A full-automatic load distribution method for a finishing mill

Abstract

The application relates to a full-automatic distribution method of finishing mill load, which comprises the following steps: load correction determination, F1 rolling force correction, automatic load correction, load relativization calculation and the like. The full-automatic distribution method of the finishing mill load can automatically calculate the load distribution of the finishing mill, reduces on-site manual intervention, and achieves the effect of full-automatic rolling; the load distribution model table of the expert rule base can be modified and optimized outside the model, has strong maintainability, and reduces the risk of influencing on-site rolling due to maintenance of the expert base; a manual intervention window is reserved, and sudden on-site change maintenance operation can be realized.

Description

Technical Field

[0001] This invention relates to a fully automatic load distribution method for a finishing mill, belonging to the field of hot rolling technology. Background Technology

[0002] In the hot rolling production process, fully automatic load distribution in the finishing mill is a challenge for model control, requiring the development of a model that combines on-site process production with expert analysis.

[0003] The main problems are as follows:

[0004] 1. When production requires rolling thin or extreme specifications of products, the operational range of the process is small, and the process parameters are mutually restrictive and difficult to balance. For example, if the load of a single stand exceeds the limit and steel is prohibited from being fed into the rolling mill, the strip will remain in the intermediate roller table and the head temperature will be low; uneven load distribution will cause the load of the rear stand to be large, which will easily produce scrap steel.

[0005] 2. Currently, the commonly used finishing mill load distribution model is based on iterative calculations for different steel grades and specifications. It lacks automatic adjustment capabilities to adapt to specific on-site conditions. Without manual intervention, this can lead to batches of products with identical defects. Furthermore, operator intervention significantly reduces the automation rate of finishing mill load distribution on the production line. The varying skill levels and work habits of operators also have different impacts on load distribution, ultimately causing product quality issues. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned technologies and provide a fully automatic model for expert rule-based load allocation based on field processes.

[0007] To solve the above-mentioned technical problems, the technical solution proposed in this invention is: a fully automatic load distribution method for a finishing mill, wherein the finishing mill includes stands F1 to F7, and the stand load reduction rate setting data is stored in a matrix R. cal In [i], where i = 1 to 7, the following steps are included:

[0008] Step 1: Different automatic load correction models are required for different steel grades; when production requires rolling thinner products of 1.8mm and below, use the F1 rolling force correction model; otherwise, use the automatic load correction model.

[0009] Step 2: When the F1 rolling force correction model is used in Step 1, it is determined whether the F1 automatic load determination model can be called based on the quality number, type, thickness layer, and width layer of the steel grade; where the quality number, type, thickness layer, and width layer of the steel grade are 18, 2002, 7, 3 or 460, 15002, 5, 3 respectively, then the F1 automatic load determination model is called.

[0010] Step 3: When the F1 load automatic determination model is called in Step 2; obtain the F1 set rolling force F1 of the finishing mill. cal Loop 1 (1# Loop Angle Setting) CAL According to the F1 rolling force limit value F1 set =3500, Loop 1# Loop angle limit value = 45°; F1 load reduction rate correction value F1 corr =-2, adjust accordingly;

[0011] If F1 cal >F1 set And Loop1 CAL <Loop1, then the load reduction rate R[1] = R cal [1]-F1 corr ;

[0012] If F1 cal <F1 set And Loop1 CAL > Loop1, then the load reduction rate R[1] = R cal [1]+F1 corr ;

[0013] Based on the adjusted F1 load reduction rate, modify the load reduction rate matrix R of the finishing mill. cal The data at the corresponding position in [i];

[0014] Step 4: Load relativization calculation; calculation of relativization factor xrk:

[0015] xrk=(-λ1x s1 +xrk1) / (2λ2x s2 );

[0016] In the formula, λ1 = 0.9065, λ2 = 0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1;

[0017] Therefore, the final load reduction rate R[i] = R cal [i]*xrk;

[0018] Step 5: When using the automatic load correction model in Step 1, obtain the set rolling force F for each stand of the finishing mill. set [i]; then adjust the load reduction rate for each rack according to the table below:

[0019] F1 F2 F3 F4 F5 F6 F7 <![CDATA[Set the rolling force threshold value 1 / F set1 > 3300 3000 2800 2000 1650 1400 1200 <![CDATA[Automatic correction of reduction ratio 1 / R corr1 > -3 -2 -2 -2 -2 -2 -2 <![CDATA[Set the rolling force threshold value 2 / F set2 > 3600 3300 3000 2100 1750 1500 1300 <![CDATA[Automatic correction of reduction ratio 2 / R corr2 > -5 -3 -2 -3 -3 -3 -3

[0020] If F set [i]>Fset1 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr1 [i]; if F set1 [i]>F set [i]>F set2 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr2 [i];

[0021] Step 6: Adjust R0[i] as described in Step 5 according to the following table:

[0022] F1 F2 F3 F4 F5 F6 F7 <![CDATA[Set reduction rate threshold value / R set > 65 65 65 35 35 35 35 <![CDATA[Automatic correction of reduction ratio / R corr3 > -2 -2 -2 -2 -2 -2 -2

[0023] If R0[i]>R set [i], then the rack reduction ratio R[i] = R0[i] - R corr3 [i];

[0024] Step 7: Load relativization calculation; calculation of relativization factor xrk:

[0025] xrk=(-λ1x s1 +xrk1) / (2λ2x s2 );

[0026] In the formula, λ1=0.9065, λ2R[1]= R cal [1]-F1 corr ;

[0027] =0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1;

[0028] Therefore, the final load reduction rate R[i] = R cal [i]*xrk.

[0029] A further improvement to the above scheme is that the input of human intervention is added to the calculation results with a weight ratio of 1%.

[0030] A further improvement to the above scheme is that the results obtained in step 4 or step 7 are stored in a cache array matrix, and the load calculation module is called to calculate the rolling force of each stand.

[0031] The fully automatic load distribution method for finishing mills provided by this invention can automatically calculate the load distribution of finishing mills, reducing on-site manual intervention to achieve the effect of fully automatic steel rolling; the load distribution model table of the expert rule base can be modified and optimized outside the model, which is highly maintainable and reduces the risk of affecting on-site rolling due to the maintenance of the expert base; a manual intervention window is provided to realize sudden on-site change and maintenance operations. Detailed Implementation

[0032] Example

[0033] In the fully automatic load distribution method for the finishing mill in this embodiment, the finishing mill includes stands F1 to F7, and the stand load reduction rate setting data is stored in matrix R. cal In [i], where i = 1 to 7, the following steps are included:

[0034] Step 1: Different automatic load correction models are required for different steel grades; when production requires rolling thinner products of 1.8mm and below, use the F1 rolling force correction model; otherwise, use the automatic load correction model.

[0035] Step 2: When the F1 rolling force correction model is used in Step 1, it is determined whether the F1 automatic load determination model can be called based on the quality number, type, thickness layer, and width layer of the steel grade; where the quality number, type, thickness layer, and width layer of the steel grade are 18, 2002, 7, 3 or 460, 15002, 5, 3 respectively, then the F1 automatic load determination model is called.

[0036] Step 3: When the F1 load automatic determination model is called in Step 2; obtain the F1 set rolling force F1 of the finishing mill. cal Loop 1 (1# Loop Angle Setting) CAL According to the F1 rolling force limit value F1 set =3500, Loop 1# Loop angle limit value = 45°; F1 load reduction rate correction value F1 corr =-2, adjust accordingly;

[0037] If F1 cal >F1 set And Loop1 CAL <Loop1, then the load reduction rate R[1] = R cal [1]-F1 corr ;

[0038] If F1 cal <F1 set And Loop1 CAL > Loop1, then the load reduction rate R[1] = R cal [1]+F1 corr ;

[0039] Based on the adjusted F1 load reduction rate, modify the load reduction matrix R of the finishing mill. cal The data at the corresponding position in [i];

[0040] Step 4: Load relativization calculation; calculation of relativization factor xrk:

[0041] xrk=(-λ1x s1 +xrk1) / (2λ2x s2 );

[0042] In the formula, λ1 = 0.9065, λ2 = 0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1;

[0043] Therefore, the final load reduction rate R[i] = R cal [i]*xrk;

