JP2008036686A - Method of rolling rolled stock of bar steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the dimensional accuracy of a product and to prevent the generation of surface defects or the like in the multi-series (multi-strand) rolling of the rolled stock of bar steel. <P>SOLUTION: The linear velocity ratio R of the rolled stock 1 of the bar steel in each series is beforehand determined. In the first series, by determining the target middle speed V1'-1 from the actual value V0'-1 of the top speed and the linear velocity ratio R, rolling rolls 14 on the upstream side are controlled so that the halfway part of the first series becomes the target middle speed V1'-1. In the second series, by determining a target middle speed V1'-2 from the actual value V0'-2 of the top speed and the linear velocity ratio R, when V1'-2>V1'-1, the number of revolutions of the rolling rolls 14 is changed and, when V1'-2<V1'-1, the revolution of the rolling rolls 14 is not changed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling method for a strip rolled material suitable for rolling a strip rolled material in multiple lines using a rolling apparatus in which a large number of rolling rolls having a plurality of calibers are provided.

A rolling mill that continuously rolls a rolled material to produce a rolled steel strip (strip wire or bar) includes a roughing mill, an intermediate rolling mill, a finish rolling mill, and a winding device in order from the upstream side. After the rolled material heated in the heating furnace is introduced from the upstream side and continuously rolled, it becomes a rolled steel strip and is wound in a ring shape by a winding device.
The dimensional accuracy of the rolled steel bar produced by such a rolling apparatus is greatly affected by the tension between stands acting on the rolled steel bar. If the tension between the stands increases, the roundness of the rolled steel strip will deteriorate and the deviation will increase, or conversely, if the tension becomes extremely small, the rolling material will pulsate between the stands and cobble will occur. Has been revealed.

Therefore, in order to improve the dimensional accuracy of the product and reduce the dimensional fluctuation without generating a loop (sag) or cobble of the rolled steel strip, the tension acting on the rolled steel strip during rolling is not excessive and It is necessary to control to be constant.
As rolling technology of the strip rolled material based on such an idea, there are those disclosed in Patent Literature 1 and Patent Literature 2.
The technique of Patent Document 1 pays attention to the variation in the width of the outlet side of the final rolling mill when the bottom is missing, and calculates the inter-stand tension in the final rolling mill and the upstream rolling mill using the dimensional variation and the influence coefficient. The roll speed and gap amount of each rolling mill are controlled based on the deviation between the obtained inter-stand tension and the target tension.

The technique of Patent Document 2 determines in advance the linear speed ratio at which the dimensions over the entire length of the product are uniform from the transfer speed (top speed) and the transfer speed (middle speed) of the tip of the rolled steel strip, During actual rolling, the rotational speed of the drive motor of the final finish rolling mill is controlled based on the middle speed obtained from the actually measured value of the top speed and the linear speed ratio.
JP 61-30210 A JP 2004-66263 A

In recent years, the dimensional accuracy for strips and the guarantee for surface defects have become very strict, and even in multi-series rolling equipment (multi-strand rolling equipment), the quality required by the user without controlling the tension between stands. It is the present condition that cannot be satisfied.
However, even if it is going to employ | adopt the technique of patent document 1 in order to control the tension | tensile_strength between stands, patent document 1 is a technique in the "at the time of slipping out" of a strip rolling material, Comprising: Have difficulty. Even if it is applied, since the tension between the stands is estimated using the influence coefficient, it is difficult to say that the estimated tension value is high in accuracy. In addition, the number of rolls and roll gap, which are controlled quantities, are estimated from a calculation formula based on several assumptions based on the tension value. It was difficult to do.

Moreover, when the technique of patent document 1 is employ | adopted and the roll gap with respect to the middle part of a rolled steel strip is adjusted while controlling the tension between stands, in actual operation, the cross-sectional shape of the rear end portion of the rolled steel strip May bite (overfill) and cause surface wrinkles. On the contrary, when the roll gap adjustment is performed to optimize the shape of the rear end portion of the rolled steel bar, the caliber filling rate in the middle part to which the tension is applied is lowered, which is caused by the twist of the rolled steel bar. There is a great possibility of causing wrinkle wrinkles due to misroll and non-objectivity.
Further, both Patent Documents 1 and 2 are considered to have disclosed a control technique for rolling one strip rolled material with one rolling roll, and multiple strands that roll a plurality of rolled materials with one rolling roll. It is difficult to apply to a rolling mill.

