JPS59189004A - Manuacture of differential thickness plate and its rolling mill - Google Patents

Abstract

PURPOSE:To roll-form easily a differential thickness plate having a non-symmetrical shape in its thickness direction and to improve its productivity by controlling independently the drives of the upper and lower rolls of a mill. CONSTITUTION:In a state of both-rolls-driving rolling, a steel plate 12 having the thickness t1 is rolled by a little distance from the front end of a thin thickness part 2, which is set by a setter. Next, the driving state is changed into a counter-driving state by setting the ratio of the driving torque of an upper work roll 14a and the damping torque of a lower work roll 14b to the prescribed ratio. In this state, the plate 12 is rolled throughout the whole length of the thin thickness part 2. In this case, the part 2 is so formed that the thickness t4 to be deformed by the roll 14b is remarkably thin as compared with the thickness t3 to be deformed by the roll 14a. Next,when the driving torque of reverse direction is applied to the roll 14a by a program control, a differential thickness plate 1 having a thick part of thickness t1 and a thin part 2 of thickness t2 and a lower surface 3 formed into an approximately flat one is rolled out to the feeding side of the rolls 14a, 14b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a differentially thick plate having a symmetrical shape and a rolling mill used in the production.

Conventionally, rolling mills have been used to produce differentially thick plates whose thickness is asymmetrical with respect to the center line, for example, as shown in FIG. When manufacturing a differentially thick metal plate 4 having a flat lower surface 3, the following manufacturing method has been proposed.

That is, as shown in FIG. 2, the upper work roll 5 and the lower work roll 6 of a rolling mill (not shown) are set to the same driving conditions. Next, a steel plate material that has not been completely cooled is used to form a stepped thick plate A that is vertically symmetrical in the thickness direction using the upper work roll 5 and the lower work roll 6. In this case, the roll gap between the upper work roll 5 and the lower work roll 6 is changed during the rolling operation to form a thick part with a thickness tl and a thin part with a thickness t2.

In this way, on.

The stepped plate A formed by the lower operating rolls 5 and 6 is fed out in the direction of arrow 8 onto a roller table installed connected to a rolling mill, and is brought into state B. Furthermore, is the stepped plate in state B a roller table? You can run on the top in the direction of arrow 9.

In the process of traveling from state B to state C, the thin part of the stepped plate that has not been completely cooled deforms due to its own weight, causing sagging and rollers as shown in state C. Touch table 7. Finally, a differentially thick plate 4 with a flat lower surface 3 as shown in FIG. 1 is obtained.

In addition, as another method for producing the differential thickness plate 4 shown in FIG. There is a method in which rolling is performed using a pair of work rolls set to the same driving conditions in this state. In this case, since the higher temperature side of the steel plate is more easily deformed than the lower temperature side, the differential thickness plate 4 shown in FIG. 1 can be obtained by setting the upper surface to a higher temperature than the lower surface.

However, the above-mentioned methods for manufacturing the two plates with different thicknesses have the following problems.

That is, in the method of running on the roller table 7 shown in FIG. 2, the stepped thick plate A fed out from the rolling mill must be run on the long roller table 7, which increases the installation area of the equipment. However, there was a problem in that the productivity of the rolling mill decreased. On the other hand, in the method of setting a temperature difference between the upper and lower surfaces of the steel plate in advance, it is very difficult to control the temperature between the upper and lower surfaces. Furthermore, since the steel plate must be heated, an extra heat source is required, resulting in an increase in energy consumption. Furthermore, there is a problem in that the aesthetic appearance of the product is impaired due to thermal distortion.

The present invention was made based on these circumstances, and
The objective is to improve the productivity of the rolling mill and reduce production costs by controlling the drive of the upper and lower work rolls of a conventional rolling mill independently. An object of the present invention is to provide a manufacturing method and a rolling mill for the same.

An embodiment of the present invention will be described below with reference to the drawings.

