JPS61226109A - Method and apparatus for hot rolling - Google Patents

Abstract

PURPOSE:To execute tension control rolling with high accuracy over the entire length of a rolling material by adopting non-contact type tension control for the front end and rear end of the rolling material and adopting contact type tension control for the intermediate part. CONSTITUTION:A control selector 12 is preliminarily selected at the non-contact type tension control mechanism side prior to the passage of the rolling material. Rolling torque and torque arm are calculated by a non-contact type tension calculating device 8 when the rolling material 3 is bitten to a front stage stand 1. The tension is calculated by using said values when the material 3 is bitten to a rear stage stand 2. The deviation between such tension value and the target tension value is inputted to a control compensator 10 by which a speed correction value is obtd., then the total of said value and a motor command value is determined. The total value is inputted to a seed controller 11 which controls the tension by changing the speed of a mill motor 13. Tension rolls 4a, 4b for detecting the tension are raised and the selector 12 is changed over to the contact type tension calculating mechanism side. The tension is calculated from the load detected by load cells 5a, 5b and thereafter the tension is similarly controlled by the control compensator 10 and the speed controller 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot rolling method and apparatus, and more particularly to hot rolling technology using tension control that can be switched between contact and non-contact methods.

[Conventional technology]

Tension control in hot finish rolling includes a method using a mechanical contact method such as a looper and a method using a looperless method, and conventionally, one of these methods has been used. For example, Japanese Patent Publication No. 59-5364 uses a looperless method, and this method has problems in accuracy when compared with the contact method because of tension control through calculations such as rolling torque calculation, torque arm calculation, and tension calculation. There is. However, this method has the advantage of being able to control the tension from the leading end to the trailing end of the rolled material. Also, contact method (direct detection method)
However, this has the disadvantage that excessive tension is generated at the time of rise, reducing the accuracy of the plate thickness. However, in the middle part of the rolled material, control accuracy is better than the loopless method.

[Problem that the invention seeks to solve]

An object of the present invention is to combine the features of these two tension control methods and to perform control with a constant tension from the initial stage to the final stage of rolling.

[Means for solving problems]

The present invention has been made in order to advantageously achieve the above objects, and includes a non-contact tension control mechanism and a contact tension control mechanism when controlling tension between arbitrary rolling mill stands of a hot finishing mill. A hot rolling method characterized in that the tension is controlled using a non-contact tension control mechanism during the initial and final tension fluctuation periods of the sheet, and the tension is controlled using a contact type tension control mechanism during the tension stabilization period. be.

Furthermore, the present invention is characterized in that a non-contact type tension control mechanism and a contact type tension control mechanism are arranged between a few stands in a hot finishing rolling mill, and the tension is controlled by switching as the rolling progresses. This relates to a hot rolling equipment.

[Effect]

In contact type tension control, tension control cannot be performed until the rolling mill bites into the rolled material and the looper roll starts up, and furthermore, excessive tension is generated when the louver roll starts up, reducing plate thickness accuracy. In addition, non-contact tension control can start tension control as soon as the rolled material bites into the rear stand, and can further control tension up to the rear end, but in the stable period, contact method is better based on actual measurement data. Therefore, the accuracy is good. Therefore, in the present invention, by combining these two methods, the rolled material is rolled with a constant tension from the leading end to the trailing end. That is, rolling is performed using the non-contact type tension control mechanism until the material to be rolled is bitten and the tension detector (tension roll) rises and the tension becomes stable, and in the middle part, rolling is performed by switching to the contact type tension control mechanism. Furthermore, at the rear end of the rolled material, when the tension detector (tension roll) leaves the rolled material again, the rolling is performed by switching to the non-contact type tension control mechanism. This allows the entire length of the rolled material to be rolled under constant tension.

