JP2001113304A - Manufacturing method of cold rolled steel strip - Google Patents

Abstract

(57) [Problem] To provide a method of manufacturing a cold-rolled steel strip which can appropriately control the thickness of the steel strip and can improve the yield. SOLUTION: In producing a cold-rolled steel strip through hot rolling, pickling, cold rolling, and a continuous heat treatment process, the thickness of the steel strip after hot rolling is measured, and cold rolling and By adjusting the operating conditions of the continuous heat treatment step, the steel strip thickness is adjusted so that the measured value of the steel strip thickness on the output side of the continuous heat treatment step approaches the target value of the steel strip thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to hot rolling, pickling,
The present invention relates to a method for manufacturing a cold-rolled steel strip manufactured through cold rolling and a continuous heat treatment process, and more particularly to a method for manufacturing a cold-rolled steel strip capable of controlling the thickness of a steel strip or the thickness and width of the steel strip.

[0002]

2. Description of the Related Art At present, a cold-rolled steel strip is manufactured by the following method. First, in a hot rolling (hereinafter abbreviated as hot rolling) step, a slab heated in a heating furnace is passed through a rough rolling mill and a finishing rolling mill to be rolled to a thickness of approximately 1 to 5 mm, and is appropriately cooled. After rolling, a hot-rolled steel strip is manufactured. In the hot-rolled steel strip manufactured in this manner, in the pickling-cold rolling step, the oxide film generated on the surface during the production of the hot-rolled steel strip is removed by pickling, and the hot-rolled steel strip is cold-rolled by a cold rolling mill. Rolling (hereinafter abbreviated as cold rolling) is performed to finish a cold rolled steel strip having a thickness of approximately 1 to 3 mm.
However, since the cold-rolled steel strip at this stage causes work hardening due to cold rolling and has poor workability, it is recrystallized by a heat treatment furnace in a continuous heat treatment (continuous annealing, continuous galvanizing, etc.) process.
Annealing treatment and further pressure adjustment by a temper mill disposed on the exit side of the heat treatment furnace make it possible to finish the cold-rolled steel strip with appropriate workability, property characteristics, and surface roughness.

[0003] In the production process of such a cold rolled steel strip,
The steel strip thickness is set as shown in FIG. First, for the given slab thickness, in the hot rolling process, rough thickness control is performed by controlling the steel strip rolling force of each stand of the rough rolling mill and the finish rolling mill and the tension of the steel strip between stands. Will be However, in a normal hot-rolled steel strip,
Variations and errors in steel strip thickness.

Next, in the pickling-cold rolling step, the thickness of the hot-rolled steel strip is controlled quite strictly by controlling the rolling force of each stand of the cold rolling mill and the tension of the steel strip between stands. Will be

Further, in a heat treatment furnace of a continuous heat treatment step, for example, a heat treatment furnace of a continuous annealing step, at a recrystallization temperature of about 600 to 850 ° C., the cold-rolled steel strip is repeatedly bent by a roll in the furnace while applying tension. Therefore, the steel strip is elongated in the longitudinal direction, and the sheet width is reduced by that amount, and the sheet thickness is reduced. Also, when the pressure is adjusted in the delivery side temper mill, the width of the sheet is reduced depending on the pressure adjustment condition.

[0006] On the other hand, various studies have been made on the sheet thickness accuracy in the hot rolling process and the cold rolling process, but the sheet width accuracy or the sheet width change behavior has been mostly studied until recently. It wasn't.

FIG. 5 shows an outline of a current steel strip width setting method. First, for a given slab width, in the hot rolling process,
Rough width control is performed by controlling the steel strip tension of the edger and the finish rolling mill of the rough rolling mill. However, the width distribution in the longitudinal direction of a normal hot-rolled steel strip is not uniform, and as shown in FIG. 5, the width tends to be wider at the rear end of the steel strip and narrowed 50 to 100 m immediately after the front end. The difference can be as large as 10 mm when large.

Next, in the pickling-cold rolling step, the hot-rolled steel strip is cold-rolled while being tensioned by a cold rolling mill, so that the sheet width shrinks. At that time, the above-described difference in the plate width tends to further increase.

