JPH11188404A - Method of manufacturing cold-rolled steel band - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fluctuation in thickness and width of a cold-rolled steel band product and obtain desired sheet thickness and width by resetting target values and/or width of the cold-rolled steel sheet to be charged into continuous annealing on the basis of actual component records of steel of actual products and actual manufacturing conditions of hot rolling. SOLUTION: Preset target value of thickness and width of cold-rolled steel band to be inserted into continuous annealing are once cancelled, and they are calculated again and corrected in consideration of dimensional decreasing volume when continuous annealing is done, on the basis of the actual steel component records of actual products and actual manufacturing conditions of hot rolling, and the values are reset in the actual product information. Alternatively, preset target values of hot-rolled thickness and width, cold-rolled thickness, and width after pickling are once cancelled, and the values are corrected by re-calculating them in proper consideration of decreases in sheet thickness and width of actual products, on the basis of actual steel composition records of actual products and actual manufacturing conditions of hot rolling, and the values are reset in the actual product information. Thus, the dimensions after continuous annealing are made uniform and products of desired dimensions are finally obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cold-rolled steel strip, particularly to a cold-rolled steel strip manufactured through a continuous annealing process, even if the manufacturing conditions in the steel-making, hot-rolling, and cold processes are changed. The present invention relates to a method for manufacturing a cold-rolled steel strip capable of obtaining a cold-rolled steel strip product (including a surface-treated steel strip and an electromagnetic steel strip) having different thicknesses and widths.

[0002]

2. Description of the Related Art In steel production, when producing a cold rolled steel strip product through a steelmaking, hot rolling, and cold process, first, before starting production, in order to satisfy product specifications from customers. The manufacturing conditions for each process are set and stored on a database. Next, before the material is charged into each process, the manufacturing conditions set above are transmitted to a computer that supervises the process, or manufacturing is performed by instructing an operator.

FIG. 6 is a flowchart showing an example of a processing flow of the prior art, in which a cold-rolled steel strip is manufactured through a continuous annealing step. In order to create products requested by customers, planning information such as steel type and manufacturing conditions is set in advance based on order information, and a planning information database (plan D)
B). Information on the actually used steel type and actual operating conditions (actual item information) is held in an actual item information database (actual item DB).

In the flow chart of FIG. 6, the setting of the plate thickness and the plate width is performed as follows. Regarding the sheet thickness, based on the planned steel type and manufacturing conditions, based on the product sheet thickness (the target product thickness), the thickness of the coating such as plating and the amount of change in the sheet thickness due to the temper pressure regulation are obtained from a table or a calculation formula. By correcting or adding the numerical value, the target cold rolling thickness (hereinafter, referred to as
Cold rolling target thickness).

[0005] Further, a cold rolling reduction (= {hot rolling target thickness-cold rolling target thickness} / hot rolling target thickness x 100%) determined from the material properties required for the product from the target cold rolling thickness, or
The target hot rolling thickness (hereinafter referred to as the target hot rolling thickness) is determined and set using a table or a calculation formula in consideration of the facility limitations of the hot rolling mill and the cold rolling mill.

[0006] With regard to the sheet width, based on the planned steel type and production conditions, cold rolling,
The sheet width change amount in the continuous annealing is obtained by a table or a calculation formula, the numerical value is added, and the target sheet width after pickling (hereinafter, referred to as “the target sheet width”).
(It is called width after pickling).

[0007] For a material that is not side-trimmed between hot rolling and cold rolling, the width after pickling is set as it is as a hot rolling target sheet width (hereinafter, referred to as a hot rolling target width), and a material to be side trimmed. With respect to (3), the trim allowance in the pickling line was obtained by a table or a calculation formula, and the trim allowance was added to the above-mentioned width to set the hot rolling target width.

[0008]

However, in actual production, the operation is not always performed with the steel type according to the plan information and the manufacturing conditions according to the plan information. In actual production, in order to increase production efficiency, it is not rare to use a steel grade higher (higher grade) than the steel grade stored in the plan DB, or to change operating conditions such as hot rolling.

[0009] Even for such an actual product that is different from the initially planned steel type and manufacturing conditions, the initially set hot rolling target thickness, cold rolling target thickness, hot rolling target width, and width after pickling remain unchanged. Applied. As a result, the dimensional variation of the final product is increased, and the dimensional tolerance of the product may be out of tolerance.

