Method for preventing loose winding of inner ring of ultra-low carbon steel

Abstract

The application discloses a method for preventing loose winding of an inner circle of ultra-low-carbon steel, and belongs to the technical field of coil shape control of hot-rolled plate strip steel in the metallurgical industry. The application prolongs the length of a head low-temperature section, utilizes low-temperature shrinkage effect to improve the close degree of the head of the strip steel and a winding drum, forms a basic restraint layer against loose winding, and avoids the loose winding starting problem caused by the head close gap from the root; the application improves the head speed-up section slope, increases the dynamic loading efficiency of the winding tension through fast speed-up, improves the extrusion stress between the strip steel winding layers, further strengthens the overall winding tightness, and eliminates the winding layer gap; the cooperative control strategy of the alternating operation of the winding machine avoids the thermal deformation of the winding drum caused by continuous high-temperature operation through the periodic cooling of the winding drum, guarantees the close precision of the winding drum and the strip steel, and prevents the inner circle loose winding problem caused by the thermal expansion of the winding drum.

Description

Technical Field

[0001] This invention belongs to the field of hot-rolled strip steel coil shape control technology in the metallurgical industry, specifically relating to a method for preventing loosening of the inner coil of ultra-low carbon steel. Background Technology

[0002] Ultra-low carbon steel is widely used in automotive and appliance manufacturing due to its excellent formability and weldability. During hot rolling, ultra-low carbon steel is typically produced using a high-temperature coiling process at ≥700℃ to ensure the steel's microstructure and properties.

[0003] However, under high-temperature winding conditions, the strip head is prone to loose contact with the drum due to thermal expansion. At the same time, continuous winding operations will cause the drum temperature to rise continuously, causing thermal deformation of the drum and further aggravating the problem of loose winding of the inner ring of the strip.

[0004] Loose coils not only affect the appearance quality of steel coils, but also prevent subsequent uncoiling, cold rolling and other processes from proceeding normally, increasing production rework rate and costs.

[0005] In existing technologies, most methods for solving the problem of unwinding focus on simply adjusting the winding tension or the amount of cooling water, failing to achieve coordinated control from three dimensions: head constraint, tension loading, and drum status, resulting in limited control effectiveness.

[0006] Therefore, how to develop a multi-dimensional collaborative control method has become an important issue that urgently needs to be addressed. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a method for preventing the inner ring of ultra-low carbon steel from loosening, so as to solve the problem of loosening of the inner ring of ultra-low carbon steel in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preventing the inner ring of ultra-low carbon steel from unwinding, comprising the following steps: S1: In the hot rolling and coiling process of ultra-low carbon steel, the temperature of the strip head with a length of 5m-10m is controlled to be 15℃-30℃ lower than the temperature of the main strip body. S2: The speed slope of the acceleration section during the process of the strip head entering the coiler is 20%-30% higher than that of the conventional acceleration section; S3: Use a coiler to alternately coil ultra-low carbon steel, and cool it during the coiling interval between two adjacent coils. When the coil is cooled to a surface temperature ≤120℃, it is coiled.

[0009] The slope of the conventional acceleration section is 0.40 m / s².

[0010] The strip body temperature is obtained by cooling the strip body that has just undergone the hot rolling process; the strip body is the remaining part that has not undergone strip head temperature control.

[0011] The speed-up section and the conventional speed-up section both refer to the part from when the strip head enters the coiler until the strip body begins to be coiled.

[0012] Based on the above technical solution, furthermore, the temperature fluctuation at each point from the head of the strip in S1 (5m-10m) is controlled within -15℃ to 15℃.

[0013] Among them, the temperature fluctuation of the main strip steel body is controlled within ±10 degrees Celsius.

[0014] Based on the above technical solution, the temperature fluctuation is further controlled by adjusting the head cooling water volume of the laminar flow cooling system.

[0015] Based on the above technical solution, furthermore, the strip tension fluctuation amplitude in the speed-up section of S2 is controlled within -10MPa to 10MPa.

[0016] Among them, the strip tension fluctuation range is controlled within -10MPa to 10MPa to avoid strip deformation or coiling instability caused by sudden tension changes.

[0017] Based on the above technical solution, the tension fluctuation amplitude of the strip steel is further monitored by a real-time tension monitoring system.

[0018] Based on the above technical solution, further, the cooling method in S3 adopts natural cooling.

[0019] Based on the above technical solution, the winding operation time of each winding machine is ≤40min.

[0020] The process involves using three coilers to perform the coiling operation alternately. The alternation cycle of the three coilers is determined based on the coiling time of a single coil of ultra-low carbon steel. The continuous operation time of each coiler is strictly controlled to not exceed 40 minutes. During the coiling interval between two adjacent coils of steel, the coil is allowed to cool naturally. The next coil of steel is then coiled after the surface temperature of the cooled coil drops to ≤120℃.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention extends the length of the low-temperature section at the head, utilizing the low-temperature contraction effect to improve the fit between the strip head and the coil, forming a basic constraint layer to prevent loosening and fundamentally avoiding loosening issues caused by gaps in the head fit. It also increases the slope of the head acceleration section, rapidly increasing the dynamic loading efficiency of the winding tension, enhancing the compressive stress between strip coil layers, further strengthening overall winding tightness, and eliminating layer gaps. A collaborative control strategy involving alternating coiler operations prevents thermal deformation of the coil due to continuous high-temperature operation through periodic cooling of the coil, ensuring the fit accuracy between the coil and the strip and preventing inner coil loosening caused by coil thermal expansion. Through the extended low-temperature section at the head, increased acceleration slope, and collaborative control of alternating coiler operations, the invention optimizes the thermal expansion effect, winding tightness, and coil cooling effect, solving the problem of inner coil loosening in ultra-low carbon steel, ensuring the stability of finished coil quality, and reducing subsequent processing costs.