Further, as described above, in a heat treatment furnace of a continuous heat treatment step, for example, a continuous annealing step, 600 to 85
At a recrystallization temperature of about 0 ° C., the cold-rolled steel strip is repeatedly bent by the rolls in the furnace while applying tension. For this reason, the steel strip elongates in the longitudinal direction, and the width of the plate shrinks accordingly,
A reduction in plate thickness occurs. Also, when the pressure is adjusted in the delivery side temper mill, the width of the sheet is reduced depending on the pressure adjustment condition. At that time, the above-described difference in the plate width tends to further increase. After that, both ends of the steel strip are cut by an edge trimmer arranged on the outlet side so as to have a predetermined steel strip width.

[0010]

However, the above prior art has the following disadvantages. First, regarding the setting of the steel strip thickness, (1) the steel strip thickness reduction amount in the continuous heat treatment step is based on the steel type,
Prediction is difficult because it changes depending on the steel strip dimensions, operating conditions, and the like. (2) When the steel strip thickness reduction amount in the continuous heat treatment step is too large or small than expected in advance (FIG. 4)
A or C; that is, when there is a difference between the measured value of the steel strip thickness and the target value of the steel strip thickness on the output side of the continuous heat treatment step),
A cold rolled steel strip having the target steel strip thickness cannot be obtained. In particular, when the error is large, the steel strip thickness accuracy defined by the JIS standard or the like cannot be satisfied, and the product cannot be shipped.

Therefore, in order to avoid a reduction in product yield, each steel strip thickness measurement value on the output side of the continuous heat treatment step is set so as to be a “steel strip thickness target value (this is also referred to as product thickness)”. It is necessary to adjust the operating conditions in the process.

Further, regarding the setting of the steel strip width, it is difficult to predict (3) the amount of shrinkage of the steel strip width in the cold rolling and / or the continuous heat treatment step varies depending on the steel type, the steel strip dimensions, the operating conditions and the like. is there. (4) When the steel strip width shrinkage amount in the cold rolling and / or the continuous heat treatment step is smaller than expected in advance (that is, when the steel strip width before the edge trimming is too wide: A in FIG. 5);
Chips at both ends of the steel strip, which are discarded as trim scraps, increase and the yield decreases. (5) When the strip width shrinkage in the cold rolling and / or continuous heat treatment process is larger than expected, especially when the strip width before edge trimming is smaller than the product width, the strip is shipped as a product. You can't do that. If the width of the steel strip before the edge trimming does not become smaller than the product width, but the cutoff width at both ends of the steel strip is too small (C in FIG. 5), the edge trimming operation cannot be performed. The minimum cut-off width at which this edge trimming operation cannot be performed is called the minimum trim allowance.
Usually, it is about 5 mm on one side.

Therefore, in order to perform the edge trimming operation without any trouble while avoiding a decrease in the yield in consideration of both the steel strip thickness and the steel strip width, it is necessary to measure the steel strip thickness on the exit side of the above continuous heat treatment step. Operation in each process so that the value is the product thickness and the minimum value of the steel strip width before edge trimming is "product width + 2 x minimum trim allowance (this is also called the steel strip width target value)" It is necessary to adjust the conditions (B in FIG. 4 and B in FIG. 5).

The present invention has been made in view of such circumstances, and provides a method of manufacturing a cold-rolled steel strip which can appropriately control the thickness of the steel strip and can improve the yield. With the goal. It is another object of the present invention to provide a method of manufacturing a cold-rolled steel strip capable of appropriately controlling the thickness of the steel strip and the width of the steel strip before edge trimming, thereby preventing the occurrence of defective width and improving the yield. .

[0015]

To solve the above problems, the present invention provides the following (1) to (11). (1) In producing a cold-rolled steel strip through hot rolling, pickling, cold rolling, and a continuous heat treatment process, the thickness of the steel strip after hot rolling is measured, and cold rolling and / or Or by adjusting the operating conditions of the continuous heat treatment process,
A method for producing a cold-rolled steel strip, comprising adjusting a steel strip thickness such that an actual measured value of the steel strip thickness on the exit side of the continuous heat treatment step approaches a target value of the steel strip thickness.

(2) In the manufacturing method of (1), the method of adjusting the steel strip thickness in the cold rolling step is performed by adjusting the steel strip rolling force of each stand and the steel strip tension between each stand. A method for producing a cold-rolled steel strip, which is a feature.

(3) In the manufacturing method of (1) or (2), the method of adjusting the thickness of the steel strip in the continuous heat treatment step includes the method of controlling the tension of the steel strip, the heat treatment temperature, and the pressure adjusting device provided on the discharge side of the continuous heat treatment apparatus. At least one of the rolling force and the pressure on the inlet / outlet side of the pressure regulator
A method for producing a cold-rolled steel strip, wherein the method is carried out by adjusting the number of the strips.