For example, in the flowchart of FIG.
If the steel type is changed, the target information of hot rolling target thickness, cold rolling target thickness, hot rolling target width, and post-pickling width is applied as it is, so the sheet thickness defect and sheet width defect may remain. there were.

In recent years, demands for dimensional accuracy of cold rolled steel strip products on the market have become strict, and the need to improve the above-mentioned problems has increased. In order to improve the thickness accuracy, the improvement of hardware aspects such as the development and introduction of hot-rolling mills and cold-rolling mills that can control the thickness profile has been carried out. The fact is that it has not been done.

Further, in recent years, the production amount and specification types of cold-rolled steel strip products produced in a continuous annealing line or a hot-dip galvanizing line having a continuous annealing furnace have increased, and steel strips of various types have been produced in many lines. Began to be manufactured. The present inventors,
Investigations on the dimensional variation of the steel strips produced in these lines revealed that the sheet thickness was reduced even in a continuous annealing furnace, and it was found that the effect of this on the sheet thickness accuracy could not be ignored.

Further, conventionally, the amount of reduction in the width of the sheet in temper pressure control has not been taken into consideration. Alternatively, when a temper mill is equipped for continuous annealing, the sheet width reduction is simply determined by the difference between the sheet width on the inlet side of the annealing furnace and the sheet width on the exit side of the temper mill. Was represented. However, it has also been found that when the annealing conditions and / or elongation are changed, in order to obtain a steel sheet having the intended dimensions, it is necessary to consider the amount of sheet width shrinkage that matches the changed conditions.

[0014] In view of the above problems, an object of the present invention is to provide a method of manufacturing a cold rolled steel strip capable of obtaining a desired product size.

[0015]

Means of the present invention for solving the above problems are as follows.

(1) In manufacturing a cold-rolled steel strip through a continuous annealing step, the predetermined standard manufacturing conditions
Cold-rolled steel characterized by resetting the target cold-rolled thickness and / or strip width of the cold-rolled steel strip to be charged to continuous annealing based on the actual results of steel composition and the results of hot-rolling production A method for producing a belt (first invention).

(2) In producing a cold-rolled steel strip through a continuous annealing step, the following is applied to a predetermined standard production condition.
At least one of the target hot-roll thickness and the target cold-roll thickness, and / or
A method for producing a cold-rolled steel strip, wherein at least one of the target width of hot rolling and the width after pickling is reset (second invention).

(Action) In the first invention, the target cold-rolled thickness and the strip width of the cold-rolled steel strip to be charged into the continuous annealing set in advance are canceled once, and the actual production conditions of the steel composition and the hot-rolled steel strip are reduced. On the basis of this, recalculation is performed in consideration of the dimension reduction amount during continuous annealing and correction is performed, and the value is reset in the actual product information, so that the dimensions after continuous annealing can be made uniform.

Further, in the second invention, the preset hot rolling target thickness, cold rolling target thickness, hot rolling target width, and width after pickling are canceled once, and the actual steel component results and the actual manufacturing conditions of the hot rolling are changed. Based on
Appropriately taking into account the thickness reduction and the width reduction of the current product, recalculate and correct it, and reset it in the current product information. When loading the actual product into each manufacturing process, the hot strip target thickness, cold roll target thickness, hot roll target width, and acid Since the width after washing is specified, a product having the intended dimensions can be finally obtained.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described with reference to an example in which a cold rolled steel strip is manufactured through a continuous annealing step.

FIG. 1 is a flow chart showing main processing portions of the present invention when a cold-rolled steel strip is manufactured through a continuous annealing step. In order to create the product requested by the customer, planning information such as steel type and manufacturing conditions for each process is set in the manufacturing condition setting block in accordance with the preset manufacturing condition setting program based on the order information. It is stored on an information database (planning DB).
In the planning information, steel type, steel composition and its allowable range, planned passing line, the manufacturing conditions and the allowable range in the planned passing line and the planned hot rolling target thickness based on the above, the planned cold rolling target thickness, the planned hot rolling target width, The width after the pickling is set.

Further, information (actual item information) on the actually used steel type, steel composition, and actual operating conditions in each manufacturing process is held in an actual item information database (actual item DB).