  That is, when rolling a single strip steel strip with a rolling roll and simultaneously rolling a four strip strip rolled material, the rolling roll gap fluctuates due to fluctuations in the rolling roll due to the rigidity of the rolling mill. Since the transfer speed changes, the tension between the stands varies at the rotation speed set for one line. Also, in the simultaneous rolling of 4 strips, when rolling with 3 strips for a while due to misrolling and then rolling again with 4 strips, the amount of wear of the caliber of the rolling rolls differs depending on each series, so With the rotation speed and roll gap amount, slack (loop) occurs in the rolled steel strip, and misrolling may occur again. In particular, when the steel grade of the rolled steel strip changes, the stand tension fluctuates at the rotation speed set in the initial state due to the change in stretching due to the steel grade, and the surface due to dimensional fluctuation, misroll due to the occurrence of a loop, contact with the guide Prone to wrinkles.

  Therefore, the present invention uses a rolling device in which a large number of rolling rolls having a plurality of calibers are used, and when rolling a steel strip in multiple lines, a steel strip with high dimensional accuracy and no occurrence of surface defects etc. An object of the present invention is to provide a method for rolling a rolled steel bar that can be manufactured.

In order to achieve the above object, the present invention takes the following technical means.
That is, the rolling method of the strip rolled material according to the present invention, when rolling the strip rolled material in multiple series, using a rolling device provided with a large number of rolling rolls having a plurality of calibers,
(i) A line that can be optimally rolled in each series of rolled steel from the top speed V0 that is the speed of the tip of the rolled steel and the middle speed V1 that is the middle speed of the rolled steel. The speed ratio R = (V1−V0) / V0 is obtained in advance,
(ii) In the first series of rolled steel strip that is initially rolled, the top speed V0'-1 of the rolled steel strip is measured, and the actual value V0'-1 and the linear speed ratio are measured. The target middle speed V1′-1 is obtained from R, and the number of rotations of the upstream rolling roll is set so that the middle part of the strip rolled material becomes the target middle speed V1′-1.
(iii) In the case of the second series of rolled steel that starts rolling after the rolling of the first series of rolled steel, the top speed V0′-2 of the rolled steel is measured and the results A target middle speed V1'-2 is obtained from the value V0'-2 and the linear speed ratio R,
(iv) When the target middle speed V1′-2 for the second series of rolled steel bars is greater than the target middle speed V1′-1 for the first series of rolled steel bars, the middle of the whole series of rolled steel bars Change the number of rotations of the rolling roll so that the part becomes the target middle speed V1'-2,
(v) When the target middle speed V1′-2 for the second series of rolled steel bars is smaller than the target middle speed V1′-1 for the first series of rolled steel bars, the rotational speed of the rolling roll is changed. Without,
It is characterized by rolling each strip rolled material.

By carrying out like this, even if it is a case where a 2 series strip rolling material is rolled using a multi-strand rolling device, the transfer speed of the tip part of the strip rolling material used as tensionless rolling and the middle part used as tension rolling The difference can be made as small as possible, and the tension between the stands can be minimized. Therefore, it is possible to produce a strip-rolled material having a small dimensional deviation from the front end portion to the midway portion to the rear end portion and having no surface flaws.
Preferably, in the third series of steel strip rolled material that starts rolling after the start of rolling of the first and second steel strip rolled material,
(vi) The top speed V0′-3 of the third series of rolled steel bars is measured, and the target middle speed V1′-3 for the rolled steel bars is calculated from the actual value V0′-3 and the linear speed ratio R. Seeking
(vii) When the target middle speed V1′-3 is higher than any of the target middle speeds V1′-1 and V1′-2 for the first and second series of rolled steel bars, all series of steel bars are rolled. The number of rotations of the rolling roll is changed so that the middle part of the material becomes the target middle speed V1′-3,
(viii) The target middle speed V1′-3 for the third series of rolled steel bars is any one of the target middle speeds V1′-1 and V1′-2 for the first and second series of rolled steel bars. If small, without changing the number of rotation of the rolling roll,
It is advisable to perform rolling on each strip rolled material.