(4) In carrying out any of the methods (1) to (3), at least (a) the exit side of the hot rolling device or the entrance side of the cold rolling device, and (b) the exit side of the cold rolling device. Alternatively, a steel strip gauge is provided on the furnace inlet side of the continuous heat treatment apparatus, (c) the furnace outlet side and the pressure control apparatus inlet side of the continuous heat treatment apparatus, and (d) the steel strip thickness gauge is disposed on the continuous heat treatment apparatus outlet side. Method of manufacturing cold rolled steel strip.

(5) The method for manufacturing a cold-rolled steel strip according to the method (4), wherein each steel strip thickness gauge has a function of correcting thermal expansion due to the temperature of the steel strip.

(6) In producing a cold-rolled steel strip through hot rolling, pickling, cold rolling, and a continuous heat treatment step, the thickness of the steel strip after hot rolling is measured, and the cold strip is determined based on the measured value. By adjusting the operating conditions of the rolling and / or continuous heat treatment step, (a) the steel strip thickness is adjusted so that the measured value of the steel strip thickness on the output side of the continuous heat treatment step approaches the steel strip thickness target value, and (b) A method for producing a cold-rolled steel strip, characterized in that the measured value of the steel strip width on the exit side of the continuous heat treatment step is close to the target value of the steel strip width and the steel strip width is adjusted so as not to fall below the target value.

(7) In the manufacturing method of (6), the method for adjusting the steel strip thickness and / or the steel strip width in the cold rolling step adjusts the steel strip rolling force of each stand and the steel strip tension between each stand. A method for producing a cold-rolled steel strip.

(8) In the manufacturing method of (6) or (7), the method for adjusting the steel strip thickness and / or the width of the steel strip in the continuous heat treatment step is provided on the steel strip tension, the heat treatment temperature, and the continuous heat treatment apparatus exit side. A method for producing a cold-rolled steel strip, wherein the method is performed by adjusting at least one of the rolling force of the pressure regulator and the tension on the inlet / outlet side of the pressure regulator.

(9) In any of the above-mentioned methods (6), (7) and (8), when the actual measured value of the steel strip thickness on the output side of the continuous heat treatment step cannot be brought close to the target value of the steel strip thickness; and If the actual measured strip width is close to the target strip width and it is not possible to adjust the strip width so that it does not fall below that value, the strip width shall be considered in the cold rolling and continuous heat treatment processes. Even so, the actual measured value of the steel strip thickness on the output side of the continuous heat treatment process is brought closer to the target value of the steel strip thickness, and / or the actual measured value of the steel strip width on the output side of the continuous heat treatment process is brought closer to the target value of the steel strip width and the value thereof The steel strip thickness during hot rolling and / or the minimum value of the steel strip width distribution in the longitudinal direction of the steel strip is adjusted by changing the operating conditions of the hot rolling step so as not to fall below. Method of manufacturing cold rolled steel strip.

(10) In carrying out any of the methods (6) to (8), at least (a) the exit side of the hot rolling device or the entrance side of the cold rolling device, and (b) the exit side of the cold rolling device. Alternatively, a steel strip thickness gauge and a strip width gauge are provided on the furnace entrance side of the continuous heat treatment apparatus, (c) the furnace exit side and the pressure control apparatus entrance side of the continuous heat treatment apparatus, and (d) the pressure control apparatus exit side of the continuous heat treatment apparatus. A method for producing a cold-rolled steel strip.

(11) In the manufacturing method of (10),
A method for manufacturing a cold-rolled steel strip, wherein each of the steel strip thickness gauge and the steel strip width gauge has a function of correcting a thermal expansion component due to a steel strip temperature.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view showing a manufacturing process and equipment of a cold-rolled steel strip to which the present invention is applied. As shown in FIG. 1, the method for manufacturing a cold-rolled steel strip includes three major steps: a hot rolling step, an pickling-cold rolling step, and a continuous heat treatment step. First, in the hot rolling step, the slab 31 heated in the heating furnace 1 is passed through the rough rolling mill 2 and the finishing rolling mill 4 to be rolled to a thickness of approximately 1 to 5 mm, and is appropriately cooled on the runout table 5. After going downcoiler 6
The hot rolled steel strip 32 is manufactured by winding. In addition,
Reference numeral 3 denotes an edger (width killer).

