JP2020049519A - Setting method and setting device for pass schedule for manufacturing cold rolled metal stip, and cold rolled metal strip - Google Patents

Abstract

To provide a setting method and a setting device for a pass schedule for manufacturing a cold rolled metal strip having plural finished plate thickness parts in a metal strip lengthwise direction while suppressing increase in the pass number, and a cold rolled metal strip.SOLUTION: Provided are: a setting method and a setting device for a pass schedule for manufacturing a metal strip having plural parts with different finished plate thicknesses along a longitudinal direction of the metal strip by repeatedly performing cold rolling of a raw material metal strip over plural passes; and a cold rolled metal strip. A pass schedule for performing cold rolling from a plate thickness Hof the raw material metal strip to a finished plate thickness hfor a first plate thickness part, which has a relatively larger plate thickness, of plural parts is set. A rolling reduction amount ΔDhat an i-th pass for a second plate thickness part which has a plate thickness smaller than that of the first plate thickness part is set so that a ratio of a rolling reduction amount (H-Dh) of the second plate thickness part to a rolling reduction amount (H-h) of the first plate thickness part becomes constant.SELECTED DRAWING: Figure 4

Description

  The present invention relates to, for example, a method and an apparatus for setting a pass schedule for manufacturing a cold-rolled metal strip having a plurality of finished plate thickness portions in the longitudinal direction of the metal strip, and a cold-rolled metal strip.

  When manufacturing a cold rolled metal strip using a cold rolling mill, a plurality of passes are rolled according to a pass schedule. In particular, when manufacturing a cold-rolled metal strip having a plurality of finished sheet thickness portions in the length direction of the metal strip, it is necessary to set a pass schedule optimized for the finished sheet thickness.

  As a method of manufacturing a cold-rolled metal strip having a plurality of finished plate thickness portions in the length direction of the metal strip, for example, in Patent Document 1, a pass schedule is calculated for each sheet thickness to determine the number of temporary passes, A technique for recalculating a pass schedule using the maximum number of passes among the number of provisional passes as the number of rolling passes is disclosed.

JP-A-2017-144450 (see especially paragraphs [0037] to [0039])

  However, according to the technology described in Patent Literature 1, the number of passes increases because the pass schedule is recalculated with the largest number of passes among the provisional passes as the number of rolling passes, and the time required for cold rolling increases. There is a problem that it becomes.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a cold-rolled metal strip having a plurality of finished plate thickness portions in the length direction of the metal strip while suppressing an increase in the number of passes. The present invention provides a method and an apparatus for setting a pass schedule for manufacturing a metal roll, and a cold-rolled metal strip.

(1) The pass schedule setting method of the present invention
It is a method of setting a pass schedule for manufacturing a metal strip having a plurality of portions in which the material metal strip is repeatedly rolled over a plurality of passes and the finished plate thickness is different along the longitudinal direction of the metal strip,
A pass schedule for performing cold rolling from the thickness of the material metal strip to the finish thickness of the first thickness portion is set for the first thickness portion having a relatively large finish thickness among the plurality of portions. One step,
The reduction amount at the i-th pass for the second plate thickness portion having a finished plate thickness smaller than the first plate thickness portion is defined as the ratio of the reduction amount of the second plate thickness portion to the reduction amount of the first plate thickness portion. Is set to be constant, and
It is characterized by the following.

  According to the pass schedule setting method of the above (1), when manufacturing a metal strip having a plurality of portions having different finish sheet thicknesses along the longitudinal direction of the metal strip, the finish sheet thickness is larger than the first sheet thickness portion. Can be rolled to the finished thickness with the same number of passes as the first thickness portion. Therefore, it is possible to manufacture a cold-rolled metal strip having a plurality of finished plate thickness portions without increasing the number of passes.

(2) In the path schedule setting method of the above (1),
Reduction amount DerutaDh i of the second thickness portion in the i th _pass, the i-th pass Δh the reduction ratio of the first thickness portion of _i, the thickness H ₀ of the material the metal _strip, a second thickness finishing thickness Dh n _parts, and, when the finishing thickness of the first thickness portion and the h _n,
Rolling reduction ratio ΔDh _{i /} Δh i of the second thickness portion to rolling reduction of the first thickness portion,
It is _(H 0 _-Dh n) _/ which is characterized in that expressed by _(H 0 -h _n).

