JP2004243398A - Method for measuring thrust in cross rolling mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the accident of a bearing or the like by detecting excessive thrust even when any load cell breaks down by comparing a measured value of the thrust with an assessed value. <P>SOLUTION: In the method for measuring the thrust between each work roll and each back-up roll of a 4-high cross rolling mill, the crown and the shape of which are controlled by crossing only upper and lower work rolls and backing them up with upper and lower back-up rolls, the thrust on the upper side is measured by using the measured value of a load cell attached to a chock of the lower back-up roll, the value of the hydraulic pressure of a cylinder for shifting the upper work roll and the value of the hydraulic pressure of a cylinder for shifting the lower work roll or/and the thrust on the lower side is measured by using the measured value of the load cell attached to a chock of the upper back-up roll, the value of the hydraulic pressure of the cylinder for shifting the upper work roll and the value of the hydraulic pressure of the cylinder for shifting the lower work roll. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for measuring a thrust force in a cross rolling mill, and particularly to an improvement in a method for detecting an excessive thrust force in a cross rolling mill in hot rolling of steel.
[0002]
[Prior art]
In general, a work roll of a rolling mill bends due to a rolling load, generates a sheet crown, and causes a great loss of sheet flatness. Conventionally, to compensate for this, a roll was given a crown by grinding before the start of rolling.In recent years, however, the needs of users for plate crown and flatness have become diversified and severe, and in the conventional method, It has become difficult to satisfy them sufficiently. Therefore, a cross-rolling machine having a structure in which the work roll axes can cross at the time of rolling is used as a solution to this problem, and by controlling the crossing angle at the time of rolling, the same rolling effect as in the case where a roll is crowned is obtained. A rolling method has been implemented.
[0003]
In a four-stage work roll cloth rolling mill that crosses only the upper and lower work rolls in contact with the rolled material and controls the crown and shape of the plate material, when a load occurs between the rolls, the rotation direction of the work roll and the backup roll crosses. Due to the angular offset, both rolls produce a thrust force that is up to 30% of the inter-roll load.
Also, when the material to be rolled bites into the work roll, an excessive thrust force may be generated.In this case, a large moment acts on the roll chock, and a harmful bias load is applied to the bearing provided in the roll chock. Accidents such as bearing surface separation occur.
To solve the above-mentioned problems, the load cell detects the thrust force between the work roll and the backup roll, and if an excessive thrust force exceeding a certain dangerous value occurs, instantaneously sets the crossing angle to zero and reduces the thrust force. However, it is necessary to take measures to prevent the occurrence of harmful unbalanced load on the bearing provided in the roll chock and to prevent the occurrence of accidents such as surface separation of the bearing.
[0004]
[Problems to be solved by the invention]
Since the conventional method for measuring the thrust force in the cross rolling mill is configured as described above, the following problems exist. In other words, since the load cell that detects the thrust force is a sensor installed in hot equipment, there are cases where the use environment is extremely severe and a detection error occurs, or there is a state where measurement is impossible due to failure, and cross rolling can be performed. There was a problem of disappearing.
In particular, the load cell is a sensor installed inside the roll chock of the backup roll. Since the roll chock of this backup roll has been incorporated into the rolling mill equipment for a long period of time, maintenance such as periodic measurement accuracy confirmation cannot be performed. Because of the state, it was necessary to regularly check the detection accuracy and to provide a backup function when a failure occurred.
[0005]
The present invention has been made in order to solve the above-described problems.Especially, when an excessive thrust force is detected by a load cell, an estimated value is obtained by using an estimation operation formula for estimating the thrust force. The load cell detection accuracy can be confirmed using the measured value and the load cell actual value, and even if one of the upper and lower load cells fails, an excessive thrust force is detected, and a harmful offset load is applied to the bearing. An object of the present invention is to provide a method for measuring a thrust force in a cross rolling mill capable of preventing an accident such as surface peeling.
[0006]
[Means for Solving the Problems]
The method for measuring the thrust force in the cross rolling mill according to the present invention controls the crown and the shape of the rolled material by crossing only the upper work roll and the lower work roll in contact with the rolled material and backing up with the upper backup roll and the lower backup roll. A method of measuring a thrust force between each of the work rolls and each of the backup rolls of the four-stage cross rolling mill, wherein the upper thrust force is a load cell measurement value attached to a lower backup roll chock, and Measure using the work cylinder shift cylinder hydraulic pressure value and the lower work roll shift cylinder hydraulic pressure value, and / or the lower thrust force is the load cell measurement value attached to the upper backup roll chock, Cylinder hydraulic pressure value for upper work roll shift and lower work roll A method of measuring using the shift cylinder hydraulic pressure value.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of a method for measuring a thrust force in a cross rolling mill according to the present invention will be described with reference to the drawings.