In FIG. 1, the planned hot rolling target thickness, the planned cold rolling target thickness, etc. are the hot rolling target thickness, the cold rolling target thickness, etc. set in the plan information. The cold rolling target thickness and the like represent a hot rolling target thickness, a cold rolling target thickness, and the like, which are corrected and reset based on the actual product information.

Table 1 is an example of plan information such as steel type, steel composition, and manufacturing conditions in the plan DB. The items of the actual item information in the actual item DB are the same as those in the plan DB, however, the processed steps are set as actual, and the unprocessed steps are set with the planned passing lines in the future and the planned manufacturing conditions in those lines.

[0025]

[Table 1]

A method for resetting the sheet thickness and the sheet width based on the plan information and the actual product information will be described below. First, a method of resetting the sheet width will be described. The target width of hot rolling and the width after pickling of the plan information are calculated and set as shown in Table 2 based on the order information. The sheet width is set separately for the continuous annealing width contraction amount and the temper pressure adjustment width contraction amount.

[0027]

[Table 2]

Before the hot rolling, it is determined whether or not the actual steel composition is out of the permissible range of the plan information by the determiner.
According to the preset production condition resetting program, based on the actual information such as plan information and actual steel type, actual steel composition, actual steelmaking conditions, etc., the scheduled production conditions in the scheduled passing line and each passing scheduled line after hot rolling, for example, Reset the hot rolling temperature conditions, annealing conditions, elongation rate of temper pressure control, etc.
Update and store the actual product DB.

Next, in the hot-rolling / pickling width resetting block, according to the preset hot-rolling / pickling width resetting program, as described below, the steel type of the plan information and the actual product information is set.
Read the steel composition, production conditions, etc., recalculate the width reduction due to cold rolling, the width reduction due to annealing, and the width reduction due to temper pressure regulation. Correction of the sheet width shrinkage amount at the time of annealing due to deviation from the target of the hot rolling temperature result is corrected, the hot rolling target width and the width after pickling are corrected and reset, and the current DB is updated and stored.

First, the amount of shrinkage of the sheet width due to cold rolling is determined. In advance, for each cold rolling line, a sheet width reduction amount is investigated for each steel type, sheet thickness, and sheet width, and a table or a formula is prepared (in this embodiment, a table as shown in FIG. 2 is prepared). There). Cold rolling line, steel grade of the material,
It is read from the actual product DB, and the corresponding plate width reduction amount () is extracted from FIG.

Next, the amount of sheet width contraction due to annealing is determined. In advance, for each annealing line, the amount of sheet width shrinkage is investigated for each steel type, annealing condition, sheet thickness, and sheet width, and a table or a formula is prepared (in this embodiment, a table as shown in FIG. 3 is prepared). ing). The annealing line, steel type, and annealing conditions of the material are read from the actual product DB, and the corresponding sheet width contraction amount () is extracted from FIG.

Next, the amount of shrinkage of the plate width due to the temper pressure adjustment is determined. In advance, the sheet width reduction amount is investigated for each steel type, sheet thickness, and sheet width for each elongation rate, and a table or a formula is prepared (in the present embodiment, a table is used as shown in FIG. 4). . Read the elongation rate of the material from the actual DB,
The corresponding plate width reduction amount () is extracted from FIG.

Subsequently, the deviation of the actual steel component from the reference and the deviation of the actual hot-rolling temperature from the target are converted into the sheet width shrinkage during annealing, respectively, and corrected. The influence of the sheet width shrinkage amount during annealing due to the deviation of the steel composition from the standard and the influence of the sheet width shrinkage amount during the annealing due to the deviation of the actual hot-rolling results from the schedule are investigated. ), And held as in equation (2). Using this, the sheet width correction amount () based on the actual steel composition and the sheet width correction amount () based on the hot rolling result are obtained.

[0034]

(Equation 1)

[0035]

(Equation 2)

Recalculated sheet width shrinkage due to cold rolling (), sheet width shrinkage due to annealing (), sheet width shrinkage due to tempering (()), deviation of actual steel composition from standard, hot rolling temperature The sum total of the correction amounts (,) of the sheet width shrinkage amount during annealing due to the deviation of the actual result from the target is H1. However, H1 = ++++ (3) Based on the calculation result, the hot-rolling target width and the width after pickling are corrected and reset according to the equations (4) and (5), respectively, and stored in the actual product DB. . Hot rolling is performed using the reset hot rolling target width.

