Continuous casting billet corner thermal compensation type slow cooling device and slow cooling method

Abstract

The invention relates to the technical field of continuous casting, in particular to a continuous casting billet corner thermal compensation type slow cooling device and method. The slow cooling device comprises a thermal compensation temperature control airflow nozzle assembly, a cold and hot air mixer, a hot air pipeline, a heater, an air compressor, a cold air pipeline and an air fan. The number of the thermal compensation temperature control airflow nozzle assemblies is multiple, each thermal compensation temperature control airflow nozzle assembly comprises four slit type polygonal nozzles, and the four slit type polygonal nozzles are arranged on the outer sides of the four corners of the continuous casting billet in a one-to-one correspondence mode. The slit type polygonal nozzle is provided with a plurality of jet orifices. The thermal compensation temperature control airflow with the set temperature is jetted to the corner of the continuous casting billet, the temperature difference between the corner of the continuous casting billet and other parts is reduced, thermal stress exceeding the strength limit of the corner of the continuous casting billet due to too low temperature of the corner of the continuous casting billet is prevented, hot cracks can be effectively prevented, and the defect rate of the corner of the continuous casting billet is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting, and particularly relates to a hot compensation type slow cooling device and a slow cooling method for the corner of a continuous casting billet. Background Art

[0002] During the continuous casting process of metals, since the heat dissipation area per unit volume at the corners is much larger than that of other parts, the temperature drop at the corners is greater than that of other parts, resulting in defects such as corner cracks often occurring during the bending and straightening of the casting billets. Defective casting billets need to be taken offline for cleaning or scrapped, thus causing economic losses. Currently, the commonly used methods for reducing the temperature drop rate at the corners of casting billets include adjusting the drawing speed or adjusting the cooling intensity, etc., but the effects are not ideal.

[0003] The Chinese invention patent with the authorization announcement number CN113145813 B discloses "a method for preventing corner cracks in continuous casting billets of small square billet bulb flats". During the continuous casting process, after the continuous casting billet exits the secondary cooling zone and before being straightened by the straightening machine, within a distance of 100 mm to 500 mm, a rapid and strong cooling method is adopted for the corners of the casting billet to reduce the corner temperature of the casting billet to 100 °C to 300 °C, ensuring that the corner temperature of the continuous casting billet is lower than 350 °C after entering the straightening process, so as to improve the strength of the corners and avoid the brittle zone at the same time. The advantages of this method are: the inclusions in the molten steel are significantly reduced, not only improving the cleanliness of the casting billet, but also reducing the sensitivity of corner cracks; the incidence rate (average value) of corner cracks in the casting billet has dropped from 4.5% to 0.5%, greatly improving the quality of the continuous casting billet. For the casting billets with corner defects, after the corners of the casting billets are peeled and cleaned, they can fully meet the rolling requirements of the bulb flats, improving the quality of the corners of the casting billets. In order to ensure that the local temperature at the corners of the casting billet can be reduced to the set temperature range instantaneously, the cooling medium used is dry ice or liquid nitrogen.

[0004] The Chinese invention patent with the authorization announcement number CN102653835 A discloses "a method for reducing transverse cracks at the corners of continuous casting billets of boron-containing steel wide and thick plates". The water flow velocities in the water channels on the wide and narrow faces of the mold are respectively controlled within the ranges of 6.6 to 7.0 m / s and 6.9 to 7.3 m / s, and the inlet water temperature is controlled at 28 °C to 30 °C; the mold taper should be set at 1.05% to 1.15%; the melting point of the mold powder ≤ 1150 °C, and the viscosity ≤ 0.145 (Pa·s at 1300 °C); the total water volume of the inner and outer arcs in the first zone of secondary cooling is 95 to 110 L / m 2 ; the total water volume of the left and right sides in the foot roll zone is 35 to 45 L / m 2 ; the specific water consumption per ton of casting billet in secondary cooling is controlled within the range of 0.45 to 0.65 L / kg; the water flow density within the corners of the casting billet and within 15 cm from the corners ≤ 25 L / (m 2· min). After adopting this method, the corner defect rate of boron-containing steel wide and thick slab continuous casting billets has been reduced from the original 12.6% to less than 3.5%. However, this method is only applicable to the continuous casting production process of boron-containing steel wide and thick slab billets with a billet width of 1600 mm - 2300 mm, a billet thickness of 180 mm - 300 mm, and the steel type meeting a specific range.