The hot-rolled steel strip 32 thus manufactured
Is sent to the pickling-cold rolling step. In this step, first, the hot-rolled steel strip 32 is unwound from the payoff reel 7,
It is sent to the pickling tank 10 via the entry looper 9, where it is pickled, the oxide film generated on the surface during the production of the hot-rolled steel strip is removed, and then sent to the cold rolling mill 12 via the delivery looper 11. Then, it is subjected to cold rolling and finished into a cold rolled steel strip 33 having a thickness of approximately 1 to 3 mm,
It is wound up by a tension reel (winding machine) 14.
Reference numeral 8 denotes a welder (welding machine), and 13 denotes a shear (cutting machine).

At this stage, the cold-rolled steel strip 33 undergoes work hardening due to cold rolling and has poor workability, and thus is subjected to a continuous heat treatment step. In this process, first, the payoff reel 1
After the cold rolled steel strip 33 is unwound from 5 and the rolling oil is removed by the washing machine 17, it is sent to the annealing furnace 19 through the entry looper 18, where recrystallization and annealing are performed, and then the delivery looper 20 is removed. Thereafter, the pressure is adjusted by a temper mill 21 disposed on the exit side of the heat treatment furnace, whereby the cold-rolled steel strip 34 having appropriate workability, property characteristics, and surface roughness is finished. After that, the cold-rolled steel strip 34 is adjusted by the edge trimmer 22 so as to be aligned with a predetermined steel strip width.
Is cut at both ends of the tension reel (winding machine)
It is wound up by 24. Reference numeral 16 denotes a welder (welding machine), and 23 denotes a shear (cutting machine).

Although the above is a general process, in the first embodiment of the present invention, a steel strip thickness gauge is provided at an appropriate position in each process. That is, (1) the position 41 on the exit side of the hot rolling apparatus or the position 42 on the entrance side of the cold rolling apparatus, (2) the position 43 on the exit side of the cold rolling apparatus or the entrance side of the annealing furnace of the continuous heat treatment apparatus (in front of the furnace). Position 44, (3) position 45 on the exit side of the annealing furnace of the continuous heat treatment apparatus and on the entrance side of the temper mill (pressure regulator).
(4) A steel strip thickness gauge is provided at a position 46 on the exit side of a temper mill (pressure adjusting device) of the continuous heat treatment apparatus. It is desirable for each steel strip thickness gauge to have a function of correcting the thermal expansion due to the temperature of the steel strip at that position.

In the first embodiment of the present invention, as shown in FIG. 2, after the continuous casting step (STEP 1) and the hot rolling step (STEP 2) are completed, the steel strip thickness gauge existing at the position 41 or 42 is obtained. Is used to measure the steel strip thickness of the hot-rolled steel strip 32 (STEP 3).

Next, in the pickling-cold rolling step and the continuous heat treatment step, the reduction in the steel strip thickness when the hot-rolled steel strip 32 is subjected to cold rolling and heat treatment under the normally specified operating conditions is predicted. (STEP 4).

This STEP 4 is performed as follows using a computer for determining the conditions of cold rolling and continuous heat treatment.
First, the hot-rolled steel strip 3 measured in STEP 3 described above was used.
Based on the steel strip thickness of No. 2, the steel strip thickness reduction under the pickling-cold rolling process standard conditions is predicted (STEP 4-1). Further, this value and the cold rolled steel strip 33 measured in STEP 6 described later are further estimated. Based on the steel strip thickness, the steel strip thickness reduction under the continuous heat treatment process standard condition is predicted (STEP 4-2).

The change in the steel strip thickness during cold rolling and pressure regulation can be predicted from the rolling theory, and the change in the steel strip thickness in the furnace during continuous heat treatment can be predicted from the repeated bending theory. The method of estimating the steel strip thickness reduction amount is described in JP-A-8-127820 and JP-A-8-127820.
A technique described in Japanese Patent Application Laid-Open No. 1-29825 is known.

The above STEP 4-1 and STEP 4-2
The steel strip thickness immediately after the temper mill 21 on the exit side of the continuous heat treatment apparatus is predicted from the prediction result of the steel strip thickness reduction amount in STEP 4 (STEP 4).
-3).

It is determined whether or not the predicted result matches the steel strip thickness target value (product thickness) (STEP 4-4). If the result matches, the cold rolling and the continuous heat treatment process are performed under the standard conditions. A command is issued (STEP 4-5).