By carrying out like this, even if it is a case where 3 series steel strip rolling material is rolled using a multi-strand rolling device, with the transfer speed of the tip part of the steel strip rolling material used as tensionless rolling, and the middle part used as tension rolling The difference can be made as small as possible, and the tension between the stands can be minimized. Therefore, it is possible to produce a strip-rolled material having a small dimensional deviation from the front end portion to the midway portion to the rear end portion and having no surface flaws.
More preferably, in the n-th series (n> 3) steel strip rolled material in which rolling is started after the rolling of the third steel strip rolled material is started,
(ix) The top speed V0′-n of the rolled steel strip of the n-th series is measured, and the target middle speed V1′-n for the rolled steel strip is calculated from the actual value V0′-n and the linear speed ratio R. Seeking
(x) When the target middle speed V1'-n is higher than any of the target middle speeds V1'-1 to V1 '-(n-1) for the first to (n-1) th series rolled steel bars. , Changing the number of rotations of the rolling roll so that the middle part of the rolled steel bars of all series becomes the target middle speed V1′-n,
(xi) The target middle speed V1'-n for the n-th series of rolled steel bars is the target middle speed V1'-1 to V1 '-(n-1) for the first to (n-1) th series of rolled steel bars. If less than any one of the above, without changing the number of rotation of the rolling roll,
It is advisable to perform rolling on each strip rolled material.

By carrying out like this, even if it is a case where an n series (n> 3) strip rolled material is rolled using a multi-strand rolling apparatus, the front-end | tip part of the strip rolled material used as tensionless rolling and the intermediate part used as tension rolling The difference from the transfer speed can be made as small as possible, and the tension between the stands can be minimized. Therefore, it is possible to produce a strip-rolled material having a small dimensional deviation from the front end portion to the midway portion to the rear end portion and having no surface flaws.
In addition, it is good to perform the change of the rotation speed of the said rolling roll with respect to the rolling roll arrange | positioned upstream from the position which measured the said top speed.

By performing such upstream processing, the middle part of the rolled steel bar can be set to the target middle speed as quickly as possible.
When rolling the front end of the strip rolled material, the rotation of the rolling roll provided on the upstream side before the front end reaches the rolling roll provided on the downstream side closest to the position where the top speed is measured. It is very suitable to control the number.
By carrying out like this, rolling of the front-end | tip part of a strip rolled material can be performed favorably.

  According to the present invention, when rolling a steel strip in a multi-line using a rolling device in which a large number of rolling rolls having a plurality of calibers are rolled, a steel strip with high dimensional accuracy and no occurrence of surface defects etc. Manufacturable.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
What is shown in FIG. 1 and FIG. 2 is the outline | summary of the rolling apparatus 2 which hot-rolls the strip rolled material 1 such as a strip wire.
The rolling device 2 includes, from the upstream side, a rough rolling row 4 composed of a plurality of rough rolling mills 3, a first intermediate rolling train 6 composed of a plurality of intermediate rolling mills 5, and a plurality of rolling mills. A second intermediate rolling row 7, a finish rolling mill 8, and a winding device 9 (laying head) are sequentially arranged. Although not shown, a water cooling device or the like is provided between the second intermediate rolling row 7 and the finish rolling mill 8. After the billet heated in the heating furnace 10 is introduced from the upstream side of the rolling device 2 and continuously rolled, it becomes the strip rolled material 1 and is wound in a ring shape by the winding device 9. ing.

The rough rolling row 4 is composed of seven rough rolling mills 3 (# 1 rolling mill to # 7 rolling mill), and the first intermediate rolling row 6 is composed of four intermediate rolling mills 5 (# 8 rolling mill). ~ # 11 rolling mill). Each rolling mill 3 and 5 has a rolling roll 14 (horizontal roll) and a drive motor for driving it.
The second intermediate rolling row 7 employs a block mill, and a plurality of rows of work rolls (a combination of horizontal rolls and vertical rolls) are arranged in series. A single roll for rotationally driving these work rolls. A drive motor is provided. The finishing mill 8 employs a sizing mill, a plurality of rows of work rolls (a combination of horizontal rolls and vertical rolls) are arranged in series, and a single drive motor is provided for rotationally driving the work rolls. It has been.

