KR100328928B1 - Apparatus and method for measuring meandering of strip in hot rolling using load cells - Google Patents

Abstract

PURPOSE: An apparatus and a method for measuring meandering of strip from the inlet side of finishing rolling (first finishing mill) to the outlet side of finishing rolling (seventh finishing mill) in hot rolling process are provided. CONSTITUTION: In a looper system comprising a roll(102) which is installed each rolling mills of finishing rolling of the hot rolling process, and which supports a threading strip upwardly along a width direction of the strip, a looper driving shaft(104) for supporting the roll(102) through a looper arm(103), and a looper driving electric motor(105) for driving the roll(102) up and down by rotating the looper driving shaft(104), the apparatus for measuring meandering of strip in hot rolling using load cells comprises load cells(106) mounted on a 1/2 position of the looper arm(103) at left and right ends; an encoder(201) mounted on the looper driving shaft(104); and a signal analyzer for measuring the degree of meandering of the strip by receiving tension values measured from the left and right load cells(106) and receiving looper angle measured from the encoder(201).

Description

Meander measuring device and measuring method of steel sheet in hot rolling using load cell

The present invention relates to an apparatus and a method for measuring meandering of a steel sheet from the finishing rolling entry (FM1: 1st Finishing Mill) (FM7: 7th Finishing Mill) of the hot rolling process.

In general, the hot rolling process is performed by using a slab heated in a furnace to roll a strip having a desired thickness and width from a finishing mill through a roughing mill, and then a cooler. It is the process of making hot rolled steel sheet. The finishing rolling is a part for determining the quality of the hot rolled steel sheet. Here, the phenomenon according to the poor control occurs such as plate thickness defects, width defects, shape defects, and twisting of the steel sheet.

On the other hand, an important factor in the hot rolled control as described above is to control the flow of the plate. In this case, when the flow of plate is hindered, it develops in meandering and becomes a big obstacle to quality. Therefore, a looper is installed between finishing mills of finishing rolling in order to improve the flowability, which is the degree of plate flow. The looper acts as a buffer in the flow of the plate to help the steel sheet to progress smoothly at the same time as the rolling. In the looper, it is important to measure the tension acting on the steel sheet.

In the related art, in calculating the tension to prevent meandering, the current value of the electric motor driving the looper is calculated by a mathematical model.

However, in the conventional tension measuring method, since tension is calculated by a simple equation, various situations of the looper system, that is, disturbance, instantaneous change in operating conditions, etc., are not considered, and an error which is a limit of the mathematical model is It is always present, and since the input of the motor is a current value, it is not only difficult to obtain the tension change value between the normal state and the transient state under the momentary load, but also to estimate the tension of the steel plate. Since it is impossible to measure the tension acting on the steel sheet by the conventional calculation, there is a problem that the meandering of the steel sheet cannot be determined.

The present invention has been made to solve the above problems, the operator is measured by measuring the tension of both ends of the steel plate in order to prevent the plateability is impaired due to the unbalance of the tension of both ends of the steel plate and further developed into meandering It is an object of the present invention to provide a meander measuring apparatus and a measuring method of a steel sheet in hot rolling using a load cell that can prevent meandering and improve mail flow through early action based on information.

1 is a block diagram of a hot rolling looper system and a meander measuring device according to the present invention

2 is a plan view of the meander measuring apparatus according to the present invention

Figure 3 is a side view of the meander measuring device according to the present invention

4 is a signal input diagram of the meander measuring device according to the present invention

5a and 5b is an operation of the looper auxiliary drive shaft according to the present invention

Figure 6 is a meander measurement method of the steel sheet according to the present invention

Figure 7 is an illustration of a meandering measuring method of the steel sheet according to the present invention

<Description of the code | symbol about the principal part of drawing>

101: strip 102: roll

103: Looper Arm 104: Looper Drive Shaft

105: looper drive motor 106: Load Cell

107: Looper auxiliary drive shaft 201: Encoder

301: analog input board 302: digital input board

303: Signal Analyzer

In order to achieve the said subject, this invention is provided between each rolling mill of finishing rolling of a hot rolling process, The roll 102 which supports the steel plate 101 which passes through along the width direction, and the said roll 102 In the looper system consisting of a looper driving shaft 104 for supporting the through the looper arm 103 and a looper driving motor 105 for rotating the looper driving shaft 104 to drive the roll 102 up and down. Load cells 106 mounted at half points of the looper arms 103 at the left and right ends thereof; An encoder 201 mounted to the looper drive shaft 104; A signal for measuring the meandering degree of the steel sheet 101 by receiving the tension values T1 and T2 measured from the left and right load cells 106 and the looper angle Θ measured from the encoder 201. Provided is a meander measuring apparatus for a steel sheet including an analyzer (303).

