JPS632501A - Cross rolling method for hot slab - Google Patents

Abstract

PURPOSE:To prevent flawing of a slab surface by a slip between table rollers and the slab by detecting the retreating and advancing speeds of the slab during the cross rolling by a press and synchronizing the speeds of the table rollers with the retreating and advancing speeds of the slab. CONSTITUTION:Rollers 7, 8 for detecting an inlet or outlet side speed rotate and the roller revolutions are converted to pulses by pulse oscillators 9, 10 when the retreat or advance arises in the slab 1. The pulse signals are inputted to arithmetic units 11, 12 for inlet and outlet side table speeds, by which the table speeds are calculated. The calculated speeds are transmitted to control units 13, 14 for inlet and outlet side table speeds, by which the speeds of the inlet and outlet side tables 5, 6 are controlled and are synchronized with the retreat and advance speeds of the slab. While the speed detecting rolls are used in the above, the detection of the speed by means for measuring the position changes at the front and rear ends of the slab by distances using pinch rolls 2, 3 or ultrasonic waves or laser beams is also possible.

Description

[Detailed description of the invention] 3. Detailed explanation of the invention [Object of the invention 1 (Industrial application field) The present invention relates to a method for width reduction of hot slabs.

(Conventional technology and problems to be solved) Direct rolling and hot charge rolling by synchronized operation of a hot strip mill and a continuous casting machine bring great advantages such as energy saving, labor saving, and shortening of process days.

Furthermore, by consolidating the width of continuously cast slabs, it becomes possible to increase continuous casting capacity, reduce surplus slabs by integrating materials, and combine width opportunities between continuous casting and hot strip mill rolling.
Synchronized operation rate will increase.

As a countermeasure to this problem, there is a large reduction technology that increases the amount of width change in hot strip mills.

Conventionally, this method has been carried out using the V-H rolling method, and many problems remain, such as poor width reduction efficiency and increased crop loss.

Therefore, in recent years, a sizing technique has been introduced as a more effective method, which involves pressing the entire length of the slab in the width direction. (Japanese Unexamined Patent Publication No. 59-101201) In this case, scratches occur due to speed mismatch between the table roller and the slab due to the back and forth movement of the slab that occurs as the width of the slab is reduced, leading to deterioration of product quality. The forward and backward movement of the slab is due to the metal flow that occurs not only in the thickness direction but also in the longitudinal direction of the slab when the slab width is rolled down.

This point will be explained in more detail.

The method of reducing the width of a slab using a press is to open and close the anvils at a constant frequency and amplitude, and periodically feed the slab between the anvils in the longitudinal direction by lengths L, thereby rolling down the side edges of the slab over the entire length. . Table rollers and pinch rolls are used to feed the slab, and both are stopped when the press is rolled down. Pinch rolls were mainly used to control the stopping position of the slab. Both the pinch roll and the table roller use DC motors to control their speed, but when the pinch roll moves back and forth in the slab when it is stopped (no electricity), its own inertia (GD2) is small. In addition, because the slab is compressed, the friction coefficient of the contact area with the slab is large, so it can rotate to follow the forward and backward movement and no slipping occurs. However, because the inertia (GD2) of the table roller is large, it cannot follow the back and forth movement of the slab even if the electric motor is de-energized, and slippage occurs between the slab and the table roller surface, causing scratches on the back surface of the slab. This is a quality problem. The object of the present invention is to eliminate the above-mentioned drawbacks.

[Structure of the Invention] (Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and consists of periodically opening and closing a pair of anvils, and controlling the movement of the anvils in the opening direction. When the width of the hot slab is reduced by a press that transfers the slab into the press and moves the anvil in the closing direction to reduce the width of the slab, the backward speed and forward speed of the slab due to plastic deformation of the material during width reduction are determined by the press. Detect the input and output sides of the
This invention provides a method for width reduction of a hot slab using a press, characterized in that, based on this detection signal, the speeds of a table roller on the entry side of the press and a table roller on the exit side are synchronized with the backward speed and forward speed of the slab. be.

Next, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 3 is a plan view showing a conventional method for reducing the width of a slab using a press. Since the pair of anvils 4, 4 are not opened and closed at a constant cycle and amplitude, the slab 1 is sequentially moved in the longitudinal direction between the anvils 4, 4. It feeds in and rolls down the side edge of the slab over its entire length.

In FIG. 3, the sluf is sent in the direction of arrow F and is successively rolled down by a pair of anvils 4, 4, or the anvils 4, 4 are
It opens and closes periodically with an amplitude of 2a. The open state of the anvils 4, 4 is shown by a solid line, and the closed (rolled down) state is shown by a broken line, and the width of the shaded portion of the slab 1 is reduced by one rolling down. Slab 1 is fed when there is no interference between the anvils 4, 4 and slab 1, that is, during the opening stroke of the anvil, and one feeding distance is a
The margin for preventing collision between n θ and the slab 1, and O is the inclination angle on the entry side of the anvil.