Furthermore, the rolling device 2 is provided with a control unit 11 that controls the drive motors of the rolling mills 3 and 5 and the drive motor of the winding device 9. The control unit 11 includes a process computer provided in the rolling device 2.
Between the rolling mills of the rough rolling row 4 (between rolling stands) and between the rolling mills of the first intermediate rolling row 6 (between rolling stands), a linear velocity measuring means for measuring the transport speed of the strip 1 12 is provided. The linear velocity measuring means 12 is composed of a laser Doppler linear anemometer.
At the place where the laser Doppler linear anemometer 12 is provided, tip detecting means 13 for detecting that the tip of the rolled steel strip 1 has arrived is provided. The tip detection means 13 is constituted by, for example, an infrared detection sensor that can detect the hot strip rolled material 1.

The rolling device 2 of the present embodiment is a multi-strand rolling device that can roll a plurality of rolled steel strips 1 with a single rolling roll 14. Specifically, one caliber roll 14 is provided with four calibers (hole type), and four series of rolled steel strips 1 can be rolled at a time.
Thus, when rolling the multi-strip steel strip 1, in order to make the final product shape of a predetermined quality and prevent surface flaws, the number of rolling rolls 14 is controlled and the steel strip rolled during rolling is controlled. It is necessary to accurately control the tension between the stands. The control unit 11 has such a control function.

3 and 4 show a rolling method of the strip rolled material performed by the control unit 11, that is, a method for controlling the number of rotations of the rolling roll 14. FIG.
Hereinafter, in order to simplify the description, attention is paid to the laser Doppler linear speedometer 12 provided between the # 6 rolling mill and the # 7 rolling mill, and the control unit 11 rotates the rolling roll 14 based on the measured value. The number shall be controlled. Of course, the same concept can be applied to all laser Doppler linear speedometers 12.
First, when rolling the rolled steel strip 1, the dimensional shape and dimensional deviation of the final product are within predetermined values based on the rolling conditions (rolling speed, temperature, rolling reduction, steel type, etc.) of the rolled steel strip 1 in advance. The “linear velocity ratio R” that reduces the occurrence of surface flaws is calculated. In calculating the linear velocity ratio R, it is preferable to use a data table or an experimental result that summarizes past rolling results.

The linear speed ratio R is the moving speed V0 (hereinafter also referred to as the top speed) of the strip rolled material 1 and the moving speed V1 of the intermediate portion of the rolled steel sheet 1 (hereinafter referred to as the middle speed). Is also required),

R = (V1-V0) / V0 (1)

[S1]. In the case of the present embodiment, the steel strip 1 is caught in the downstream rolling mill (# 7) closest to the position where the top speed V0 is measured (the position where the laser Doppler linear speedometer 12 is installed). The speed after that.

  The value calculated by Equation (1) may be multiplied by 100 and expressed as a percentage. The large absolute value of the linear speed ratio R means that the difference between the top speed and the middle speed is large, excessive tension is applied between the tip and midway, loops (sagging) and cobbles are generated. Shows the situation. Conversely, a small absolute value of the linear speed ratio R means that the difference between the top speed and the middle speed is small, and the tension acting between the tip and midway is minimal. Is shown. Therefore, if the linear speed ratio R is appropriately controlled, the tension between the stands applied to the strip 1 can be controlled, and thus the dimensional shape of the product can be controlled.

Thereafter, the first series of rolled steel 1 (sometimes simply referred to as the first series) is first rolled. At that time, as shown in FIG. 3 (a), the leading end detecting means 13 provided between the # 6 to # 7 stands of the rough rolling row 4 detects the leading end of the first series, and the laser Doppler linear velocity The actual value V0′−1 of the top speed is measured with a total of 12. Then, from the actual value V0′-1 and the linear velocity ratio R1 of the first series, the target middle speed V1′-1 is obtained using Expression (2).

V1′−1 = V0′−1 + V0′−1 × R1 (2)

