JP2002137007A - Operation method of grinding system in malfunction of online roll grinding system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage of a grindstone due to overload by quickly removing the grindstone from the roll and placing it in an evacuating condition in the malfunction of online roll grinding system. SOLUTION: When the rolls are conditioned by surface grinding system within the rolling schedule of the same cycle preset between rolling mills or built in a rolling mill, in case the situation as judged to be an abnormal grinding happens plural times in a row during grinding a roll in the grinding system, this grinding system stops roll grinding. When it is judged that the system malfunctions, the damage to the grindstone is prevented by quickly removing a grindstone from the roll. Furthermore, misconception of abnormal grinding can be minimized and it is helpful to improve the utilization of grindstone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an on-line grinding apparatus for rolling rolls installed between rolling mills or in a rolling mill, and to perform a grinding operation when an abnormal condition is determined during grinding. It relates to a method of interrupting or stopping.

[0002]

2. Description of the Related Art Generally, a rolling roll used in a hot or cold rolling mill for a steel sheet rolls, when the steel sheet is rolled, only the threaded portion of the roll is worn away, so that the roughness deteriorates, and the roll surface is deteriorated. It causes surface roughness and causes scale flaws in the steel sheet. Further, a step is generated between the threaded portion and the non-threaded portion of the roll due to abrasion, and the profile of the roll surface changes.

As the wear step progresses, the profile of the rolled steel sheet changes (for example, in a sheet thickness shape, a portion corresponding to a worn portion of a roll becomes thicker), and a product having a large sheet thickness deviation occurs. Furthermore, the end is extended in the steel plate,
It may have a very unfavorable shape, such as mid-stretch.

[0004] Under such circumstances, the rolling of the steel sheet is usually performed as follows.
Roll schedule is set so that rolling from wide sheet material and rolling of narrow sheet material gradually, and to replace rolls in anticipation of the time when roll wear becomes large, use used rolling rolls. Rolls are taken off-line and rolls are ground. Recently, online roll grinding has been considered to reduce the frequency of roll changeover with the aim of improving productivity.

As described above, as a grinding apparatus or a grinding control method provided with a roll grinding unit in a rolling roll incorporated between or within rolling mills, for example, Japanese Patent Application Laid-Open No.
The technology is disclosed in, for example, JP-A-335715, JP-A-6-335716, and JP-A-6-304614, and some of them are put to practical use.

[0006]

In such an online roll grinding apparatus, a trouble sometimes occurs on the hardware side. For example, depending on the behavior of the roll during rolling while grinding the roll with a grinding wheel, a large load is applied to the grinding wheel due to the fluctuation of the roll, despite the grinding with the normal pressing force, and the fluctuation of the pressing force It appears as If roll grinding is continued in such a state, a situation in which the grinding wheel is finally broken may be caused. In order to avoid such a situation, a measure is taken to immediately interrupt or stop the grinding when a situation that is judged to be abnormal in grinding occurs.

[0007] However, when it is determined that the grinding is abnormal, the grinding wheel is separated from the roll and retracted, and the state is maintained until the rolling of the steel plate being ground is completed.
These operations were performed each time by the operator's judgment, so if the operator did not give a grinding command when rolling the steel sheet between the rolling roll schedules in the same cycle, the grinding device would remain in the retracted state for a long time. After that, the roll was not ground.

However, when the grinding device is actually inspected after rolling even in the case where it is determined that the grinding is abnormal, a case in which no abnormality is confirmed in the grinding device itself, that is, a load is temporarily applied to the grinding wheel due to fluctuations of the rolling rolls. It was found that there were not a few cases where it could be judged as a transient abnormality.

In such a case, if a temporary abnormality such as a roll fluctuation converges, grinding can be performed again. However, when a grinding abnormality occurs, a means for immediately determining whether a transient abnormality or a continuous abnormality is present. However, the operator had to check the grinding device by checking it. The operation of the operator during the rolling of the steel sheet is complicated and has a large amount of work, and sometimes there is no time to confirm the presence or absence of an abnormality for giving a movable command to the operation panel of the online grinding device. When a grinding abnormality occurs, rolling of many steel sheets is continued without using the roll grinding device, which is a major cause of reducing the operation rate of the grinding device.

