JP3478119B2 - Hot rolling method for metal strip - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for a metal strip, and more particularly, it continuously joins several to several tens of steel pieces such as a sheet bar, slab, billet or bloom. The present invention relates to a hot rolling method for a metal strip for rolling.

[0002]

2. Description of the Related Art Conventionally, in a hot rolling line for billets, the billets to be rolled are individually heated, rough-rolled and finish-rolled to finish a hot-rolled sheet having a desired thickness. Such a batch rolling method has an unavoidable disadvantage in finish rolling in which line stoppage due to defective biting of the rolled material is unavoidable and yield loss due to defective shape of the front and rear ends of the rolled material. It was

For this reason, recently, prior to finish rolling, an endless rolling system in which the rear end portion and the front end portion of steel pieces to be rolled are joined and continuously fed to a hot rolling line for rolling. It is being adopted.

In this endless rolling, the problems of the bite defect and the shape defect occur only in the tip end of the first and the tail end of the last piece of the plural rolled materials to be joined. The defective biting and the defective shape can be significantly reduced. In addition, defective biting and defective shape are more likely to occur as the thickness of the finished rolled plate becomes thinner, and thus, in the conventional batch rolling method, defective biting and defective shape become problems, and the plate thickness of the rolled material that can be manufactured is limited. there were. However, in the endless rolling, as for the tip, a thick sheet is rolled, and after the tip passes through a finish rolling mill, the running sheet thickness is changed so that a thin sheet is rolled at the second or later rolling. Now, it is possible to manufacture a rolled material that is thinner than before.

As a hot rolling facility capable of carrying out the endless rolling, for example, in Japanese Unexamined Patent Publication No. 7-241601, as shown in FIG. 2, for example, R1 to R3 installed on the outlet side of the heating furnace 20 are installed. From the three-stand rough rolling machine group 22, the winding / rewinding device 70 and the leveler 7 are sequentially arranged along the line.
2, centering guide 74, joining crop shear 3
0, a movable joining device (welding machine) 40 that travels in synchronization with the transportation of steel billets, a crop shear 24, for example, a finishing rolling mill group 26 of 7 stands of F1 to F7, for alternately winding, for example, A hot rolling line provided with two winders 28 is disclosed.

Further, as an example of a movable joining device, Japanese Patent Laid-Open No. 7-83200
-1007 is a plurality of lifting table rollers to which balance hydraulic pressure is supplied from hydraulic pipes connected by connecting pipes, which are interlocked with the traveling of the joining device and are pushed down by a guide attached to the joining device, or the balance hydraulic pressure. Discloses that the height of the steel billet is raised to the original height to avoid collision between the table roller and the joining device.

[0007]

However, in the prior art,
In such a continuous hot rolling line, there is no description of measures to be taken when an abnormality occurs. If there is no corrective action when an abnormality occurs, it will cause a serious trouble.

Generally, during finish rolling, for the purpose of applying tension to the material between the stands, as shown in FIG. 3, the material (the preceding steel strip 10
And the trailing billet 12) are pushed up. Therefore, for example, as shown in FIG. 4, although the tail end 10B of the preceding steel piece and the tip 12A of the following steel piece are not completely joined, and the strength of the joining portion 11 is insufficient, FIG. When the joint 11 is subjected to finish rolling by erroneously recognizing that it is completely joined, as shown in FIG. 6, the joint 11 is broken by tensile force and the tip 12A of the trailing steel piece is broken as shown in FIG. It is flipped up by the looper 16, cannot be caught in the subsequent stands, and is clogged between the stands, making it impossible to continue rolling and stopping the operation of the line. In FIG. 5, 14 is a burr generated by joining.

The forms of abnormality are roughly classified into the following three cases. The joining of steel pieces cannot be started. Joining failed due to an abnormality during joining. Although joined, the strength is weak and imperfect.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is an object of the present invention, in particular, to deal with the case where the above-mentioned abnormality occurs.

[0011]

SUMMARY OF THE INVENTION The present invention is an endless pressure machine.
Remove the rolled joints and batch press the rolled material after the joints are removed.
The above problems were solved by switching to rolled material and rolling.
It is a thing. Further, it is possible to join the front end of the material to be rolled to the tail end of the front material with a joining device installed on the entrance side of the finish rolling mill and continuously finish roll the material to be rolled and the front material. In the hot rolling method for metal strips using a hot rolling facility, it is determined whether or not the joining has been normally performed, and when the result of the determination is abnormal, both sides of the joined portion are finish-rolled with the joining device. The above problem is solved by cutting between the rolling mill and the rolling mill and allowing the tip of the material to be rolled to be caught in the finish rolling mill for batch rolling.

