A secondary cooling zone spraying device for a billet continuous casting machine

Abstract

The invention discloses a secondary cooling zone spraying device for a square billet continuous casting machine. By arranging full water nozzles in each spraying section of the secondary cooling zone, and setting the arrangement mode and spraying range of the nozzles in each section, the uniformity of cooling water is improved, the occurrence of cracks is effectively controlled, and the occurrence of de-squareness is also avoided. When a continuous casting machine optimized by the device is used to produce low-carbon steel, there is no obvious temperature recovery (≤150℃ / m) on the surface of the billet, which effectively reduces the corner cracks and steel leakage, prevents the billet straightening temperature from being too high to generate internal cracks, and the maximum steel drawing speed reaches 4.0m / min, and the number of steel leakage is greatly reduced. The billet straightening temperature is lower than 1030℃, the billet quality and external dimensions meet the national standard requirements, and the low-multiple quality meets the central crack, the middle crack is less than 2.0 level, and the central shrinkage cavity is less than 2.0 level. At the same time, the device uses all water nozzles, does not use compressed air, and significantly reduces the energy consumption cost.

Description

Technical Field

[0001] The invention relates to continuous casting equipment, in particular to a secondary cooling zone spraying device of a square billet continuous casting machine. Background Art

[0002] The continuous casting machine spray system is an important part of the entire system of the continuous casting machine. It determines the performance of the casting machine and the quality level of the billet to a large extent. Its main function is to spray and cool the liquid core billet out of the crystallizer to make the billet completely solidified and control the billet temperature to drop evenly along the billet drawing direction. Under high-speed production conditions, the billet continuous casting machine will reduce the billet shell thickness as the drawing speed increases, and the risk of steel leakage during the continuous casting process will increase. It is easy to have uneven cooling of the billet and the phenomenon of reheating the billet surface. At the same time, it is accompanied by low-magnification corner cracks, internal cracks, and de-squareness of the billet, which seriously affects the quality of the rolled material.

[0003] During the secondary cooling process, excessive fluctuations in the surface temperature of the billet will cause excessive thermal stress, which requires optimizing the secondary cooling water distribution to make the billet surface temperature return to ≤150℃ / m, and maintain the stability of the secondary cooling system equipment. The secondary cooling water volume, improper distribution of each section, nozzle position, spray angle, and coverage area will lead to uneven billet shell temperature, affecting the secondary cooling effect, and then affecting the uniformity of billet temperature and causing internal cracks. Summary of the invention

[0004] Purpose of the invention: In order to overcome the defects of the prior art, the present invention provides a secondary cooling zone spraying device for a billet continuous casting machine, which can effectively reduce the number of steel leaks when the billet continuous casting machine is at a high casting speed.

[0005] Technical solution: The secondary cooling zone spray device of a square billet continuous casting machine described in the present invention comprises a foot roll section spray zone, a fan-shaped zone 1, a fan-shaped zone 2 and a fan-shaped zone 3 arranged in sequence from the crystallizer downward, and the foot roll section spray zone, the fan-shaped zone 1, the fan-shaped zone 2 and the fan-shaped zone 3 are each provided with a spray pipe extending along the billet drawing direction on their four surfaces; each spray pipe of the foot roll section spray zone is provided with a flat water nozzle, and the spray range of the flat water nozzle transversely covers the middle area of ​​the billet surface; each spray pipe of the fan-shaped zone 1, the fan-shaped zone 2 and the fan-shaped zone 3 is provided with a plurality of conical water nozzles, and the spray range of each conical water nozzle transversely covers the entire billet surface; wherein, the conical water nozzles on each spray pipe of the fan-shaped zone 1 include a zone arranged from top to bottom on The conical water nozzles on each spray pipe in the sector two include an upper nozzle for the sector two and a lower nozzle for the sector two arranged from top to bottom, and the upper nozzles for the sector two are arranged at a fan-shaped central angle of 1.7°, and the lower nozzles for the sector two are arranged at a fan-shaped central angle of 1.9°; the conical water nozzles on each spray pipe in the sector three are arranged at a fan-shaped central angle of 2.2-2.8°, and the spacing angle tends to increase from top to bottom.

