A method of rolling long continuous cast steel billets

Abstract

The present application relates to the technical field of cast steel, and particularly discloses a long fixed-length continuous casting billet rolling method, which comprises the following steps: continuously casting a hot billet; a conveying roller way with a length of 70 m is installed between a continuous casting machine and a rolling mill, the width of the conveying roller way satisfies the side-by-side arrangement of 6 billets, and the conveying roller way is covered with a heat preservation cover; when the billets are rolled, the billets need to be cut once at No. 1 flying shear, No. 2 flying shear, No. 3 flying shear and a coiled head tail; after the billets are rolled, the rolled billets are sequentially subjected to water cooling, wire laying and air cooling; the air-cooled billets are wound; and after the billets are wound, the billets are wound, inspected, weighed and labeled, and then warehousing is completed. The long fixed-length continuous casting billets are rolled, the loss of the cut head and tail during rolling is reduced, the proportion of the idle time of the rolling mill is greatly reduced, the production efficiency of the rolling mill is improved, and the production rhythm is accelerated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cast steel, in particular to a long fixed-length continuous casting billet rolling method. BACKGROUND

[0002] At present, the continuous casting process is a process in which the molten steel releases heat and gradually solidifies into a certain shape of the billet under continuous production. The molten steel is completed by the upstream treatment and is transported to the turret by the ladle. It is divided into several strands by the molten steel distributor, injected into the mold, and then cooled and solidified into a shape. Then the billet is drawn into the arc-shaped casting channel, and the secondary cooling continues to solidify to complete solidification. After straightening, it is cut, and the billet head reaches the cutting point.

[0003] However, in the prior art, the fixed length is limited by the heating furnace, the transport vehicle and the size of the cooling bed, the fixed length is short, the rolling mill is idle for a long time, the production capacity of the rolling mill is reduced, and the secondary heating increases the manufacturing cost. SUMMARY

[0004] The purpose of the present application is to provide a long fixed-length continuous casting billet rolling method, which aims to solve the technical problems of the prior art that the fixed length is limited by the heating furnace, the transport vehicle and the size of the cooling bed, the fixed length is short, the rolling mill is idle for a long time, the production capacity of the rolling mill is reduced, and the secondary heating increases the manufacturing cost.

[0005] To achieve the above-mentioned purpose, a long fixed-length continuous casting billet rolling method is adopted, which comprises the following steps:

[0006] Continuous casting hot billet;

[0007] A conveying roller is installed between the continuous casting machine and the rolling mill, with a length of 70m and a width that can accommodate 6 billets side by side, and the conveying roller is covered with a heat preservation cover;

[0008] When rolling the billet, it needs to be cut once at No. 1 flying shear, No. 2 flying shear, No. 3 flying shear and disc head tail;

[0009] After rolling the billet, the rolled billet is sequentially water-cooled, wire-cooled and air-cooled;

[0010] The air-cooled billet is divided into coils;

[0011] After the billet is divided into coils, the billet is collected, inspected, weighed and labeled before being put into storage.

[0012] Among them, a blocking device is arranged in front of No. 1 rolling mill to ensure that only one billet enters the rolling mill, avoiding the simultaneous entry of billets causing blockage.

[0013] The wind cooling roller way at 5m in front of the collecting is provided with a shearing machine, the coil is sheared into two parts, then the rotating speed of the roller way in front of the collecting is increased, the front and rear parts of the coil are dislocated, and subsequent collecting is facilitated.

[0014] Wherein, when the billet is water-cooled, the cooling water flows into the grouting device from the cooling pipeline, and then is sprayed to the surface of the casting billet through the nozzle at a specific angle and direction to form water mist or water splashes, and the secondary cooling zone adopts gas mist cooling or water spray cooling.

[0015] Wherein, the gas mist cooling sprays the water vapor mixture through the nozzle to realize slow and uniform cooling of the billet.