[0022] 2. This invention requires no new equipment investment and can be achieved simply by optimizing process parameters. It has low modification costs, strong applicability, and can be widely applied to the high-temperature coiling production of various ultra-low carbon steels. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0024] Figure 1 This is a winding temperature curve of Embodiment 1 of the present invention. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0026] Comparative Example 1 The difference between this comparative example and Example 1 is that it does not employ strip head low-temperature section control, head acceleration section slope control, and coiler alternating operation control. Specifically, the strip head and main body target temperatures are consistent, with temperature fluctuations controlled within ±10℃; the head uses a conventional acceleration slope of 0.40 m / s²; and the coiler is selected in any mode, with the drum temperature reaching over 200℃ in the continuous operation zone.

[0027] According to production testing, the ultra-low carbon steel appliance panel coil of this specification has a regular shape, and the subsequent uncoiling and processing procedures are smooth, with a loose coil occurrence rate of 9.8%.

[0028] Example 1 For ultra-low carbon steel appliance sheets with a thickness of 2.5mm and a width of 1250mm, the main strip temperature is set at 720℃. The control method of this invention is used to prevent inner coil loosening. The specific implementation parameters and steps are as follows: 1. Low-temperature section control at the head of the strip: The length of the low-temperature section at the head of the strip is set to 10m. The cooling water volume at the head is adjusted by the laminar flow cooling system to control the temperature of this section at 690℃ (30℃ lower than the main body). The temperature fluctuation range is controlled within ±10℃ to form a low-temperature constraint layer.

[0029] 2. Head acceleration section slope control: Increase the slope of the head acceleration section from the conventional 0.40m / s² to 0.52m / s² (an increase of 30%). During the acceleration process, the strip tension fluctuation is controlled within ±10MPa, thereby increasing the interlayer extrusion stress.

[0030] 3. Coiler alternating operation control: Three coilers operate alternately, with the continuous operation time of a single coiler not exceeding 40 minutes. The next roll is wound after the roll cools to a surface temperature of 100°C.

[0031] Production testing showed that the inner ring of the ultra-low carbon steel appliance sheet coil of this specification was free of loose coils, the coil shape was regular, and the subsequent uncoiling and processing procedures were smooth. The occurrence rate of loose coils was reduced from 9.8% in conventional processes to 0%.

[0032] Example 2 The difference between this embodiment and embodiment 1 is that: Low-temperature section control at the head of the strip: The length of the low-temperature section at the head of the strip is set to 5m. The cooling water volume at the head is adjusted by the laminar flow cooling system to control the temperature of this section to 695℃ (25℃ lower than the main body). Head acceleration slope control: Increase the head acceleration slope from the conventional 0.40m / s² to 0.48m / s² (an increase of 20%). Production testing showed that the inner ring of the ultra-low carbon steel appliance sheet coil of this specification was free of loose coils, the coil shape was regular, and the subsequent uncoiling and processing procedures were smooth. The occurrence rate of loose coils was reduced from 9.8% in conventional processes to 0.3%.

[0033] Example 3 The difference between this embodiment and embodiment 2 is that: Low-temperature section control at the head of the strip: The cooling water volume at the head is adjusted by the laminar flow cooling system to control the temperature of this section to 705℃ (15℃ lower than the main body). Production testing showed that the inner ring of the ultra-low carbon steel appliance sheet coil of this specification was free of loose coils, the coil shape was regular, and the subsequent uncoiling and processing procedures were smooth. The occurrence rate of loose coils was reduced from 9.8% in conventional processes to 0.5%.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing the inner ring of ultra-low carbon steel from unwinding, characterized in that, Includes the following steps: S1: In the hot rolling and coiling process of ultra-low carbon steel, the temperature of the strip head with a length of 5m-10m is controlled to be 15℃-30℃ lower than the temperature of the main strip body. S2: The speed slope of the acceleration section during the process of the strip head entering the coiler is 20%-30% higher than that of the conventional acceleration section; S3: Use a coiler to alternately coil ultra-low carbon steel, and cool it during the coiling interval between two adjacent coils. When the coil is cooled to a surface temperature ≤120℃, it is coiled.

2. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 1, characterized in that, In S1, the temperature fluctuation at various points from the head of the strip (5m-10m) is controlled within -15℃ to -15℃.

3. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 2, characterized in that, The temperature fluctuation is controlled by adjusting the amount of cooling water at the head of the laminar flow cooling system.

4. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 1, characterized in that, The strip tension fluctuation range in the acceleration section of S2 is controlled within -10MPa to 10MPa.

5. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 4, characterized in that, The tension fluctuation of the strip is monitored by a real-time tension monitoring system.

6. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 1, characterized in that, The cooling method in S3 is natural cooling.

7. The method for preventing loosening of the inner ring of ultra-low carbon steel according to claim 6, characterized in that, The winding operation time for each winding machine is ≤40 minutes.

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