Method for distributing the reductions in the primary and secondary cold rolling of quasi-2-step cold rolling

Abstract

This invention relates to a method for allocating the reduction amount between primary and quasi-secondary cold rolling in quasi-secondary cold rolling, comprising the following steps: acquiring strip steel and model parameters, acquiring process parameters, establishing a strip steel strength model during the quasi-secondary cold rolling process, establishing the relationship between the finished strip steel strength index and the reduction amount of the quasi-secondary cold rolling mill, determining the maximum and minimum values, and calculating the allocation domain. The method for allocating the reduction amount between primary and quasi-secondary cold rolling in quasi-secondary cold rolling provided by this invention eliminates problems such as excessive mill load and high defect rates, effectively improving mill capacity and reducing the defect rate.

Description

Technical Field

[0001] This invention relates to a method for allocating the reduction amount between primary and quasi-secondary cold rolling in a quasi-secondary cold rolling process, belonging to the field of metal smelting technology. Background Technology

[0002] Before the tin plating process, the strip steel undergoes a first cold rolling and a second cold rolling to achieve the target thickness. The reduction amount in the first and second cold rolling processes determines the thickness of the finished tinplate. After the first cold rolling and annealing, the tinplate enters a double-stand second cold rolling process. The distribution of reduction amounts between the first and second cold rolling processes becomes a key indicator in actual production.

[0003] In recent years, as users of high-quality tinplate have increasingly complex and diverse requirements for their products, they have also paid more attention to the strength of finished tinplate products. In actual production, tinplate undergoes primary and secondary cold rolling processes during the quasi-secondary cold rolling process, resulting in changes in its strip strength and making the final product strength uncontrollable. The reduction amount during primary and secondary cold rolling in quasi-secondary cold rolling becomes a key indicator of the finished material's strength grade, and further research and exploration are needed regarding the allocation of this reduction amount. Currently, the allocation of reduction amount between primary and quasi-secondary cold rolling in the field often lacks a defined range. This leads to problems such as overloading and difficulty in controlling defects in the primary or quasi-secondary cold rolling mills for certain steel grades and specifications during the allocation process. Summary of the Invention

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of the aforementioned technologies, and by combining the characteristics of the quasi-secondary cold rolling process, establish a strength model for tinplate during the quasi-secondary cold rolling process. Taking the finished strength index of the tinplate as the target, a model is established to relate it to the reduction amount of the quasi-secondary cold-rolled tinplate. Furthermore, a reduction allocation method is established to establish the relationship between the quasi-secondary reduction amount and the allocation coefficient. Tinplate can be classified into grades based on its material strength. The strength index of each grade falls within a certain range, which is not a fixed value, and within this range, the strength index has a minimum and maximum value. Therefore, the reduction amount in the quasi-secondary cold rolling process is allocated based on the relationship between the reduction amount and the strength index.

[0005] To solve the above-mentioned technical problems, the present invention proposes a technical solution: a method for distributing the reduction amount between primary cold rolling and quasi-secondary cold rolling in quasi-secondary cold rolling, comprising the following steps:

[0006] Step (1): Obtain the characteristic parameters of the strip steel material and the parameters of the strength index model to be set;

[0007] Strip parameter B, material work hardening index Actual carbon equivalent Initial deformation resistance of strip steel Deformation speed influence coefficient The central value of the strength index of cold-rolled strip steel Center value of strength index of finished strip steel Fluctuation value of strength index of cold-rolled strip steel Fluctuation value of finished strip steel strength index ;

[0008] Step (2): Obtain rolling process parameters, reduction rate Export thickness of secondary cold-rolled strip ;

[0009] Step (3): Establish a strip strength model during the quasi-secondary cold rolling process. ;

[0010] Step (4): Combining the strip strength model during the quasi-secondary cold rolling process, let the strip strength grade after primary cold rolling annealing be k. With the strip finished product strength index K as the target, establish the relationship between the strip finished product strength index K and the reduction amount of the quasi-secondary cold rolling mill. relation, ;

[0011] Step (5): Derive the reduction amount of the quasi-secondary cold rolling mill with the strip steel finished product strength index K as the independent variable. The dependent variable relationship is... ;

[0012] Step (6): The strength index of the primary and secondary cold-rolled strips in the quasi-secondary cold rolling process is within a certain range, and is not a fixed value. Establish the relationship between the strip strength index k after primary cold rolling and annealing and the finished strip strength index. expression, ; ;

[0013] Step (7): When the strength value of the incoming strip from the primary cold rolling mill is the minimum and the strength value of the finished strip is the maximum, the total reduction is allocated to the quasi-secondary cold rolling mill, and an expression is established for the minimum strength index of the incoming strip from the primary cold rolling mill and the maximum strength index of the finished strip. ; ;

[0014] Step (8): When the strength value of the incoming cold-rolled strip is the minimum and the strength value of the finished strip is the maximum, then the expression for the maximum reduction of the quasi-secondary cold-rolling mill required to meet the target strength index of the finished strip is obtained. ;

