of the surface of the crystallizer copper tube, each row of holes is evenly spaced, and the two sides of each row of holes are arranged at the tangent point of the corner of the crystallizer copper tube, and the adjacent upper and lower rows of holes are staggered, and the center of the lower row of holes is the center of the position where the adjacent upper row has no holes, and the total area of ​​the holes accounts for 30%~40% of the surface area of ​​the hole position.

2. The open-hole high-efficiency crystallizer copper tube according to claim 1, characterized in that: The hardness of the crystallizer copper tube is HB≥90, and the hardness of the crystallizer copper tube can only be increased by extrusion to prevent thermal deformation.

3. The open-hole high-efficiency crystallizer copper tube according to claim 1, characterized in that: The inner cavity of the crystallizer copper tube adopts a composite coating of Ni+Cr-Cr with a coating thickness of 0.1mm-0.13mm to increase the coating bonding strength and improve the coating wear resistance.

4. The open-hole high-efficiency crystallizer copper tube according to claim 1, characterized in that: The copper tube of the crystallizer is made of silver copper or chromium zirconium copper to increase the recrystallization temperature and prevent high-temperature deformation.

5. The open-hole high-efficiency crystallizer copper tube according to claim 1, characterized in that: The thickness of the crystallizer copper tube is 8-10% of the specification of the crystallizer copper tube.

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