On the other hand, the predicted result is a steel strip thickness target value (product thickness).
(A in FIG. 4), the operating conditions of the pickling-cold rolling step and the continuous heat treatment step are changed within a predetermined range using at least one of the following methods (1) to (3) ( STE
P4-6).

(1) The tension between the stands in the cold rolling step is increased within a predetermined range. And / or reduce the rolling force of each stand within a predetermined range (increase the thickness reduction in the cold step). (2) Raise the furnace tension in the continuous heat treatment step within a predetermined range. And / or raise the heat treatment temperature within a predetermined range (increase the thickness reduction in the continuous heat treatment step). (3) Reduce the rolling force in a predetermined range while increasing the input / output tension of the temper mill 21 in a predetermined range in the continuous heat treatment process (increase the thickness reduction while securing a predetermined elongation).

Conversely, the predicted result is the steel strip thickness target value (product thickness).
(C in FIG. 4), the operating conditions of the pickling-cold rolling step and the continuous heat treatment step are changed within a predetermined range by using at least one of the following methods (4) to (6) ( STE
P4-6).

(4) Raise the steel strip rolling force of each stand in a predetermined range while reducing the tension between the stands in the cold rolling step in a predetermined range (reduce the thickness reduction in the cold step). (5) The furnace tension in the continuous heat treatment step is reduced within a predetermined range. And / or lowering the heat treatment temperature within a predetermined range (reducing the thickness reduction in the continuous heat treatment step). (6) Raise the steel strip rolling force within a predetermined range while lowering the entrance and exit side tension of the temper mill 21 in a predetermined range in the continuous heat treatment step (reduce the thickness reduction while securing a predetermined elongation).

In both cases where the predicted result is above or below the steel strip thickness target value, the steel strip thickness immediately after the temper mill 21 (before edge trimmer) on the output side of the continuous heat treatment step is determined based on these changed conditions. Predict (STEP4-
7) It is determined whether or not there is an operating condition whose predicted value matches the steel strip thickness target value (product thickness) (STEP 4).
8).

If there is an operating condition that matches the steel strip thickness target value, a command is issued to perform the pickling-cold rolling process and the continuous heat treatment process on the hot-rolled steel strip 32 according to the operating condition (STEP 4). -9).

On the basis of the calculation result, a pickling-cold rolling step (STEP 5) is performed, and a continuous heat treatment step (S5) is performed.
TEP7) is performed. And, during these steps, position 43
Or, using the steel strip thickness gauge existing at 44, the cold rolled steel strip 33 is used.
The thickness of the steel strip is measured (STEP 6), and the result is also used in the above-described arithmetic processing as described above.

By manufacturing a cold-rolled steel strip as described above, it is possible to prevent the occurrence of a steel strip thickness defect in the manufacturing process, and it is possible to suppress a decrease in yield.

Next, a second embodiment of the present invention will be described. In the second embodiment of the present invention, the same position as the first embodiment, that is, (1) the position 41 on the exit side of the hot rolling device or the position 42 on the entrance side of the cold rolling device, (2) the cold rolling A position 43 on the exit side of the apparatus or a position 44 on the entrance side (before the furnace) of the annealing furnace of the continuous heat treatment apparatus; (3) a position 45 on the exit side of the annealing furnace and on the entry side of the temper mill (pressure regulator) of the continuous heat treatment apparatus;
(4) A steel strip thickness gauge and a steel strip width gauge are provided at a position 46 on the exit side of a temper mill (pressure regulating device) of the continuous heat treatment apparatus.
It is desirable that each steel strip thickness gauge and the steel strip width gauge have a function of correcting a thermal expansion component due to a steel strip temperature at the position.

In the second embodiment, as shown in FIG.
Continuous casting process (STEP 11) and hot rolling process (S
After the completion of (TEP12), the thickness of the hot-rolled steel strip 32 and at least the minimum value of the longitudinal width distribution are measured using the steel strip width meter located at the position 41 or 42 (STEP 12).
13).

Next, in the pickling-cold rolling step and the continuous heat treatment step, the amount of reduction in the steel strip thickness and the steel strip when the hot-rolled steel strip 32 is subjected to cold rolling and heat treatment under the normally specified operating conditions. The amount of width reduction is predicted (STEP 14).

