Method and device for pre-judging inconformity of pattern rolling height

Abstract

The invention discloses a method and device for pre-judging the inconsistency of the pattern height of a pattern roll, and the method specifically comprises the following steps: (1) collecting the rolling parameters of a finishing mill group after the coiling of the pattern roll is finished; and (2) detecting whether the actual rolling force of the F7 rack at the head part of the pattern roll is lower than the lower limit value of the rolling force of the corresponding steel grade, and if the detection result is yes, determining that the corresponding pattern roll has the risk of unqualified pattern height. After the steel coil is produced, the inconformity of the steel coil grain height can be automatically judged within an extremely short time, the abnormal steel coil is blocked, an operator does not need to uncoil and measure the grain height at a high temperature, the occurrence probability of safety accidents is greatly reduced, and the labor cost and the process cost are reduced.

Description

Technical Field

[0001] This invention belongs to the field of hot rolling technology, and more specifically, this invention relates to a method and apparatus for pre-judging the discrepancy between pattern coil height and other parameters. Background Technology

[0002] Hot-rolled patterned coils are a special type of steel coil with patterns on the upper surface in the hot-rolling zone. The resulting patterned steel plates have raised edges on their surface, providing an anti-slip effect, and can be used for flooring, factory ladders, work platform treads, ship decks, car flooring, etc.

[0003] The pattern height of hot-rolled patterned coils is one of the important attributes of this product. However, controlling the pattern height during the hot rolling process is quite difficult. The national standard GBT-709 sets forth clear requirements for the pattern height of patterned steel products. To ensure that the pattern height meets the usage requirements, the pattern height must be measured after the patterned steel coils are produced to ensure compliance with the national standard.

[0004] In actual mass production, because the temperature of the steel coils exiting the production line is above 500℃, the coils must be allowed to cool down to near room temperature after uncoiling before the groove height can be measured. This measurement poses safety risks and has extremely low efficiency, resulting in a low frequency of groove height measurements. This leads to the risk of coils with incorrect groove heights being shipped out. If the groove height were measured on a leveling unit for each coil individually, it would significantly increase process and labor costs, and also put pressure on the leveling unit's capacity. Summary of the Invention

[0005] The present invention provides a method for pre-judging the discrepancy between pattern and curl height, which aims to improve at least one of the above-mentioned problems.

[0006] This invention is implemented as follows: a method for pre-determining discrepancies in pattern curl height, the method being as follows:

[0007] (1) After the patterned coil is finished, collect the rolling parameters of the finishing mill;

[0008] (2) Check whether the actual rolling force of the F7 stand at the head of the patterned coil is lower than the lower limit of the rolling force of the corresponding steel grade. If the test result is yes, it is determined that the corresponding patterned coil has a risk of unqualified pattern height.

[0009] Furthermore, check whether the difference between the set total rolling force and the actual total rolling force of the F7 stand exceeds the total rolling force deviation threshold. If the test result is yes, then the corresponding patterned coil is at risk of having an unqualified pattern height.

[0010] Furthermore, check whether the difference between the set reduction rate and the actual reduction rate of the F7 frame exceeds the reduction rate deviation threshold. If the test result is yes, then the corresponding patterned coil is at risk of having an unqualified pattern height.

[0011] Furthermore, the actual head thickness of the patterned coil after finishing rolling is collected, the difference between the upper limit of the target thickness of the patterned coil and the actual head thickness of the patterned coil after finishing rolling is calculated, and it is detected whether the difference exceeds the thickness deviation threshold. If the detection result is yes, then the corresponding patterned coil is identified as having a risk of unqualified pattern height.

[0012] Furthermore, the method for determining the lower limit of rolling force is as follows:

[0013] The lower limit of rolling force under the reference pattern height is determined based on the yield strength of the current patterned coil.

[0014] Based on the ratio of the current pattern height to the reference pattern height, the lower limit of the rolling force under the reference pattern height is adjusted according to the corresponding ratio, and used as the lower limit of the rolling force for the current steel grade.

[0015] Furthermore, the average actual rolling force of the F7 stand along the rolling direction within the length range of the patterned coil head is taken as the actual rolling force of the F7 stand at the patterned coil head.

[0016] Furthermore, the thickness deviation threshold is set to 5%.