[0015] Step (9): When both the strength values ​​of the incoming cold-rolled strip and the finished strip are taken as the center value, the reduction of the quasi-secondary cold rolling mill is the minimum. Therefore, the expression for the minimum reduction of the quasi-secondary cold rolling mill that satisfies the strength index of the finished strip is obtained. ;

[0016] Step (10): After the strip steel undergoes a first cold rolling, annealing, and quasi-second cold rolling process, it is formed into a finished strip steel. The total reduction in the first cold rolling and quasi-second cold rolling processes is... At a given time, a reduction distribution coefficient is introduced. Cold rolling reduction per cycle and quasi-secondary cold rolling The reduction amounts are respectively, , ;

[0017] Step (11): The maximum reduction of the quasi-secondary cold rolling mill required to meet the target strength index of the finished strip steel. and minimum reduction Calculate the reduction distribution coefficient The allocation domain, ;

[0018] Step (12): Output the reduction distribution coefficient between primary and secondary cold rolling in quasi-secondary cold rolling. In the allocation domain, select any value and adjust the first cold rolling reduction and the quasi-second cold rolling reduction according to step (10).

[0019] The present invention provides a method for allocating reduction amounts in primary and quasi-secondary cold rolling processes during quasi-secondary cold rolling. Combining the characteristics of the quasi-secondary cold rolling process, a strength model of the tinplate is established during the quasi-secondary cold rolling process. Using the finished strength index of the tinplate as the target, a relationship model is established between the tinplate reduction amount and the reduction amount of the quasi-secondary cold-rolled tinplate, and further, the relationship between the quasi-secondary reduction amount and the allocation coefficient is established. This method eliminates problems such as excessive unit load and high defect rates, effectively improving the unit's capacity and reducing the defect rate. Detailed Implementation

[0020] Example 1

[0021] Taking the company's first type of tinplate as an example,

[0022] First, in step A), the characteristic parameters of the tinplate strip material and the parameters of the strength index model to be set are collected, mainly including: strip material parameters. =0.005, material work hardening index =0.70, actual carbon equivalent =1.2%, initial deformation resistance of strip steel =200MPa, Deformation speed influence coefficient =0.78, the central value of the strength index of cold-rolled strip steel. =330 MPa, center value of finished strip steel strength index =550 MPa, fluctuation value of strength index of cold-rolled strip steel =50MPa, fluctuation value of finished strip steel strength index =50 MPa;

[0023] Subsequently, in step B), key rolling process parameters are collected, mainly including: reduction rate. =10%, Exit thickness of secondary cold-rolled strip steel =0.18mm;

[0024] Subsequently, in step C), a strength model for tinplate during the quasi-secondary cold rolling process is established based on actual production: ;

[0025] Subsequently, in step D), based on the tinplate strength model during the quasi-secondary cold rolling process, the strength grade after primary cold rolling annealing is set as follows: Based on the strength index of tinplate finished products To establish its reduction rate compared to the quasi-secondary cold rolling mill unit. relation: ;

[0026] Subsequently, in step E), the strength of the tin-plated sheet product is derived. The independent variable is the reduction of the quasi-secondary cold rolling mill. The dependent variable relationship is as follows: ;

[0027] Subsequently, in step F), the strip strength index after cold rolling annealing is established. Strength index of tin-plated sheet expression: , ;

[0028] Subsequently, in step G), the minimum strength index of the cold-rolled incoming strip and the maximum strength index of the finished strip are calculated: =280Mpa, =600 MPa;

[0029] Then, in step H), the maximum reduction of the quasi-secondary cold rolling mill required to meet the target strength index of the finished strip is calculated: =0.14mm;

[0030] Then, in step I), the minimum reduction of the quasi-secondary cold rolling mill required to meet the target strength index of the finished strip is calculated: =0.08mm;

[0031] Then, in step J), the total reduction amount is set. =2mm, introducing the reduction distribution coefficient Cold rolling reduction per cycle and quasi-secondary cold rolling The reduction amounts are respectively

[0032]

[0033]

[0034] Subsequently, the secondary cold rolling reduction from step J) is used in step K). With allocation coefficient Substituting the minimum and maximum reduction values ​​of the quasi-secondary cold rolling mill in steps H) and I) respectively, the extreme values ​​of the distribution coefficients are calculated: =0.93, =0.96;

[0035] Subsequently, in step L), the distribution coefficient distribution domain of the reduction amount between the primary and secondary cold rolling in the quasi-secondary cold rolling is output. = (0.93~0.96).

[0036] M) In production, a specific number is selected in the allocation domain to adjust the amount of pressure.