Subsequently, the transfer speed of the middle part of the first series is changed to the laser Doppler linear speed meter until the tip of the rolled steel strip 1 reaches the downstream rolling mill closest to the laser Doppler linear speed meter 12 (# 7 rolling mill). 12 and when the speed is different from the target middle speed V1′-1 calculated earlier, the upstream rolling mill closest to the laser Doppler linear speedometer 12 (# 6 rolling mill) and the upstream side thereof The respective drive motors of the rolling mills (# 1 to # 5 rolling mills) are controlled to change the peripheral speed of the rolling roll 14 so that the first-line transfer speed at each position becomes the target middle speed V1′-1. (Upstream). [S2 to S4]
Next, the rolled steel strip 1 of the second series (sometimes simply referred to as the second series) is rolled. In the second series, rolling is started after the rolling of the first series of rolled steel bars. At that time, as shown in FIG. 3B, the tip portion of the second series is detected by the tip detecting means 13, and the actual value V0′-2 of the top speed is measured by the laser Doppler linear speedometer 12. Then, the target middle speed V1′-2 is obtained from the actual value V0′-2 and the linear velocity ratio R2 of the second series using Expression (3). [S5, S6]

V1′−2 = V0′−2 + V0′−2 × R2 (3)

Subsequently, the transfer speed of the middle part is measured by the laser Doppler linear speedometer 12 until the tip of the second series reaches the downstream rolling mill closest to the laser Doppler linear speedometer 12 (# 7 rolling mill). When the speed is different from the previously calculated target middle speed V1′-2, the target middle speed V1′-2 is compared with the first series of target middle speed V1′-1. [S7]
As a result of S7, when the second series target middle speed V1′-2 is higher than the first series target middle speed V1′-1, the transfer speed in the middle of the first and second series is the target middle speed. The rotational speed of the rolling roll 14 of the # 6 rolling mill is increased so as to be V1′-2. [S8]
As a result of S7, when the second series target middle speed V1′-2 is smaller than the first series target middle speed V1′-1, the number of rotations of the rolling roll 14 of the # 6 rolling mill is kept as it is, and the first And the transfer speed in the middle part of the second series is set as the target middle speed V1′-1. [S9]
Hereinafter, similarly, the third series of rolled steel bars 1 and the fourth series of rolled steel bars 1 are rolled (hereinafter also simply referred to as the third series and the fourth series). In the third series, rolling is started after the rolling of the second series of rolled steel bars is started, and in the fourth series, rolling is started after the rolling of the third series of rolled steel bars is started.

That is, as shown in FIG. 3C, the actual value V0′-3 of the top speed is measured by the laser Doppler linear speedometer 12. Then, the target middle speed V1′-3 is obtained from the actual value V0′-3 and the third-series linear speed ratio R3 by using the equation (4). [S10, S11]

V1′-3 = V0′-3 + V0′-3 × R3 (4)

Thereafter, when the target middle speed V1′-3 is higher than both the first and second series of target middle speeds V1′-1 and V1′-2, the transfer speed in the middle part of the whole series is set to the target middle speed. The rotation speed of the rolling roll 14 of the # 6 rolling mill is increased while the tip of the third series does not reach the # 7 rolling mill so that the speed V1′-3 is obtained. [S12, S13]
When the target middle speed V1′-3 of the third series is smaller than either one of the target middle speeds V1′-1 and V1′-2 of the other series, the rotational speed of the rolling roll 14 of the # 6 rolling mill is Leave as it is. [S12, S14]
When rolling the fourth series, the actual value V0′-4 of the top speed is measured by the laser Doppler linear speed meter 12, as shown in FIG. Then, the target middle speed V1′-4 is obtained from the actual value V0′-4 and the linear speed ratio R4 of the fourth series using Expression (5). [S15, S16]

V1′−4 = V0′−4 + V0′−4 × R4 (5)

Thereafter, when the target middle speed V1′-3 is higher than any of the first to third series of target middle speeds V1′-1 to V1′-3, the first to third series of the target middle speed V1′-3 is the target middle speed. The rotation speed of the rolling roll 14 of the # 6 rolling mill is increased until the leading end of the fourth series reaches the # 7 rolling mill so as to be V1′-4. [S17, S18]
When the target middle speed V1′-3 for the fourth series is lower than any one of the first to third series target middle speeds V1′-1, V1′-2, V1′-3, # The number of rotations of the rolling roll 14 of the 6 rolling mill is kept as it is. [S17, S19]
By controlling the number of rotations of the rolling roll 14 in this way, the upstream rolling roll 14 is calculated from the four series of linear speed ratios R1 to R4 with respect to the stands where the linear speed is measured. Among the roll speeds, the roll speed is the fastest, and the downstream roll speed is the slowest roll speed.

