JPS62130708A - Tension control method for tandem rolling - Google Patents

Abstract

PURPOSE:To perform tension control of a bar stock between every stands with a high accuracy by detecting a deformation of a vertical stand, adjusting roll rotating speeds of a stand biting the top part of the stock, and controlling a tension of the top end of the stock between adjacent stands. CONSTITUTION:A carried bar stock 7 is bitten by a vertical stand 2 following after a horizontal stand 1. A displacement of the stand 2 is detected by a differ ence transformer 11, is inputted to a detecting circuit 12, and is calculated by an arithmetic control circuit 13. As the result, the circuit 13 gives a motor 2b a rotating speed control command of a roll 2a which makes a tension be tween the stands 1 and 2 a prescribed tension. When the stock 7 is bitten by a horizontal stand 3, a displacement of the stand 2 is detected by the trans former 11 and a rotating speed control command of a roll 3a which makes a tension between the stands 2 and 3 a prescribed tension is given to a motor 3b. As the stock 7 is bitten by downstream stands 4 and 5 sequentially, a dis placement of vertical stand 4, etc., is detected and the rotating speed of every rolls 4a, 5a, etc., is adjusted sequentially.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to tandem rolling in which strips are sequentially caught in alternately arranged horizontal stands and vertical stands to perform continuous rolling. , relates to a tension control method for controlling inter-stand tension to a target tension in tandem rolling.

(Prior art and its problems) A strip of appropriate length heated in a heating furnace (billet 1-)
For example, as a long steel passes through a rough rolling train, an intermediate rolling train, and a finishing rolling train, the cross-sectional area of the rolled material is sequentially reduced by the grooves cut into the rolls of about 10 to 25 rolling mills, and the speed gradually increases. However, it is drawn into a wire rod having a predetermined size and shape. In such tandem rolling, in order to obtain a product with good dimensional accuracy, it is necessary to perform the rolling operation while accurately adjusting the tension acting between the stands to a target tension.

By the way, in tandem rolling, direct methods and indirect methods are known as methods for adjusting inter-stand tension. The direct method is a method in which a load cell is directly attached to the chock of a rolling mill to detect tension between stands, and the indirect method is a method in which tension is calculated based on rolling torque and rolling load. However, in the former case, it is necessary to set the sensitivity of the load cell, which is a sensor, sufficiently high in places where the absolute value of tension is small, such as in intermediate rolling rows and finishing rolling rows. Due to its location, it is easily affected by dust generated during rolling, intrusion of roll cooling water, etc., and therefore has the problem of requiring frequent maintenance. Furthermore, the latter has a problem in that the error in estimating the calculated tension increases as it moves toward the rear stand, resulting in a decrease in control ability.

(Object of the Invention) The present invention was made to solve the above problems, and is a tension control method that can control the tension i and IJ between stands in tandem rolling with high precision, and also facilitates sensor maintenance. The purpose is to provide

(Means for Achieving the Object) The present invention is a method for controlling tension between stands in tandem rolling in which strips are sequentially bitten by alternately arranged horizontal stands and vertical stands to continuously roll. ,
In order to achieve the above purpose, the displacement m of the vertical stand is detected from when the strip is caught in the vertical stand until it is caught in the horizontal stand on the downstream side, and based on the displacement detection signal. , the roll rotation speed of the vertical stand is adjusted so that the tension between the vertical stand and the horizontal stand on the upstream side becomes the target tension, and after the strip is caught in the horizontal stand, the vertical stand on the downstream side The displacement ω of the vertical stand on the upstream side of the horizontal stand is detected before it is bitten by the stand, and based on the displacement detection signal, the tension between the upstream vertical stand and the horizontal stand is set to the target tension. The roll rotation speed of the horizontal stand is adjusted so that

(Example) FIG. 1 shows a schematic diagram of a tandem rolling mill in which the tension control method of the present invention is implemented. As shown in the figure, in this tandem rolling machine, horizontal stands 1.3.5
. . . and vertical stands 2, 4, . . . are arranged alternately along the arrow A direction □, and the horizontal stands 1.3.5
... have horizontal rolling rolls 1a, 3a, 5a...,
Also, the vertical stand 2.4... has vertical rolling rolls 2a.
, 4a... are attached in pairs.