[0016] Wherein, the water spray cooling directly sprays water mist to the surface of the billet to accelerate heat transfer, thereby realizing cooling of the billet.

[0017] Wherein, the secondary cooling zone is divided into multiple spray areas, each spray area is independently controlled, and the water quantity, water pressure and water temperature parameters of the spray can be controlled according to different needs of the billet in the cooling process.

[0018] The beneficial effect of the long-length continuous casting billet rolling method is that long-length continuous casting billets are used for rolling, the tail loss of the shearing head is reduced, the proportion of the idling time of the rolling mill is greatly reduced, the production efficiency of the rolling mill is improved, and the production rhythm is accelerated. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 It is a step flow chart of the long-length continuous casting billet rolling method of the present application. DETAILED DESCRIPTION

[0021] Please refer to Figure 1 The present application provides a long-length continuous casting billet rolling method, which comprises the following steps:

[0022] S1: continuously casting hot billets;

[0023] S2: a conveying roller way with a length of 70m is installed between the continuous casting machine and the rolling mill, the width satisfies the side-by-side arrangement of 6 billets, and the conveying roller way is covered with a heat preservation cover;

[0024] S3: when the billets are rolled, each of the 1st flying shear, the 2nd flying shear, the 3rd flying shear and the coil head and tail needs to be sheared once;

[0025] S4: after the billet is rolled, the rolled billet is sequentially water-cooled, wire-spun and air-cooled;

[0026] S5: the billet after air-cooling is divided into coils;

[0027] S6: after the billet is divided into coils, the billet is coiled, inspected, weighed and labeled, and then warehoused.

[0028] In the embodiment, the billet does not need to be cooled on the cooling bed, transported and heated in the heating furnace after coming out of the continuous casting machine, the fixed size is no longer limited by the size of the cooling bed, the transport vehicle and the heating furnace, the fixed size of the billet can be increased from the previous 6m to 20m, the continuous casting billet with long fixed size is rolled, the tail loss of the rolling is reduced, the proportion of the idle time of the rolling mill is greatly reduced, the production efficiency of the rolling mill is improved, and the production rhythm is accelerated.

[0029] Further, a blocking device is arranged in front of the No. 1 rolling mill to ensure that only one billet enters the rolling mill, avoiding the blockage caused by the simultaneous entry of billets.

[0030] In the embodiment, the blocking device avoids the blockage caused by the simultaneous entry of multiple billets, ensures the stability of the billet during long fixed size processing, and effectively improves the efficiency of billet processing.

[0031] Further, a shearing machine is arranged on the air-cooled roller at 5m in front of the coiling to shear the coil into two parts, and then the speed of the roller in front of the coiling is increased to misalign the front and rear parts of the coil, facilitating subsequent coiling.

[0032] In the embodiment, the misalignment adjustment of the sheared coil facilitates subsequent coiling, thereby improving the production efficiency of the billet.

[0033] Further, when the billet is water-cooled, the cooling water flows into the grouting device from the cooling pipeline, and then is sprayed to the surface of the casting billet at a specific angle and direction through the nozzle to form water mist or water spray, and the secondary cooling zone adopts air mist cooling or water spray cooling.

[0034] In the embodiment, the billet water cooling is an intermediate water cooling in the steel rolling process, and the main purpose is to rapidly cool the heated billet through high-pressure water jet. The intermediate water cooling can rapidly reduce the temperature of the billet, so that the billet reaches the designed forming temperature, thereby improving the rolling efficiency. The billet plastic deformation stress can be reduced by cooling, and the generation of tensile and shear stress is reduced, so that the billet is more easily deformed, thereby improving the rolling efficiency. The intermediate water cooling helps to improve the structure and performance of the billet surface layer, so that the rolling process is more stable, thereby improving the quality of the product. The rolling roller is prone to deformation and even cracking at high temperature. The intermediate water cooling can effectively reduce the temperature of the rolling roller, reduce wear and deformation, protect the equipment and prolong the service life. The secondary cooling zone is a region for secondary cooling of the billet. The billet water cooling and the secondary cooling zone jointly act in the process of processing and preparation to improve the product quality, protect the production equipment and improve the production efficiency. The billet cooling has beneficial effects of improving cooling efficiency, improving cooling uniformity, saving water, improving working environment, improving product quality, and flexibility and adaptability.