The pass schedule setting method (2) is specifically shows the amount of reduction ratio ΔDh _{i /} Δh i of the second thickness portion to rolling reduction of the first thickness portion shown in the above (1) It is.

(3) In the path schedule setting method of (1) or (2),
The length of the second thickness portion in the i-th pass was multiplied by the length of the second thickness portion in the i-th pass and the thickness of the second thickness portion in the i-th pass. The value and a value obtained by multiplying the finish length of the second plate thickness portion by the finish plate thickness of the second plate thickness portion are set to be the same or substantially the same value.

  According to the configuration of the above (3), when the metal strip is cold-rolled, the second plate thickness portion can have a desired length.

(4) The path schedule setting device of the present invention comprises:
It is a pass schedule setting apparatus for manufacturing a metal strip having a plurality of portions having different finish plate thicknesses along the longitudinal direction of the metal strip by repeatedly performing cold rolling on the raw metal strip over a plurality of passes,
A pass schedule for performing cold rolling from the thickness of the material metal strip to the finish thickness of the first thickness portion is set for the first thickness portion having a relatively large finish thickness among the plurality of portions. 1 setting means;
The reduction amount at the i-th pass for the second plate thickness portion having a finished plate thickness smaller than the first plate thickness portion is defined as the ratio of the reduction amount of the second plate thickness portion to the reduction amount of the first plate thickness portion. And second setting means for setting the value to be constant.

  According to the pass schedule setting device of the above (4), when manufacturing a metal strip having a plurality of portions having different finish sheet thicknesses along the longitudinal direction of the metal strip, the finish sheet thickness is larger than the first sheet thickness portion. Can be rolled to the finished thickness with the same number of passes as the first thickness portion. Therefore, it is possible to manufacture a cold-rolled metal strip having a plurality of finished plate thickness portions without increasing the number of passes.

(5) In the invention of the above (4),
Reduction amount DerutaDh i of the second thickness portion in the i th _pass, the i-th pass Δh the reduction ratio of the first thickness portion of _i, the thickness H ₀ of the material the metal _strip, a second thickness part of the finished thickness of the _{specification} Dh _Nn, and, when the finishing thickness of the first thickness portion and the h _n,
The second setting means,
Wherein the amount of reduction ratio ΔDh _{i /} Δh i of the second thickness portion to rolling reduction of the first thickness portion is set to be constant.

  The configuration of the above (5) specifically shows the processing by the second setting means shown in the above (4).

(6) The cold-rolled metal strip of the present invention comprises:
It is characterized by having two or more portions having different finished plate thicknesses along the longitudinal direction of the metal strip, which are cold-rolled according to the pass schedule described in any one of the above (1) to (3). Things.

  According to the present invention, a method and an apparatus for setting a pass schedule for manufacturing a cold-rolled metal strip having a plurality of finished plate thickness portions in the length direction of the metal strip while suppressing an increase in the number of passes, and A rolled metal strip can be provided.

It is an example of the schematic diagram which shows the whole cold rolling stand. FIG. 2 is a schematic cross-sectional view of a raw metal strip and a schematic cross-sectional view of a steel strip after being cold-rolled to a final pass. It is an example of the cross-sectional schematic diagram which cut | disconnected the steel strip along the length direction, (A) It is a cross-sectional schematic diagram of a 1st board thickness part, (B) It is a cross-sectional schematic diagram of a 2nd board thickness part. 6 is a table illustrating an example of a path schedule set by the path schedule setting device. 6 is a flowchart illustrating an example of a path schedule setting process performed by the path schedule setting device. It is an example of a cross-sectional schematic diagram which shows the change of the plate thickness of the 2nd plate thickness part when a steel strip is cold-rolled, Comprising: (A) Cross-sectional schematic diagram of a material metal strip, (B) Cross-sectional schematic in the i-th pass. FIG. 3C is a schematic cross-sectional view when cold rolling is performed to the final pass.