Each rolling roll 1a, 2a, 3a, 4a, 5a...
Motors 1b, 2b attached to each stand 1.2°3.4.5...

3b, 4b, 5b, . . . are rotated to roll the bar 7 caught between the respective rolls and send it out in the direction of arrow A.

FIG. 2 is a view of the vertical stand 2 seen from the left side of FIG. A pair of vertical rolling rolls 2a, 2a rotated by a spindle 8 are supported by a vertical stand 2, and one end of the vertical stand 2 is clamped to a stand support frame 10 via a clamp member 9. A differential transformer 11 is installed between the vertical stand 2 and the stand support frame 10. It is configured to detect displacement in the direction perpendicular to the plane of the drawing (displacement in the direction between the stands). The displacement detection position of the differential transformer 11 may be selected from a position where the displacement due to the tension between the stands is large; for example, as shown in FIG. 2, an upper end corner position away from the clamp member 9 is preferable.

The output signal of the differential transformer 11 is given to the displacement detection circuit 12 shown in FIG. 1, where the amount of displacement at the position P is determined and outputted to the 8Mp control section 13 as a displacement detection signal. Based on the displacement detection signal, the logic control unit 13
It is configured to calculate the roll rotation speed at which the inter-stand tension becomes a predetermined tension, and output a roll rotation speed control command to the motor 2b or motor 3b according to the calculation result (details thereof will be described later).

Next, the operation of this tandem rolling mill will be explained. First, at the beginning of operation of the rolling mill, each rolling roll 1a,
2a, 3a, 4a, 5a, . . . are each rotated at a predetermined speed. As shown in FIG. 3(a), when the bar 7 is fed into this rolling mill, the bar 747 is
It is bitten into the second horizontal stand 1, subjected to first rolling by the rolling roll 1a, and sent to the second vertical stand 2 side.

Next, the bar 7 is inserted into the second vertical stand 2, as shown in FIG. 3(b), and rolled by the rolling rolls 2a. At this time, if tension is applied between stands 1 and 2, due to the structure of the stand, horizontal stand 1
Since the rigidity of is large and the rigidity of vertical stand 2 is small,
Vertical stand 2 is displaced. That is, stand 1
, 2, the vertical stand 2 is displaced to the left in Fig. 3(b), and conversely, when a compressive force is applied between the vertical stand 2, the vertical stand 2 is displaced as shown in Fig. 3(b). Displaced to the right. FIG. 4 is a graph showing the relationship between the tension acting between the stands 1 and 2 and the displacement of the vertical stand 2. The horizontal axis shows the displacement of the vertical stands, and the vertical axis shows the tension acting between the stands. As shown in the figure, a certain proportional relationship is established between the tension between the stands and the amount of displacement of the vertical stands.

This displacement of the vertical stand 2 is detected by the differential transformer 11 and provided to the displacement detection circuit 12, and the amount of displacement is determined by the displacement detection circuit 12 and provided to the arithmetic control section 13 as a displacement detection signal. Based on the displacement detection signal, the performance control unit 13 determines the rolling roll 2 such that the tension between the stands 1 and 2 is a predetermined tension, in this case - no tension as an example.
The rotation speed of rolling roll a is calculated, and a roll rotation speed control command according to the calculation result is given to the motor 2b, and the rolling roll 2
The rotation speed of a is adjusted. That is, when a tensile force is acting between the stands 1 and 2, the rotational speed of the rolling roll 2 is made close to each other, and conversely, when a compressive force is acting between the stands 1 and 2, the rotational speed is increased, and the rolling speed is increased between the stands 1 and 2. The rotational speed of the rolling rolls 2a is adjusted so that the tension between the rolling rolls 2a becomes zero. (See Figure 3(C)). This adjustment of the rotational speed of the rolling roll 2a is performed until the tip of the bar 7 is bitten into the next horizontal stand 3.