[0017] This invention is implemented as follows: a pre-determination device for discrepancy between texture height and surface area, the device comprising:

[0018] Data acquisition unit, judgment unit, and prompting unit;

[0019] After the patterned coil is wound up, the data acquisition unit collects the rolling parameters of the finishing mill and sends them to the judgment unit. The judgment unit determines whether there is a risk of the current patterned coil having an unqualified pattern height based on the above-mentioned patterned coil height discrepancy pre-judgment method. If so, it issues a reminder through the prompting unit.

[0020] Furthermore, the judgment unit is connected to the MES system. When the judgment unit determines that there is a risk of the patterned coil having an unqualified pattern height, it generates a blocking signal and sends it to the MES system. The MES system blocks the steel coil based on the blocking signal.

[0021] The pattern height discrepancy pre-judgment method provided by the present invention has the following beneficial technical effects: the automatic judgment of pattern height discrepancy of steel coil can be completed in a very short time after the steel coil is produced, and the abnormal steel coil is blocked. Operators do not need to unwind and measure the pattern height at high temperature, which greatly reduces the probability of safety accidents and reduces labor costs and process costs. Attached Figure Description

[0022] Figure 1 This is a flowchart of the pattern and curl height mismatch pre-judgment method provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the pre-judgment device for pattern roll height mismatch provided in an embodiment of the present invention. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0025] The load distribution for patterned steel plates differs significantly from that for flat rolling. In flat rolling, the load gradually decreases; however, in patterned steel plate rolling, a sufficiently large reduction must be ensured for the printing roll stand, typically ranging from 17% to 23%. The printing roll is located on the last stand of the finishing mill, which includes stands F1 through F7. The load distribution strategy is that the loads on stands F1, F2, F3, and F4 are roughly the same, while the loads on stands F5 and F6 are relatively minimal. The load on stand F7 is increased, ensuring a reduction rate of 17% to 25% for stand F7. However, patterned steel plate products currently use a variety of steel grades, and the compositions of different steel grades vary. (The last sentence appears to be incomplete and possibly refers to a specific type of steel plate, FSU, and its composition.) The calculated values ​​of reduction rate and rolling force may deviate significantly from the set values. In addition, the actual reduction rate or rolling force of the F7 stand may not meet the set requirements, which may lead to discrepancies in the strip height. In order to ensure that the strip height meets the requirements as much as possible, this invention uses the rolling parameters in the finishing rolling process of the steel coil to predict whether the strip height meets the requirements and to control the steel coil with discrepancies in strip height.

[0026] Figure 1 The flowchart of the pattern curl height mismatch pre-judgment method provided in the embodiment of the present invention is as follows:

[0027] (1) The pattern is heated, rough rolled, finish rolled, layer cooled and coiled to complete the production process. After the pattern coil is coiled, the rolling parameters of the finish rolling mill are collected.

[0028] (2) Check whether the actual rolling force of the F7 stand at the head of the patterned coil is lower than the lower limit of the rolling force of the corresponding steel grade. If the test result is yes, it is determined that the corresponding patterned coil has a risk of unqualified pattern height.

[0029] In this embodiment of the invention, the method for determining the lower limit of the rolling force is as follows:

[0030] The lower limit of rolling force under the reference pattern height is determined based on the yield strength of the current patterned coil.

[0031] Based on the ratio of the current pattern height to the reference pattern height, the lower limit of the rolling force under the reference pattern height is adjusted accordingly.

[0032] During the rolling process, the rolling force formula for flat roll rolling is: P = σy × A, where σy is the deformation resistance of the rolled piece, and A is the deformation area of ​​the rolled piece. For patterned coils, the calculation of the deformation area A becomes complicated due to the presence of patterns. This invention considers the total deformation area A of the patterned coil as the sum of the deformation area A1 of the flat rolled portion and the deformation area A2 of the patterned portion, i.e., A = A1 + A2. Let the height of the pattern be h, the area of ​​the pattern be s, the length of the deformation zone of the rolled piece be L, and the width of the deformation zone of the rolled piece be B. The deformation area A1 of the flat rolled portion is: A1 = B × L; the deformation area A2 of the patterned portion is related to the pattern height and the distribution of the pattern. Assuming that the pattern is uniformly distributed and the number of patterned plates per unit width is n / m, the deformation area A2 of the patterned portion is approximately B × n × s × h. Therefore, the total deformation area of ​​the patterned coil is: A = A1 + A2 = B × L + B × n × s × h = B × (L + n × s × h).

[0033] Substituting A = B × (L + b × h / (l + b)) into the rolling force formula P = σy × A, we get:

[0034] P = σy × B × (L + b × h / (l + b));

[0035] Based on the above formula, it can be seen that when the yield strength σy of the rolled material, the width B of the rolled material, and the rolling length L are constant, the rolling force P is linearly related to the groove height h. The larger the groove height h is, the larger the rolling force P is.