[0006] Among them, each spray pipe in the foot roll section spray area is provided with three flat water nozzles arranged in sequence from top to bottom, and the edge of the spray range of each flat water nozzle is not less than 10 mm away from the corner of the ingot.

[0007] Specifically, the two flat water nozzles located at the top are spaced 120 mm apart, the two flat water nozzles located at the bottom are spaced 80 mm apart, and each flat water nozzle is 70 mm away from the ingot.

[0008] Among them, each spray pipe in the fan-shaped zone is provided with 13 conical water nozzles from top to bottom, among which the 1st to 5th from top to bottom are the upper nozzles of the zone, the 6th to 8th are the middle nozzles of the zone, and the 9th to 12th are the lower nozzles of the zone.

[0009] The 5th and 6th conical water nozzles are arranged at intervals of 0.9° at the central angle of the fan circle, and the 8th and 9th conical water nozzles are arranged at intervals of 1.0° at the central angle of the fan circle.

[0010] Furthermore, each conical water nozzle in the fan-shaped zone 1 is 110 mm away from the casting.

[0011] Among them, each spray pipe of the fan-shaped second zone is provided with 11 conical water nozzles from top to bottom, among which the 2nd to 7th ones from top to bottom are the upper nozzles of the second zone, and the 8th to 11th ones are the lower nozzles of the second zone.

[0012] The 7th and 8th conical water nozzles are arranged at intervals of 1.9° at the central angle of the fan.

[0013] Furthermore, each conical water nozzle in the second sector zone is 150 mm away from the casting.

[0014] Among them, each spray pipe in the three fan-shaped zones is provided with 9 conical water nozzles from top to bottom, and each conical water nozzle is 150 mm away from the casting.

[0015] Beneficial effects: The secondary cooling zone spraying device of the square billet continuous casting machine improves the uniformity of cooling water, effectively controls the occurrence of cracks, and avoids the occurrence of de-squareness by setting full water nozzles in each spraying section of the secondary cooling zone, and setting the arrangement mode and spray range of the nozzles in each section. When using the continuous casting machine optimized by the device to produce low-carbon steel, there is no obvious temperature recovery (≤150℃ / m) on the surface of the billet, which effectively reduces the corner cracks and steel leakage, prevents the billet straightening temperature from being too high to produce internal cracks, and the maximum steel drawing speed reaches 4.0m / min, and the number of steel leakage is greatly reduced. The billet straightening temperature is lower than 1030℃, the billet quality and external dimensions meet the national standard requirements, and the low-multiple quality meets the central crack, the middle crack is less than 2.0 level, and the central shrinkage cavity is less than 2.0 level. At the same time, the device uses all water nozzles, does not use compressed air, and significantly reduces energy consumption costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a spray device in the secondary cooling zone of a square billet continuous casting machine according to the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to the accompanying drawings.

[0018] In this embodiment, the modification of the spray device is mainly based on the efficient and low-cost production of 150mm*150mm threaded steel, and the impact on the existing production quality is minimized. By optimizing the layout and nozzle selection of the secondary cooling nozzle of the small square billet, the cooling uniformity of the small square billet continuous casting machine is improved under high-speed production conditions, the surface temperature recovery and straightening temperature of the billet are reduced, and the generation of low-multiple corner cracks and internal cracks of the continuous casting billet is effectively reduced, which is conducive to improving the quality of the billet under high-speed production conditions and stabilizing the smooth production; at the same time, the full water nozzle is used to reduce the consumption of compressed air and significantly reduce costs.