  Hereinafter, embodiments of a method and an apparatus for setting a pass schedule for manufacturing a cold-rolled metal strip according to the present invention and a cold-rolled metal strip will be described with reference to the drawings. In the present embodiment, a steel strip is described as an example of the metal strip, but the metal body of the present invention is not limited to the steel strip.

[Overview of Cold Rolling Stand]
FIG. 1 is an example of a schematic diagram showing the entire cold rolling stand 1. As shown in FIG. 1, a cold rolling stand 1 according to the invention includes a rolling device 10, a right tension reel 20, a left tension reel 30, an X-ray thickness gauge 40, a control device 50, a pass schedule And a setting device 60.

  The rolling device 10 rolls a steel strip 100 by applying a load from above and below, and a backup roll 12, a first middle roll 14, a second middle roll 16, and a work And a roll 18. The rolling device 10 of the present embodiment is configured as a 20-high rolling device having a total of 20 rolls above and below, but the number of stages is not limited to this.

  The coiled steel strip 100 is sent out from a payoff reel (not shown) to the cold rolling stand 1 and reverse-rolled between the right tension reel 20 and the left tension reel 30 over a plurality of passes.

  An X-ray thickness gauge 40 for detecting the thickness of the steel strip 100 is disposed on the entry side and the exit side of the rolling device 10, and the thickness before and after rolling is measured by the X-ray thickness gauge 40. . Although not shown in FIG. 1, a shape detection roll may be disposed instead of or in addition to the X-ray thickness gauge 40.

  The pass schedule setting device 60 receives information necessary for rolling of the steel strip 100 from the control device 50, and sets, as a pass schedule, a sheet thickness, a reduction amount, an entrance tension, an exit tension, a rolling load, and the like in each pass. .

  The control device 50 controls the rolling device 10 based on the pass schedule set by the pass schedule setting device 60, and controls the entrance tension, the exit tension, the rolling load, and the like of the steel strip 100 in each pass.

  Then, the steel strip 100 rolled to the final pass is cut by a shear (not shown) and wound into a coil on the right tension reel 20 or the left tension reel 30.

  When manufacturing a cold rolled steel strip having a plurality of finished plate thickness portions, a pass schedule is set so that not only the finished plate thickness but also the plate thickness is different in each pass.

  The control device 50 controls the rolling device 10 so that the sheet thickness is set by the pass schedule setting device 60 for each pass, and controls the rolling device 10 to become the finished sheet thickness after the execution of the final pass.

[Pass schedule setting processing for a cold rolled steel strip having a plurality of finished plate thickness portions]
Next, a process of setting a pass schedule of a cold-rolled steel strip having a plurality of finished plate thickness portions will be described with reference to FIGS.

  FIG. 2 is a schematic cross-sectional view of a steel strip 100 before cold rolling, which is a raw metal strip (hereinafter, referred to as a “raw steel strip”), and a schematic cross-sectional view of the steel strip 100 after being cold-rolled to the final pass. is there. 2 is the length direction of the steel strip 100, and the schematic cross-sectional view shown in FIG. 2 is a schematic cross-sectional view of the steel strip 100 cut along the length direction.

  As shown in FIG. 2, in the longitudinal direction of the steel strip 100 after the raw steel strip has been cold-rolled to the final pass, a part having a relatively large finished plate thickness is referred to as a first plate part. The part having a relatively small finished plate thickness is referred to as a second plate thickness portion.

FIG. 3 is a schematic diagram of a cross section of the steel strip 100 cut along the length direction, in which (A) a schematic cross-sectional view of a first thick portion, and (B) a schematic cross-sectional view of a second thick portion. This is an example. As shown in FIG. 3, the plate thickness of the material steel strip H _0, when the finishing thickness of the first thickness portion finish thickness of h _n and the second thickness portion is Dh _n, first thickness total rolling reduction of parts can be expressed by _[H 0 -h _n], the total reduction ratio of the second thickness portion can be expressed by _[H 0 -Dh _n].