That is, FIG. 3 is a block diagram showing a Leonard type drive control device for work rolls of a rolling mill. A rolling mill that rolls and forms the steel plate 12 includes support rolls 13a and 1.
Upper work roll 14 supported by 3b and sandwiching the steel plate 12
A and a lower work roll 14b are provided, and the upper work roll 14a and the lower work roll 14b each serve as a power supply converter 15a as a power supply device.

The motors 16a and 16b are connected to DC motors 16a and 16b, which are driven and controlled by DC power supplied from the motor 15b. On the other hand, in the figure, 17 is a DC motor 16a.

The speed setting signal a output from the speed setting circuit 17 is input to the speed control devices 19a and 19b via the switches 18a and 18b. be done. The speed control devices 19u, 19bK are also input with speed feedback signals corresponding to the rotational speeds of the DC motors 16a, 16b detected by speed detectors 20*, 20b connected to the DC motors 16a, 16b. Then, the speed control signal C is applied to the DC motor 16h based on the speed setting signal a and the speed feedback signal S.
A current control device 21 &, which controls the load current of 16b.
Input to 21 b・This current control device 21h, 21
b, current limit signals from current limit signal generators 23a, 23b that compare signals from current detectors 22a, 22b that detect the load current of DC motors 16th, 16b with current limit set values set in their immediate family; A signal d is also input. And a current control device 21a.

21b inputs a current control signal e based on the current limit signal d and speed control signal C to voltage control devices 24h and 24b that control the terminal voltage of the DC motors 16a and 16b. The voltage control devices 24m and 24b include a DC motor 16a.

A voltage detector 25a detects the terminal voltage of 16b.

A voltage limit signal generator 26& which compares the signal from 25b with an internally set voltage limit setting value.

A voltage limit signal f from 26b is also input. And voltage control device fi! , 24a, :z, tb generate the voltage control signal g based on the voltage limit signal f and the current control signal e, and the firing angle control device 27a, , ? 7b.

The firing angle control devices 27'a and 27b control the DC motor 16a based on the voltage control signal g.

power supply converter 15a so that the terminal voltage of 16b becomes a voltage value corresponding to this voltage control signal g.

Controls the firing position of the thyristor 15b.

On the other hand, the load current values of the DC motors 16th, 16b detected by the current detectors 22a, 22b are converted into load current feedback signals ha, hb and input to the load balancing circuit 28. In this load balancing circuit 28, the difference between the two load current feedback signals ha and hb is calculated, and this difference is used as a correction signal 1 to be sent to the speed setting signal a and the speed feedback signal as well as to the speed control devices 19&, 19b. input. That is, when an imbalance occurs between the load currents of the DC motors 16L and 16b, the correction signal i controls the speed of the DC motor with a small load current value so that the speed control signal C of the DC motor with a small load current value increases. The current is input to the device and is configured so that the load currents of the two DC motors 16a and 16b are eventually balanced.

Furthermore, this work roll drive control device includes a setting device 2.
An electronic computer 30 is provided to programmatically control the roll gap, rotation speed, number of rotations, etc. of the upper work roll 14a and the lower work roll 14b in accordance with the shape of the differential thickness plate to be rolled and formed as set in No. 9. There is. A speed change circuit 3 is connected to the electronic computer 30 to send a speed change command j to the current limit signal generators 23m and 23b.

In addition, a load current signal of the DC motor 16b and a load current signal of the load detector 32 are sent to the computer 3o via the current detector 22b.
through the work roll 14a.

A load signal of 14b and a length signal of the differential thickness plate fed out from the work rolls 14g and 14b are inputted via the length detector 33. Further, this electronic computer 3o includes a relay 34a inserted between each output terminal of the load balancing circuit 28 and ground.

An opening/closing command signal k is sent to 34b.

The rolling mill configured as described above is used to roll the steel plate 12 into the first
When manufacturing a differentially thick plate 4 formed of a thick part 1 with a thickness tl and a thin part 2 with a thickness tl as shown in the figure, first, the fourth
As shown in FIG. Under program control of the computer 3o, an opening/closing command signal k is sent to the relay 34a.

