A control method for the longitudinal distribution of strip crown
By detecting and analyzing the attenuation of the strip convexity, selecting the appropriate CVC rolling mill rolling curve and adjusting the working roller lateral movement and bending roller force, the problem of uneven longitudinal distribution of the convexity of the strip steel plate is solved, and efficient plate shape control of hot continuous rolling strip steel is achieved.
Patent Information
- Application Number
- CN202310591766.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-24
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2043-05-24
AI Technical Summary
In the prior art, the uneven longitudinal distribution of the convexity of the strip steel plate leads to plate-shaped defects, which in severe cases affects production continuity and product quality, especially in thin-spec strip steel, where the convexity of the tail plate is lower than the lower limit of the target convexity.
The thickness gauge detects the attenuation of the strip convexity, selects the CVC rolling mill roll curve for the analysis results, and adjusts the horizontal movement of the working roller and the rolling mill bending force to control the longitudinal distribution of the convexity of the strip convexity.
Without changing the production equipment and rolling rhythm, the convexity attenuation of the head and tail plate of the hot continuous rolling strip steel is significantly improved or eliminated, providing a larger working roller cross-moving capacity and bending roller force control window, and improving the plate convexity control effect.
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Figure CN116765148B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of strip shape control of thin strip products, and particularly relates to a control method for the longitudinal distribution of strip crown of strip steel. Background Art
[0002] Strip shape control has always been the research focus of hot continuous rolling production technology. As an important index of strip shape control, strip crown is an important process factor affecting the quality of hot-rolled thin gauge strip steel products and the strip shape of cold-rolled strip steel. Deviations in strip crown of strip steel may not only cause strip shape defects, but in severe cases, may even lead to production interruption, resulting in significant waste and potential use risks. Moreover, in actual production, thin gauge strip steel may also exhibit longitudinal attenuation of strip crown or even the strip crown at the tail being lower than the lower limit of the target crown, seriously affecting the quality and use of strip steel. Summary of the Invention
[0003] The purpose of the present invention is to provide a control method for the longitudinal distribution of strip crown of strip steel to solve the problems existing in the above-mentioned prior art.
[0004] To achieve the above purpose, the present invention provides a control method for the longitudinal distribution of strip crown of strip steel, including:
[0005] Based on a thickness gauge, the strip crown at the outlet of the strip steel is detected to obtain the actual strip crown attenuation of the strip steel;
[0006] Analyze the actual strip crown attenuation of the strip steel, and select the CVC mill roll profile curve based on the analysis results;
[0007] Set the work roll transverse shift amount and the mill bending force of the CVC stand to obtain a setting result, and control the longitudinal distribution attenuation of the strip crown of the strip steel based on the setting result and the CVC mill roll profile curve.
[0008] Preferably, the process of obtaining the actual strip crown attenuation of the strip steel includes:
[0009] Based on a thickness gauge, the strip crown at the head of the strip steel and the strip crown at the tail of the strip steel are detected to obtain the strip crown data at the head of the strip steel and the strip crown data at the tail of the strip steel;
[0010] Calculate the strip crown data at the head of the strip steel and the strip crown data at the tail of the strip steel to obtain the actual strip crown attenuation of the strip steel.
[0011] Preferably, the process of analyzing the actual strip crown attenuation of the strip steel includes:
[0012] Set a threshold range, and analyze and classify the actual strip crown attenuation of the strip steel based on the threshold range to obtain an analysis result.
[0013] Preferably, the process of selecting the CVC mill roll profile curve based on the analysis result includes:
[0014] Obtain the data of the CVC mill roll profile curve, and set the stand modification plan based on the data of the CVC mill roll profile curve;
[0015] Select the stand of the CVC mill based on the analysis result and the stand modification plan.
[0016] Preferably, the CVC mill roll profile curve includes a roll profile curve with the equivalent convexity of the roll increasing by 100 - 300 μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increasing by 300 - 500 μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increasing by 500 - 700 μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increasing by 700 - 900 μm compared to the original roll profile, and a roll profile curve with the equivalent convexity of the roll increasing by 900 - 1000 μm compared to the original roll profile.