That is, the load cells are mounted on the looper arms of the left and right ends supporting the looper rolls of the hot rolled looper system between the finishing mills, and the tension values at both ends are directly measured to obtain more accurate tension values. The principle is to measure and determine the meandering of the steel sheet by comparing the difference in the tension values acting on both ends of the looper arm using this.

1 is a block diagram of a hot rolling looper system and a meander measuring apparatus according to the present invention. The steel sheet 101 passes through the looper between the rolling mills of finishing rolling. The steel sheet 101 is supported by the roll 102 and passed through to the next rolling mill, and at 1/2 of each looper arm 103 to measure the tension acting between the steel sheet 101 and the roll 102. The load cell 106 is installed. The load cells 106 are installed on the looper arms at the left and right ends thereof using two pieces. If the load cell 106 is installed a lot, it is expensive and requires a lot of manpower to maintain it, so install at least two one at each of the left and right looper arms. The installation position is suitably one half of the looper arm. This is a mechanically suitable position for transmitting the output of the looper electric motor 105 to the steel sheet 101 and measuring the tension between the steel sheet 101 and the roll 102.

2 is a plan view of the meander measuring apparatus according to the present invention, Figure 3 is a side view of the meander measuring apparatus according to the present invention. Here, the looper auxiliary drive shaft 107 is mounted at 90 ° so as to produce a large output with a small looper motor under the looper driving shaft 103, and is designed to produce a large output with a looper motor 105 having a small capacity. This is very economical since the capacity of the motor can be reduced by using the auxiliary drive shaft 107 when the output of the same motor.

For example, in FIG. 5A, the looper motor (not shown) and the steel plate 101 which directly rotate the looper drive shaft 104 to drive the roll 102 up and down are directly engaged in a one-to-one manner, and the roll 102 ) And the distance between the looper drive shaft 104 is L and the motor efficiency is 0.7, the capacity of the motor is expressed by the following formula (1).

On the other hand, when the looper auxiliary drive shaft is used in FIG. 5B, the steel plate 101 and the looper electric motor (not shown) are engaged at 90 °, and the distance between the roll 102 and the looper drive shaft 104 is L, and the drive shaft 104 is used. In the case where the distance between the looper auxiliary drive shaft 107 and L is also L, the capacity of the electric motor is converted into horsepower HP.

Accordingly, when comparing Equation 1 and Equation 2, the capacity of the motor increases in the case of Equation 1 by a value corresponding to the length L of the shaft, and in the case of Equation 2, the capacity of the motor decreases. Therefore, Equation 2 is more economical because the price of the electric motor is lowered. Here, the looper auxiliary drive shaft 107 is not an essential element of the present invention, and the looper drive shaft 103 and the looper electric motor 105 may be directly engaged in a one-to-one manner.

4 is a signal input diagram of a meander measuring apparatus according to the present invention. In the meander measuring apparatus of the steel sheet 101 according to the present invention, the analog input board 301 having a tension acting on the steel sheet 101 output from the load cell 106 of the looper arm is embedded in the signal analyzer 303. Is entered. In addition, the encoder 201 is mounted at one end of the drive shaft 104 for driving the looper arm 103 to detect the position of the looper. The encoder 201 uses an optical absolute type to measure a precise looper position and is an encoder having 12 bit resolution. Since the value output from the encoder 201 is a digital value, the digital input board 302 was used to input it to the signal analyzer 303. The signal analyzer 303 used a general-purpose industrial computer (PC). The signal analyzer 303 has a tension value which is an output of the load cell 106 and a looper position value that is an output of the encoder 201. Measure and analyze the meandering degree in 101).

6 is a meander measurement method diagram of the steel sheet 101 according to the present invention. In FIG. 6, the elements acting on the steel sheet 101 are as follows.

F1: vertical force acting on the left side of the steel sheet 101

F2: vertical force acting on the right side of the steel sheet 101

sigma 1: horizontal force acting on the left side of the steel sheet 101

sigma 2: horizontal force acting on the right side of the steel sheet 101

T1: Tension measured on the left load cell 106 of the looper arm

T2: tension measured on the right load cell 106 of the looper arm

Θ: looper angle measured by encoder 201 of looper drive shaft 104

In FIG. 6, the relationship between the forces acting on the steel sheet 101 by the triangular method is shown in Equations 3 and 4 below.

Therefore, Equation 4 is rewritten as Equation 5 and Equation 6 below.