[0035] Further, the gas mist cooling sprays the water vapor mixture through the nozzle to achieve slow and uniform cooling of the billet.

[0036] In the embodiment, the gas mist cooling atomizes the water droplets by compressed air, so that the diameter of the water droplets is greatly reduced, most of which are less than 100 μm. This is conducive to more uniform distribution of water droplets on the surface of the billet, thereby improving the cooling efficiency. The atomized water droplets can cover a wider surface of the billet, thereby effectively increasing the cooling area and making the cooling more uniform. Due to the uniform cooling, the thermal stress generated during the cooling process of the billet is also reduced, which helps to reduce cracks. The amount of water required for gas mist cooling is greatly reduced compared with complete water cooling, which saves water resources to some extent. The atomized water droplets evaporate quickly on the hot billet, which can more effectively utilize water resources for cooling. Due to the uniform cooling, the residual stress generated during the cooling process of the billet is also reduced, thereby improving the product quality. The improvement of cooling uniformity and cooling efficiency helps to reduce the crack defects generated during the cooling process of the billet. The gas mist cooling can rapidly reduce the surface temperature of the billet, thereby shortening the cooling time and improving the production efficiency. The shortening of the cooling time means that the equipment can be put into the next round of production faster, thereby improving the utilization rate of the equipment.

[0037] Further, the water spray cooling directly sprays water mist to the surface of the billet to accelerate heat transfer, thereby achieving cooling of the billet.

[0038] In the embodiment, the water spray cooling atomizes water into fine droplets through the nozzles, which can quickly contact the billet surface and carry away a large amount of heat, thereby achieving rapid cooling. The atomized water droplets can cover a wider billet surface, thereby effectively increasing the cooling area and improving the cooling efficiency. The water spray cooling system can ensure uniform distribution of water droplets on the billet surface, avoiding local overheating or overcooling, and improving the uniformity of cooling. Due to uniform cooling, the thermal stress generated during the cooling process of the billet is also reduced, which helps to reduce the generation of crack defects. The water spray cooling system can adjust the spray amount, water pressure and other parameters as needed to adapt to different steel grades and cooling requirements. The nozzles and other components of the water spray cooling system are relatively simple and easy to maintain and replace.

[0039] Further, the secondary cooling zone is divided into multiple spray areas, each of which is independently controlled to adapt to different requirements of the billet during the cooling process and control the water amount, water pressure and water temperature parameters of the spray.

[0040] In the embodiment, through zoning control, the cast billet can reach the required cooling effect in a shorter time, thereby shortening the cooling time and improving the production efficiency. The shortening of the cooling time means that the equipment can be put into the next round of production faster, improving the utilization rate of the equipment. For different specifications of continuous casting billets, the parameters of each spray area can be adjusted to adapt to their cooling requirements, improving the flexibility and adaptability of the production line. When the process conditions change, such as speed adjustment, steel grade change, etc., the parameters of each spray area can be adjusted to cope with these changes, ensuring stable cast billet quality. The division of the secondary cooling zone into multiple spray areas has significant beneficial effects on improving cooling efficiency and uniformity, improving cast billet quality, improving production efficiency, and enhancing flexibility and adaptability.

[0041] Further, when air cooling the billet, the billet is placed in a turnover cooling bed or stacking area, and at the same time, each group of billets needs to be spaced apart during placement to facilitate air circulation and improve heat dissipation efficiency.