[0005] The present invention provides a corner thermal compensation type slow cooling device and a slow cooling method for continuous casting billets. A thermally compensated temperature-controlled air flow with a set temperature is sprayed onto the corners of the continuous casting billets to reduce the temperature difference between the corners and other parts of the continuous casting billets, prevent the corners of the continuous casting billets from generating thermal stress exceeding their strength limit due to too low temperature, effectively prevent the generation of thermal cracks, and reduce the defect rate of the corners of the continuous casting billets.

[0006] In order to achieve the above object, the present invention is realized by adopting the following technical solutions:

[0007] A corner thermal compensation type slow cooling device for continuous casting billets includes a thermally compensated temperature-controlled air flow nozzle assembly, a hot and cold air mixer, a hot air pipeline, a heater, an air compressor, a cold air pipeline, and an air blower; multiple groups of the thermally compensated temperature-controlled air flow nozzle assemblies are provided, and each group of the thermally compensated temperature-controlled air flow nozzle assemblies is arranged between two adjacent rollers in the secondary cooling zone of continuous casting; each group of the thermally compensated temperature-controlled air flow nozzle assemblies includes 4 slit-type multi-angle nozzles, and the 4 slit-type multi-angle nozzles are respectively arranged on the outer sides of the 4 corners of the continuous casting billet; the slit-type multi-angle nozzles are provided with multiple injection ports; the air inlet ends of the slit-type multi-angle nozzles are simultaneously connected to the hot air pipeline and the cold air pipeline through the hot and cold air mixer; the hot air pipeline is additionally connected to the air compressor, and a radiator in the continuous casting mold cooling water circulation system is arranged in the hot air pipeline, and a heater is also provided on the hot air pipeline; the cold air pipeline is additionally connected to the air blower.

[0008] Electric valves are respectively arranged on the hot air pipeline and the cold air pipeline close to the hot and cold air mixer.

[0009] Infrared thermometers are respectively arranged beside the slit-type multi-angle nozzles, and the infrared thermometers are interlocked and controlled with the electric valves on the hot air pipeline and the cold air pipeline of the corresponding slit-type multi-angle nozzles through a control system.

[0010] The slit-type multi-angle nozzle is a flat-shaped hollow structure, with a nozzle air chamber in the middle, one end as the air inlet end, and the other end as the injection end; a pipe interface is arranged at the air inlet end and connected to a connecting pipe, and the connecting pipe is additionally connected to the hot and cold air mixer; the injection end is provided with slit-type injection ports, and there are multiple injection ports, which are arranged in a fan-shaped layout.

[0011] The injection port includes 1 vertical injection port and 2 outward-inclined injection ports, and the 2 outward-inclined injection ports are arranged on both sides of the vertical injection port; the center line of the vertical injection port is coaxial with the center line of the pipe interface, and the included angle between the center line of the outward-inclined injection port and the center line of the vertical injection port is 5° - 35°.

[0012] Both the vertical nozzle and the inclined nozzle are conical nozzles that expand outwards. The axial height of both the vertical nozzle and the inclined nozzle is 5 - 30 mm, the transverse width is 2 - 30 mm, and the outer opening length is 5 - 50 mm. The angle between the inner wall of the nozzle and the center line is 5° - 35°.

[0013] The slit - type multi - angle nozzle, the hot - and - cold air mixer, the hot air pipeline, the heat exchanger and the air compressor are all made of heat - resistant stainless steel, and the cold air pipeline is made of stainless steel.

[0014] A continuous casting billet corner thermal compensation slow - cooling method specifically includes the following steps:

[0015] 1) Start the air compressor. After the compressed air passes through the radiator of the mold cooling water circulation system, pressurized hot air is generated and directly sent to the hot - and - cold air mixer, or is sent to the hot - and - cold air mixer after being heated by the heater. At the same time, start the air blower to send pressurized cold air to the hot - and - cold air mixer. The pressurized hot air and the pressurized cold air are mixed in the hot - and - cold air mixer to obtain a thermal compensation temperature - controlled air flow. Control the opening degree of the electric valve through the control system, and then control the temperature of the thermal compensation temperature - controlled air flow within the range of 50°C - 600°C;