[0017] Preferably, the process of obtaining the setting result includes:
[0018] In the first one - third of the total rolling time of the strip steel, set the work roll transverse shift amount of the first stand and the second stand of the rolling mill to the maximum equivalent convexity position, keep the work roll transverse shift amount of the remaining stands unchanged, and set the upper limit of the CVC stand bending force;
[0019] In the last two - thirds of the total rolling time of the strip steel, set the work roll transverse shift amount of the first stand and the second stand of the rolling mill to the maximum equivalent convexity position, keep the work roll transverse shift amount of the remaining stands unchanged, set the bending force of the first stand and the second stand of the rolling mill based on the lower limit value of the bending force, and set the remaining stands based on the upper limit value and the lower limit value of the bending force to obtain the setting result.
[0020] Preferably, the process of controlling the longitudinal distribution attenuation of the strip steel convexity based on the setting result and the CVC mill roll profile curve includes:
[0021] Set the control range, and control the mid - tail plate convexity value of the strip steel based on the setting result, the control range and the CVC mill roll profile curve to obtain the control result of the longitudinal distribution attenuation of the strip steel convexity.
[0022] The technical effects of the present invention are:
[0023] The present invention can significantly improve or even eliminate the head - tail plate convexity attenuation phenomenon of hot - rolled strip steel without changing the on - site production equipment, cooling device, and rolling rhythm of the production line; secondly, the present invention can provide a larger working roll transverse shift amount and bending force regulation window for plate convexity control. Description of the Drawings
[0024] The accompanying drawings, which form a part of this application, are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:
[0025] Figure 1 It is a comparison diagram of the optimized roll profile curve and the original roll profile curve in the embodiment of the present invention;
[0026] Figure 2 It is the longitudinal distribution diagram of the original plate crown of the 1.5×1250mm strip steel in the embodiment of the present invention;
[0027] Figure 3 It is the longitudinal distribution diagram of the plate crown of the 1.5×1250mm strip steel after regulation in the embodiment of the present invention. Detailed implementation manners
[0028] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the accompanying drawings and combine with the embodiments to detail this application.
[0029] Embodiment 1
[0030] As Figure 1 shown, this embodiment provides a control method for the longitudinal distribution of strip steel plate crown, including:
[0031] A computer program for calculating the plate crown at the strip steel outlet, which inputs process parameters such as the roll profile curve function of the hot continuous rolling CVC mill, the roll profile curve function of the non-CVC mill, the work roll transverse shift amount, the width, thickness, temperature, speed, and bending roll force of the rolled piece, and can obtain the plate crown value at the strip steel outlet after calculation.
[0032] The above calculation program is used to control the plate crown of the strip steel with plate crown attenuation, and the following steps are carried out:
[0033] (1) Use a thickness gauge to detect the plate crown at the outlet of the whole strip steel to obtain the actual plate crown attenuation amount of the strip steel;
[0034] (2) According to the different plate crown attenuation amounts, select different CVC mill roll profile curves. The specific optional curves are as follows;
[0035] The specific feature of the CVC roll No. 1 roll profile curve is the roll profile curve with the equivalent convexity of the roll increased by 100 - 300μm compared with the original roll profile;
[0036] The specific feature of the CVC roll No. 2 roll profile curve is the roll profile curve with the equivalent convexity of the roll increased by 300 - 500μm compared with the original roll profile;
[0037] The specific feature of the roll profile curve of the 3rd roll of the CVC roll is that the equivalent convexity of the roll increases by 500 - 700 μm compared with the original roll profile curve;
[0038] The specific feature of the roll profile curve of the 4th roll of the CVC roll is that the equivalent convexity of the roll increases by 700 - 900 μm compared with the original roll profile curve;
[0039] The specific feature of the roll profile curve of the 5th roll of the CVC roll is that the equivalent convexity of the roll increases by 900 - 1000 μm compared with the original roll profile curve;
[0040] When the convexity attenuation of the strip steel is 0 - 5 μm, the rolls corresponding to the first stand of the CVC mill can be selected to be modified to the above-mentioned 1st roll profile curve, 2nd roll profile curve or 3rd roll profile curve, and the roll profile curves of the remaining rolls remain unchanged;
[0041] When the convexity attenuation of the strip steel is 5 - 10 μm, the rolls corresponding to the 1st stand of the CVC mill can be selected to be modified to the above-mentioned 2nd roll profile curve, 3rd roll profile curve or 4th roll profile curve, or the rolls corresponding to the 1st - 2nd stands of the CVC mill can be selected to be modified to the above-mentioned 2nd roll profile curve, 3rd roll profile curve or 4th roll profile curve, and the roll profile curves of the remaining rolls remain unchanged;