It is an object of the present invention to determine whether a transient abnormality or a continuation abnormality has occurred in a case where the above-mentioned grinding apparatus is judged to be a grinding abnormality, and to automatically issue an appropriate movable command. If it is determined that a transient grinding abnormality has occurred, the grinding wheel is once removed from the roll and the grinding is interrupted, but the next time the steel sheet is rolled, the grinding wheel is automatically rolled again. Return to the predetermined position of the roll to resume grinding. However, in the case of a continuous abnormality such as an abnormal state of grinding repeatedly occurring, the grinding is stopped based on the set abnormality determination criterion, the grinding device is separated from the roll, and the grinding wheel is not damaged. Is to do so.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional method, and its gist lies in the following means. (1) When grinding a rolling roll by a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in the rolling mill, a plurality of situations in which the grinding device determines that there is a grinding abnormality during the grinding of the rolling rolls. A method for operating a grinding device in the event of an abnormality in an online rolling roll grinding device that causes the grinding device to stop grinding the rolling rolls when the occurrence occurs consecutively.

(2) When grinding a rolling roll with a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in the rolling mill, a situation in which a grinding abnormality is determined during the grinding of the rolling roll is determined. A method of operating a grinding device in the event of an abnormality in an on-line rolling roll grinding device for stopping the grinding of a rolling roll by the grinding device when two consecutive occurrences occur in the device. (3) When grinding a rolling roll by a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in the rolling mill, a situation occurs in the grinding device where a grinding abnormality is determined during the grinding of the rolling roll. In the case of, once the rolling roll grinding is interrupted, after restarting the grinding of the rolling roll by the grinding device between the same rolling roll schedule, if a situation that is determined to be grinding abnormal again occurs once or more, An operation method of a grinding device when an abnormal condition of an online rolling roll grinding device causes the grinding device to stop grinding the rolling roll.

(4) When determining an abnormality during the grinding of the rolling roll during the grinding of the rolling roll, the pressing force of the grinding device on the rolling roll exceeds a preset reference value, At the time when a preset time has elapsed, it is determined that the grinding is abnormal, and the grinding of the rolling roll by the grinding device is interrupted or stopped (1).
The method for operating a grinding device when an online rolling roll grinding device is abnormal according to any one of (3) to (3). (5) When grinding the rolling roll, when determining an abnormality during grinding during the grinding of the rolling roll, when the roll gap between the rolling rolls exceeds a preset reference range value, it is determined that the grinding is abnormal. And a method of operating the grinding device when the online rolling roll grinding device is abnormal, wherein the grinding of the rolling roll by the grinding device is interrupted or stopped.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The outline of the method of the present invention will be described below with reference to FIG. In FIG. 1, a roll stand (not shown) incorporates a rolling roll 1 and a backup roll 2, and the rolling roll 1 further includes a grinding unit 3 of a grinding device corresponding to the upper and lower rolling rolls 1. It is provided. The grinding unit 3 is provided with a grinding wheel 4 having a tip portion abutting against the rolling roll 1. The grinding wheel 4 is moved to the rolling roll 1 by a driving mechanism disposed inside the grinding unit 3 and a load cell for actually measuring the pressing force. While controlling the pressing force of No. 4, the roll surface is brought into contact with the surface of the rolling roll 1 during the rolling of the steel sheet S on the basis of the command regarding the pressing force of the grinding wheel output from the online roll grinding machine control computer (not shown). The operation of the grinding device is set and controlled so as to perform the grinding operation.

The grinding unit 3 is provided with wheels 6 for moving the unit in the longitudinal direction of the rolling roll 1 and rails 7 for guiding the wheels 6, and the grinding device can be moved to an arbitrary position on the rolling roll 1. Can be ground. Further, a cylinder 8 is attached to the grinding unit 3 to separate from the rolling roll 1 when an abnormality occurs, and the cylinder 8 can move from the grinding position (A) to the retracted position (B). ing.

Although FIG. 1 shows the grinding unit 3 of the upper rolling roll 1, a grinding unit having the same configuration is also provided for the lower rolling roll 1, and is omitted to simplify the drawing. did.