Hot rolling target width after reset = target product width + pickling trim margin + H1 (4) Width after pickling after reset = product target width + H1 (5) The pickling trim margin is: This is the trim width used to set the width of the plan information. In this embodiment, as shown in Table 3, the trim width is set in a table.

[0038]

[Table 3]

The amount of sheet width contraction calculated based on the plan information, the amount of sheet width contraction due to annealing, and the amount of sheet width contraction due to temper pressure control are represented by k, k, and k, respectively, and the sum thereof is represented by H2.
(= K + k + k), the correction amount H3 of the reset hot rolling target width and the post-pickling width with respect to the set width of the plan information
Corresponds to H3 = H1-H2.

Next, before the pickling, it is determined whether or not the steel composition and the hot rolling conditions of the actual product are out of the allowable ranges set in the plan information by the determiner. In the production condition re-setting block, based on plan information and actual production information such as actual production conditions up to the hot rolling process of the actual product, according to a preset production condition re-setting program, a scheduled passing line after the pickling process and each Scheduled production conditions in the schedule passage line, for example, annealing conditions, elongation rate of temper pressure adjustment, and the like are reset, and the current product DB is updated and stored.

Next, for the material to be trimmed before cold rolling, before pickling, the pickling width reset block follows a pickling width reset program set in advance, as described below. The width after pickling determined in the hot-rolling / pickling width reset block is re-corrected and set again, and the actual DB is updated and stored.

The re-correction is performed based on the actual steel type, actual steel composition, the actual hot rolling conditions in the actual DB before the side trimming operation, and the working conditions in the scheduled cold process based on the scheduled line information to be passed. In the same procedure as the procedure of the width resetting block, the width shrinkage amount by cold rolling (n), the width shrinkage amount by annealing (n), the width shrinkage amount by temper pressure adjustment (
n), the correction amount (n) based on the actual steel composition, and the correction amount (n) based on the actual hot rolling result. This sum is defined as H4. However, H4 = n + n + n + n + n (6) In this case, the width after pickling to be reset is given by Expression (7). A side trimming operation is performed using the post-pickling width that has been set again. Width after pickling after re-setting = target product width + H4 (7)

Next, a method of resetting the sheet thickness will be described.
Before the cold rolling, in the cold rolling thickness resetting block, according to a preset cold rolling thickness resetting program, as described below, the planning information and the steel type, steel composition, actual product information such as manufacturing conditions, etc. After reading, the thickness reduction due to annealing,
The thickness reduction due to the temper pressure adjustment is recalculated based on the information in the results DB, and the correction of the thickness reduction during annealing due to the deviation of the steel composition results from the standard and the hot rolling temperature results from the target is corrected. Correct the cold rolling target thickness and set again.
Update and save B.

First, the thickness reduction due to annealing is recalculated. In advance, for each annealing line, the amount of thickness reduction is investigated for each steel type, annealing condition, thickness, and width, and a table or equation is prepared to show this relationship (in this embodiment, shown in FIG. 5). Like a table). Read the annealing line, steel type, and annealing conditions of the material before cold rolling from the actual DB,
The corresponding thickness reduction () is extracted from FIG.

Next, the thickness reduction amount due to the temper pressure adjustment is recalculated. The temper elongation rate of the material is taken out from the actual product DB, and the thickness reduction () is determined from Expression (8).

Sheet thickness shrinkage due to temper pressure adjustment () = (100 + ε) / 100 (8) where ε = temper elongation (%) The deviation from the target is converted into the amount of reduction in the thickness of the sheet during annealing, and is corrected. The influence of the thickness reduction during annealing due to the deviation of the steel composition from the standard and the influence of the thickness reduction during annealing due to the deviation of the actual hot rolling performance from the target were investigated in advance, and for example, each of the equations (9) ), And held as in equation (10). Using these, the sheet thickness correction amount () based on the actual steel composition and the sheet thickness correction amount () based on the hot rolling result are obtained.

[0047]

(Equation 3)

[0048]

(Equation 4)

The target cold-rolled thickness of the preset plan information is temporarily canceled, the target cold-rolled thickness is corrected and reset by the equation (11), and the reset target cold-rolled thickness is updated and stored in the current product DB. I do. Cold rolling is performed using the reset cold rolling target thickness.

