JPH03226301A - Method for controlling thickness of rolled sheet with reversing mill - Google Patents

Abstract

PURPOSE:To improve the yield of rolled product by narrowing the gap between rolling rolls when front and rear end parts are passed, enlarging into a prescribed gap when a middle part of the material to be rolled is passed and also fixing the roll gap of the final rolling. CONSTITUTION:To a target thickness from the first rolling of the material 1 to be rolled, the set value of the gap between the rolling rolls 2, 2a with which the front and rear end parts of that material 1 to be rolled are rolled is varied. As the result, the difference of the gap between the rolling rolls 2, 2a in the rolling of the front and rear end parts and middle part of the material 1 to be rolled can be decreased. At the time of the final rolling of the material 1 to be rolled, the gap between the rolling rolls is fixed. In this way, because many of the front and rear end parts of the material 1 to be rolled is made into the target thickness, the yield of rolled products can be considerably improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is particularly directed to a reverse rolling method that can roll a material to be rolled to a thickness at both ends within the same target thickness as the thickness at an intermediate portion thereof. The present invention relates to a method for controlling rolled plate thickness using a mill.

[Conventional technology]

As is well known, in a reverse mill, the material to be rolled is passed through the gap between the rolling rolls from the front and back of one mill, and each time the roll reduction device is operated to reduce the set value of the gap between the rolling rolls, thereby achieving the target value. This is a method of manufacturing a rolled material with a plate thickness.

[Problem to be solved by the invention]

However, since the material to be rolled is rolled by passing it back and forth through the gap between the rolling rolls from the front and back of the mill, the rolling speed of the material to be rolled is necessarily lower at the acceleration section at the leading end and the deceleration section at the rear end than at the intermediate section. will be late.

Furthermore, as the rolling speed becomes slower due to the need for lubrication to the material to be rolled, the thickness of the material tends to increase.

In other words, even if the rolled material is rolled with the set gap of the rolling rolls constant, the acceleration/deceleration region at the front and rear ends will generally be rolled thicker than the middle part of the rolled material, resulting in a uniform plate over the entire length. It is not possible to obtain a thick rolled material.

Hereinafter, Fig. 4(a), which is an explanatory diagram of changes in rolling shape of rolled material,
0)), (C), and (d) and FIG. 5, which is an explanatory diagram of the rolling state of the rolled material, to explain the conventional rolled plate thickness control method of a reverse mill. The sign (+) shown in a) indicates that the material to be rolled before rolling with a length of plate thickness H1 is
2 peaks) respectively indicate the rolled material (1) that has been rolled for the first time with the setting of the target plate thickness S1.

According to these figures, the thickness of the intermediate part of the material to be rolled (1) is Hl, which is equal to the target thickness S1, but the thickness of the leading and trailing ends is H61, and the thickness of the intermediate part is H1. FIG. 4(C) shows the case of the second rolling, and shows that the plate thickness at the front and rear ends of the rolled material (1) is as thick as H02.

In addition, Fig. 4(d) shows the case of the final n-th rolling.
The thickness of the middle part of the material to be rolled (1) is H7 and the target thickness S,
However, the plate thickness at the leading and trailing ends is H111.
1, which is thicker than the target plate thickness Sn.

The range indicated by the plate thickness Lo is off-gauge, that is, it is a non-standard thickness, which suggests that it cannot be a rolled product.

Further, FIG. 5 shows the rolling state of the material to be rolled, with the horizontal axis representing the dimension in the plate thickness direction and the vertical axis representing the deformation load of the material to be rolled or the roll stand.

Now, assuming that in the (n-2)th rolling, which is two times before the final rolling number n, the thickness of the intermediate part and the leading and trailing ends of this rolled material is Hfl-ffi = HaR-2. The plasticity coefficient resulting from the difference in rolling speed of the material to be rolled when performing the (n-1)th rolling before the first rolling is Q7-1 at the middle part of the material to be rolled, and Q at the leading and trailing ends. -I, while
If the material to be rolled is rolled with the mill constant of the roll stand being M, the thickness of the material after rolling at that time is Q at the middle part, the thickness obtained by the intersection C of -1 and M.
I,, -I, and Q,,, -I at the front and rear ends.
The plate thickness Ha++-1 is obtained by the intersection of and M.

Then, by rolling the material to be rolled the final n times in the same manner as above, the thickness of the material to be rolled is reduced to H at the intermediate part.
7. Plate thickness H at the front and rear ends. Therefore, the plate thickness at the front and rear end portions of this rolled material is rolled to be thicker than the plate thickness at the intermediate portion.

By the way, the difference in plate thickness between the front and rear ends and the middle part of the material to be rolled, which occurred during the first half of rolling, is reduced by rolling the roll rolls from only the front and rear ends near the final rolling to reduce the gap between the rolls.
It may be possible to change it from ll to S all.

