JP5920119B2 - LP steel sheet rolling method and rolling apparatus - Google Patents

Description

  The present invention relates to a rolling method and apparatus for LP (Longitudinally Profiled) steel sheets.

  In general, a steel plate rolled by changing the thickness of the steel plate in a taper shape in the longitudinal direction of the steel plate is referred to as an LP steel plate. The use of LP steel sheets has many advantages, such as being able to reduce the weight of the structure and omitting the welding process, so that the demand for LP steel sheets is expanding.

  When rolling in the LP steel plate manufacturing process, for example, as disclosed in Patent Document 1, a target value of the plate thickness of the steel plate that changes every moment is estimated by a plate thickness control method called absolute value AGC. The roll gap (rolling position) of the work roll of the rolling mill is calculated and adjusted based on the target value of the plate thickness.

  At that time, the longitudinal tracking of the rolled material is usually an advanced rate that is the ratio of the speed of the rolled material on the exit side to the speed of the work roll on the accumulated length of the pulse generated by the pulse generator attached to the work roll. And the rolling length of the rolled material is calculated every moment.

JP-A-51-97565

  When the taper dimension (taper control amount) to be added to the LP steel sheet is large, the taper adding schedule covers a plurality of passes. At this time, the tracking position of the taper added up to the previous pass may shift in the next pass. For example, due to errors in measurement of slab dimensions, errors in the thickness and width of rolled material, variations in length due to the crown of the rolled material (difference in thickness in the width direction), and errors in the advance rate Thus, the tracking position may be shifted. If the tracking position shifts, an excessive load (rolling load) may be applied exceeding the upper limit value of the equipment during rolling. If the load exceeds the upper limit value of the equipment, the reduction control system judges that rolling is impossible and releases the reduction for the purpose of equipment protection, resulting in a serious failure, and the rolled material becomes semi-finished.

  Therefore, in order to prevent the rolling material from being semi-finished due to the tracking position shift, in order to improve the tracking accuracy, the accuracy of the advance rate is improved, and the actual value of the length of the previous pass is fed back to the taper of the next pass. The introduction of a tracking learning function that adjusts the starting position of addition is being studied. However, the tracking position shift and the semi-finishing of the rolled material due to it often occur.

  This invention is made in view of the above, Comprising: It aims at providing the rolling method and rolling apparatus of the LP steel plate which can prevent the semifinishing of the rolling material by the shift | offset | difference of a tracking position.

  In order to solve the above-described problems and achieve the object, the LP steel sheet rolling method according to the present invention is a LP steel sheet rolling method in which the steel sheet is tapered, and the rolling load reaches a predetermined abnormal load. At this time, when taper addition is performed, the taper addition is stopped to hold the reduction position, and when the rolling load reaches a predetermined hold release load, the taper addition is resumed, and the rolling load is a predetermined abnormal load. And when the taper addition is not performed, the step of starting the taper addition is included.

  Further, the LP steel sheet rolling apparatus according to the present invention is an LP steel sheet rolling apparatus for adding a taper to a steel sheet, and when the tape load is applied when the rolling load reaches a predetermined abnormal load, the taper is provided. Stopping the addition and holding the reduction position, the taper addition is not performed when the rolling load reaches a predetermined abnormal load, and means for restarting the taper addition when the rolling load reaches a predetermined hold release load And a means for starting the taper addition.

  According to the present invention, even if a tracking position shift occurs during the taper-added rolling, it is possible to prevent the load from exceeding the upper limit value of the equipment and avoid a serious failure. Can be prevented.

FIG. 1 is a schematic diagram showing a schematic configuration of a rolling mill according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the transition of rolling load when rolling the steel sheet from the thick part to the thin part. FIG. 3 is a schematic diagram showing a change in rolling load when the steel sheet is rolled from the thin part to the thick part. FIG. 4 is a flowchart showing the rolling position control processing procedure of the present embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. Moreover, in description of drawing, the same code | symbol is attached | subjected and shown to the same part.

  First, a schematic configuration of a rolling device (rolling mill, mill) according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, a rolling mill 1 according to an embodiment of the present invention includes a pair of upper and lower work rolls 3a and 3b for rolling a steel plate 2 and a pair of upper and lower backups for backing up a pair of upper and lower work rolls 3a and 3b. Rolls 4a and 4b. The rolling mill 1 rolls a steel plate into a desired shape by repeating a rolling process (hereinafter referred to as a pass) for conveying the steel plate 2 between a pair of upper and lower work rolls 3a and 3b. 1 shows a path for rolling the steel plate 2 in the direction of arrow A, the next path is in the direction opposite to that of arrow A. FIG.

  The rolling mill 1 includes a pass schedule calculation device 11, a load cell 12, a pulse generator 13, a plate thickness control device 14, a controller 15, a servo valve 16, and a hydraulic cylinder 17.