  The rolling method of the strip-rolled material, in other words, the rotational speed control method of the rolling roll 14 measures and controls the linear velocity between the tip portion of the strip-rolled material 1 to be tensionless rolling and the midway portion to be tension rolling. Thus, it is a technique for minimizing the “tension between the stands” during rolling of the tip part to the middle part. This rolling method is not applied only at the time of rolling the front end portion of the rolled steel strip 1, and can also be applied to the middle portion of the rolled steel strip 1. By doing so, the linear speed ratio R, that is, the tension between the stands, can be minimized over the entire length of the rolled steel strip 1, and the dimensional deviation from the front end portion to the midway portion to the rear end portion of the rolled steel strip 1 is predetermined. It will be within the value.

From another point of view, the rolling method of the strip-rolled material according to the present invention presets the smallest linear speed ratio among the four series in order to suppress variations in the four series linear speed ratios (interstand tension). Then, by setting the predetermined rolling roll 14 to the number of rotations based on the linear speed ratio, it is possible to perform rolling with the smallest tension without generating a loop in all the series. By doing so, the tension control corresponding to the steel type change and the variation for each rolling opportunity is performed, and it becomes possible to always obtain a stable cross-sectional shape of the rolled steel strip 1.
In addition, when setting the transfer speed of the middle part of the rolled steel strip 1 as the target middle speed, the roll peripheral speed Vr is obtained from the “relationship between the roll peripheral speed and the rolled steel strip transfer speed” obtained in advance, The rotational speed M of the drive motor may be calculated from the speed increasing ratio G of the rolling mill and the roll diameter D using equation (6).

M = Vr / (G × π × D) (6)

The above-described rolling method of rolled steel strip can be similarly applied even when the rolled strip material 1 is increased to 5, 6... N series.

FIG. 5 shows an embodiment in which four types of rolled steel strips 1 are rolled using the rolling method of the rolled steel strip 1 according to the present invention. The experimental conditions are as follows.

-Steel type: JIS SCM435
-Product wire diameter: φ5.5
・ Rolling speed: 80m / s
-Billet diameter: □ 155
・ Temperature on the rolling side: 1000 ° C

Specifically, as in the rolling device 2 shown in FIGS. 1 and 2, ten laser Doppler linear speedometers 12 are installed between # 1 to # 11 stands per line, and the above-described rolled steel strip 1 described above. It is the result of having performed this rolling method.

Condition A is a result of a conventional method in which no control based on the linear speed ratio R is performed, and Condition B is a case where the rolling method of the present invention is applied between # 1 to # 8 rolling stands (rough rolling row 4). Condition C is when the rolling method of the present invention is applied between # 7 to # 11 rolling stands (first intermediate rolling row 6). Condition D is a case where it is applied to everything between # 1 to # 11 rolling stands.
In the conventional method of Condition A, although there are rolling mills of # 12 or later where a tension control device exists, the dimensional tolerance of the 3 series of 4 series is “± 0 due to the influence of the tension between the stands on the upstream side. .1 mm or less ”, or surface defects of 0.02 mm to 0.03 mm were present (Δ in the figure), or surface defects of 0.03 mm or more were generated (× in the figure).

On the other hand, in the case of conditions B and C, the dimensional tolerance over the full length of the strip 1 is ± 0.1 mm or less, and in all cases, no surface flaw of 0.02 mm or more is generated, compared with the conventional method. Dimensional accuracy and surface quality are greatly improved.
In the case of condition D, the dimensional tolerance over the entire length of rolled steel 1 is ± 0.1 mm or less, and no surface defects of 0.01 mm or more are generated in all, and the dimensional accuracy and surface quality are higher than those of conventional methods. The result was significantly improved. That is, by applying the rolling method of the rolled steel bar of the present invention between all the stands, it becomes possible to produce a rolled steel bar that has no dimensional deviation and hardly generates surface defects.

The present invention is not limited to the above embodiment.
The rolling method of the rolled bar material according to the present invention is not limited to the rolling of the front end portion of the rolled bar material 1, and can also be applied to the rear end portion (bottom portion) of the rolled bar material 1. When the linear velocity ratio R is obtained by measuring the linear velocity (bottom velocity) at the rear end, the control may be applied to the preset of the next material.

It is a front view of the rolling apparatus of a strip rolling material. It is a top view of the rolling apparatus of a strip rolling material. It is the figure which showed the rolling condition of the front-end | tip part of a strip rolled material. It is the flowchart which showed the rolling method of the strip rolled material which concerns on this invention. It is the figure which showed the result of the Example.