However, the plasticity coefficient of the rolled material increases toward the end of rolling, and if you try to forcibly roll the material to the target thickness, the material will undergo ΔF as shown in Figure 5.
As a result of the applied force, the shape of the material to be rolled becomes disordered or slippage occurs between the material to be rolled and the rolling rolls, making it impossible to roll the material to be rolled.

In other words, in the rolling plate thickness control method using a reverse mill as described above, the gap between the rolling rolls is kept constant over the entire length of the material to be rolled, so the plate thickness at the leading and trailing edges where the rolling speed is slow is lower than that at the middle part. This resulted in a yield problem in that parts thicker than the target plate thickness became off-gauge and non-standard.

Therefore, the present invention eliminates the off-gauge portion that deviates from the target plate thickness by changing the gap between the rolling rolls between the front and rear ends and the intermediate portion of the rolled material without causing the rolled material and the rolling roll to slip. The object of the present invention is to provide a method for controlling rolled plate thickness using a reverse mill, which makes it possible to reduce the thickness of a rolled plate by using a reverse mill.

[Means to solve the problem]

The present invention has been made in view of the above problems, and includes:
Therefore, the gist of the method for controlling rolled plate thickness using a reverse mill according to the present invention is to operate the roll reduction device to change the gap between the rolling rolls, and each time the gap is changed, the material to be rolled is passed back and forth through the gap. In a rolling plate thickness control method using a reverse mill for manufacturing a rolled material with a predetermined thickness, the gap between the rolling rolls through which the front and rear ends of the material to be rolled pass is set to a predetermined thickness before the final rolling of the material to be rolled. The gap is narrower than the gap from which the rolled material is obtained, and when the intermediate part of the rolled material is passing through, the gap is widened to a predetermined gap, and the gear of the rolling roll is kept constant during the final rolling of the rolled material. Features [Function] According to the rolled plate thickness control method using a reverse mill according to the present invention, the front and rear ends of the rolled material are adjusted from the first rolling of the rolled material to the target thickness. Since the setting value of the gap between the rolls to be rolled is varied, it is possible to reduce the difference between the gears and the wheels of the rolls in rolling between the leading and trailing ends and the intermediate part of the material to be rolled.

[Example] An example of the present invention is shown in Fig. 1 of Pro-7 Rien showing a method of controlling rolled plate thickness using a reverse mill, and Fig. 2 (a) and (a) of a drawing explaining changes in rolling shape of a rolled material. b), (C1, (d)) and FIG. 3, which is an explanatory diagram of the rolling state of the rolled material, will be described below.

As shown in Fig. 1, a reverse mill includes upper and lower rolling rolls (2), (2a) for rolling a material to be rolled (+), and a roll stand that supports these rolling rolls (2), (2a). (3) and the rolling roll (2) is installed on the upper part of this roll stand (3) and is moved up and down.
), and a roll-down device (4) for adjusting and setting the gap of (2a).

Then, the rolling speed of the material to be rolled (+1) by this reverse mill is a predetermined value determined by the material, thickness, etc. of the material to be rolled (+).
The rotation speed (7) of (2a) is controlled by a rolling speed control device (5). Next, rolling rolls (2), (2a)
The gap control device (6) controls the roll reduction device (
4) to set the gap between the rolling rolls (2) and (2a) in accordance with the target thickness (8) of the material to be rolled (1). Moreover, this rolling roll (2), (2
The length from the tip of the material to be rolled (1) is calculated by the calculator (9) from the roll rotation speed (7) and target plate thickness (8) in a), and the length from the tip of the material to be rolled (1) is calculated based on the rolling speed change during rolling acceleration and deceleration. In addition, when the rolling speed of the material to be rolled (1) is slow, the target plate is narrow, and when the rolling speed is constant, the target plate is determined by the rolling pass schedule 011! (
8), the gap between the rolling rolls (2) and (2a) is set by a gap setting device 00).

Hereinafter, the method of controlling the rolled plate thickness using the reverse mill having the above configuration will be explained. The code (1) shown in FIG.
This is a rolled material with a thickness H1 and a length L before rolling.

In addition, Fig. 2 (℃) shows the rolled material (1) that has been rolled for the first time with the setting of the target thickness Sl, and the thickness of the middle part of this rolled material (1) is the target thickness Hl. The plate thickness is equal to Sl, but the plate thickness at the front and rear ends is H,..., S...
This indicates that the plate thickness is thinner than the plate thickness H at the intermediate portion.

In addition, Fig. 2 (C) shows the state of the rolled material (+1) after the second rolling, and the plate thickness at the front and rear ends of this rolled material (1) is Het-Set. It is shown that.

In addition, the second roll (d) shows the rolled material (1) after the final rolling number (n), and the plate thickness H2 at the front and rear ends of this rolled material (1), and the plate W in the middle
-H, are both equal to the target plate thickness S, , indicating that there are almost no off-gauge parts that result in non-standard rolled products.