Corrected cold target thickness = target product thickness ×××× (11) Also, if necessary, a hot rolling / cold rolling thickness resetting block before hot rolling is used to set a preset hot rolling.・ According to the cold rolling thickness resetting program, the cold rolling target thickness is corrected in the same procedure as the cold rolling thickness resetting block already described, and the hot rolling target thickness is calculated based on the corrected cold rolling target thickness. Reset. For example, when the corrected cold-rolled target thickness is inappropriate due to equipment limitations of the hot rolling mill, or when the average plastic strain ratio predicted based on the corrected cold-rolled target thickness is lower than the target range, When the final material predicted value of the actual product based on the corrected cold-rolled target thickness falls below the target range, such as when it is necessary to change the cold rolling rate, the corrected cold-rolled target thickness after the correction The hot-rolling target thickness is calculated and corrected using a previously determined table or formula so that the cold rolling rate falls within the target range, and the result is compared with the actual product D.
Reset to B. The hot rolling is performed using the corrected hot rolling target thickness.

According to the above, the target cold-rolled thickness and the width of the steel strip (the target width of the hot-rolled steel, the width after pickling) of the cold-rolled steel strip to be charged into the preset continuous annealing are temporarily canceled, and the actual steel composition results Based on actual production conditions of hot rolling and hot rolling, recalculation and correction are performed in consideration of the amount of dimensional reduction during continuous annealing and resetting to the actual DB, so that an increase in dimensional fluctuation during continuous annealing can be prevented.

Also, the preset hot rolling target thickness, cold rolling target thickness, hot rolling target width, and post-pickling width are set to actual steel composition results, actual hot rolling production conditions, and post-processes changed accordingly. Based on the operating conditions described above, the amount of reduction in the thickness of the actual product and the reduction in the width of the current product are properly calculated and corrected, and the actual product DB is reset. When loading the actual product in each manufacturing process, the target thickness and target width, which are appropriately reset to reflect the reduction in the thickness and the width of the actual product, are instructed. Products with the desired thickness and width can be obtained.

In the present invention, the sheet thickness and sheet width to be reset are at least one of the target thickness of hot rolling and the target thickness of cold rolling, or at least one of the target width of hot rolling and the width after pickling. This also has the effect of reducing variations in the thickness and width of the final product.

[0054]

According to the present invention, the target cold-rolled thickness, the width of the cold-rolled steel strip, or the cold-rolled steel strip of the cold-rolled steel strip to be charged into the continuous annealing, based on the actual steel type, steel composition, and hot-rolling conditions. The target hot-rolled thickness, cold-rolled target thickness, hot-rolled target width, and target width after pickling are appropriately corrected and instructed, so that the manufacturing conditions in steelmaking, hot rolling, and cold processes are changed. In addition, it is possible to reduce variations in the thickness and width of the cold-rolled steel strip product, and to obtain a cold-rolled steel strip product having the desired thickness and width.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a main processing portion for correcting a thickness and a width of a steel strip described in an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a method of determining a sheet width shrinkage amount in a cold press facility in the flowchart of FIG.

FIG. 3 is a diagram showing an example of a method of determining a sheet width shrinkage amount in a continuous annealing line in the flowchart of FIG.

FIG. 4 is a diagram showing an example of a method of determining a sheet width reduction amount in temper pressure regulation in the flowchart of FIG. 1;

FIG. 5 is a view showing an example of a method for determining a thickness reduction in a continuous annealing line in the flowchart of FIG. 1;

FIG. 6 is a flowchart showing a work flow of a conventional steel strip.

Claims (2)

[Claims] When manufacturing a cold-rolled steel strip through a continuous annealing process, the steel sheet is subjected to continuous annealing based on actual steel composition results and hot-rolling manufacturing performance conditions with respect to predetermined standard manufacturing conditions. A method for manufacturing a cold-rolled steel strip, comprising resetting a target cold-rolled thickness and / or a steel strip width of a cold-rolled steel strip to be inserted. 2. When manufacturing a cold-rolled steel strip through a continuous annealing process, a target hot-rolled thickness is determined based on actual steel composition results and hot-rolling manufacturing performance conditions with respect to predetermined standard manufacturing conditions. And / or resetting at least one of the target cold-roll thickness and / or the target hot-roll width and the width after pickling.