〔Example〕

Next, an example of a rolling mill suitable for carrying out the method of the present invention will be described. The drawing is an explanatory diagram showing an example of the present invention, and in the drawing, l is a front stage stand, 2 is a rear stage stand, 3 is a rolled material, 4a,
4b is a tension roll, 5a and 5b are load cells, 6
is an adder, 7 is a contact type tension calculation device, 8 is a non-contact type tension calculation device, and 9a.

9b is a load cell, 10 is a control compensation device, 11 is a speed control device, 12 is a control switching device, and 13 is a mill motor.

First, the contact type tension calculation mechanism will be briefly explained. This consists of two rolls 4a called tension rolls,
4b, the rolls 4a and 4b can be raised and lowered by a lifting mechanism (not shown), and each roll has a load cell 5a.
, 5b are attached. The rolled material is held horizontally between the rolls 4a and 4b. Then, the load is detected at the same time as the roll contacts the rolled material, and the value is input to the adder 6. The adder 6 adds the two load values to determine the total load, which is manually input to the contact tension calculation device 7. This contact type tension calculation device 7 calculates the tension of the rolled material based on the total load value determined by the adder 6, and outputs the obtained tension value.

Next, the operation of the illustrated device will be explained. Before passing the rolled material, the control switching device 12 is set to the non-contact tension control mechanism side as shown in the figure. When the rolled material 3 is caught in the front stand 1,
Non-contact tension calculation device 8 for rolling torque and torque arm
Calculate with. Furthermore, when the rolled material is caught in the rear stage stand 2, the tension is calculated using these values. The deviation between this tension value and the target tension to is determined and input to the control compensation device 10. Here, the speed correction value Δω is determined, and then the sum with the motor command value ω0 is determined. This value is the optimal speed command value, and is input to the speed control device 11, and the mill motor 13
The tension is controlled by changing the speed of the

Next, the tension rollers 4a and 4b for tension detection are activated and raised. At this time, control is still being performed using the non-contact tension calculation method. Load cell 5a.

When load detection by 5b becomes stable, the control switching device 12 is switched to the contact type tension calculation mechanism side. Then, the tension is calculated using the method described above from the loads detected by the load cells 5a and 5b. The deviation between the obtained tension value and the target tension to is obtained and input to the control compensation device 10. Here, the speed correction value Δω is determined, and the sum with the motor command value ω0 is determined. This value is the optimum speed command value, and is input to the speed control device 11 to change the speed of the mill motor 13 and control the tension. In this way, the contact type tension calculation mechanism is used in the middle part of the rolled material.

Before the rolled material passes through the front stand, the control switching device 1
2 to the non-contact tension calculation mechanism side.

Then, the tension rollers 4a and 4b for tension detection are lowered to stop detecting the load. In other words, non-contact tension control is performed at the rear end portion of the rolled material.

Although contact type tension control has been described above using an example of a tension roll system, the present invention is not limited to this; a conventionally known looper roll system may also be used. In the case of the tension roll method shown in the drawings, the rolled material is held in a horizontal state between the tension rolls, so it is possible to incorporate an induction heating device or a width reduction device at that position to perform necessary operations.

〔Effect of the invention〕

As described above, the present invention provides a non-contact tension control system and a contact tension control system between the stands, and employs non-contact tension control at the leading and trailing ends of the rolled material, and at the intermediate part. Since this method employs contact-type tension control, highly accurate tension-controlled rolling is possible over the entire length of the rolled material.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing one embodiment of the present invention.

Claims (2)

[Claims] (1) When controlling the tension between any rolling mill stands of a hot finishing mill, a non-contact tension control mechanism and a contact tension control mechanism are installed, and the tension fluctuation period at the beginning and end of the strip is non-contact. A hot rolling method characterized by controlling the tension using a die tension control mechanism and controlling the tension using a contact type tension control mechanism when the tension is stable. (2) In a hot finishing rolling mill, a non-contact type tension control mechanism and a contact type tension control mechanism are arranged between at least one stand, and tension control is performed by switching according to the progress of rolling. Inter-rolling equipment.