[0042] In the embodiment, air cooling is a relatively simple cooling method, which does not require additional cooling equipment such as cooling towers, water pumps and the like, thereby saving equipment investment and operating costs, and compared with water cooling, air cooling does not require the use of a large amount of water resources, and is particularly economical and feasible in water resource-deficient areas. In the air cooling process, the billet directly utilizes natural convection and radiation in the air for heat dissipation without consuming additional energy. In the air cooling process, the cooling speed of the billet is relatively slow and uniform, which helps to reduce thermal stress generated due to rapid cooling, thereby reducing the generation of crack defects. Air cooling is suitable for a variety of steel grades, especially those that do not form martensite or semi-martensite structure after air cooling, such as low-carbon steel, ordinary low-alloy high-strength steel and the like. Air cooling is generally carried out on a special cooling bed, and the cooling bed has various forms such as step-by-step type and disc roller type. The design of the cooling bed should ensure that the billet can uniformly dissipate heat and reduce scratches caused by bending and friction.

[0043] Further, in the air cooling process, the temperature of the billet in the air cooling section is monitored, and real-time adjustment control is performed according to the monitoring data to make the monitoring data reach a reasonable range.

[0044] In the embodiment, through the data monitoring of the billet, the cooling of the billet can be adjusted in real time, so that the cooling temperature and rate meet the temperature range.

[0045] In the present application, long-sized continuous casting billets are used for rolling, which reduces the loss of shearing head and tail in rolling, greatly reduces the proportion of rolling idling time, improves the production efficiency of the rolling mill, and speeds up the production rhythm.

[0046] Billet water cooling is intermediate water cooling in the steel rolling process, and the main purpose is to rapidly cool the heated billet through high-pressure water jet. The intermediate water cooling can rapidly reduce the temperature of the billet to the designed forming temperature, thereby improving the rolling efficiency. Through cooling, the plastic deformation stress of the billet can be reduced, the generation of tensile and shear stress can be reduced, the billet can be more easily deformed, and the rolling efficiency can be improved. The intermediate water cooling helps to improve the structure and performance of the surface layer of the billet, so that the rolling process is more stable, thereby improving the quality of the product. The rollers at high temperature are prone to deformation and even cracking. The intermediate water cooling can effectively reduce the temperature of the rollers, reduce wear and deformation, protect the equipment and prolong the service life. The secondary cooling zone is a region for secondary cooling of the billet. The billet water cooling and the secondary cooling zone jointly act in the process of preparation to improve the product quality, protect the production equipment and improve the production efficiency. The billet cooling has beneficial effects of improving cooling efficiency, improving cooling uniformity, saving water, improving working environment, improving product quality and flexibility and adaptability.

[0047] The gas-atomized cooling is through compressed air to atomize water droplets, so that the water droplet diameter is greatly reduced, most of which is less than 100 μm, which is beneficial to more uniform distribution of water droplets on the surface of the billet, improves the cooling efficiency, the atomized water droplets can cover a wider surface of the billet, thereby effectively increasing the cooling area, and the cooling is more uniform, and the thermal stress generated during the cooling process of the billet is also reduced, which helps to reduce cracks, the water required for the gas-atomized cooling is greatly reduced compared with the complete water cooling, which saves water resources to some extent, the atomized water droplets evaporate quickly on the hot billet, which can more effectively utilize water resources for cooling, and the residual stress generated during the cooling process of the billet is also reduced due to the uniform cooling, thereby improving the product quality, the improvement of the cooling uniformity and the cooling efficiency helps to reduce the crack defects generated during the cooling process of the billet, the gas-atomized cooling can quickly reduce the surface temperature of the billet, thereby shortening the cooling time and improving the production efficiency, and the shortening of the cooling time means that the equipment can be put into the next production round faster, thereby improving the utilization rate of the equipment;