In the grinding operation of the online rolling roll during operation by the grinding wheel having such a configuration, the pressing force of the grinding wheel to the rolling roll, which is usually required for grinding the rolling roll, is based on the past experience of the present inventors. A value to be ground is set within a certain range in accordance with the amount of wear of the rolling roll, grinding is performed while maintaining the pressing force, and the amount of grinding is increased or decreased.

However, as described above, an abnormal condition that may cause damage to the grinding device may occur for some reason during rolling mill grinding. This is performed by detecting a change in the pressing force against the roll and a change in the gap between the rolling rolls.

However, the inventors of the present invention have conducted extensive investigations and studies. As a result, it has been found that grinding abnormalities during the rolling of rolls are caused by a large change in the transient pressing force due to fluctuations in the rolling rolls, and cases in which the abnormalities occur. The gap between the rolling rolls is out of the predetermined range, the case where the pressing force continues due to the abnormality of the grinding device itself or the rolling mill itself, and the abnormality occurs, and the gap between the upper and lower rolling rolls also continues from the predetermined range. In the former case, since the abnormality is transient, the grinding device is temporarily evacuated and the grinding is interrupted.However, after the abnormality has converged for a while, It turned out that there were many cases where grinding was possible.

Therefore, it has been found that the operation rate of the grinding apparatus can be improved if the transient grinding abnormality and the continuously occurring grinding abnormality can be determined separately. Therefore, a set value as a criterion for determining a grinding abnormality is given in advance for each grinding device, and the value is given as a plus or minus range, and then the value is managed as a limit value. If the time outside the range exceeds a preset time, it is determined that an abnormal situation has occurred. Thereby, it is possible to suppress occurrence of erroneous detection due to signal noise or the like of the measured value of the pressing force of the grinding wheel.

In this way, when it is determined that the grinding is abnormal, the grinding of the rolling roll is interrupted and the cylinder is contracted, so that the grinding device is quickly detached from the rolling roll being ground, and the process shifts from A to B in FIG. Then, it is made to temporarily wait at a predetermined evacuation position. Then, the grinding device is returned to the grinding position again by the rolling schedule timing rolling of the same rolling roll, and the grinding is restarted.

Here, if the abnormality is a transient abnormality, it returns from the retracted position to a predetermined position for grinding the rolling roll again, and even if grinding is restarted, the pressing force or the upper / lower rolling is performed. The abnormality in the gap between the rolls does not occur, and the grinding can be continued as it is.

However, if the abnormality such as the failure of the grinding apparatus itself is continuous, the pressing force or the gap between the upper and lower rolling rolls occurs again even if the grinding is restarted. Things happen multiple times. Then, even if the predetermined number of times is reached, the same continuous grinding abnormality occurs, and if the abnormal situation is not resolved, it is determined that the failure is caused by the own equipment, etc., and the grinding command is automatically canceled. Then, the grinding of the rolling roll is stopped, and the grinding device maintains the standby state at the retracted position.

Therefore, if this state is maintained, the grinding roll is not ground by the grinding device. When the cause of the grinding abnormality is determined and an appropriate measure is taken, a grinding command is issued again to restart the grinding of the roll.

According to the conventional experience of the present inventors, even if it is determined that the on-line rolling roll grinding is abnormal and the grinding device is temporarily retracted, there is no abnormality in the rolling roll grinding at the next steel sheet rolling. There were many examples where grinding could be performed. This means that various occurrence factors are involved when it is determined that grinding is abnormal, and as a result of a single factor or a combination of other factors, there are many cases where it is determined that grinding is abnormal. In addition, it indicates that it is possible to mistakenly recognize that a temporary grinding abnormality appears similar to a continuous grinding abnormality state for some reason and determine that there is an abnormality as soon as possible.

If a grinding abnormality is found even once, stopping the grinding of the whole rolling lot thereafter significantly lowers the operation rate of the grinding apparatus, and also affects the rolled steel sheet, To judge that the grinding is abnormal, it is necessary to set an appropriate standard.