[0016] 2) The thermal compensation temperature - controlled air flow is ejected through the slit - type multi - angle nozzle installed between two rollers in the secondary cooling zone of the continuous casting, and the ejection direction is directly opposite to the four corners of the continuous casting billet;

[0017] 3) When the continuous casting starts pouring, when the continuous casting billet runs to the secondary cooling zone, according to the casting speed and the measured temperature of the continuous casting billet corner in real - time, determine the set temperature of the thermal compensation temperature - controlled air flow ejected by each slit - type multi - angle nozzle, and control the opening degree of the corresponding electric valve through the control system to ensure that the thermal compensation temperature - controlled air flow with the set temperature is ejected to the corresponding corner of the continuous casting billet, and precisely control the temperature of the continuous casting billet corner;

[0018] 4) After the continuous casting is completed, turn off the air compressor, the heater and the air blower, and the continuous casting billet corner thermal compensation slow - cooling device stops running.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) Eject the thermal compensation temperature - controlled air flow with a set temperature to the corners of the continuous casting billet, reduce the temperature difference between the corners of the continuous casting billet and other parts, prevent the thermal stress exceeding its strength limit due to too low temperature at the corners of the continuous casting billet, effectively prevent the generation of thermal cracks, and reduce the defect rate of the corners of the continuous casting billet;

[0021] (2) It is especially suitable for the continuous casting production of steel grades sensitive to corner cracks;

[0022] (3) The slow - cooling device has a simple structure, is easy to manufacture, has a low manufacturing cost, and is convenient to use. Description of the Drawings

[0023] Figure 1 It is a schematic structural view of a corner thermal compensation type slow cooling device for continuous casting billets according to the present invention.

[0024] Figure 2a It is a front sectional view of a slit type multi-angle nozzle according to the present invention.

[0025] Figure 2b is Figure 2a side view of.

[0026] Figure 2c is Figure 2a A-A sectional view in.

[0027] Figure 3 It is a schematic view of a corner thermal compensation type slow cooling method for continuous casting billets according to the present invention.

[0028] In the figure: 1. Slit type multi-angle nozzle 11. Nozzle air chamber 12. Outward inclined nozzle 13. Vertical nozzle 14. Pipe interface 2. Hot and cold air mixer 3. Hot air pipeline 4. Cold air pipeline 5. Thermal compensation temperature control air flow 6. Electric valve 7. Continuous casting billet 8. Roller Specific embodiments

[0029] The following further describes the specific embodiments of the present invention with reference to the accompanying drawings:

[0030] As Figure 1 , Figures 2a - 2c shown, a corner thermal compensation type slow cooling device for continuous casting billets according to the present invention includes a thermal compensation temperature control air flow nozzle assembly, a hot and cold air mixer 2, a hot air pipeline 3, a heater, an air compressor, a cold air pipeline 4 and an air blower; multiple groups of the thermal compensation temperature control air flow nozzle assemblies are provided, and each group of the thermal compensation temperature control air flow nozzle assemblies is arranged between two adjacent rollers 8 in the secondary cooling zone of continuous casting; each group of the thermal compensation temperature control air flow nozzle assemblies includes four slit type multi-angle nozzles 1, and the four slit type multi-angle nozzles 1 are correspondingly arranged outside the four corners of the continuous casting billet 7 (as Figure 3 shown); the slit type multi-angle nozzle 1 is provided with a plurality of spray openings; the air inlet end of the slit type multi-angle nozzle 1 is connected to the hot air pipeline 3 and the cold air pipeline 4 through the hot and cold air mixer 2 at the same time; the hot air pipeline 3 is additionally connected to the air compressor, a radiator in the continuous casting mold cooling water circulation system is arranged in the hot air pipeline 3, and a heater is also arranged on the hot air pipeline 3; the cold air pipeline 4 is additionally connected to the air blower.

[0031] Electric valves 6 are respectively arranged on the hot air pipeline 3 and the cold air pipeline 4 close to the hot and cold air mixer 2.

[0032] An infrared thermometer is provided one by one beside the slit multi-angle nozzle 1, and the infrared thermometer is interlocked and controlled with the electric valves 6 on the hot air pipeline 3 and the cold air pipeline 4 of the corresponding slit multi-angle nozzle 1 through a control system.