  The pass schedule calculation device 11 is configured by a calculation device such as a computer, and calculates a plate thickness change amount (taper control amount), an advance rate, an initial value of a reduction position, a rolling length, etc. in each pass, and the calculation result is a plate thickness. Input to the controller 14. The load cell 12 detects the rolling load of the pair of upper and lower work rolls 3 a and 3 b and inputs a signal indicating the detected rolling load to the plate thickness control device 14. The pulse generator 13 detects the rotation speed of the work roll 3 a and inputs a signal indicating the detected rotation speed to the plate thickness control device 14.

  The plate thickness control device 14 controls the opening degree of the servo valve 16 via the controller 15 based on input information from the path schedule calculation device 11, the load cell 12, and the pulse generator 13. The hydraulic cylinder 17 moves up and down according to the opening degree of the servo valve 16 and adjusts the roll gap (reduction position) between the work roll 3a and the work roll 3b.

  In the rolling mill 1 having such a configuration, the plate thickness control device 14 performs the reduction position control process shown below, so that the load remains at the upper limit of the equipment even if a tracking position shift occurs during rolling to add a taper. Suppresses exceeding the value.

  Here, first, the principle of the reduction position control of the present embodiment will be described with reference to FIG. 2 and FIG. FIG. 2 is a schematic diagram showing a change in rolling load when the steel plate 2 is rolled from the thick part to the thin part. This FIG. 2 shows a case where the rolling position of the work rolls 3a and 3b is changed from an open state (right side toward the paper surface in FIG. 2) to a closed state (left side toward the paper surface in FIG. 2) as the steel plate 2 is rolled. The transition of rolling load from P0 is illustrated.

  As shown by a dotted line in FIG. 2, when there is no shift in the tracking position, the rolling load is smaller and the rolling position is closed (the steel plate 2 is thin) as the rolling position is in the open state (the steel plate 2 is thicker). ) The rolling load is large, and the rolling load is constant if the reduction position is constant. However, as shown by a solid line in FIG. 2, when the tracking position is shifted backward from the plan, the reduction positions of the work rolls 3a and 3b are controlled in accordance with the plan shape of the steel plate 2, so that the taper of the steel plate 2 is reduced. Prior to the portion to be added (tapered portion), a process of adding a taper by changing the reduction position (taper addition) is started (time point a1 in FIG. 2). If it does so, rolling load will become excessive from plan.

  Therefore, in this embodiment, as indicated by a chain line in FIG. 2, when the rolling load reaches a predetermined abnormal load, the taper addition is temporarily stopped and the reduction position is held at that position (time point a2). Then, as the rolling load decreases with the passage of the taper portion of the steel plate 2 (time point a3) and reaches a predetermined hold release load (time point a4), taper addition is started again.

  FIG. 3 is a schematic diagram showing a change in rolling load when the steel plate 2 is rolled from the thin part to the thick part. In this FIG. 3, when the rolling position of the steel plate 2 is changed, the reduction position of the work rolls 3 a and 3 b is changed from the closed state (left side toward the paper surface in FIG. 3) to the open state (right side toward the paper surface in FIG. 3). The transition of rolling load from P0 is illustrated.

  As shown by a dotted line in FIG. 3, when there is no shift in the tracking position, as in the example shown in FIG. 2, the rolling load is larger as the rolling position is closed (the steel plate 2 is thinner), and the rolling position is The rolling load is smaller as the plate is opened (the steel plate 2 is thicker), and the rolling load is constant if the reduction position is constant. However, as shown by a solid line in FIG. 3, when the tracking position deviates from the planned position, the reduction position of the work rolls 3 a and 3 b is controlled in accordance with the planned shape of the steel plate 2, and therefore the tapered portion of the steel plate 2. The start of taper addition of the work rolls 3a and 3b is delayed from the arrival of time (time b1 in FIG. 3). If it does so, rolling load will become excessive from plan.

  Therefore, in the present embodiment, as indicated by a chain line in FIG. 3, when the rolling load reaches a predetermined abnormal load (time point b2), taper addition is started immediately from that point.

  Hereinafter, with reference to the flowchart shown in FIG. 4, the operation of the plate thickness controller 14 when executing the reduction position control process will be described. The flowchart of FIG. 4 starts, for example, at the timing when a signal indicating the rolling load from the pulse generator 13 is input to the plate thickness control device 14, and the reduction position control process proceeds to step S1.

  In the process of step S1, when the sheet thickness control device 14 detects that the signal indicating the rolling load input from the pulse generator 13 has reached a predetermined abnormal load (time points a2, b2), the reduction position control process Advances to step S2. The predetermined abnormal load is set to a value that is 500 to 1000 tons lower than the upper limit value of the equipment. In this embodiment, it is 8500 tons.