This STEP 14 is performed as follows using a computer for determining the conditions of cold rolling and continuous heat treatment. First, based on the thickness of the hot-rolled steel strip 32 measured in the above-described STEP 13 and the minimum value of the width distribution in the longitudinal direction, the steel strip thickness reduction under the pickling-cold rolling process standard conditions is predicted (STEP 14). -1) Further, based on this value and the thickness of the cold-rolled steel strip 33 measured in STEP 16 described later, the steel strip thickness reduction amount is predicted under the continuous heat treatment process standard conditions (STEP 14-2). Similarly, pickling-
Prediction of steel strip width shrinkage under cold rolling process standard conditions (ST
EP14-3), furthermore, this value and STEP16 which will be described later.
Based on the minimum value of the width distribution in the longitudinal direction of the cold-rolled steel strip 33 measured in the above, the steel strip width shrinkage amount is predicted under the continuous heat treatment process standard condition (STEP 14-4).

The change behavior of steel strip thickness and steel strip width during cold rolling and pressure regulation is predicted from rolling theory, and the change behavior of steel strip thickness and steel strip width in the furnace during continuous heat treatment is predicted from cyclic bending theory. In particular, a method for predicting the steel strip thickness reduction and the steel strip width shrinkage in the continuous heat treatment furnace is described in JP-A-8-127820 and JP-A-11-127820.
A technique described in Japanese Patent No. 29825 is known.

The above STEP14-1 and STEP14
-2, the steel strip thickness immediately before the edge trimmer 22 on the output side of the continuous heat treatment apparatus is predicted (STEP 14-5).
From the prediction results in STEP14-3 and STEP14-4, the minimum value of the steel strip width immediately before the edge trimmer 22 on the exit side of the continuous heat treatment apparatus is predicted (STEP14-6).

It is determined whether or not the prediction result matches the steel strip thickness target value (product thickness) and the steel strip width target value represented by (product width + 2 × minimum trim allowance) (STEP 14-7). If so, a command is issued to perform the cold rolling and the continuous heat treatment process under the standard conditions (STEP 14-8).

On the other hand, when the prediction results do not match these, the operating conditions of the pickling-cold rolling step and the continuous heat treatment step are changed within a predetermined range as described in the following (1) to (4). (Step 14-9).

(1) The predicted result is the steel strip thickness target value (product thickness)
(A in FIG. 4) The operating conditions of the pickling-cold rolling step and the continuous heat treatment step are changed using at least one of the following methods (a) to (c).

(A) Raise the tension between the stands in the cold rolling step within a predetermined range. And / or reduce the rolling force of each stand within a predetermined range (increase the thickness reduction in the cold step). (B) Raise the furnace tension in the continuous heat treatment step within a predetermined range. And / or raise the heat treatment temperature within a predetermined range (increase the thickness reduction in the continuous heat treatment step). (C) In the continuous heat treatment step, the rolling force is lowered in a predetermined range while increasing the input-output side tension of the temper mill 21 in a predetermined range (increase the thickness reduction while securing a predetermined elongation).

(2) The predicted result is the steel strip thickness target value (product thickness)
(C in FIG. 4) The operating conditions of the pickling-cold rolling step and the continuous heat treatment step are changed using at least one of the following methods (d) to (f).

(D) Raise the steel strip rolling force of each stand in a predetermined range while reducing the tension between the stands in the cold rolling step in a predetermined range (reduce the thickness reduction in the cold step). (E) The furnace tension in the continuous heat treatment step is reduced within a predetermined range. And / or lowering the heat treatment temperature within a predetermined range (reducing the thickness reduction in the continuous heat treatment step). (F) Raise the steel strip rolling force in a predetermined range while lowering the input and output side tension of the temper mill 21 in a predetermined range in the continuous heat treatment step (reduce the thickness reduction while securing a predetermined elongation).

(3) When the prediction result exceeds the steel strip width target value (FIG. 5A) At least one of the following (g) to (i) is used,
The operating conditions of the above pickling-cold rolling step and continuous heat treatment step are changed.

(G) Reduce the steel strip rolling force of each stand in a predetermined range while increasing the tension between each stand in a predetermined range in the cold rolling process (increase the amount of width reduction while securing a predetermined plate thickness). (H) Increase the furnace tension in the continuous heat treatment step within a predetermined range. And / or raise the heat treatment temperature within a predetermined range (increase the width shrinkage). (I) Decrease the steel strip rolling force in a predetermined range while increasing the entrance and exit side tension of the temper mill 21 in a predetermined range in the continuous heat treatment process (increase the width shrinkage while securing a predetermined elongation).