Therefore, as described above, as a criterion for judging that there is an abnormality in the grinding and stopping the grinding, the fact is determined only when the grinding has occurred continuously for a plurality of times.
The determination of whether or not to determine the fact that there is an abnormality only when it occurs consecutively or how to determine the criteria depends on the characteristics of the rolling equipment (including the rolling rolls) itself. In doing so, it is necessary to appropriately determine and implement them taking these factors into consideration.

There are various possible causes related to the grinding abnormality. The present inventors consider the abnormality of the pressing force of the grinding wheel and the abnormality of the rolling roll gap value, which occur relatively frequently, among them as grinding abnormality determination items. Selected. This is because if these two are the judgment items, the majority of items considered to be grinding abnormalities are covered.

Here, in determining whether the pressing force of the grinding wheel is abnormal, the result of the determination is that the load of the pressing force on the load cell pressing the grinding wheel against the rolling roll (for example, at a constant pressure) is within a set range. It can be recognized by deviating from the value. In this case, the force (pressing force) of the grinding wheel in contact with the roll during roll grinding is detected by the load on the load cell and the value is detected. The constant pressing force required for grinding is set as a reference value, and this value is added or subtracted from this value. Is taken into account as a control limit range value in consideration of the above value, and a reference value is set so as to judge that the grinding is abnormal when the limit value is exceeded.

That is, the plus value is usually caused by various factors (for example, fluctuations in the thickness of the rolled material, variations in the contact of the backup roll in the roll stand, and mechanical play in the roll rotation transmission mechanism). Although it fluctuates, if the value fluctuates within a normal range, the value is set to have a certain width so as to be allowed. Therefore, in determining that the grinding is abnormal, when the grinding of the rolling roll is performed in a normal state, the set grinding pressing force exceeds the abnormality determination reference value for some reason, and even if the value elapses a predetermined time. When it is recognized that a similar state continues to occur, it is determined that there is a grinding abnormality for the first time, and the grinding wheel is immediately separated from the rolling rolls, evacuated to a predetermined location, and waits.

Next, although the gap value of the rolling rolls is abnormal, the gap value between the upper and lower rolling rolls is usually constantly measured for each rolling roll, and the rolling operation is performed within the normal fluctuation range. Have been done. If a situation that shows a large value beyond the normal fluctuation range occurs for some reason while work is changing in this state, it will cause a large damage to the grinding wheel of the grinding device that is in contact with the rolling roll, If such a situation occurs, it is necessary to take up as a determination factor of the grinding abnormality so as to determine that the grinding is abnormal.

That is, although the value of the roll gap between the rolling rolls during the normal rolling operation constantly fluctuates somewhat, the detected value increases and becomes extremely large, and the reference value provided in advance is set. When the situation exceeds, the grinding roll wheel gap value is determined to be abnormal and the same judgment as grinding abnormality is performed, and the same measures are taken as when the pressing force during grinding is determined to be abnormal. It is intended to prevent the breakage of as much as possible.

[0033]

EXAMPLE In a hot finishing rolling mill having seven stands, grinding units were provided on the upper and lower rolling rolls of the roll stands F5 to F7, and the rolling rolls were ground during the rolling of the steel sheet. As the grinding conditions, the theoretical pressing force: 350 N,
The traversing speed of the grinding head unit was 30 mm / s, and the rotating speed of the grindstone was 1500 rpm.

(Example 1) As shown in FIG. 2, after a certain period of time, in the grinding wheel during the rolling mill grinding operation, the grinding pressing force exceeds the set judgment reference value (590 N), Continued for 2 seconds, the grinding wheel was determined to be abnormal and the grinding wheel was immediately removed from the rolling roll.
It was evacuated to a predetermined place and placed in a standby state. Since the rolling of the steel sheet was completed and the rolling of the next steel sheet was started, the grinding wheel was returned from the retracted position to the predetermined position for grinding the rolling roll again, and when the grinding was started again, the previous grinding was performed. Since a phenomenon similar to that at the time when it was judged to be abnormal occurred again, the grinding wheel was immediately separated from the rolling roll and returned to the retracted state, and the grinding wheel was put on standby in this state.