[0033] The slit multi-angle nozzle 1 is a flat hollow structure, with a nozzle air chamber 11 in the middle, one end being the air inlet end and the other end being the jet end; a pipe interface 14 is provided at the air inlet end and is connected to a connecting pipe, and the connecting pipe is additionally connected to a hot and cold air mixer 2; the jet end is provided with a slit-shaped jet orifice, and there are multiple jet orifices, arranged in a fan shape.

[0034] The jet orifice includes 1 vertical jet orifice 13 and 2 outward-inclined jet orifices 12, and the 2 outward-inclined jet orifices 12 are arranged on both sides of the vertical jet orifice 13; the center line of the vertical jet orifice 13 is coaxial with the center line of the pipe interface 14, and the included angle between the center line of the outward-inclined jet orifice 12 and the center line of the vertical jet orifice 13 is 5° to 35°.

[0035] Both the vertical jet orifice 13 and the outward-inclined jet orifice 12 are tapered jet orifices that expand outward, the axial height of both the vertical jet orifice 13 and the outward-inclined jet orifice 12 is 5 to 30 mm, the transverse width is 2 to 30 mm, and the outer mouth length is 5 to 50 mm; the included angle between the inner wall of the jet orifice and the center line is 5° to 35°.

[0036] The slit multi-angle nozzle 1, the hot and cold air mixer 2, the hot air pipeline 3, the heat exchanger and the air compressor are all made of heat-resistant stainless steel, and the cold air pipeline 4 is made of stainless steel.

[0037] The method for compensating heat at the corner of a continuous casting billet and slowly cooling according to the present invention specifically includes the following steps:

[0038] 1) Start the air compressor, and the compressed air generates pressurized hot air after passing through the radiator of the mold cooling water circulation system. The pressurized hot air is directly sent to the hot and cold air mixer 2, or is sent to the hot and cold air mixer 2 after being heated by a heater; at the same time, start the air blower to send pressurized cold air to the hot and cold air mixer 2; the pressurized hot air and the pressurized cold air are mixed in the hot and cold air mixer 2 to obtain a heat compensation temperature-controlled air flow 5; control the opening degree of the electric valve 6 through the control system, and further control the temperature of the heat compensation temperature-controlled air flow 5 within the range of 50°C to 600°C;

[0039] 2) The heat compensation temperature-controlled air flow 5 is ejected through the slit multi-angle nozzle 1 installed between 2 rollers 8 in the secondary cooling zone of the continuous casting, and the ejection direction is directly opposite to the four corners of the continuous casting billet 7 (as Figure 3 shown);

[0040] 3) At the start of continuous casting, when the continuous casting billet 7 runs to the secondary cooling zone, based on the drawing speed and the corner temperature of the continuous casting billet 7 measured in real time, determine the set temperature of the thermally compensated temperature-controlled air flow 5 ejected by each slit-type multi-angle nozzle 1. Control the opening degree of the corresponding electric valve 6 through the control system to ensure that the thermally compensated temperature-controlled air flow 5 with the set temperature is ejected to the corresponding corners of the continuous casting billet 7, and accurately control the corner temperature of the continuous casting billet 7;

[0041] 4) After continuous casting is completed, turn off the air compressor, heater, and air blower, and the corner thermal compensation type slow cooling device for continuous casting billets stops operating.

[0042] In the corner thermal compensation type slow cooling device for continuous casting billets of the present invention, the structure of the slit-type multi-angle nozzle 1 is as Figures 2a - 2c shown, and it is composed of a nozzle air chamber 11, a vertical nozzle 13, an outward-inclined nozzle 12, and a pipe connection 14. The pipe connection 14 is preferably connected to the connecting pipe by internal threads. The thermally compensated temperature-controlled air flow 5 mixed by the hot and cold air mixer 2 enters the nozzle air chamber 11 through the pipe connection 14, and then is ejected simultaneously by 2 outward-inclined nozzles 12 and 1 vertical nozzle 13, and is directly ejected to the four corners of the corresponding position of the continuous casting billet 7 ( Figure 3 the upper left, lower left, upper right, and lower right corners in