[0036] Because the actual production of patterned steel products involves a wide variety of steel grades, the yield strength σy varies considerably. To ensure the pattern height meets customer requirements, different steel grades require different minimum rolling pressures. This invention categorizes the steel grades of patterned coil products into four yield strength levels. Combining theoretical models and production practice, the lower limit values ​​of the rolling force corresponding to the benchmark pattern height under different yield strength levels are derived, as shown in Table 1. When the rolling force of the rolled steel grade is lower than the lower limit of the rolling force, the patterned coil faces the risk of insufficient pattern height.

[0037] According to national standards, the texture height should generally be greater than or equal to 10% to 15% of the substrate thickness. To ensure compliance with national standards, 15% of the substrate thickness is used as the baseline texture height.

[0038] Table 1. Lower limit of rolling force corresponding to yield strength at different reference groove heights.

[0039]

[0040] In this embodiment of the invention, the average actual rolling force of the F7 stand within a length range of 10m to 20m along the rolling direction of the patterned coil is calculated as the actual rolling force of the F7 stand at the head of the patterned coil.

[0041] Rolling force deviation refers to the difference between the actual rolling force and the model's calculated set value. Rolling force deviation = (Actual rolling force - Rolling force set value) / Rolling force set value × 100%. The finishing mill FSU setting calculation model calculates the target rolling force value based on parameters such as steel grade and entry thickness. If the actual rolling force deviates significantly from the set value (>8%), it indicates a significant difference between the current process parameters (such as friction coefficient and deformation resistance) and the model prediction, potentially leading to uncontrolled pattern height. In actual production, process parameters fluctuate, such as fluctuations in workpiece entry thickness, roll surface condition (wear / roughness), changes in lubrication conditions affecting actual deformation resistance, and insufficient estimation accuracy of the finishing mill FSU setting calculation model for special deformations of patterned plates (such as the additional deformation area A2 of the pattern). All these factors can lead to calculation deviations in rolling force. However, the finishing mill FSU setting calculation model has high prediction accuracy for conventional steel grades (deviation ≤5%), but for high-strength steel or special working conditions (such as non-fixed and highly variable patterned plate steel grades), the prediction error may expand to 8%-10%. The 8% threshold is a critical threshold determined through comprehensive analysis of production data statistics, model accuracy calibration, and theoretical models (Ph linear relationship). When the rolling force deviation exceeds this value, the actual total rolling force is insufficient to maintain the required roll height. Based on this, the present invention performs the following tests:

[0042] Check whether the difference between the set total rolling force and the actual total rolling force of the F7 stand exceeds the total rolling force deviation threshold (5%). If the test result is yes, it indicates that there is a risk of unqualified pattern height for the corresponding patterned coil. The total rolling force is the sum of the rolling forces of the work rolls on both sides.

[0043] The F7 frame is the final forming frame for printing. Its actual reduction rate directly affects the final indentation depth of the pattern, i.e., the pattern height h. The two are directly proportional. The F7 reduction rate is set at 17%~20% (adjusted according to the steel grade). This is a critical process window to ensure that the pattern height is ≥20% of the substrate thickness. If the actual reduction rate is more than 5% lower than the set reduction rate, it will lead to insufficient pattern indentation depth and a significant reduction in pattern height h. Production practice shows that when the reduction rate deviation exceeds 5%, the pattern height is likely to be less than 15% of the substrate thickness. Although the reduction rate setting range is different for different steel grades, the allowable deviation threshold is uniform. If the actual reduction rate is 5% lower than the set reduction rate, it means that the actual process deviates too much from the optimal window, and the risk of insufficient pattern height is extremely high. Based on this, the present invention also conducts the following tests:

[0044] The difference between the set reduction rate and the actual reduction rate of the F7 frame is checked to see if it exceeds the reduction rate deviation threshold (8%). If the test result is yes, it indicates that there is a risk of unqualified pattern height for the corresponding patterned coil. The actual reduction rate of the F7 frame is calculated based on the exit thickness curves of the F6 and F7 frames.