(4) When the prediction result is lower than the steel strip width target value (C in FIG. 5) At least one of the following methods (j) to (l) is used.
The operating conditions of the above pickling-cold rolling step and continuous heat treatment step are changed. (J) Raise the steel strip rolling force of each stand in a predetermined range while reducing the tension between the stands in the cold rolling process in a predetermined range (reduce the amount of width shrinkage while securing a predetermined plate thickness). (K) Reduce the furnace tension in the continuous heat treatment step within a predetermined range. And / or lower the heat treatment temperature within a predetermined range (reduce the amount of width shrinkage). (L) Raise the steel strip rolling force within a predetermined range while lowering the inlet and outlet tension of the temper mill 21 in a predetermined range in a continuous heat treatment process (reduce the width shrinkage while securing a predetermined elongation).

In both cases where the steel strip thickness prediction result exceeds the steel strip thickness target value and falls below the target value, the temper mill 21 immediately before the continuous heat treatment step (before the edge trimmer) is based on these changed conditions. Predict steel strip thickness (S
TEP14-10).

In both cases where the predicted result of the steel strip width is greater than or less than the target value of the steel strip width, the minimum value of the steel strip width immediately before the continuous heat treatment process output side edge trimmer 22 is determined based on these changed conditions. Predict the value (STEP 14-
11).

It is determined whether there is an operating condition in which the predicted values of the steel strip thickness and the steel strip width match the target values of the steel strip thickness and the steel strip width (STEP 14-12).

When there are operating conditions that match the target values of the steel strip thickness and the steel strip width, the hot rolling steel strip 32 is subjected to the pickling-cold rolling step and the continuous heat treatment step depending on the operating conditions. A command is issued (STEP 14-13).

By the above operations (1) to (4),
(A) When the steel strip thickness (predicted value) immediately after the temper mill does not reach the steel strip thickness target value, and / or (b) When the steel strip width minimum value immediately before the edge trimmer does not become the steel strip width target value, The operating conditions of the hot rolling process are changed so as to adjust the steel strip dimensions on the exit side of the hot rolling process by the error (STEP 14).
-14).

The pickling-cold rolling step (STEP 15) and the continuous heat treatment step (STEP 17) are performed based on the calculation results. Then, using the steel strip thickness gauge and the steel strip width gauge existing at the position 43 or 44 during these steps, the steel strip thickness of the cold-rolled steel strip 33 and at least the minimum value of the longitudinal width distribution are measured ( (Step 16) As described above, this result is also used for the above-described arithmetic processing.

By manufacturing a cold-rolled steel strip as described above, the thickness of the steel strip and the width of the steel strip before edge trimming can be appropriately controlled. Can be planned.

The present invention is not limited to the above embodiment, but can be variously modified. For example, the prediction of steel strip width change behavior during cold rolling and pressure regulation, the steel strip width change behavior in the furnace during continuous heat treatment, the method of predicting the steel strip width shrinkage amount in the continuous heat treatment furnace, and the like are described in the above examples. The present invention is not limited to this, and various techniques conventionally used can be adopted. Further, in the above-described embodiment, the case where the continuous annealing is performed as the continuous heat treatment step has been described. However, the present invention is not limited thereto, and another processing such as continuous zinc plating may be performed.

[0067]

As described above, according to the present invention,
Since the thickness of the steel strip can be appropriately controlled, the yield can be improved. Further, since the thickness of the steel strip and the width of the steel strip before the edge trimming can be appropriately controlled, it is possible to prevent the occurrence of the width defect and to improve the yield.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a manufacturing process and equipment of a cold-rolled steel strip to which the present invention is applied.

FIG. 2 is a view showing a flow of the first embodiment of the present invention.

FIG. 3 is a diagram showing a flow according to a second embodiment of the present invention.

FIG. 4 is a view schematically showing a current plate thickness setting method.

FIG. 5 is a view schematically showing a current plate width setting method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Slab heating furnace 2: Rough rolling mill 4: Finish rolling mill 5; Run-out table 6; Down coiler 10; Pickling tank 12; Cold rolling mill 19; Heat treatment furnace 21; Hot-rolled steel strip 33; cold-rolled steel strip (before heat treatment) 34; hot-rolled steel strip 41, 42, 43, 44, 45, 46; installation position of steel strip thickness gauge or steel strip thickness gauge and steel strip width gauge

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Soya 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Yuji Uehara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun F-term in Honko Co., Ltd. (reference) 4E002 AD05 BA01 BD09 CA08

Claims (11)