[0042] When the convexity attenuation of the strip steel is 10 - 15 μm, the rolls corresponding to the 1st - 2nd stands of the CVC mill can be selected to be modified to the above-mentioned 3rd roll profile curve, 4th roll profile curve or 5th roll profile curve, or the rolls corresponding to the 1st - 3rd stands of the CVC mill can be selected to be modified to the above-mentioned 3rd roll profile curve, 4th roll profile curve or 5th roll profile curve, and the roll profile curves of the remaining rolls remain unchanged;
[0043] When the convexity attenuation of the strip steel is ≥15 μm, the rolls corresponding to the 1st - 3rd stands of the CVC mill can be selected to be modified to the above-mentioned 3rd roll profile curve, 4th roll profile curve or 5th roll profile curve, or the rolls corresponding to the 1st - 4th stands of the CVC mill can be selected to be modified to the above-mentioned 3rd roll profile curve, 4th roll profile curve or 5th roll profile curve, and the roll profile curves of the remaining rolls remain unchanged;
[0044] (3) Set the lateral shift amount of the work rolls of the first two stands of the CVC mill to the maximum equivalent convexity, and combine the dynamic adjustment of the bending roll force of all CVC mills. The specific steps are as follows:
[0045] Within the first one - third of the total rolling time of the strip steel (the strip head), the lateral shift amounts of the work rolls of the first two CVC mills are set to the maximum equivalent convexity position, the lateral shift amounts of the work rolls of the remaining stands remain unchanged, and the bending roll force of the CVC stands is set to 80% - 95% of the upper limit, so that the strip head convexity level is maintained within ±1 - 3 μm of the original value;
[0046] In the last two-thirds of the total rolling time of the strip (the middle and tail of the strip), the lateral shift of the work rolls of the first two CVC mills is set to the maximum equivalent convexity position, and the lateral shift of the work rolls of the remaining stands remains unchanged at the original value. The bending force of the first two CVC stands is dynamically adjusted to be 20 - 400 kN higher than the lower limit of the bending force, and the bending force of the remaining CVC stands is dynamically adjusted to be between 80% - 95% of the upper limit of the bending force and 20 - 400 kN higher than the lower limit of the bending force, so that the plate convexity value of the middle and tail of the strip is increased to within ±1 - 5 μm of the head value of the strip;
[0047] Good results in plate convexity control can be obtained by using this method for ordinary carbon steel plates with a thickness specification in the range of 1 - 5 mm.
[0048] Example 2
[0049] Taking the Q235B steel plate with a specification of 1.5×1250 mm rolled on the 1780 hot continuous rolling production line of a certain steel plant as an example, the finishing mill unit adopts 7 rolling passes, and the first 4 stands are CVC mills. The original main rolling process parameters are as shown in Table 1 and Table 2 below:
[0050] Table 1
[0051]
[0052] Table 2
[0053]
[0054] For the further optimization plan, (1) a thickness gauge is used to detect the exit plate convexity of the whole strip. The plate convexity at the head of the strip is about 42 μm, and the plate convexity at the tail is about 28 μm, obtaining an actual plate convexity attenuation of 14 μm for the strip;
[0055] (2) Given that the plate convexity attenuation is 14 μm, the following CVC roll profile curves can be selected;
[0056] The specific characteristic of the 3rd roll profile curve of the CVC roll is a roll profile curve with an equivalent convexity of the roll increased by 500 - 700 μm compared to the original roll profile;
[0057] The specific characteristic of the 4th roll profile curve of the CVC roll is a roll profile curve with an equivalent convexity of the roll increased by 700 - 900 μm compared to the original roll profile;
[0058] The specific characteristic of the 5th roll profile curve of the CVC roll is a roll profile curve with an equivalent convexity of the roll increased by 900 - 1000 μm compared to the original roll profile;
[0059] In this example, it is selected to modify the rolls corresponding to the 1st - 2nd stands of the CVC mill to the above 4th roll profile curve, with the equivalent convexity of the roll increased by 800 μm compared to the original roll profile, and the roll profile curves of the remaining rolls remain unchanged;
[0060] (3) Set the work roll transverse shift of the first two stands of the CVC mill to the maximum equivalent crown, and combine the dynamic adjustment of the bending force of all CVC mills. The specific steps are as follows:
[0061] Within the first one-third of the total rolling time of the strip (strip head) - about 33 s, set the work roll transverse shift of the first two CVC mills to the maximum equivalent crown position, that is, -130 mm. The work roll transverse shift of the remaining stands remains unchanged, and the bending force of the CVC stands is set to 80% - 95% of the upper limit (1500 kN), that is, 1400 kN, so that the strip crown level at the head is maintained within the original value of ±1 - 3 μm.