[0045] Thickness measurements within the 10-20m range of the initial strip rolling section can be used to evaluate the accuracy of the finishing mill FSU setting calculation model for the strip head setting. Thickness gauges are typically installed approximately 10m from the last stand exit. AGC (Automatic Gauge Control) for strip thickness generally intervenes about 1 second after threading; therefore, head thickness deviation primarily reflects model setting deviation, rather than AGC lag correction. By utilizing the deviation between the actual head thickness and the target thickness, the direction and magnitude of the systematic deviation in the finishing mill FSU setting calculation model can be inferred. From industry practice and control objectives, a head thickness deviation exceeding 5% is generally considered a "significant deviation," especially for high-precision products, where a 5% deviation may exceed internal control standards, affecting product quality and subsequent processing. The pattern height of checkered plate products is formed by "effective reduction." If the F7 head substrate is 5% thicker than the target thickness, under the premise that the last stand reduction rate and roll gap remain unchanged, the available reduction space at the last stand exit passively decreases, leading to a relatively insufficient pattern height formation and the risk of a thick plate with low pattern height. Based on this, the present invention also conducts the following tests:

[0046] Calculate the difference between the upper limit of the target thickness of the patterned coil and the actual head thickness of the patterned coil after precision rolling. Check whether the difference exceeds the thickness deviation threshold. If the detection result is yes, it indicates that the corresponding patterned coil has a risk of unqualified pattern height.

[0047] Figure 2 This is a schematic diagram of the pre-judgment device for pattern and curl height discrepancy provided in an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown. The device includes:

[0048] The system includes a data acquisition unit, a judgment unit, and a prompting unit.

[0049] After the patterned coil is coiled, the data acquisition unit collects the rolling parameters of the finishing mill and sends them to the judgment unit. The judgment unit determines whether there is a risk of the current patterned coil having an unqualified pattern height based on the above-mentioned patterned coil height discrepancy pre-judgment method. If so, the unit issues a reminder through the prompting unit and sends a blocking signal to the MES system. The MES system blocks the steel coil according to the message signal.

[0050] The present invention has been described by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for pre-judging discrepancies in pattern scroll height, characterized in that, The method is as follows: (1) After the patterned coil is finished, collect the rolling parameters of the finishing mill; (2) Check whether the actual rolling force of the F7 stand at the head of the patterned coil is lower than the lower limit of the rolling force of the corresponding steel grade. If the test result is yes, it is determined that the corresponding patterned coil has a risk of unqualified pattern height.

2. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, Check whether the difference between the set total rolling force and the actual total rolling force of the F7 stand exceeds the total rolling force deviation threshold. If the test result is yes, it indicates that there is a risk of unqualified pattern height for the corresponding patterned coil.

3. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, Check whether the difference between the set reduction rate and the actual reduction rate of the F7 frame exceeds the reduction rate deviation threshold. If the test result is yes, it indicates that there is a risk of unqualified pattern height for the corresponding patterned coil.

4. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, The actual head thickness of the patterned coil after finishing rolling is collected, the difference between the upper limit of the target thickness of the patterned coil and the actual head thickness of the patterned coil after finishing rolling is calculated, and the difference is checked to see if it exceeds the thickness deviation threshold. If the detection result is yes, then the corresponding patterned coil is identified as having a risk of unqualified pattern height.

5. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, The specific method for determining the lower limit of rolling force is as follows: The lower limit of rolling force under the reference pattern height is determined based on the yield strength of the current patterned coil. Based on the ratio of the current pattern height to the reference pattern height, the lower limit of the rolling force under the reference pattern height is adjusted according to the corresponding ratio, and used as the lower limit of the rolling force for the current steel grade.

6. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, The average actual rolling force of the F7 stand along the rolling direction within the length of the patterned coil head is taken as the actual rolling force of the F7 stand at the patterned coil head.

7. The method for pre-judging discrepancies in texture height as described in claim 1, characterized in that, The thickness deviation threshold is set to 5%.

8. A device for pre-judging discrepancies in texture height, characterized in that, The device includes: Data acquisition unit, judgment unit, and prompting unit; After the patterned coil is wound up, the data acquisition unit collects the rolling parameters of the finishing mill and sends them to the judgment unit. The judgment unit determines whether there is a risk of the current patterned coil having an unqualified pattern height based on the patterned coil height non-compliance pre-judgment method described in any one of claims 1 to 7. If so, a reminder is issued through the prompting unit.

9. The pre-judgment device for discrepancy in texture height as described in claim 8, characterized in that, The judgment unit is connected to the MES system. When the judgment unit determines that there is a risk of the patterned coil having an unqualified pattern height, it generates a blocking signal and sends it to the MES system. The MES system blocks the steel coil based on the blocking signal.

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