When the width press is performed as described above, the slab 1 undergoes plastic deformation, and the width W of the slab decreases by ΔW, and with this decrease, the length increases as shown by the broken line in FIG. 4. Therefore, in the part of the slab 1 before the anvil 4.4, the slab 1 moves forward, and in the part after the anvil 4.4, the slab 1 moves backward. During this time, the table rollers and pinch rolls (both not shown in Figure 4, but see Figure 1) are used to feed the slab the above distance, and are in a stopped state at the time of reduction of the press, and the pinch rolls are Rolls are mainly used to control the stopping position of the slab.

As mentioned above, both pinch rolls and table rollers
If the speed is controlled using a DC motor, or if the pinch roll moves back and forth in a stopped state (no electricity), the inertia of itself (GD2) is small and the slab is being pinched. Therefore, the coefficient of friction at the contact part with the slab is large, so it can rotate to follow the forward and backward movement and no slip phenomenon occurs. However, because the table roller has a large inertia (GD2), it cannot follow the forward and backward movement of the slab even if the electric motor is de-energized, and slippage occurs between the slab and the table roller surface, resulting in scratches on the back surface of the slab. occurs.

In order to solve this problem, in the present invention, as shown in FIG. installed to detect the slab's retreat and advance speed. There are no particular limitations on this speed detection roller, and it is usually I! Meshalling rolls used for lli length can be suitably used. In addition, as mentioned above, the pinch roll itself has a small inertia, and since the slab is pinched by a considerable reduction blade to control the position of the slab, slippage cannot occur, so the pinch roll can also be used as a speed detection roller. You can also do that.

FIG. 2 is a flowchart for explaining the present invention in detail.

Note that the following explanation will be made regarding the slab entry side, and the exit side will be indicated in parentheses.

When the slab 1 moves backward (forward) due to the pressing operation, the roller 7 (8) for detecting the speed of the incoming (outgoing) pieces starts rotating, and the pulse oscillator (PLO) 9 (attached to this roller) starts rotating. 1
0) converts the rotation of the roller 7 (8) into pulses.

Furthermore, the pulse bow is input to the input (output) side table speed calculation device, and the table speed is calculated. This calculated speed is determined by the input (output) side table speed control device 11 (12)
The speed of the input (output) side table 5 (6) is dynamically controlled and synchronized with the backward (forward) speed of the slab.

In the above description, a separately installed speed detection roll was used, but it goes without saying that the same control can be achieved by using the pinch roll 2 (3). Alternatively, speed detection may be performed by measuring changes in the position of the front and rear ends of the slab using a distance meter that uses ultrasonic waves or laser beams. Furthermore, when the forward and backward speed of the slab is detected by a detection means other than the pinch rolls, the speeds of the pinch rolls themselves can be synchronized as necessary.

Once one round of rolling with the anvil is completed, repeat the same process the next time.

[Effects of the Invention] According to the present invention, before the slab by any pressing operation,
Even when moving backward, the rotations of the presser and the outlet table roller can be synchronized, making it possible to prevent slippage between the table roller and the slab and the accompanying scratches on the surface of the slab.

[Brief explanation of drawings]

Figure 251 is a front view for explaining the present invention in detail;
The figure is a flowchart for explaining the present invention in detail, and FIGS. 3 and 4 are a front view and a front view, respectively, for explaining the conventional method. In addition, in the figure, 1 is a slab, 2 is an entry side pinch roll, 3 is an exit side pinch roll, 4 is an anvil, 5 is an entry side table roller,
6 is an exit side full roller, 7 is six backward speed detection rollers, 8 is an exit side forward speed detection roller, 9 is an input side pulse transmitter, 10 is an output side pulse transmitter, 11 is an input side table speed calculation device, 12 Reference numeral 13 indicates an output table speed calculation device, 13 indicates an input table speed control device, and 14 indicates an output table speed control device. Figure 1 Figure 2 Figure 7 (8) 9 (to) Figure 3

Claims (4)

[Claims] (1) When reducing the width of a hot slab by a press that periodically opens and closes a pair of anvils, transports the slab while the anvils are moving in the opening direction, and reduces the width of the slab when the anvils are moving in the closing direction,
The backward speed and forward speed of the slab caused by plastic deformation of the material during width reduction are detected on the entry and exit sides of the press, respectively, and based on these detection signals, the speeds of the table rollers on the entry side of the press and the table rollers on the exit side are adjusted. . A method for width reduction of a hot slab using a press, characterized in that the width reduction is performed in synchronization with the backward speed and forward speed of the slab. (2) The method for rolling down a hot slab according to claim 1, wherein speed detection is performed by a detection roller. (3) The heat according to claim 1 or 2, characterized in that the press entry side pinch roll and the press exit side pinch roll are synchronized at the same time as the table roller based on the detection signals of the backward speed and the forward speed. Width reduction method for intermediate slabs. (4) The second claim characterized in that the speed detection rollers are pinch rolls provided on the input side and the output side of the press.
3. The method for reducing the width of a hot slab according to item 3 or item 3.