When a plate thickness range in which the batch rolling is possible is set in advance and the planned finish plate thickness of the material to be rolled is not within the plate thickness range, the finish plate thickness at least at the tip of the material to be rolled is set. Finished thickness after changing the thickness within the above range and changing the thickness
The finish rolling is performed so that Further, the succeeding rolled material that follows the rolled material after cutting is joined to the rolled material after cutting and rolled. Also, disconnect
Subsequent rolled material subsequent to the later rolled material, the rolled material after the cutting
When joining and rolling, the amount of change in plate thickness from the finished plate thickness of the rolled material after the plate thickness change to the planned finished plate thickness of the next succeeding rolled material is within the plate thickness changeable range. If it is not within the plate thickness changeable range, the finish plate thickness of at least the tip of the subsequent rolled material is changed to a value within which the plate thickness change amount is within the plate thickness changeable range. hand,
The subsequent rolled material is finish-rolled. Further, also for the rolled material after the subsequent rolled material, among the rolled material that is not within the plate thickness changeable range, up to the final final planned material for continuous hot rolling, at least the tip thereof is This is a process in which the process of changing to a value within the range in which the plate thickness can be changed is sequentially repeated. Further, it is determined whether or not the amount of change in plate thickness from the finished plate thickness of the rolled material after the plate thickness change to the planned finished plate thickness of the next succeeding rolled material is within the plate thickness changeable range, When the strip thickness is not within the changeable range, the succeeding rolled material is switched to the batch rolled material and rolled.

[0013] In addition, the junction device is installed, which is mounted to the base car
In the case where the joining device is a joining device that moves the elevator table roller while the cart is running, the table roller is sequentially pushed down while the entrance-side table pressing guide and the exit-side table pressing guide of the joining device are lowered. After the joining is completed, the carriage is stopped at a position where the relative relationship between the position of the joining device and the position of the lifting-type table roller is in an appropriate state when the exit-side table pressing guide is at the upper limit. Then, the delivery-side table pressing guide is raised to the upper limit, and the joining portion is conveyed downstream of the joining device. Further, the junction device is installed which is mounted to the base vehicle
In the case where the joining device is a joining device that moves the elevator table roller while the cart is running, the table roller is sequentially pushed down while the entrance-side table pressing guide and the exit-side table pressing guide of the joining device are lowered. After the joining is completed, the carriage is stopped at a position where the relative relationship between the position of the joining device and the position of the lifting-type table roller is in an appropriate state when the exit-side table pressing guide is at the upper limit. The upper and lower sides of the inlet and outlet table pressing guides,
The rolled material subsequent to the rolled material after cutting is finish-rolled as a batch rolled material.

[0014] Also, junction device is installed, the bonding apparatus,
The rolled material and the front material are clamped so that a predetermined gap is opened between the front end portion of the rolled material and the rear end portion of the front material, and in this state, the leading end portion and the rear end portion. In the case of a joining device that joins by pressing the front end portion and the rear end portion after heating, determines whether or not the joining is normally performed based on the displacement amount due to the pressing. It was done like this.

[0015] Also, junction device is installed, between the the joint device the finishing mill, the post-processing apparatus for processing a junction
When the post-processing apparatus is installed, the post-processing device is configured to allow the post-processing device to pass through the post-processing device when the post-processing device is not processed.

[0016] In addition, the junction device is installed, specifications and the bonding apparatus
Between the upper rolling mill, sandwiching the joint portion by the rotary blade rotating in the material to be rolled in the opposite direction arranged above and below the pass line, the burr removal apparatus is installed to remove burrs generated in the joint If the welding is successful,
Whether or not it is determined, and when the result of the determination is abnormal, the burr removal by the burr removal device is stopped. The present invention also relates to the case where joining is not performed normally.
Change endless rolling to batch rolling
The succeeding rolled material following the changed rolled material at the beginning is
The material is joined to the material to be rolled and rolled.

In the present invention, due to some abnormality,
When the joining is not completed, the region sandwiching the joined portion is cut off before the finish rolling, and the trailing steel slab after the cutting of the region is finish rolled.

In the present invention, after joining is performed, it is determined whether or not the joining portion is normally completed. Then, when it is determined that the joining was not normally performed, between the joining device and the finish rolling mill, the region sandwiching the joint is cut off, and the trailing steel slab after the region is cut off is a batch. Finish rolling is performed by setting the finish rolling machine for rolling.