[0043] As Figure 2a 、 Figure 2c shown, the transverse width of both the outward-inclined nozzle 12 and the vertical nozzle 13 is D, and the axial height is H; both the vertical nozzle 13 and the outward-inclined nozzle 12 are conical nozzle structures with a smaller inner opening and a larger outer opening. The outer opening length of the vertical nozzle 13 is L1, and the outer opening length of the outward-inclined nozzle 12 is L2; the angle between the axis of the outward-inclined nozzle 12 and the axis of the vertical nozzle 13 (the axis inclination angle of the outward-inclined nozzle 12) is α, and the angle between the inner wall of the nozzle and the axis (the inner wall inclination angle) is β. The value ranges of the above parameters are: D: 2 - 30 mm, L1: 5 - 50 mm, L2: 5 - 50 mm, α: 5° - 35°, β: 5° - 35°, H: 5 - 30 mm.

[0044] The function of the hot air pipeline 3 is: heat the compressed air from the air compressor by taking heat from the crystallizer circulating cooling water radiator, and then heat it up through the heater (this step can be omitted depending on the situation).

[0045] The function of the hot and cold air mixer 2 is: the high-temperature compressed air from the hot air pipeline 3 and the normal-temperature compressed air from the cold air pipeline 4 enter the hot and cold air mixer 2 for mixing according to the required temperature after controlling the flow rate by the electric valves 6 on the corresponding pipelines, so as to obtain the thermally compensated temperature-controlled air flow 5 with the required temperature.

[0046] The hot-compensation temperature-controlled air flow 5 with a set temperature is sprayed onto the corner of the continuous casting billet 7, which can accurately control the temperature of the corner of the continuous casting billet 7 and prevent thermal stress exceeding its strength limit from being generated at this part due to too low temperature, thereby preventing the generation of thermal cracks.

[0047] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in combination with the embodiments. The following embodiments are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the technical scope disclosed by the present invention, including simple changes or equivalent replacements, are within the protection scope of the present invention.

[0048]

Embodiment 1

[0049] In this embodiment, the hot-compensation slow cooling device and slow cooling method for the corner of the continuous casting billet described in the present invention are adopted to continuously cast the ship plate steel AH32. The specific process is as follows:

[0050] 1. Prepare or purchase the following equipment: the slit multi-angle nozzle 1, the hot and cold air mixer 2, the hot air pipeline 3, the heater, the air compressor, the cold air pipeline 4 and the air blower, and install them as Figure 1 shown. The values of the parameters of the slit multi-angle nozzle 1 are: D = 5mm, L1 = 30mm, L2 = 25mm, α = 35°, β = 18°, H = 18mm.

[0051] 2. Connect the hot air pipeline 3 to the air compressor, the radiator of the crystallizer cooling water circulation system, the heater and the electric valve 6, and finally connect the hot and cold air mixer 2. Connect the cold air pipeline 4 to the electric valve 6 and the hot and cold air mixer 2; the electric valves 6 are all connected to the computer control system. The hot and cold air mixer 2 is connected to the slit multi-angle nozzle 1 through a connecting pipeline;

[0052] 3. Install the above devices in the gaps between two adjacent rollers in the secondary cooling zone of the continuous casting (as Figure 1 shown), and make the spraying end of the slit multi-angle nozzle face the corner of the continuous casting billet (as Figure 3 shown);

[0053] 4. Before the continuous casting starts pouring, turn on the heater and the air compressor on the hot air pipeline 3, and at the same time turn on the air blower on the cold air pipeline 4. By adjusting the electric valve 6, obtain the hot-compensation temperature-controlled air flow 5 with a temperature of 400 ± 20°C;

[0054] 5. After the continuous casting starts pouring, when the continuous casting billet 7 runs to the secondary cooling zone, according to the casting speed and parameters such as the corner temperature of the continuous casting billet 7 measured in real time, the computer control system automatically calculates and determines the set temperature of the heat compensation temperature control air flow 5 ejected by each slit multi-angle nozzle 1, and by controlling the opening degrees of the electric valves 6 on each cold air pipeline 4 and hot air pipeline 3, the heat compensation temperature control air flow 5 obtained after mixing by the cold and hot air mixer 2 reaches the set temperature;

[0055] 6. The heat compensation temperature control air flow 5 with a set temperature is ejected from multiple nozzles of the slit multi-angle nozzle 1 to the corner of the continuous casting billet 7, precisely controlling the corner temperature of the continuous casting billet 7, preventing it from generating thermal stress exceeding its strength limit due to too low temperature, and thus preventing the generation of thermal cracks;

[0056] 7. After the continuous casting ends, the corner heat compensation type slow cooling device of the continuous casting billet stops running.