Example 2 In a grinding wheel during a rolling roll grinding operation, as shown in FIG. 3, when a certain time has passed, the value of the roll gap between the rolling rolls during the operation of the rolling mill is determined by setting. Since the value exceeded the reference value (15 mm), the grinding wheel was determined to be abnormal and immediately separated from the rolling roll, retracted to a predetermined location, and held in a standby state.

By carrying out the above Examples 1 and 2, the work without damaging the grinding wheel could be performed, and the frequency of replacement with a new grinding wheel could be reduced.
In each of the above examples, only the case where the grinding abnormality was judged was shown. However, once the grinding abnormality was recognized, the rolling of the next steel sheet was started, and the grinding roll was again ground by the grinding wheel. When the grinding was started, there were many cases in which the phenomenon determined to be abnormal during the previous grinding did not occur and the grinding of the rolling roll was continued as it was. As a result, the operation rate of the grinding device can be greatly increased, and rolling can be continued without using the grinding device.

[0037]

As described above, according to the present invention, in the on-line grinding of a rolling roll, the grinding wheel is quickly separated from the rolling roll when the grinding device is determined to be abnormal in grinding, and the grinding wheel is retracted. By arranging, it is possible to prevent breakage of the grinding wheel without imposing an excessive load on the grinding wheel, and it is not necessary to replace the grinding wheel with a new one. In addition, it is possible to reduce misidentification of grinding abnormality,
It helped to improve the operation rate of the grinding equipment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a rolling roll and a grinding device for explaining an outline of a method of the present invention.

FIG. 2 is a diagram showing an example of a grinding abnormality determination (grinding wheel pressing force) in an embodiment.

FIG. 3 is a diagram showing an example of a grinding abnormality determination (roll gap value between rolling rolls) in an embodiment.

[Explanation of symbols]

 1 Roll Roll 2 Backup Roll 3 Grinding Head Unit 4 Grinding Wheel 6 Wheel 7 Rail 8 Cylinder S Steel Plate A Grinding Position B Retreat Position

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Onose 4-6-1 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Shigeharu Ueno 1 Nishinosu, Oita, Oita, Nippon Steel Corporation Oita Works F-term (reference) 3C034 AA02 AA13 BB37 BB91 CB03 DD18 3C043 AC17 DD06

Claims (5)

[Claims] When grinding a roll by a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in a rolling mill, a situation in which a grinding abnormality is determined during the grinding of the rolling roll is determined. The method of operating a grinding device in the event of an abnormality in an online rolling roll grinding device, wherein the grinding of the rolling roll by the grinding device is stopped when a plurality of continuous occurrences occur. 2. When grinding a roll by a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in a rolling mill, a situation in which a grinding abnormality is determined during the grinding of the rolling roll is determined. The method of operating a grinding device in the event of an abnormality in an online rolling roll grinding device, wherein the grinding of the rolling roll by the grinding device is stopped when the grinding has occurred twice consecutively. 3. When grinding a rolling roll by a surface grinding device between rolling mills or between rolling roll schedules of the same cycle incorporated in the rolling mill, a situation in which a grinding abnormality is determined during the grinding of the rolling roll is determined. In the case of occurrence of the above, when the rolling roll grinding is temporarily interrupted, and after restarting the grinding of the rolling roll by the grinding device between the same rolling roll schedule, a situation in which it is determined that the grinding is abnormal again occurs once or more. And a method of operating the grinding device when the online rolling roll grinding device is abnormal, wherein the grinding of the rolling roll by the grinding device is stopped. 4. When grinding the rolling roll, when determining an abnormality during grinding during the grinding of the rolling roll, the pressing force of the grinding device on the rolling roll exceeds a preset reference value, and The online rolling roll grinding apparatus according to any one of claims 1 to 3, wherein a grinding abnormality is recognized when a preset time has elapsed, and grinding of the rolling roll by the grinding apparatus is interrupted or stopped. How to operate the grinding machine when abnormal. 5. When grinding an abnormal condition during the grinding of the rolling roll during the grinding of the rolling roll, a grinding error occurs when the roll gap between the rolling rolls exceeds a predetermined reference range value. Characterized in that the grinding of the rolling roll by the grinding device is interrupted or stopped.