In FIG. 1, the reference numeral 1 denotes a four-stage cross rolling mill. The cross rolling mill 1 includes an upper work roll 3 and a lower work roll 4 for directly rolling a rolled material 2 and an upper work roll 3. An upper backup roll 5 for backing up, a lower backup roll 6 for backing up the lower work roll 4, an upper cylinder 7 for shifting the upper work roll 3 connected to the upper work roll 3, and And a lower cylinder 8 connected to the lower work roll 4 for shifting the lower work roll 4.
[0008]
As shown in FIG. 2, each of the work rolls 3 and 4 of the above-described cross rolling mill 1 is configured to be pressed against each other in a state of crossing in the directions different from each other with respect to the axial direction of each of the backup rolls 5 and 6. The rolled material 2 is passed between the work rolls 3 and 4 in the cross state, and the work rolls 3 and 4 are moved in the axial direction by the cylinders 7 and 8, whereby a work roll shift and a work roll The cross state is configured to be adjusted.
[0009]
Next, the operation will be described. That is, the thrust force between the work rolls 3 and 4 and the backup rolls 5 and 6 is measured by the following equation.
a = E + D−F (1)
d = F + AE (2)
a: Thrust force between the upper backup roll 5 and the upper work roll 3 A: Thrust force measured by a load cell provided on the chock of the upper backup roll 5 d: Thrust force between the lower backup roll 6 and the lower work roll 4 D: Lower backup Thrust force measurement value E by load cell provided on the chock of roll 6 E: Hydraulic pressure measurement value of shift cylinder of upper work roll 3 F: Hydraulic pressure measurement value of shift cylinder of lower work roll 4 Each thrust force a, d represents a thrust force between each of the work rolls 3 and 4 and each of the backup rolls 5 and 6, and a measuring method is performed by a load cell (A, D) provided on a choke (not shown) of each of the backup rolls 5 and 6.
The measured hydraulic pressure values E and F represent the measured hydraulic pressure values of the shift cylinders of the work rolls 3 and 4, respectively. The measuring method is performed by measuring the hydraulic pressures of the cylinders 7 and 8.
[0010]
There is a method of directly measuring the thrust force between the upper work roll 3 and the upper backup roll 5 by a load cell attached to a chock (not shown) of the upper backup roll 5 (that is, a method of directly measuring A). Is measured using the load cell attached to the chock of the lower backup roll 6 and the hydraulic pressure values of the cylinders 7 and 8 according to the equation a = E + DF. That is, the thrust force between the upper work roll 3 and the upper backup roll 5 is not measured by the load cell attached to the chock of the upper backup roll 5 but is measured using the equation a = E + D−F, The measurement is performed using the attached load cell and the hydraulic pressure values of the lower cylinders 7 and 8 after being connected to the respective work rolls 3 and 4.
Also, when the formula d = F + AE is used, the thrust force between the lower work roll 4 and the lower backup roll 6 is not measured by the load cell attached to the chock of the lower backup roll 6, and the formula d = F + AE is used. Is measured using the load cell attached to the chock of the upper backup roll 5 and the hydraulic pressure values of the respective cylinders 7 and 8.
FIG. 3 shows the relationship between the value actually measured by the direct load cell, the load cell attached to the chock of the lower backup roll 6, and the result of measurement using the hydraulic pressure values of the cylinders 7 and 8 by the method of the above formula.
As a result of the experiment, the error between the measured value of the thrust force and the estimated value according to the present invention is about ± 20 ton, which is applicable to the present control.
[0011]
Further, in a four-stage work roll cross rolling mill in which only the upper and lower work rolls 3 and 4 in contact with the rolled material 2 are crossed to control the crown and shape of the plate material, between the work rolls 3 and 4 and the backup rolls 5 and 6 The method of directly measuring the acting thrust force by a load cell attached to the chocks of the backup rolls 5 and 6, the method of the present invention, the load cells attached to the chocks of the other backup rolls 5 and 6, and the cylinders 7 and 8 By using each detection value of the method of measuring using the hydraulic pressure value, even if the measurement value of one of the upper and lower load cells is abnormal, or if it is faulty, it always detects the occurrence of excessive thrust force. In addition, it is possible to avoid the cross angle and to prevent equipment failure due to excessive thrust.