[0057] In this embodiment, after 20 continuous casting heats are applied, for the AH32 continuous casting billet of shipbuilding steel obtained by continuous casting, the corner crack defect rate is reduced from 1.5% before implementation to 0.01% after implementation, and the effect is remarkable.

[0058]

Embodiment 2

[0059] In this embodiment, the corner heat compensation type slow cooling device and slow cooling method of the present invention are adopted to continuously cast the spring steel 55CrSi. The specific process is as follows:

[0060] 1. Prepare or purchase the following equipment: slit multi-angle nozzle 1, cold and hot air mixer, hot air pipeline 3, heater, air compressor, cold air pipeline 4 and air blower, and install them as Figure 1 shown. The values of each parameter of the slit multi-angle nozzle 1 are: D = 4mm, L1 = 32mm, L2 = 26mm, α = 30°, β = 15°, H = 16mm.

[0061] 2. Connect the hot air pipeline 3 to the air compressor, the radiator of the crystallizer cooling water circulation system, the heater and the electric valve 6, and finally connect the cold and hot air mixer 2. Connect the cold air pipeline 4 to the electric valve 6 and the cold and hot air mixer 2; the electric valves 6 are all connected to the computer control system. The cold and hot air mixer 2 is connected to the slit multi-angle nozzle 1 through a connecting pipeline;

[0062] 3. Install the above devices in groups in the gap between two adjacent rollers 8 in the secondary cooling zone of the continuous casting (as Figure 1 shown), and make the ejection end of the slit multi-angle nozzle 1 face the corner of the continuous casting billet 7 (as Figure 3 shown);

[0063] 4. Before the continuous casting starts, turn on the heater and air compressor on the hot air pipeline 3, and at the same time turn on the air blower on the cold air pipeline 4. By adjusting the electric valve 6, obtain a thermally compensated temperature-controlled air flow 5 with a temperature of 450 ± 20 °C;

[0064] 5. After the continuous casting starts, when the continuous casting billet 7 runs to the secondary cooling zone, according to parameters such as the casting speed and the corner temperature of the continuous casting billet 7 measured in real time, the computer control system automatically calculates and determines the set temperature of the thermally compensated temperature-controlled air flow 5 sprayed by each slit multi-angle nozzle 1, and by controlling the opening degree of the electric valves 6 on each cold air pipeline 4 and hot air pipeline 3, make the thermally compensated temperature-controlled air flow 5 obtained after mixing by the hot and cold air mixer 2 reach the set temperature;

[0065] 6. The thermally compensated temperature-controlled air flow 5 with a set temperature is sprayed from multiple nozzles of the slit multi-angle nozzle 1 to the corner of the continuous casting billet 7, precisely controlling the corner temperature of the continuous casting billet 7, preventing it from generating thermal stress exceeding its strength limit due to too low temperature, and thus preventing the generation of thermal cracks;

[0066] For 7. After the continuous casting ends, the corner thermal compensation type slow cooling device of the continuous casting billet stops running.

[0067] In this embodiment, after 20 continuous casting campaigns, for the 55CrSi spring steel continuous casting billets obtained by continuous casting, the corner crack defect rate is reduced from 1.3% before implementation to 0.009% after implementation, and the effect is remarkable.

[0068] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A continuous casting billet corner thermal compensation type slow cooling device, characterized in that, It includes a thermal compensation temperature-controlled air nozzle assembly, a hot and cold air mixer, a hot air pipeline, a heater, an air compressor, a cold air pipeline and an air blower; there are multiple groups of the thermal compensation temperature-controlled air nozzle assemblies, and each group of the thermal compensation temperature-controlled air nozzle assemblies is arranged between two adjacent rollers in the secondary cooling zone of continuous casting; each group of the thermal compensation temperature-controlled air nozzle assemblies includes 4 slit-type multi-angle nozzles, and the 4 slit-type multi-angle nozzles are correspondingly arranged on the outer sides of the four corners of the continuous casting billet; the slit-type multi-angle nozzle is provided with multiple injection ports; the air inlet end of the slit-type multi-angle nozzle is connected to the hot air pipeline and the cold air pipeline through the hot and cold air mixer at the same time; the hot air pipeline is additionally connected to the air compressor, the radiator in the cooling water circulation system of the continuous casting mold is arranged in the hot air pipeline, and a heater is also arranged on the hot air pipeline; the cold air pipeline is additionally connected to the air blower.