Next, as shown in FIG. 3(d), the bar 7 is inserted into the third horizontal stand 3. At this time, stand 2
．． If a tensile force is applied between 3, the vertical stand 2 will be displaced to the right in Fig. 3(d), and if a compressive force is applied conversely, the vertical stand 2 will be displaced to the right as shown in Fig. 3(d). Displaced to the left.

At this time as well, the displacement of the vertical stand 2 is
1 is detected and given to the displacement detection circuit 2, and the displacement amount is determined by the displacement detection circuit 12 and given to the arithmetic control section 13 as a displacement detection signal. The calculation control unit 13 calculates the rotation speed of the rolling roll 3a such that the tension between the stands 2 and 3 becomes zero tension based on the displacement detection signal,
The roll rotation speed control command according to the calculation result is sent to the motor 3.
b, the rotation speed of the rolling roll 3a is adjusted. This adjustment of the rotational speed of the rolling rolls 3a is performed until the tip of the bar 7 is bitten into the next vertical stand 4.

Thereafter, in the same manner, the bar 7 is sequentially bitten into the stands 4.5 on the downstream side, and the vertical stand 4.5 corresponding to the biting position. The displacement of... is detected by the differential transformer 11 attached to each vertical stand 4, and each rolling roll 4a, 5a is adjusted so that the tension acting between the stands at the tip of the bar becomes zero. The rotational speeds of ... are adjusted in order in the downstream direction.

According to this tension control method, the displacement of the vertical stands 2, 4, etc., which are displaced according to the tension acting between the stands, is detected by the differential transformer 11, and the tension at the tip of the bar is controlled. Therefore, the tension between the stands, which is suitable for tandem rolling, can be controlled with high precision. Further, the differential transformer 11 for displacement detection is connected to the vertical stand 2.4.
Because it is mounted outside the machine, it is not affected by dust, roll cooling water, etc., and maintenance is easy.

In the above embodiments, a case where a steel bar is rolled has been described, but a bar may generally be used, and the same applies to a bar made of copper or other alloys in addition to steel.

(Effects of the Invention) As described above, according to the tension control method in tandem rolling of the present invention, since the displacement of the vertical stand is detected to control the tension at the tip of the strip, the tension between the stands can be controlled. This has the advantage that it can be carried out with high precision and that the maintenance of the sensor is easy.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a tandem rolling machine in which the tension control method of the present invention is implemented, Fig. 2 is a side view of the vertical stand, Fig. 3 is a diagram explaining the i, II rn operation, and Fig. 4 is It is a graph showing the relationship between the tension acting between the stands and the displacement of the vertical stands. 1.3.5...Horizontal stand, 2.4...Vertical stand, 1a, 2a, 3a, 4a, 5a... Rolling roll, 1b
, 2b, 3b, 4b, 5b...Motor, 11...Differential transformer, 12...Displacement detection circuit, 13...Calculation control section Fig. 1

Claims (1)

[Claims] (1) In tandem rolling, in which strips are sequentially rolled by horizontal stands and vertical stands arranged alternately, the strips are bitten by the vertical stand and then bitten by the downstream horizontal stand. The amount of displacement of the vertical stand is detected until the vertical stand is inserted into the vertical stand, and based on the displacement detection signal, the roll of the vertical stand is adjusted so that the tension between the vertical stand and the horizontal stand upstream thereof becomes the target tension. The rotation speed is adjusted, and the amount of displacement of the vertical stand upstream of the horizontal stand is detected from when the strip is caught in the horizontal stand until it is caught in the vertical stand downstream of it, and the displacement is calculated. A tension control method in tandem rolling, characterized in that the roll rotation speed of the horizontal stand is adjusted based on a quantity detection signal so that the tension between the upstream vertical stand and the horizontal stand becomes a target tension.