[0012]
Example By using the method described above, the thrust force acting on the work rolls 3 and 4 and the backup rolls 5 and 6 was measured, and the detection accuracy of the load cell was confirmed using the result to prevent erroneous detection of the load cell. , Accuracy can be checked. For example, when checking the accuracy of the load cell for detecting the upper thrust force, the following equation is used.
Upper thrust load cell check | (E + DF) -A |> 30 ton or lower thrust load cell check | (F + AE) -D |> 30 ton
In the above case, it is considered that a failure has occurred in the load cell for detecting the thrust force, and an alarm is output. If the failure occurs continuously, the load cell is replaced. That is, when the difference between the estimated value and the measured value exceeds a predetermined value, it is determined that a failure has occurred.
[0013]
Further, even when one of the upper and lower load cells fails, the thrust force acting on the work rolls 3 and 4 and the backup rolls 5 and 6 can be similarly measured using the method shown in the above equation. Thereby, when an excessive thrust force is generated, an alarm is output or the cross angle of each of the work rolls 3 and 4 is retracted to zero to prevent equipment failure due to the generation of the excessive thrust.
For example, if the thrust force acting on the work rolls 3 and 4 and the backup rolls 5 and 6 exceeds 230 tons for 10 seconds, an alarm is output. If the thrust force exceeds 260 tons for 3 seconds, the crossover angle is reduced to zero. When control is performed to prevent equipment failure due to excessive thrust by retreating, the detection of this thrust force is measured by a load cell attached directly to the chocks of the upper backup roll 5 and a method of the above formula. By selecting the load cell attached to the chock of the lower backup roll 6 and the measured values measured using the hydraulic pressure values of the upper and lower cylinders 7 and 8, the measured value of either the upper or lower load cell is selected. Can be controlled normally even if the unit is abnormal or has failed It made.
[0014]
【The invention's effect】
The thrust force measuring method in the cross rolling mill according to the present invention is configured as described above, so that the following effects can be obtained. That is, a method of directly measuring a thrust force acting between a work roll and a backup roll by a load cell attached to a chock of a backup roll, and a load cell attached to a chock of a backup roll of a counterpart of the present invention; The estimated value is measured using the hydraulic pressure value of the lower cylinder. By selecting and discarding both measured values, even if the measured value of one of the upper and lower load cells is abnormal or broken, the excessive thrust force is always maintained. Is detected, the cross angle is saved to zero, and equipment failure due to excessive thrust can be prevented.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a thrust force acting between each roll of a cross rolling mill applied to a method for measuring a thrust force according to the present invention.
FIG. 2 is a schematic perspective view of a main part of FIG.
FIG. 3 is a characteristic diagram showing a result of comparing an actual measurement value obtained by actually measuring a thrust force between a work roll and a backup roll with a load cell with an estimated value estimated;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cross rolling machine 2 Rolled material 3 Upper work roll 4 Lower work roll 5 Upper backup roll 6 Lower backup roll a Upper thrust force A Load cell measurement value d attached to the upper backup roll chock d Lower thrust force D Lower backup roll chock Load cell measurement value E mounted on the upper work roll shift cylinder hydraulic pressure value F Lower work roll shift cylinder hydraulic pressure value

Claims (1)

Only the upper work roll (3) and the lower work roll (4) in contact with the rolled material (2) are crossed and backed up by the upper backup roll (5) and the lower backup roll (6), and the crown of the rolled material (2) And a method for measuring the thrust force (a, d) between each of the work rolls (3, 4) and each of the backup rolls (5, 6) of a four-stage cross rolling mill (1) whose shape is controlled. And
The upper thrust force (a) is obtained by measuring the load cell (D) attached to the choke of the lower backup roll, the shift cylinder hydraulic pressure value of the upper work roll (E), and the shift cylinder hydraulic pressure value of the lower work roll ( F) and
And / or the lower thrust force (d) is the measured load cell value (A) attached to the chock of the upper backup roll, the cylinder hydraulic pressure value for shifting the upper work roll (E), and the lower thrust force for shifting the lower work roll. A thrust force measuring method in a cross rolling mill, wherein the thrust force is measured using a cylinder hydraulic pressure value (F).

Images