Explanation of symbols

1 Rolled steel 2 Rolling device 4 Rough rolling row 6 First intermediate rolling row 7 Second intermediate rolling row 8 Finishing rolling mill 9 Winding device (laying head)
11 Controller 12 Linear velocity measuring means (laser Doppler linear anemometer)
13 Tip detection means 14 Rolling roll

Claims (5)

When rolling a strip rolled material in multiple lines using a rolling device in which a large number of rolling rolls having a plurality of calibers are deployed,
(i) A line that can be optimally rolled in each series of rolled steel from the top speed V0 that is the speed of the tip of the rolled steel and the middle speed V1 that is the middle speed of the rolled steel. The speed ratio R = (V1−V0) / V0 is obtained in advance,
(ii) In the first series of rolled steel strip that is initially rolled, the top speed V0'-1 of the rolled steel strip is measured, and the actual value V0'-1 and the linear speed ratio are measured. The target middle speed V1′-1 is obtained from R, and the number of rotations of the upstream rolling roll is set so that the middle part of the strip rolled material becomes the target middle speed V1′-1.
(iii) In the case of the second series of rolled steel that starts rolling after the rolling of the first series of rolled steel, the top speed V0′-2 of the rolled steel is measured and the results A target middle speed V1'-2 is obtained from the value V0'-2 and the linear speed ratio R,
(iv) When the target middle speed V1′-2 for the second series of rolled steel bars is greater than the target middle speed V1′-1 for the first series of rolled steel bars, the middle of the whole series of rolled steel bars Change the number of rotations of the rolling roll so that the part becomes the target middle speed V1'-2,
(v) When the target middle speed V1′-2 for the second series of rolled steel bars is smaller than the target middle speed V1′-1 for the first series of rolled steel bars, the rotational speed of the rolling roll is changed. Without,
A rolling method for rolled steel bars, comprising rolling each rolled steel bar. In the third series of rolled steel bars, the rolling of which starts after the rolling of the first and second series of rolled steel bars is started,
(vi) The top speed V0′-3 of the third series of rolled steel bars is measured, and the target middle speed V1′-3 for the rolled steel bars is calculated from the actual value V0′-3 and the linear speed ratio R. Seeking
(vii) When the target middle speed V1′-3 is higher than any of the target middle speeds V1′-1 and V1′-2 for the first and second series of rolled steel bars, all series of steel bars are rolled. The number of rotations of the rolling roll is changed so that the middle part of the material becomes the target middle speed V1′-3,
(viii) The target middle speed V1′-3 for the third series of rolled steel bars is any one of the target middle speeds V1′-1 and V1′-2 for the first and second series of rolled steel bars. If small, without changing the number of rotation of the rolling roll,
The method for rolling a strip rolled material according to claim 1, wherein each strip rolled material is rolled. In the n-th series (n> 3) steel strip rolled material in which rolling is started after the rolling of the third steel strip rolled material,
(ix) The top speed V0′-n of the rolled steel strip of the n-th series is measured, and the target middle speed V1′-n for the rolled steel strip is calculated from the actual value V0′-n and the linear speed ratio R. Seeking
(x) When the target middle speed V1'-n is higher than any of the target middle speeds V1'-1 to V1 '-(n-1) for the first to (n-1) th series rolled steel bars. , Changing the number of rotations of the rolling roll so that the middle part of the rolled steel bars of all series becomes the target middle speed V1′-n,
(xi) The target middle speed V1'-n for the n-th series of rolled steel bars is the target middle speed V1'-1 to V1 '-(n-1) for the first to (n-1) th series of rolled steel bars. If less than any one of the above, without changing the number of rotation of the rolling roll,
The rolling method for rolled steel bars according to claim 2, wherein each rolled steel bar is rolled.   The steel strip rolled material according to any one of claims 1 to 3, wherein the rotation speed of the rolling roll is changed with respect to the rolling roll disposed upstream of the position where the top speed is measured. Rolling method.   When rolling the front end of the strip rolled material, the rotation of the rolling roll provided on the upstream side before the front end reaches the rolling roll provided on the downstream side closest to the position where the top speed is measured. The method for rolling a strip according to claim 4, wherein the number is controlled.

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