Here, in the endless rolling, the first tip of the endless rolling is rolled to a thick plate thickness so that the finishing mill can be passed through, and the tip is finished. There is a case where an operating mode is adopted in which the running plate thickness of the finish rolling mill is changed after passing through, and a thin one is rolled. Therefore, when changing the end of the endless rolling from the second end to batch rolling and biting it into the finishing mill, it may be impossible to perform rolling because the plate thickness is too thin and the stripability becomes unstable. is there. Assuming such a case, a plate thickness range in which batch rolling is possible is set in advance, and when the planned finishing plate thickness of the trailing steel strip is not within the plate thickness range, the tip of the trailing steel strip is set. It is preferable to change the finish plate thickness of the part to a value within the above plate thickness range for finish rolling. As a result, even when the following steel strip has a thin predetermined plate thickness, the leading end portion can be stably finish-rolled.

Further, prior to the cutting of the joint portion, when the incompletely joined joint portion is conveyed from the joining device to the downstream side,
Stop the joining device at a position where it is not necessary to generate a table gap, and at least on the downstream side (outlet side for the joining device)
The table pressing guide is raised and the leading and trailing steel strips can be transported as they are at the transport speed of the preceding steel strip whose tip has already been rolled by the finishing mill without stopping at that time. .

Further, the joint between the incompletely joined leading and trailing steel slabs is conveyed in synchronization with the traveling speed of the welding device, and the welding device travels to the most downstream of the running zone and stops. However, the preceding steel piece and the following steel piece can be conveyed as they are at the conveyance speed of the preceding steel piece whose tip has already been rolled by the finishing mill without stopping.

Further, the joining device clamps the material to be rolled and the front material such that a predetermined space is provided between the front end of the trailing steel piece and the rear end of the preceding steel piece. If the joining device performs joining by heating the front end portion and the rear end portion in this state and then pressing the front end portion and the rear end portion, the joining is normally performed. Whether or not it can be determined based on the amount of displacement associated with the pressing.

After the joint is cut off, each equipment related to the joint is operated in a state where the tip of the trailing steel piece can pass through (for example, a roll-up state), and the operation is expected to be completed. Alternatively, after the operation is completed, the tip of the trailing steel strip after the removal of the joint can be introduced into the equipment.

Further, when the joining is incomplete, the removal of the defective portion such as a burr formed in the incompletely joined portion can be stopped.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a continuous hot rolling equipment row (including a joining equipment row) for billets suitable for application of the present invention. Like the conventional hot rolling equipment, the heating furnace 20, the rough rolling mill group 22, the crop shear 24, the finishing rolling mill group 26, and the winding device 28 are sequentially arranged from the upstream side of the line. In addition to these, a post-treatment device such as a joining crop shear 30, a movable joining device 40, a deburring device, etc. is provided between the rough rolling mill group 22 and the finishing rolling mill group 26 as equipment for joining steel pieces. 50 is arranged, and a cutting device 60 such as a strip shear is arranged on the inlet side of the winding device 28.

As a derivative form of the equipment sequence shown in FIG.
As shown in FIG. 2, a winding / rewinding device 70 for timing adjustment and a leveler 72 for correcting the warp of the tip may be arranged on the entrance side of the joining crop shear 30.

FIG. 7 shows an enlarged view of only the intermediate equipment between the rough rolling mill group 22 and the finishing rolling mill group 26.
In the figure, 10 is a preceding steel piece, 10B is its tail end, 12
Is a trailing steel piece, 12A is its tip, 74 is a centering guide of the joining crop shear 30, 32 and 34 are steel piece detecting devices, and 62 is a joining device provided with a table roller 66 which is moved up and down by an elevating cylinder 64. A table elevating device for traveling, 68 is a joint cooling device.

The joining device 40 includes an inductor 43, which is a heater for joining, fixed to a central portion of a carriage 42 which travels in the steel piece conveying direction by wheels 41 which engage with rails (not shown), and an inductor 43 at the time of joining. An output side clamp 44B mounted on the carriage 42 for fixing the tail end 10B of the preceding steel slab 10 and a tip 12A of the trailing steel slab 12 also at the time of joining.
For fixing the input side clamp 44A mounted on the dolly 42, and the output side pressing guide 45B and the input side pressing guide fixed to the dolly 42 for vertically moving the table roller 66 of the joining device running portion. 45 A and a roller 46 for conveying the steel bill in the joining device 40.

At the time of joining, the output side clamp 44B
The tail end 10B of the preceding steel slab is fixed by the above, and the tip 12A of the trailing steel slab is fixed to the tail end 10 by the entrance side clamp 44A.
After being fixed at a predetermined distance from B, the tip end 12A and the tail end 10B are heated by the inductor 43, and then the tip end 12A and the tail end 10B are pressed to join them. At this time, the welding device 40 also travels in the traveling direction in the traveling direction shown in FIG. 8 at the same speed in accordance with the transportation of the billet. Further, in order to prevent the table roller from interfering with this joining, the table roller 66 at the running portion of the joining device 40 is made to be able to move up and down by the elevating cylinder 64, and the joining device is guided by the exit side pressing guide 45B and the entrance side pressing guide 45A. The part of the table roller 66 is pushed down.