Open 84b. Then, the output of 31 speed change circuits is stopped, and the speed change command j is set to zero. In this case, the load balancing circuit 28 operates normally, so the DC motor 16. h,
The load current values of the upper work rolls 16b and 16b are equal.
The driving torques of the lower work roll 14b and the driving torque of the lower work roll 14b become equal.

This state is referred to as a double drive rolling state. Then, in the double drive rolling state, the steel plate J2 having a thickness tl is rolled by a short distance from the tip of the thin wall portion 2 set by the setter 29 as shown in FIG. 4(b). In this case, work roll 14th
, 14b, the tip end portion of the steel plate 12 is symmetrical in the thickness direction of the steel plate 12, as shown in the figure. Next, under the program control of the computer 30, the relays 34&, 34b are closed by the opening/closing command signal k.

Then, a speed change command j via the electronic computer 3o of the speed change circuit 31 is input to the current limit signal generator 23b, and the current limit signal d sent from the current limit signal generator 23b is changed to control the current. The current control signal e outputted from the device 21b is set to have the opposite polarity to the current control signal e outputted from the current control device 21a of the upper work roll 74a. Finally, the lower work roll 14b
In order to make the reverse polarity load current flowing through the DC motor 16b, that is, the braking current I, as large as possible, it is set as shown in the following equation.

From=IITlax-Eng.

However, Ic is the maximum allowable current aX when driving in the forward direction, It is the rolling load current indicating the sum of the load currents of the DC motors 16m and 16b, and Ic is the margin current for protecting the power supply. In the example, each of the above-mentioned current values is adjusted,
As shown in FIG. 4(C), the ratio of the driving torque of the upper work roll 141L and the braking torque of the lower work roll 14b is set to 180:80. This state is called a counter-driving state. Then, the steel plate 12 is rolled over the entire length of the thin wall portion 2 in the non-driving state. In this case, the work roll 14a.

The shape of the steel plate 12 fed out from the lower work roll 14b, that is, the shape of the thin wall portion 2, is as shown in FIG. 4(c).
The thickness tl deformed by b is the upper work roll 14
It is much thinner than the thickness t3 deformed by a. Next, when a driving torque in the opposite direction is applied to the upper work roll 14h under program control of the computer 30, as shown in FIG. A differentially thick plate 4 having a substantially flat lower surface 3 is delivered to the supply side of the work rolls 14a, 14b.

Next, a method of manufacturing the differentially thick plate 4 with the lower work roll 14b freely rotating will be described.

That is, up to the state shown in FIG. 4(b), the steel plate 12 is rolled in the double drive rolling state in the same manner as in the method described above. Next,
Relay 34a is activated by opening/closing command signal k under program control of electronic computer 30.

34b is closed. Then, the speed change command j of the speed change circuit 31 is input to the current limit signal generator 23b, and the current control signal e output from the current control device 21b is set to zero. Finally, the load current of the DC motor 16b is reduced to zero, allowing the lower work roll 14b to rotate freely. This state is called a frame drive state. Then, the steel plate 12 is rolled over the entire length of the thin wall portion 2 while the frame is being driven. In this case, the work roll 14a.

The steel plate 12 fed out from the steel plate 14b has an asymmetrical shape in the thickness direction, as shown in FIG. 4(C). Next, as in the manufacturing method described above, under program control of the electronic computer 30,
By applying a driving torque in the opposite direction to the upper work roll 14a, the differential thickness plate 4 shown in FIG. 4(d) is obtained.

In this manner, by opening the relays 34a and 34b, the upper work roll 14a and the lower work roll 14b can be independently driven and controlled.

Then, in response to a speed change command j outputted from the circuit 31 via the computer 30, the lower work roll 14
The forward driving torque or the reverse driving torque (braking torque) to be applied to b can be freely set. Steel plate 12 in state (anti-driving state)
By rolling-forming, the differentially thick plate 4 can be easily obtained.

Further, even if the drive torque of the lower work roll 14b is set to zero and the steel plate 12 is rolled in a free rotation state (frame drive state), the differential thickness plate 4 can be easily obtained in the same manner as described above.