In this specification, the last pass is referred to as an n-th pass, and a path in the course of reaching the final pass is referred to as an i-th pass. Thus the thickness of the i-th pass, City Awara in marked with i as letter notation superscript lower "h _i" and "Dh _i", the plate thickness after rolling completion of the final pass, the letter notation superscript lower denoted by n _{"h n"} and represented by "Dh _n".

The total reduction rate of the first thickness portion [H 0 _{-h n]} has a thickness in the first plate thickness of the steel strip 100 after it has been cold-rolled to thickness and the final pass of the material steel strip [H ₀ −h _n ], and can be expressed as the total sum of the reduction amounts Δh _i of the first plate thickness portion in each pass (see column B in FIG. 4 described later). The first thickness portion is the thickness of the product of the cold rolled steel strip to be manufactured.

Similarly, the total reduction ratio of the second thickness portion [H 0 _{-Dh n]} is the thickness of the second thickness portion of the steel strip 100 after it has been cold-rolled to thickness and the final pass of the material steel strip and of a difference [H ₀ -Dh _n], it can be expressed in terms of the total rolling reduction DerutaDh i of the second thickness portion in each path _(see column E of FIG. 4 to be described later).

FIG. 4 is a table showing an example of a path schedule set by the path schedule setting device 60. Pass schedule setting device 60, as the information necessary for the rolling of the steel strip 100, for example, plate thickness H ₀ of the material steel _strip, the finishing thickness of the finished plate thickness h _n and the second thickness portion of the first thickness portion It receives information of dh _n from the control unit 50 sets the pass schedule shown in FIG. 4 based on this.

  FIG. 5 is a flowchart illustrating an example of a path schedule setting process performed by the path schedule setting device 60. Hereinafter, a path schedule setting process performed by the path schedule setting device 60 will be described.

The pass schedule setting device 60 first determines whether there is a manufacturing command from the control device 50 (step S10). Production command from the controller 50, as described above, the plate thickness H ₀ of the material steel _strip, which is information of the finishing thickness h _n and finishing thickness Dh _n of the second thickness of the first thickness portion.

  If there is a manufacturing command from control device 50 (YES in step S10), the process proceeds to step S20. On the other hand, if there is no production command from the control device 50 (NO in step S10), the pass schedule setting process ends.

In step S20, the pass schedule setting device 60 performs a pass schedule setting process for the first sheet thickness portion. In pass schedule setting processing of the first thickness portion, based on the finished plate thickness h _n of the thickness H ₀ and the first thickness portion of the material steel strip, equipment limitations such as a load of the rolling device 10 in each pass The thickness h _i , the reduction amount Δh _i, and the rolling load of the first thickness portion in each pass are set so as to be substantially equal. Although not shown in FIG. 4, the entry-side tension and the exit-side tension when performing cold rolling are set as common values for the first plate thickness portion and the second plate thickness portion. When the processing in step S20 ends, the process moves to step S30.

In step S30, the path scheduling apparatus 60 calculates the thickness Dh _i and rolling reduction DerutaDh _i of the second thickness portion in each path.

As described above, the plate thickness H ₀ of the material steel _strip, information about the finishing thickness Dh _n finishing thickness h _n and the second thickness portion of the first thickness portion, the path scheduling device 60 control device 50 This is known information because it is information received from the Internet. Further, reduction rate Delta] h _i of the first thickness portion in each path is also known information by the processing of step S20.

Therefore, for the thickness Dh _i and rolling reduction DerutaDh _i of the second thickness portion in each path can be calculated by applying the following formula known information of (1) and (2).