2. The corner heat compensation type slow cooling device for continuous casting billets according to claim 1, characterized in that, Electric valves are respectively arranged on the hot air pipeline and the cold air pipeline close to the hot and cold air mixer.

3. The hot compensation type slow cooling device for the corner of a continuous casting billet according to claim 1, characterized in that An infrared thermometer is correspondingly arranged beside each of the slit-type multi-angle nozzles, and the infrared thermometer is interlocked and controlled with the electric valves on the hot air pipeline and the cold air pipeline of the corresponding slit-type multi-angle nozzle through a control system.

4. A continuous casting billet corner thermal compensation type slow cooling device according to claim 1, characterized in that, The slit-type multi-angle nozzle is a flat-shaped hollow structure, with a nozzle air chamber in the middle, one end being the air inlet end and the other end being the injection end; a pipe interface is arranged at the air inlet end and is connected to a connecting pipe, and the connecting pipe is additionally connected to the hot and cold air mixer; the injection end is provided with slit-type injection ports, and there are multiple injection ports, which are arranged in a fan shape.

5. A continuous casting billet corner thermal compensation type slow cooling device according to claim 4, characterized in that, Each of the injection ports includes 1 vertical injection port and 2 outward-inclined injection ports, and the 2 outward-inclined injection ports are arranged on both sides of the vertical injection port; the center line of the vertical injection port is coaxial with the center line of the pipe interface, and the included angle between the center line of the outward-inclined injection port and the center line of the vertical injection port is 5° to 35°.

6. The hot compensation type slow cooling device for the corner of continuous casting billet according to claim 5, characterized in that, Both the vertical injection port and the outward-inclined injection port are conical injection ports that expand outward. The axial height of both the vertical injection port and the outward-inclined injection port is 5 to 30 mm, the transverse width is 2 to 30 mm, and the outer port length is 5 to 50 mm; the included angle between the inner wall of the injection port and the center line is 5° to 35°.

7. A continuous casting billet corner thermal compensation type slow cooling device according to claim 1, characterized in that The slit-type multi-angle nozzle, the hot and cold air mixer, the hot air pipeline, the heat exchanger and the air compressor are all made of heat-resistant stainless steel, and the cold air pipeline is made of stainless steel.

8. A method for slow cooling of continuous casting billet with corner thermal compensation, characterized in that, It is realized based on the continuous casting billet corner thermal compensation type slow cooling device according to any one of claims 1 to 7; specifically, it includes the following steps: 1) Start the air compressor, and the compressed air generates pressurized hot air after passing through the radiator of the cooling water circulation system of the continuous casting mold, and the pressurized hot air is directly sent to the hot and cold air mixer, or is sent to the hot and cold air mixer after being heated by the heater; at the same time, start the air blower to send the pressurized cold air to the hot and cold air mixer; the pressurized hot air and the pressurized cold air are mixed in the hot and cold air mixer to obtain a thermal compensation temperature-controlled air flow; control the opening degree of the electric valve through the control system, and further control the temperature of the thermal compensation temperature-controlled air flow within the range of 50°C to 600°C; 2) The thermal compensation temperature-controlled air flow is ejected through the slit-type multi-angle nozzles installed between two rollers in the secondary cooling zone of continuous casting, and the ejection direction is directly opposite to the four corners of the continuous casting billet; 3) At the start of continuous casting, when the continuous casting billet runs to the secondary cooling zone, determine the set temperature of the thermocompensation temperature-controlled air flow sprayed by each slit multi-angle nozzle according to the casting speed and the corner temperature of the continuous casting billet measured in real time. Control the opening degree of the corresponding electric valve through the control system to ensure that the thermocompensation temperature-controlled air flow with the set temperature is sprayed onto the corresponding corner of the continuous casting billet, and accurately control the corner temperature of the continuous casting billet; 4) After continuous casting is completed, turn off the air compressor, heater and air blower, and the corner thermal compensation slow cooling device of the continuous casting billet stops running.

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