[Claims] In producing a cold rolled steel strip through hot rolling, pickling, cold rolling and continuous heat treatment steps, the thickness of the strip after hot rolling is measured, and the cold rolling is performed based on the measured value. And / or adjusting the operating conditions of the continuous heat treatment step to adjust the steel strip thickness so that the measured value of the steel strip thickness at the output side of the continuous heat treatment step approaches the target value of the steel strip thickness. The production method of the belt. 2. The steel strip thickness adjusting method in the cold rolling step is performed by adjusting a steel strip rolling force of each stand and a steel strip tension between the stands. Manufacturing method of cold rolled steel strip. 3. A method for adjusting a thickness of a steel strip in the continuous heat treatment step, wherein at least one of a tension of a steel strip, a heat treatment temperature, a rolling force of a pressure control device provided on an output side of the continuous heat treatment device, and a tension on an input / output side of the pressure control device. The method for producing a cold-rolled steel strip according to claim 1, wherein the method is performed by adjusting the temperature. In carrying out the method according to any one of claims 1 to 3, at least (a) the exit side of the hot rolling device or the entrance side of the cold rolling device, (b) the exit side of the cold rolling device or A steel strip gauge is provided on the furnace inlet side of the continuous heat treatment apparatus, (c) the furnace outlet side of the continuous heat treatment apparatus and the pressure control apparatus inlet side, and (d) the pressure control apparatus outlet side of the continuous heat treatment apparatus. Method of manufacturing cold rolled steel strip. 5. The method for manufacturing a cold-rolled steel strip according to claim 4, wherein each steel strip thickness gauge has a function of correcting a thermal expansion due to a temperature of the steel strip. 6. In producing a cold-rolled steel strip through hot rolling, pickling, cold rolling and continuous heat treatment steps, the thickness of the steel strip after hot rolling is measured, and the cold rolling is performed based on the measured value. And / or by adjusting the operating conditions of the continuous heat treatment step, (a) at the same time as adjusting the steel strip thickness so that the actual measured value of the steel strip thickness on the output side of the continuous heat treatment step approaches the steel strip thickness target value,
(B) A method of manufacturing a cold-rolled steel strip, wherein the measured value of the steel strip width on the exit side of the continuous heat treatment step is brought close to the steel strip width target value and the steel strip width is adjusted so as not to fall below the target value. 7. The method of adjusting a steel strip thickness and / or a steel strip width in the cold rolling step is performed by adjusting a steel strip rolling force of each stand and a steel strip tension between the stands. A method for producing a cold-rolled steel strip according to claim 6. 8. A steel strip thickness and / or a steel strip thickness in a continuous heat treatment step.
Alternatively, the method of adjusting the width of the steel strip is performed by adjusting at least one of the tension of the steel strip, the heat treatment temperature, the rolling force of the pressure control device disposed on the output side of the continuous heat treatment device, and the tension on the input / output side of the pressure control device. The method for producing a cold-rolled steel strip according to claim 6 or 7, wherein: 9. The method according to claim 6, 7 or 8, wherein the measured value of the steel strip thickness on the output side of the continuous heat treatment step cannot be brought close to the target value of the steel strip thickness, and / or Alternatively, when the measured strip width is close to the target strip width and it is not possible to adjust the strip width so that it does not fall below that value, consider the strip width reduction in the cold rolling and continuous heat treatment processes. Even so, the actual measured value of the steel strip thickness on the output side of the continuous heat treatment process should be close to the target value of the steel strip thickness, and / or the actual measured value of the steel strip width on the output side of the continuous heat treatment process should be close to the target value of the steel strip width and the value should be adjusted By changing the operating conditions of the hot rolling step so as not to fall below, the minimum value of the steel strip thickness during hot rolling and / or the steel strip width distribution in the longitudinal direction of the steel strip is adjusted. Manufacturing method of cold rolled steel strip. 10. The method according to claim 6, wherein at least (a) the exit side of the hot rolling device or the entrance side of the cold rolling device, (b) the exit side of the cold rolling device or A steel strip thickness gauge and a sheet width gauge are provided on the furnace entrance side of the continuous heat treatment apparatus, (c) the furnace exit side of the continuous heat treatment apparatus and the pressure control apparatus entrance side, and (d) the pressure control apparatus exit side of the continuous heat treatment apparatus. A method for producing a cold-rolled steel strip, comprising: 11. The method for producing a cold-rolled steel strip according to claim 10, wherein each of the steel strip thickness gauge and the steel strip width gauge has a function of correcting a thermal expansion caused by a steel strip temperature.