_{ΔDh i = Δh i × (H} 0 -D hi) / (H 0 -h n) ··· (1)

_{Dh i = Dh (i-1} ) -ΔDh i ··· (2)

Above formula (1) is an expression for calculating the reduction rate DerutaDh _i of the second thickness portion of the i th pass. Specifically, rolling reduction of the second thickness portion of the i pass DerutaDh _i, the total reduction rate of the second thickness portion to the total rolling reduction of the first thickness portion _{(H 0 -h n) (H} 0 is a value of the ratio multiplied by the reduction rate of the first thickness portion of the i-pass -dh _n). Here, since the total reduction amount of the first thickness portion _(H 0 -h _n) and the total rolling reduction of the second thickness portion _(H 0 -Dh _n) is a constant value, the first thickness portion the ratio of the total reduction amount _(H 0 -h _n) total rolling reduction of the second thickness portion to _(H 0 -Dh _n) is a constant value.

Further, the above equation (2) is an equation for calculating the thickness Dh _i of the second thickness portion of the i th pass. Specifically, the thickness Dh _i of the second thickness portion of the i pass is, (i-1) th pass of the second thickness portion of the plate thickness _{Dh (i-1)} the second i pass from This value is obtained by subtracting the amount of reduction in the thickness part.

With this calculated plate thickness Dh _i and rolling reduction DerutaDh _i of the second thickness portion in each path in Step S30, the procedure proceeds to step S40.

In step S40, the pass schedule setting device 60 sets a pass schedule for the second sheet thickness portion. Specifically, the path scheduling device 60, the thickness H ₀ of the material steel _strip, the finishing thickness Dh n of the second thickness _portion, the thickness Dh _i and rolling reduction ΔDh the second thickness portion in each path _The rolling load is set based on _i . After performing the processing in step S40, the path schedule setting device 60 ends the path schedule setting processing.

Thus, the thickness Dh _i and rolling reduction DerutaDh _i of the second thickness portion in each path, using known information by calculation based on the above equation (1) and (2), finishing plate Even if there are a plurality of parts having different thicknesses, a pass schedule for manufacturing a cold-rolled steel strip with the same number of passes as the first thickness portion, that is, the minimum number of passes without increasing the number of passes is set. Becomes possible.

[About the length of the second thick part]
By the way, when the steel strip 100 is cold-rolled, the cold-rolled steel strip 100 extends in the length direction. When a cold-rolled steel strip having a plurality of finished plate thickness portions is to be manufactured, if it is desired to make the finished length of the second plate thickness portion a desired length, for example, by using the following equation (3), i it can be calculated length Dm _i of the second thickness portion in the pass. The concept of Expression (3) will be described with reference to FIG.

  FIG. 6 is a schematic view of a cross section (cross section cut along the length direction) showing a change in the thickness of the second thickness portion when the steel strip 100 is cold-rolled. It is a schematic cross-sectional view of a band, (B) a schematic cross-sectional view at the i-th pass, and (C) a schematic cross-sectional view when cold rolling is performed up to the final pass.

the thickness of the second thickness portion and the Dh _i and length as Dm _i in the i th pass (see FIG. 6 (B)), the finishing thickness of the second thickness portion when it is cold rolled to the final pass the (see FIG. 6 (C)) When Dh _n and finishing lengths Dm _i, because the volume of the second thickness portion before and after rolling is constant, the thickness of the second thickness portion of the i th pass Dh _i and the value obtained by multiplying the Dm _i the length, the value of the finished plate thickness of the second thickness portion obtained by multiplying the Dm _i the Dh _n and finishing length when it is cold rolled to final pass Is the same. Accordingly, the second thickness portion of the i pass the length Dm _i, can be determined using the following formula (3).

_{Dm i = (Dm n × Dh} n) / Dh i ··· (3)

In this manner, by using the equation (3), on the basis of finishing thickness Dh _n of the second thickness portion, finished length _Dm i, the thickness Dh _i of the second thickness portion of the i th pass, i it is possible to calculate the length Dm _i of the second thickness portion of the pass, the second thickness portion desired length (i.e., the desired position of the boundary between the first thickness portion and the second thickness portion Position).