[0044] Step 5: When using the automatic load correction model in Step 1, obtain the set rolling force F for each stand of the finishing mill. set [i]; then adjust the load reduction rate for each rack according to the table below:

[0045] F1 F2 F3 F4 F5 F6 F7 <![CDATA[Set the rolling force threshold value 1 / F set1 > 3300 3000 2800 2000 1650 1400 1200 <![CDATA[Automatic correction of reduction ratio 1 / R corr1 > -3 -2 -2 -2 -2 -2 -2 <![CDATA[Set the rolling force threshold value 2 / F set2 > 3600 3300 3000 2100 1750 1500 1300 <![CDATA[Automatic correction of reduction ratio 2 / R corr2 > -5 -3 -2 -3 -3 -3 -3

[0046] If F set [i]>F set1 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr1 [i]; if F set1 [i]>F set [i]>F set2 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr2 [i];

[0047] Step 6: Adjust R0[i] as described in Step 5 according to the following table:

[0048] F1 F2 F3 F4 F5 F6 F7 <![CDATA[Set the rolling reduction threshold value / R set > 65 65 65 35 35 35 35 <![CDATA[Automatic correction of reduction ratio / R corr3 > -2 -2 -2 -2 -2 -2 -2

[0049] If R0[i]>R set [i], then the rack reduction ratio R[i] = R0[i] - R corr3 [i];

[0050] Step 7: Load relativization calculation; calculation of relativization factor xrk:

[0051] xrk=(-λ1xs1 +xrk1) / (2λ2x s2 );

[0052] In the formula, λ1 = 0.9065, λ2 = 0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1;

[0053] Therefore, the final load reduction rate R[i] = R cal [i]*xrk.

[0054] The finishing mill load model is completely open to human intervention and requires no judgment. Therefore, the input of human intervention will be added to the model calculation results with a weight ratio of 1%. The load after intervention also needs to be judged by the limit value.

[0055] The results obtained in step 4 or step 7 are stored in the cache array matrix, and the load calculation module is called to calculate the rolling force of each stand.

[0056] Take a hot-rolled strip steel with a thickness of 3.0 mm and a width of 1600 mm produced by a steel mill as an example.

[0057] Different automatic load correction models are required for different steel grades. When production requires rolling thin products of 1.8mm and below, the load distribution requirements for F1 are high, necessitating the use of the F1 rolling force correction model. For steel grades without special requirements, the automatic load correction model is automatically invoked. In this case, the steel grade is 3.0mm, so the automatic load correction model is used.

[0058] Table 1 of the load distribution model is established, with specific values ​​determined by actual production tests and on-site process personnel based on experience. Information such as the automatically corrected steel coil, specifications, type, layer, and date is recorded, and the load distribution model table in the expert database is regularly optimized and adjusted to more accurately meet actual production requirements.

[0059] Load sharing model table 1:

[0060] F1 F2 F3 F4 F5 F6 F7 <![CDATA[Set rolling force threshold value / F set1 > 3300 3000 2800 2000 1650 1400 1200 <![CDATA[Automatic correction of reduction ratio / R corr1 > -3 -2 -2 -2 -2 -2 -2 <![CDATA[Set rolling force threshold value / F set2 > 3600 3300 3000 2100 1750 1500 1300 <![CDATA[Automatic correction of reduction ratio / R corr2 > -5 -3 -2 -3 -3 -3 -3

[0061] Table 2 establishes the load distribution model. When the load on a single stand exceeds the maximum reduction rate that the stand can withstand, it will have a significant impact on the product's sheet shape, such as single-sided waviness, double-sided waviness, and higher-order waviness, which can lead to scrap steel in severe cases. There is a limit threshold value for the maximum reduction rate of each stand, regardless of steel grade or specification.

[0062] Load sharing model table 2:

[0063]

[0064]

[0065] For steel grades requiring automatic load correction, the pre-calculated load data [3170,2596,2508,2294,1517,1632,1067] for each stand, calculated by the finishing mill setting model, is cached in an array matrix. The automatic load correction model is then called to determine that the pre-calculated load for stands F4 and F6 is lower than the set rolling force in Table 1 of the load distribution model.