Normalize sigma 1 and sigma 2 obtained in Equations 5 and 6 above. The reason for standardization as above is to tune the values of sigma 1 and sigma 2 to the equipment, rather than specific values, because the mechanical specifications and environments are different for each facility. The result of the standardization is shown in Equations 7 and 8 below.

In Equations 7 and 8

sigma 1nor: horizontal force acting on the left side of the standardized steel sheet 101

σ2nor: horizontal force acting on the right side of the standardized steel sheet 101

maxσ1: the maximum value of σ1

maxσ2: the maximum value of σ2

to be. In Equations 7 and 8, the following Equations 9 and 10 are derived.

In Equations 9 and 10, Θ ranges from 0 ° to 60 °.

On the other hand, the measurement of the degree to which the steel plate 101 meanders left or right can be obtained from the difference between the equations (7) and (8). That is, the meandering determination index MD (Meandering) of the steel plate 101 is expressed by the following equation (11).

Rewriting Equation 11 is equal to Equation 12 below.

Looking at the meaning of Equation 12 is shown in Table 1 below.

Therefore, as shown in Table 1, the steel sheet 101 indicates that the steel sheet 101 meandering determination index MD of Equations 11 and 12 is more stable to pass through the rolling mill as it approaches '0', which means good flowability. do. On the other hand, as the steel sheet 101 meandering determination index MD approaches '1' or '-1', it can be seen that the steel sheet 101 strongly meanders to the left or the right.

If the above-mentioned description is given by way of example, if the tension measured in the load cell 106 on the left side of the looper arm is 4.330 [N / mm 2], the following equation (13) will be given.

Since Θ is the maximum (cos0 ° = 1) when Θ is 0 °, the following equation (14) is derived from equation (13).

On the other hand, since in most cases maxσ2 ≒ maxσ1, the following equation (15) is derived from the above equation (12).

7 is an exemplary view of a meandering measuring method of the steel sheet 101 according to the present invention. FIG. 7 shows the steel plate 101 meandering determination index in three dimensions in the range of σ1 and σ2 from 0 to 4.330, that is, 0 <= σ1 <= 4.330, 0 <= σ2 <= 4.330 will be.

Therefore, according to the present invention, the load cell is mounted on both ends of the looper of filament rolling (FM) to measure the tension directly by measuring the tension of the steel sheet, thereby preventing the slippage in advance, thereby improving the flowability of the steel sheet. This has a very significant effect on the tension control of the looper system.

Claims (3)

Roll 102 is provided between each rolling mill of finishing rolling of a hot rolling process, and supports the steel plate 101 which passes through along the width direction, and supports the roll 102 through the looper arm 103. In the looper system composed of a looper drive shaft 104 and a looper drive motor 105 for rotating the roll 102 by moving the looper drive shaft 104 upward and downward, Load cells 106 mounted at half points of the looper arms 103 at both left and right ends thereof; An encoder 201 mounted to the looper drive shaft 104; A signal for measuring the meandering degree of the steel sheet 101 by receiving the tension values T1 and T2 measured from the left and right load cells 106 and the looper angle Θ measured from the encoder 201. Meander measuring device of steel sheet in hot rolling using a load cell, characterized by comprising an analyzer (303). 2. The looper auxiliary drive shaft 107 is mounted below the looper drive shaft 104 at 90 degrees, and the looper drive motor 105 is configured to drive the looper auxiliary drive shaft 107. Meander measuring device of steel plate in hot rolling using a load cell. Using the meander measuring device of claim 1, Obtaining a horizontal force acting on the steel sheet 101 from the tension of the left and right end looper arms output from the load cell 106 and the looper angle output from the encoder 201 using Equations 5 and 6,

(Wherein σ1: horizontal force acting on the left side of the steel sheet 101 sigma 2: horizontal force acting on the right side of the steel sheet 101 T1: Tension measured on the left load cell 106 of the looper arm T2: tension measured on the right load cell 106 of the looper arm Θ: looper angle measured by the encoder 201 of the looper drive shaft 104); Using Equations 9 and 10 below

Standardizing according to the following equations 7 and 8,

(Where σ 1nor: horizontal force acting on the left side of the standardized steel sheet 101 σ2nor: horizontal force acting on the right side of the standardized steel sheet 101 maxσ1: the maximum value of σ1 maxσ2: maximum value of σ2); The meandering determination index (MD) of the steel plate 101 is represented by following formula 11 or formula 12,

Determining the meandering of the steel sheet 101 according to the result of Equation 11 or 12 and Table 1 below,

Meander measurement method of the steel sheet in hot rolling using a load cell comprising a.

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