  In addition, in this embodiment, although the steel strip 100 which has a 1st sheet thickness part and a 2nd sheet thickness part in the length direction of the steel strip 100 was demonstrated as an example as a site | part from which a finished sheet thickness differs, sheet thickness differs. The number of parts is not limited to two, and there may be three or more parts having different plate thicknesses. For example, when the portion having the largest thickness is the first thickness portion, the portion having the second largest thickness is the second thickness portion, and the portion having the third largest thickness is the third thickness portion, The pass schedule setting device 60 first sets a pass schedule for the first sheet thickness portion having the largest sheet thickness. Then, a pass schedule is set for the second and third sheet thickness portions. The pass schedule is set so that the ratio of the reduction amount of the second plate thickness portion to the reduction amount of the first plate thickness portion in the i-th pass of the second plate thickness portion is constant. Similarly, a pass schedule is set for the reduction amount of the third plate thickness portion in the i-th pass so that the ratio of the reduction amount of the third plate thickness portion to the reduction amount of the first plate thickness portion is constant. The same applies to the case where there are more parts having different finished plate thicknesses.

  According to the present invention, it is possible to provide a method and a device for setting a pass schedule for manufacturing a cold-rolled steel strip having a plurality of finished plate thickness portions, and a cold-rolled steel strip.

60 Pass schedule setting device 100 Steel strip

Claims (6)

It is a method of setting a pass schedule for manufacturing a metal strip having a plurality of portions in which the material metal strip is repeatedly rolled over a plurality of passes and the finished plate thickness is different along the longitudinal direction of the metal strip,
A pass schedule for performing cold rolling from the thickness of the material metal strip to the finish thickness of the first thickness portion is set for the first thickness portion having a relatively large finish thickness among the plurality of portions. One step,
The reduction amount at the i-th pass for the second plate thickness portion having a finished plate thickness smaller than the first plate thickness portion is defined as the ratio of the reduction amount of the second plate thickness portion to the reduction amount of the first plate thickness portion. Is set to be constant, and
A method of setting a pass schedule, characterized in that: Reduction amount DerutaDh i of the second thickness portion in the i th _pass, the i-th pass Δh the reduction ratio of the first thickness portion of _i, the thickness H ₀ of the material the metal _strip, a second thickness finishing thickness parts _finishing Dh, and, when the finishing thickness of the first thickness portion and the h _n,
Rolling reduction ratio ΔDh _{i /} Δh i of the second thickness portion to rolling reduction of the first thickness portion,
_(H 0 _-Dh n) _/ pass schedule method settings according to claim 1, characterized in that expressed by _(H 0 -h _n). The length of the second thickness portion in the i-th pass was multiplied by the length of the second thickness portion in the i-th pass and the thickness of the second thickness portion in the i-th pass. The value obtained by multiplying a value obtained by multiplying a finished length of the second plate thickness portion by a finished plate thickness of the second plate thickness portion is set to be the same or substantially the same value. How to set the pass schedule described in. It is a pass schedule setting apparatus for manufacturing a metal strip having a plurality of portions having different finish plate thicknesses along the longitudinal direction of the metal strip by repeatedly performing cold rolling on the raw metal strip over a plurality of passes,
A pass schedule for performing cold rolling from the thickness of the material metal strip to the finish thickness of the first thickness portion is set for the first thickness portion having a relatively large finish thickness among the plurality of portions. 1 setting means;
The reduction amount at the i-th pass for the second plate thickness portion having a finished plate thickness smaller than the first plate thickness portion is defined as the ratio of the reduction amount of the second plate thickness portion to the reduction amount of the first plate thickness portion. And a second setting means for setting the value to be constant. Reduction amount DerutaDh i of the second thickness portion in the i th _pass, the i-th pass Δh the reduction ratio of the first thickness portion of _i, the thickness H ₀ of the material the metal _strip, a second thickness finishing thickness Dh n _parts, and, when the finishing thickness of the first thickness portion and the h _n,
The second setting means,
Pass schedule setting device according to claim 4, characterized in that the amount of reduction ratio ΔDh _{i /} Δh i of the second thickness portion to rolling reduction of the first thickness portion is set to be constant .   A cold-rolled metal strip cold-rolled by the pass schedule according to any one of claims 1 to 3 and having two or more portions having different finished plate thicknesses in a longitudinal direction of the metal strip.