[0019] like Figure 1As shown, a secondary cooling zone spraying device of a square billet continuous casting machine comprises a foot roll section spraying zone 1, a sector-shaped zone 1 2, a sector-shaped zone 2 3 and a sector-shaped zone 3 4 which are sequentially arranged downward from a crystallizer 10 .

[0020] Specifically, the four surfaces of the foot roller spray zone 1, the sector zone 1 2, the sector zone 2 3 and the sector zone 3 4 are each provided with a spray pipe 5 extending along the billet drawing direction. Three flat water nozzles 6 are provided on each spray pipe 5 of the foot roller spray zone 1, and a total of 12 flat water nozzles are provided on the four surfaces, and the model of the flat water nozzles is 1 / 4PZ12485B. Among the three flat water nozzles 6, the interval between the two nozzles located at the top is 120mm, and the interval between the two nozzles located at the bottom is 80mm, and each flat water nozzle is 70mm away from the billet. The spray range of the flat water nozzle 6 covers the middle area of ​​the billet surface laterally, and the edge of the spray range of each flat water nozzle 6 is 10mm away from the corner of the billet, which effectively avoids the occurrence of corner cracks.

[0021] Each of the spray pipes 5 of the first sector area 2, the second sector area 3 and the third sector area 4 is provided with a plurality of conical water nozzles 7, the model of which is PZ3.2-70QZ2.

[0022] Specifically, each spray pipe 5 of the sector zone 2 is provided with 13 conical water nozzles 7 from top to bottom, wherein the 1st to 5th nozzles from top to bottom are the upper nozzles of the sector, the 6th to 8th nozzles are the middle nozzles of the sector, and the 9th to 12th nozzles are the lower nozzles of the sector. The 1st to 5th nozzles are arranged at intervals of 0.8° at the sector center angle, the 5th to 8th nozzles are arranged at intervals of 0.9° at the sector center angle, and the 8th to 12th nozzles are arranged at intervals of 1.0° at the sector center angle. Figure 1 The fan shape referred to in the present invention refers to the fan shape formed by the continuous casting arc in the secondary cooling zone. Each conical water nozzle 7 in the first sector zone 2 is 110 mm away from the billet, so that the spray range of each conical water nozzle 7 covers the entire billet surface laterally.

[0023] Eleven conical water nozzles 7 are arranged from top to bottom on each spray pipe 5 of the second sector zone 3, wherein the 2nd to 7th nozzles are the upper nozzles of the second sector zone, and the 8th to 11th nozzles are the lower nozzles of the second sector zone. The 2nd to 7th nozzles are arranged at intervals of 1.7° at the central angle of the sector circle, and the 7th to 11th nozzles are arranged at intervals of 1.9° at the central angle of the sector circle. Each conical water nozzle 7 of the second sector zone 3 is 150 mm away from the ingot, so that the spray range of each conical water nozzle 7 covers the entire surface of the ingot laterally.

[0024] Each spray pipe 5 of the third sector zone 4 is provided with 9 conical water nozzles 7 arranged from top to bottom, and each conical water nozzle 7 is arranged at intervals of 2.2-2.8° at the sector center angle, and the interval angle increases from top to bottom. Each conical water nozzle 7 is 150 mm away from the ingot, so that the spray range of each conical water nozzle 7 covers the entire ingot surface laterally.

[0025] After the secondary cooling nozzle arrangement and water distribution optimization, low-carbon steel is produced without obvious temperature recovery on the surface of the ingot (≤150℃ / m), which effectively reduces corner cracks and steel leakage, prevents internal cracks caused by excessive straightening temperature of the ingot, and the maximum steel drawing speed reaches 4.0m / min.