[0066] Before calculation: load reduction rate [0.4219, 0.4335, 0.3593, 0.3004, 0.2412, 0.1889, 0.0938]. After calculation: load reduction rate [0.4219, 0.4335, 0.3593, 0.2854, 0.2412, 0.1739, 0.0938].

[0067] Load relativization calculation. The relativization factor xrk was calculated to be xrk = 0.998.

[0068] Final load reduction rate R[i] = R cal [i]*0.998. Store the corrected loads of each stand in the finishing mill into the cache array matrix.

[0069] Manual intervention module. The finishing mill load model is completely open to manual intervention and requires no judgment. Therefore, the input of manual intervention will be added to the model calculation results with a weight ratio of 1%. The load after intervention also needs to be judged by the limit value.

[0070] Load calculation module. The optimized loads for each stand have been calculated and stored in the cache array matrix. The load calculation module is then called to calculate the rolling force for each stand.

[0071] After offline functional testing and verification, and online deployment, the automatic correction range of each rack was further optimized.

[0072] This invention is not limited to the embodiments described above. All technical solutions formed by equivalent substitutions fall within the scope of protection claimed by this invention.

Claims

1. A fully automatic load distribution method for a finishing mill, the finishing mill comprising stands F1 to F7, wherein the stand load reduction rate setting data is stored in a matrix R. cal In [i], where i = 1 to 7; characterized in that, Includes the following steps: Step 1: Different automatic load correction models are required for different steel grades; when production requires rolling thinner products of 1.8mm and below, use the F1 rolling force correction model; otherwise, use the automatic load correction model. Step 2: When the F1 rolling force correction model is used in Step 1, it is determined whether the F1 automatic load determination model can be called based on the quality number, type, thickness layer, and width layer of the steel grade; where the quality number, type, thickness layer, and width layer of the steel grade are 18, 2002, 7, 3 or 460, 15002, 5, 3 respectively, then the F1 automatic load determination model is called. Step 3: When the F1 load automatic determination model is called in Step 2; obtain the F1 set rolling force F1 of the finishing mill. cal Loop 1 (1# Loop Angle Setting) CAL According to the F1 rolling force limit value F1 set =3500, Loop 1# Loop Angle Limit Value = 45°; F1 Load Reduction Rate Correction Value F1 corr =-2, adjust accordingly; If F1 cal >F1 set And Loop1 CAL <Loop1, then the load reduction rate R[1] = R cal [1]-F1 corr ; If F1 cal <F1 set And Loop1 CAL > Loop1, then the load reduction rate R[1] = R cal [1]+F1 corr ; Based on the adjusted F1 load reduction rate, modify the load reduction rate matrix R of the finishing mill. cal The data at the corresponding position in [i]; Step 4: Load relativization calculation; calculation of relativization factor xrk: xrk=(-λ1x s1 +xrk1) / (2λ2x s2 ); In the formula, λ1 = 0.9065, λ2 = 0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1; Therefore, the final load reduction rate R[i] = R cal [i]*xrk; Step 5: When using the automatic load correction model in Step 1, obtain the set rolling force F for each stand of the finishing mill. set [i]; then adjust the load reduction rate for each rack according to the table below: If F set [i]>F set1 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr1 [i]; if F set1 [i]>F set [i]>F set2 [i], then the rack reduction ratio R0[i]=R cal [i]-R corr2 [i]; Step 6: Adjust R0[i] as described in Step 5 according to the following table: If R0[i]>R set [i], then the rack reduction ratio R[i] = R0[i] - R corr3 [i]; Step 7: Load relativization calculation; calculation of relativization factor xrk: xrk=(-λ1x s1 +xrk1) / (2λ2x s2 ); In the formula, λ1 = 0.9065, λ2 = 0.9596; h0 is the inlet strip thickness of F1; h1 is the outlet strip thickness of F1; Therefore, the final load reduction rate R[i] = R cal [i]*xrk.

2. The fully automatic load distribution method for a finishing mill according to claim 1, characterized in that: The input from human intervention is added to the calculation results with a weighting of 1%.

3. The fully automatic load distribution method for a finishing mill according to claim 1, characterized in that: The results obtained in step 4 or step 7 are stored in a cache array matrix, and the load calculation module is called to calculate the rolling force of each stand.

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