[0037] Example 2:

[0038] Taking the company's second type of tin-plated sheet as an example,

[0039] First, in step A), the characteristic parameters of the tin-plated steel strip material and the parameters of the strength index model to be set are collected, mainly including: strip material parameters. =0.005, material work hardening index =0.67, actual carbon equivalent =0.4%, initial deformation resistance of strip steel =180MPa, Deformation speed influence coefficient =0.64, the central value of the strength index of cold-rolled strip steel. =420 MPa, center value of finished strip steel strength index =660MPa, fluctuation value of strength index of cold-rolled strip steel =50MPa, fluctuation value of finished strip steel strength index =40 MPa;

[0040] Subsequently, in step B), key rolling process parameters are collected, mainly including: reduction rate. =13%, Exit thickness of secondary cold-rolled strip steel =0.15mm;

[0041] Subsequently, in step C), a strength model for tinplate during the quasi-secondary cold rolling process is established based on actual production: ;

[0042] Subsequently, in step D), based on the tinplate strength model during the quasi-secondary cold rolling process, the strength grade after primary cold rolling annealing is set as follows: Based on the strength index of tinplate finished products To establish its reduction rate compared to the quasi-secondary cold rolling mill unit. relation: ;

[0043] Subsequently, in step E), the strength of the tin-plated sheet product is derived. The independent variable is the reduction of the quasi-secondary cold rolling mill. The dependent variable relationship is as follows: ;

[0044] Subsequently, in step F), the strip strength index after cold rolling annealing is established. Strength index of tin-plated sheet expression: , ;

[0045] Subsequently, in step G), the minimum strength index of the cold-rolled incoming strip and the maximum strength index of the finished strip are calculated: =370Mpa, =710 MPa;

[0046] Then, in step H), the maximum reduction of the quasi-secondary cold rolling mill required to meet the target strength index of the finished strip is calculated: =0.19mm;

[0047] Then, in step I), the minimum reduction of the quasi-secondary cold rolling mill required to meet the target strength index of the finished strip is calculated: =0.14mm;

[0048] Then, in step J), the total reduction amount is set. =2.8mm, introducing the reduction distribution coefficient Cold rolling reduction per cycle and quasi-secondary cold rolling The reduction amounts are respectively

[0049]

[0050]

[0051] Subsequently, the secondary cold rolling reduction from step J) is used in step K). With allocation coefficient Substituting the minimum and maximum reduction values ​​of the quasi-secondary cold rolling mill in steps H) and I) respectively, the extreme values ​​of the distribution coefficients are calculated: =0.95, =0.93;

[0052] Subsequently, in step L), the distribution field of the reduction distribution coefficient between the primary and secondary cold rolling in the quasi-secondary cold rolling is output. = (0.93~0.95).

[0053] M) In production, a specific number is selected in the allocation domain to adjust the amount of pressure.

[0054] 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 method for allocating the reduction amount between primary and secondary cold rolling in a quasi-secondary cold rolling process, characterized in that, Includes the following steps: Step (1): Obtain the characteristic parameters of the strip steel material and the parameters of the strength index model to be set; Strip steel parameter B=0.005, material work hardening index Actual carbon equivalent Initial deformation resistance of strip steel Deformation speed influence coefficient The central value of the strength index of cold-rolled strip steel Center value of strength index of finished strip steel Fluctuation value of strength index of cold-rolled strip steel Fluctuation value of finished strip steel strength index ; Step (2): Obtain rolling process parameters, reduction rate Export thickness of secondary cold-rolled strip ; Step (3): Establish a strip strength model during the secondary cold rolling process. ; Step (4): Based on the strip strength model during the secondary cold rolling process, let the strip strength index after the primary cold rolling annealing be k. With the finished strip strength index K as the target, establish the relationship between the finished strip strength index K and the reduction of the secondary cold rolling mill. relation, ; Step (5): Derive the reduction amount of the secondary cold rolling mill with the finished strip strength index K as the independent variable. The dependent variable relationship is... ; Step (6): The strength index of the strip steel in the quasi-secondary cold rolling process is within a certain range, and is not a fixed value. Establish the strength index k of the strip steel after primary cold rolling and annealing and the strength index of the finished strip steel. expression, ; ; Step (7): When the strength value of the incoming strip from the primary cold rolling mill is the minimum and the strength value of the finished strip is the maximum, the total reduction is allocated to the secondary cold rolling mill, and an expression is established for the minimum strength index of the incoming strip from the primary cold rolling mill and the maximum strength index of the finished strip. ; ; Step (8): When the strength value of the incoming cold-rolled strip is the minimum and the strength value of the finished strip is the maximum, then the expression for the maximum reduction of the secondary cold-rolling mill required to meet the target strength index of the finished strip is obtained. ; Step (9): When both the strength values ​​of the incoming cold-rolled strip and the finished strip are taken as the center value, the reduction of the secondary cold-rolling mill is the minimum. Therefore, the expression for the minimum reduction of the secondary cold-rolling mill that satisfies the strength index of the finished strip is obtained. ; Step (10): After the strip steel undergoes a first cold rolling, annealing, and a second cold rolling process, it is formed into a finished strip steel. The total reduction of the first and second cold rolling processes is... At a given time, a reduction distribution coefficient is introduced. Cold rolling reduction per cycle and secondary cold rolling The reduction amounts are respectively, , ; Step (11): The maximum reduction of the secondary cold rolling mill required to meet the target strength index of the finished strip steel. and minimum reduction Calculate the reduction distribution coefficient The allocation domain, ; Step (12): Output the reduction distribution coefficient between primary and secondary cold rolling in quasi-secondary cold rolling. In the allocation domain, select any value and adjust the first cold rolling reduction and the second cold rolling reduction according to step (10).

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