Claims

1. A secondary cooling zone spraying device for a billet continuous casting machine, comprising a foot roll section spraying zone (1), a sector-shaped zone 1 (2), a sector-shaped zone 2 (3) and a sector-shaped zone 3 (4) arranged in sequence downward from a crystallizer (10), characterized in that: The foot roller segment spraying area (1), the first sector area (2), the second sector area (3) and the third sector area (4) are each provided with a spraying pipe (5) extending along the direction of the billet drawing on four surfaces thereof; Each spray pipe (5) of the foot roll section spray zone (1) is provided with three flat water nozzles (6) arranged in sequence from top to bottom, the edge of the spray range of each flat water nozzle (6) is not less than 10 mm away from the corner of the ingot, the two flat water nozzles (6) located at the top are spaced 120 mm apart, the two flat water nozzles (6) located at the bottom are spaced 80 mm apart, each flat water nozzle (6) is 70 mm away from the ingot, and the spray range of the flat water nozzle (6) covers the middle area of ​​the surface of the ingot laterally; Each of the spray pipes (5) of the first sector area (2), the second sector area (3) and the third sector area (4) is provided with a plurality of conical water nozzles (7), and the spray range of each conical water nozzle (7) covers the entire surface of the casting in a transverse direction; Wherein, the conical water nozzles (7) on each spray pipe (5) of the sector-shaped zone (2) include a zone-one upper nozzle, a zone-one middle nozzle and a zone-one lower nozzle arranged from top to bottom, the zone-one upper nozzles are arranged at intervals of 0.8° at the center angle of the sector circle, the zone-one middle nozzles are arranged at intervals of 0.9° at the center angle of the sector circle, and the zone-one lower nozzles are arranged at intervals of 1.0° at the center angle of the sector circle; The conical water nozzles (7) on each spray pipe (5) of the second sector (3) include a second sector upper section nozzle and a second sector lower section nozzle arranged from top to bottom, wherein each of the second sector upper section nozzles is arranged at a sector center angle of 1.7°, and each of the second sector lower section nozzles is arranged at a sector center angle of 1.9°; The conical water nozzles (7) on the spray pipes (5) of the three sector zones (4) are arranged at intervals of a sector central angle of 2.2-2.8°, and the interval angles tend to increase from top to bottom; 13 conical water nozzles (7) are arranged on the spray pipes (5) of the first sector zone (2) from top to bottom, wherein the 1st to 5th nozzles from top to bottom are the upper nozzles of the first sector, the 6th to 8th nozzles are the middle nozzles of the first sector, and the 9th to 12th nozzles are the lower nozzles of the first sector.

2. The secondary cooling zone spraying device of the billet continuous casting machine according to claim 1, characterized in that: The 5th and 6th conical water nozzles (7) are arranged at intervals of 0.9° at the central angle of the sector circle, and the 8th and 9th conical water nozzles (7) are arranged at intervals of 1.0° at the central angle of the sector circle.

3. The secondary cooling zone spraying device of the billet continuous casting machine according to claim 2, characterized in that: Each conical water nozzle (7) of the first sector-shaped zone (2) is 110 mm away from the casting.

4. The secondary cooling zone spraying device of the billet continuous casting machine according to claim 1, characterized in that: Each spray pipe (5) of the second sector zone (3) is provided with 11 conical water nozzles (7) from top to bottom, wherein the 2nd to 7th nozzles from top to bottom are the upper nozzles of the second sector zone, and the 8th to 11th nozzles are the lower nozzles of the second sector zone.

5. The secondary cooling zone spraying device of the billet continuous casting machine according to claim 4, characterized in that: The 7th and 8th conical water nozzles (7) are arranged at intervals of 1.9° at the central angle of the sector.

6. The secondary cooling zone spraying device of the billet continuous casting machine according to claim 5, characterized in that: Each conical water nozzle (7) of the second sector-shaped zone (3) is 150 mm away from the casting.

7. The secondary cooling zone spraying device of the billet continuous casting machine according to any one of claims 1 to 6, characterized in that: Each spray pipe (5) of the three sector zones (4) is provided with 9 conical water nozzles (7) from top to bottom, and each conical water nozzle (7) is 150 mm away from the casting.

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