[0048] The water spray cooling atomizes water into fine droplets through a nozzle, which can quickly contact the surface of the billet and carry away a large amount of heat, thereby achieving rapid cooling, the atomized water droplets can cover a wider surface of the billet, thereby effectively increasing the cooling area and improving the cooling efficiency, the water spray cooling system can ensure that the water droplets are uniformly distributed on the surface of the billet, avoiding the phenomenon of local overheating or overcooling, thereby improving the uniformity of cooling, and the thermal stress generated during the cooling process of the billet is also reduced due to the uniform cooling, which helps to reduce the generation of crack defects, the water spray cooling system can adjust the spray amount, water pressure and other parameters as needed to adapt to different steel grades and cooling requirements, and the nozzle and other components of the water spray cooling system are relatively simple and easy to maintain and replace;

[0049] In the billet rolling, the billet needs to be cut once at No. 1 flying shear, No. 2 flying shear, No. 3 flying shear and disc head tail, the fixed loss after cutting is t, when the billet gauge is 12 m, the cutting loss per meter of billet is t / 12, when the gauge is adjusted to 50 m, the cutting loss per meter of billet is t / 50, the cutting loss of the billet is reduced by 76%, the rolling speed of No. 1 rolling mill is 0.3 m / s, the shortest time interval for one billet and another billet to enter No. 1 rolling mill is 10 s, when the billet gauge is 12 m, the billet load rolling time is 40 s, and the idle time is the interval time 10 s, the load rate of No. 1 rolling mill is load rolling time / (load rolling time+idle time)=80%;

[0050] When the rolling size of the billet is 50 m, the load rolling time is 166.7 s, the idle time is the interval time 10 s, and the load rate of No. 1 rolling mill is load rolling time / (load rolling time+idle time)=94.3%;

[0051] The load rate of the No. 1 rolling mill is increased by 17.9%, the power consumption per ton of steel is reduced, the corresponding rolling line production capacity is increased by 17.9%, and the continuous casting machine can be opened to 6 flows to improve the production rhythm after the production capacity of the rolling line is increased.

[0052] The above only discloses a preferred embodiment of the present application, and of course cannot limit the scope of the rights of the present application, and those skilled in the art can understand that all or part of the above-mentioned embodiments can be implemented, and equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A long-size continuous casting billet rolling method, characterized by, It comprises the following steps: Continuous casting hot billet; A conveying roller is installed between the continuous casting machine and the rolling mill, with a length of 70m and a width of 6 billets side by side, and the conveying roller is covered with an insulation cover; When the billet is rolled, it needs to be cut once at No. 1 flying shear, No. 2 flying shear, No. 3 flying shear and coiled head tail; After the billet is rolled, the rolled billet is sequentially water-cooled, wire-drawing and air-cooled; The air-cooled billet is divided into coils; After the billet is divided into coils, the billet is collected, inspected, weighed and labeled, and then stored in the warehouse; A blocking device is provided in front of No. 1 rolling mill to ensure that only one billet enters the rolling mill, avoiding the blockage caused by simultaneous entry of billets; A shear is provided on the air-cooled roller 5m in front of the coiling to cut the coil into two parts, and then the speed of the roller in front of the coiling is increased to make the front and rear parts of the coil staggered, facilitating subsequent coiling; When the billet is water-cooled, the cooling water flows into the grouting device from the cooling pipeline, and then is sprayed to the surface of the cast billet at a specific angle and direction through the nozzle to form water mist or water spray, and the secondary cooling zone adopts gas mist cooling or water spray cooling; The secondary cooling zone is divided into multiple spray areas, each spray area is independently controlled, and the water quantity, water pressure and water temperature parameters of the spray can be controlled according to the different needs of the billet in the cooling process.

2. The long-length continuous casting billet rolling method according to claim 1, characterized in that, The gas mist cooling sprays the water vapor mixture through the nozzle to achieve slow and uniform cooling of the billet.

3. The long-length continuous casting billet rolling method according to claim 1, characterized in that, The water spray cooling directly sprays water mist to the surface of the billet to accelerate heat transfer, thereby achieving cooling of the billet.

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