  In the process of step S2, the plate thickness control device 14 refers to the taper control amount information input from the pass schedule calculation device 11, and confirms whether or not the taper addition processing (taper addition) is being performed. To do. If the taper control amount is not 0 and the taper is being added, the reduction position control processing proceeds to step S3. On the other hand, when the taper control amount is 0 and no taper addition is performed, the reduction position control process proceeds to step S5.

  In the process of step S3, the plate thickness control device 14 stops the taper addition and holds the reduction position (time points a2 to a4). Thereby, the process of step S3 is completed, and the reduction position control process proceeds to the process of step S4.

  In the process of step S4, when the plate thickness control device 14 detects that the signal indicating the rolling load input from the pulse generator 13 has reached a predetermined hold release load (time point a4), the reduction position control process is performed. The process proceeds to step S5. On the other hand, when the rolling load has not reached the hold release load, the reduction position control process returns to the process of step S3. In the present embodiment, the predetermined hold release load is 7500 ton.

  In the process of step S5, the plate thickness control device 14 starts taper addition (time points a4 and b2). Thereby, the process of step S5 is completed and a series of rolling-down position control processes are complete | finished.

  Note that the plate thickness control device 14 has the same amount of taper control amount (calculated by the pass schedule calculation device 11) as the sum of the taper control amount executed before step S2 and the taper control amount in step S5. Control to be.

  With the above processing, in the case of FIG. 2, the rolling load that has reached the hold release load at the time point a4 changes until the work rolls 3a and 3b pass through the taper portion of the steel plate 2 (time point a5), as planned. Reaches the rolling load of and stabilizes. In the case of FIG. 3, the rolling load that has reached the abnormal load at time point b2 is uniformly reduced until the work rolls 3a and 3b finish adding the taper (time point b5), and the taper portion of the steel plate 2 is further reduced. It decreases and stabilizes until it passes (time point b6). Therefore, in any case, the rolling load does not exceed a predetermined abnormal load, and can be prevented from exceeding the upper limit value of the facility.

  In addition, when rolling the steel plate 2 from the thick part to the thin part, when the tracking position is shifted forward from the plan, the reduction positions of the work rolls 3a and 3b are controlled in accordance with the plan shape of the steel plate 2. Therefore, the taper part of the steel plate 2 reaches before the start of taper addition of the work rolls 3a and 3b. As a result, the rolling load becomes less than planned. In that case, as soon as the sheet thickness control device 14 detects that the signal indicating the rolling load input from the pulse generator 13 has fallen below a predetermined metal-off detection load (for example, a planned load × 0.5), Start adding taper.

  When the rolling position control was performed according to the present embodiment, the semi-finished LP steel sheet of 6 ton per month decreased. This corresponds to an economic effect of 2.1 million yen per year.

  As described above, according to the apparatus 1 of the present embodiment, even if a tracking position shift occurs during rolling to add a taper, the rolling load is prevented from exceeding the upper limit value of the facility, thereby avoiding a serious failure. Therefore, it is possible to prevent the rolling material from being semi-finished due to the tracking position shift.

  Further, the above embodiment is merely an example for carrying out the present invention, and the present invention is not limited to these, and various modifications according to specifications and the like are within the scope of the present invention. It is obvious from the above description that various other embodiments are possible within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Rolling machine 2 Steel plate 3a, 3b Work roll 4a, 4b Backup roll 11 Pass schedule calculation device 12 Load cell 13 Pulse generator 14 Plate thickness control device 15 Controller 16 Servo valve 17 Hydraulic cylinder

Claims (2)

A method of rolling an LP steel plate that adds a taper to the steel plate ,
A determination step for determining whether the rolling load has reached a predetermined abnormal load; and
When rolling load reaches a predetermined abnormal load, if implemented tapered addition, it holds the pressing position by stopping the tapered addition, resume taper additional When the rolling load reaches a predetermined hold release load And steps to
If the rolling load when it reaches a predetermined abnormal load, is not performed tapered addition, viewed contains the steps of starting the taper addition, the,
When the rolling load does not reach the predetermined abnormal load, the determination by the determination step is repeated.
Rolling method of LP plates characterized by and this. An LP steel plate rolling device for adding a taper to a steel plate ,
Determining means for determining whether the rolling load has reached a predetermined abnormal load;
When rolling load reaches a predetermined abnormal load, if implemented tapered addition, it holds the pressing position by stopping the tapered addition, resume taper additional When the rolling load reaches a predetermined hold release load Means to
When the rolling load reaches a predetermined abnormal load, if taper addition is not performed, means for starting taper addition , and
When the rolling load does not reach a predetermined abnormal load, the determination by the determination unit is repeated.
Rolling apparatus of LP plates characterized by and this.

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