Therefore, with this manufacturing method, there is no need for the process of running on a roller table in the conventional manufacturing method, so productivity can be improved, and by removing the roller table, the rolling mill used for manufacturing can be improved. Installation area can be reduced.

Further, as in this embodiment, if the shape of the differential thickness plate 4 is stored in the setting device 29 in advance, the manufacturing process can be automated by program control using the computer 30, so that production can be automated. It is possible to further improve performance and reduce production costs.

However, the present invention is not limited to the embodiments described above. In the rolling mill of the embodiment, the electronic computer 30 is used, but instead of using the electronic computer 30, the speed change command j is directly input from the speed change circuit 31 to the current limit signal generator 23b, and the relay 34a, Even if 34b is opened and closed manually, the same differential thickness plate 4 as in the embodiment can be manufactured.

Upper work roll 14a of lower work roll 14b
The set ratio of the driving torque to the drive torque is not limited to the set ratio of the embodiment, and may be set arbitrarily within a range that allows a differentially thick plate with a desired shape to be obtained.

As explained above, according to the present invention, by independently controlling the drive of the upper and lower work rolls of the rolling machine, a differential thickness plate having an asymmetrical shape in the thickness direction can be easily formed by rolling. Can be manufactured. Therefore, it is possible to provide a method for producing a differentially thick plate and a rolling mill used in the production, which can improve the productivity of rolling forming operations and reduce production costs.

[Brief explanation of drawings]

Figure 1 is a cutaway perspective view showing the differential thickness plate, and Figure 2 is the conventional differential plate.
FIG. 3 is an explanatory diagram showing a method for manufacturing an E plate, and FIG. 4(a) is a block diagram showing a drive control device for a work roll of a rolling mill according to an embodiment of the present invention. (b), (e), and (d) are explanatory diagrams showing a method of manufacturing a differential thickness plate according to an embodiment of the present invention. 1...Thick wall part, 2...Thin wall part, 4...Differential thickness plate, 1
2... Steel plate, 14a... Upper work roll, 14b.
...Lower work roll, 15a, 15b...Power converter (power supply device), 16a, 16b...DC motor, 17
...Speed setting circuit, 21a, 21b...Current control device, 28...Load balance circuit, 31...Speed change circuit, 34a, 34b...Relay. Applicant's agent Patent attorney Hiko Suzu Ebu Figure 1

Claims (3)

[Claims] (1) A method of rolling forming a differential thickness plate having an asymmetrical shape in the thickness direction using a rolling mill having a pair of work rolls connected to a pair of electric motors that are driven and controlled by electric power supplied from a power supply device. In the method for manufacturing a thick plate, the difference is applied to one of the pair of work rolls by an electric motor connected to the other work roll, while applying a driving torque in the opposite direction to the other work roll. Manufacturing method of differential thick plate by rolling forming thick plate 0 (2) Roll-forming a differential thickness plate having an asymmetrical shape in the thickness direction using a rolling mill with a pair of work rolls connected to a pair of electric motors that are driven and controlled by electric power supplied from a power supply device. In the method for manufacturing thick plates, the load current of the electric motor of one of the pair of work rolls is cut off, and the differential thickness plate is rolled and formed with the work roll freely rotating. Production method. (3) A pair of work rolls for rolling a metal material, a pair of electric motors that drive the pair of work rolls, a pair of power supply devices that supply driving power to the pair of electric motors, and a speed control of the pair of electric motors. a speed setting circuit for setting and sending a speed setting signal; and a speed setting circuit for detecting the load currents of the pair of motors, and adjusting the respective speed setting signals output from the speed setting circuit so that the load currents of the pair of motors are balanced. a load balancing circuit that sends out a correction signal to be corrected; and a pair of current control devices that sends a control signal to the pair of power supplies based on the speed setting signal from the speed setting circuit corrected by the load balancing circuit. In the rolling mill equipped with the above, the correction signal of the load balancing circuit is cut off, and a speed change command is sent to one of the pair of current control devices to change the speed setting signal from the speed setting circuit. A rolling mill for manufacturing differential pressure plates, characterized by being equipped with a speed changing circuit.