Furthermore, FIG. 3 of the rolling state explanatory diagram of the rolled material (1) is as follows:
The horizontal axis shows the plate thickness dimension, and the vertical axis shows the deformation load of the rolled material and roll stand.

Now, for example, in the (n-2)th rolling process, which is two times before the final rolling number n, the thickness of the intermediate part and the leading and trailing ends of the material to be rolled (1) is Hn-1-Hen.
−2, the number of final rolling steps (n
-1) From the difference in rolling speed of the material to be rolled (1) during the second rolling, the curlability coefficient is set as Qo-1 at the middle part and Qall-1 at the front and rear ends, and the roll stand The mill constant is M, the gap between the rolling rolls (2) and (2a) to the middle part of the rolled material (1) is 5R-1, and the rolling rolls (2) and (2a) to the leading and trailing ends thereof are
Rolled material (1) with the gap in 2a) S, , -1
Suppose that it is rolled.

Then, the thickness of the rolled material (1) after rolling is H, which is obtained by the intersection C of Q, -1 and M at the intermediate part.
At the front and rear ends, the plate thickness is Han-1 obtained by the intersection of Qea-+ and M, but H++-1>
H,,l-.

The gap 37-1 between the rolling rolls (2) and (2a) for rolling the intermediate part of the material to be rolled (+) and the gap between the rolling rolls (2) and (2a) for rolling the leading and trailing ends thereof. Set S11!1-1. Then, for the final n-th rolling, rolling rolls (2), (2a
) is set so that the target plate thickness is 37 for both the middle part of the rolled material (1) and the leading and trailing ends, then the thickness of the middle part of the rolled material (1) is Q. and QII of the leading and trailing ends coincide with the mill constant M of the roll stand (3) at the intersection f, and the rolled material after the final rolling (
The plate thicknesses of the middle part and the front and rear end parts of 1) are both H7.

That is, in the final n-th rolling, the thickness of the middle part and the front and rear ends of the material to be rolled (1) are both H, , and this is rolled in advance so that it will be defeated by the giant board yts. When planning the pass schedule, changes in the moldability coefficient of the material to be rolled (1) and changes in the number of rotations of the rolls are predicted, and the gap between the rolls is set for each rolling number.

In this way, except for the final n-th rolling step, the rolling roll (2
) and (2a), the middle part of the rolled material (1) and the front and back can be separated without slipping between the rolling rolls (2), (2a) and the rolled material (1). It is now possible to roll the ends to the same thickness.

It should be noted that the embodiments described above are merely examples of the present invention, and therefore the scope of the technical idea of the present invention is not limited by these embodiments.

〔Effect of the invention〕

According to the rolled plate thickness control method using a reverse mill according to the present invention, from the first rolling of the rolled material to the target plate thickness, the gap between the rolling rolls at the front and rear ends of the rolled material is adjusted to the set value. Since the difference in the gap between the rolling rolls can be reduced between the leading and trailing ends and the intermediate part, the material to be rolled can be rolled without slipping between the rolling rolls and the material to be rolled. With the conventional rolled plate thickness control method, the plate thickness at the leading and trailing edges was thicker than the middle part, and areas thicker than the target thickness were often off-gauge, resulting in many non-standard rolled products. Since most of the leading and trailing ends of the rolled material have the target thickness, it has become possible to significantly improve the yield of rolled products.

Moreover, as mentioned above, both ends of the material to be rolled can be rolled without strain, so the rolling surface of this part is equivalent to the middle part, and there is no need to perform forced reduction as in the conventional rolling plate thickness control method. This can greatly contribute to reducing maintenance costs for roll mills.

[Brief explanation of drawings]

1 to 3 are diagrams according to the present invention, in which FIG. 1 is a block diagram showing a method for controlling rolled plate thickness using a reverse mill, and FIG. 2 (a), (b), (C), ( d) is an explanatory diagram of the rolling shape change of the rolled material, FIG. 3 is an explanatory diagram of the rolling state of the rolled material, and FIGS. 4 and 5 are diagrams related to the prior art.
Figures (a), (a), (c), and (d) are explanatory diagrams of changes in the rolling shape of the rolled material, and FIG. 5 is an explanatory diagram of the rolling state of the rolled material. (1) - Rolled material, (2), (2a) - Roll roll, (
3)-Roll stand, (4)-Roll reduction device.

Claims (1)

[Claims] Rolled plate thickness by a reverse mill that operates a roll reduction device to change the gap between the rolling rolls, and each time the gap is changed, the rolled material is passed back and forth through the gap to produce a rolled material of a predetermined thickness. In the control method, before the final rolling of the material to be rolled, the gap between the rolling rolls through which the leading and trailing ends pass is narrower than the gap that allows the rolled material to have a predetermined thickness, so that the intermediate portion of the material to be rolled is A method for controlling rolled sheet thickness using a reverse mill, characterized in that the gap is widened to a predetermined gap while the material is passing through, and the gap between the rolling rolls is kept constant during final rolling of the material to be rolled.