[0062] Within the last two-thirds of the total rolling time of the strip (strip middle and tail) - about 66 s, set the work roll transverse shift of the first two CVC mills to the maximum equivalent crown position. The work roll transverse shift of the remaining stands remains unchanged. Dynamically adjust the bending force of the first two CVC stands to be 20 - 400 kN higher than the lower limit of the bending force, and dynamically adjust the bending force of the remaining CVC stands to be between 80% - 90% of the upper limit of the bending force and 50 - 400 kN higher than the lower limit of the bending force (400 kN), so that the strip crown value in the middle and tail is increased to within ±1 - 5 μm of the strip head value. The specific process parameters are shown in Table 3 and Table 4;
[0063] Table 3
[0064]
[0065] Table 4
[0066]
[0067] (4) The calculated strip crown at the head is about 45 μm, and at the tail is about 40 μm. The actual rolling results on-site before and after the application of the present invention are respectively as Figure 2 and Figure 3 shown.
[0068] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A control method for the longitudinal distribution of strip crown, characterized in that It includes the following steps: Based on a thickness gauge, the convexity of the strip steel at the outlet is detected to obtain the actual convexity attenuation of the strip steel; Analyze the actual convexity attenuation of the strip steel, and select the CVC mill roll profile curve based on the analysis results; Set the work roll transverse shift amount and the mill bending roll force of the CVC stand to obtain a setting result, and control the longitudinal distribution attenuation of the strip steel convexity based on the setting result and the CVC mill roll profile curve; The CVC mill roll profile curve includes a roll profile curve with the equivalent convexity of the roll increased by 100 - 300μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increased by 300 - 500μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increased by 500 - 700μm compared to the original roll profile, a roll profile curve with the equivalent convexity of the roll increased by 700 - 900μm compared to the original roll profile, and a roll profile curve with the equivalent convexity of the roll increased by 900 - 1000μm compared to the original roll profile; The process of obtaining the setting result includes: In the first one-third of the total rolling time of the strip steel, set the work roll transverse shift amounts of the first stand and the second stand of the mill to the maximum equivalent convexity position, keep the work roll transverse shift amounts of the remaining stands unchanged, and set the upper limit of the bending roll force of the CVC stand based on actual applications; In the last two-thirds of the total rolling time of the strip steel, set the work roll transverse shift amounts of the first stand and the second stand of the mill to the maximum equivalent convexity position, keep the work roll transverse shift amounts of the remaining stands unchanged, set the bending roll forces of the first stand and the second stand of the mill based on the lower limit value of the bending roll force, and set the remaining stands based on the upper limit value and the lower limit value of the bending roll force to obtain the setting result.
2. The control method for the longitudinal distribution of the strip steel crown according to claim 1, characterized in that, The process of obtaining the actual convexity attenuation of the strip steel includes: Based on a thickness gauge, detect the convexity of the strip steel head and the convexity of the strip steel tail to obtain the strip steel head convexity data and the strip steel tail convexity data; Calculate the strip steel head convexity data and the strip steel tail convexity data to obtain the actual convexity attenuation of the strip steel.
3. The control method for the longitudinal distribution of the strip camber according to claim 1, wherein The process of analyzing the actual convexity attenuation of the strip steel includes: Set a threshold range, and analyze and classify the actual convexity attenuation of the strip steel based on the threshold range to obtain an analysis result.
4. The control method for the longitudinal distribution of strip steel crown according to claim 1, characterized in that, The process of selecting the CVC mill roll profile curve based on the analysis result includes: Obtain the data of the CVC mill roll profile curve, and set the stand modification plan based on the data of the CVC mill roll profile curve; Select the stand of the CVC mill based on the analysis result and the stand modification plan.
5. The control method for the longitudinal distribution of the strip steel convexity according to claim 1, characterized in that The process of controlling the longitudinal distribution attenuation of the strip steel convexity based on the setting result and the CVC mill roll profile curve includes: Set a control range, and control the convexity value of the strip steel middle and tail based on the setting result, the control range and the CVC mill roll profile curve to obtain the longitudinal distribution attenuation control result of the strip steel convexity.