The post-processing device 50 includes an upper rotary blade 52 that is pressed down by a pressing device 51, as illustrated in FIG.
A lower rotary blade 54 that is pressed up by the pressing device 53, an openable-closable apron 55 for facilitating the passage of steel bill, and upper and lower chip collecting devices 56 and 57. The burr 14 of the joint portion 11 as shown in FIG. 5 is ground.

Now, suppose that a situation occurs in which joining is not completed. For example, in the case of the welding device 40 that heats the steel piece end face by applying a current from the inductor 43 and presses and joins the preceding steel piece 10 and the following steel piece 12, for example, the steel generated during the previous joining. The melting portion of the piece is the joining device 4
It may melt down and remain in 0. As a result, at the time of the next joining, if the remaining melted part is applied to the current path and causes a short circuit phenomenon, sufficient current does not flow to the end surface of the steel piece, resulting in insufficient temperature rise. As shown in FIG. 4, the joining strength when the leading steel piece 10 and the following steel piece 12 are pressed and joined may not be sufficient.

Therefore, when the joining is not completed, the joining portion is cut off according to the present invention prior to the finish rolling.

As the cutting means, it is preferable to use the crop shear 24 used for the purpose of adjusting the tip end shape of the steel strip even in the conventional intermittent rolling which is not continuous rolling. Of course, other cutting means may be used.

As shown in FIG. 9, the joint 11 is cut off as shown in FIG.
The cutting operation of the sheet bar by the crop shear 24 is necessary at least twice, and if the joining point cannot be removed successfully by the two cutting operations, the cutting operation is repeated until the joining portion 11 can be removed.

Since the front end of the preceding steel strip 10 after the cutting of the joint is already engaged with the finish rolling mill group 26, it is finish rolled as it is.

On the other hand, the trailing steel piece 12 after the joining portion is cut is changed to the first rolling schedule of the endless rolling or the rolling schedule of the batch rolled material.

Specifically, the trailing steel piece 12 after cutting off the joint portion
If it can be rolled to the intended thickness, it is rolled to the intended thickness.

On the other hand, when the planned rolling schedule of the succeeding steel piece 12 after cutting the joint portion is a thin material such as a finished sheet thickness of less than 1.2 mm, the tip is finished with the intended finished sheet thickness. It cannot be bitten into the rolling mill. It takes tens of seconds, and sometimes tens of seconds, to finish the rolling of the preceding billet and to re-set up the finishing mill in preparation for rolling the trailing billet. This is because the temperature of the row billet drops and becomes hard, so that it cannot be rolled with the thinness as planned. Further, generally, the thinner the material is, the more the tip 1 is passed when the tip is threaded as shown in FIG.
This is because there is a risk that 2A will meander and easily hit the side guide 75 between the stands of the finishing rolling mill group. In FIG. 10, reference numeral 16 is the looper described above with reference to FIG.

In such a case, the trailing billet 12 is rolled by changing the rolling schedule of the first endless rolling or the batch rolling material. Specifically, the entire length or at least the tip is thickened to a finished plate thickness of 1.2 mm or more, and then rolled.

Further, whether the second and subsequent succeeding billets following the trailing billet 12 are rolled according to the first endless rolling schedule or the second and subsequent endless rolling schedules. Alternatively, rolling is performed according to the rolling schedule of batch rolled material.

That is, in the case where the trailing steel strip 12 after cutting the joint can be the first endless rolling strip, the second and subsequent steel strips following the trailing steel strip 12 are rolled as scheduled. It may or may not be rolled.

For example, when the trailing steel piece 12 after cutting the joint is the first endless rolling piece, the finished sheet thickness is reset to 1.2 mm or more for the reason described above. Depending on the variation in the time from the cutting of the joint to the completion of preparation of the trailing steel strip, the specific value of the sheet thickness, which is set to what mm, will vary, but as an example, 2.3 mm Suppose you set it back to. If the expected thickness of the second succeeding steel piece following this is 2.0 mm, the change in the thickness of the first to second steel pieces is only 0.3 m.
Since it is m, there is no problem. However, assuming that the expected plate thickness of the second roll is 1.2 mm, the change amount of the plate thickness from the first roll to the second roll is 1.1 mm, and therefore, for example, as shown in FIG. Due to the controllability of the plate thickness change in the running plate thickness change, it is impossible to control the running plate thickness change by changing the plate thickness while rolling and joining the continuous steel slabs. For example, after changing the thickness to 1.6 mm and joining and rolling (2.3 mm to 1.
It is assumed that a 0.7 mm plate thickness change from 6 mm can be supported),
Alternatively, it is possible to select either rolling as a 1.2 mm intermittent rolling material without changing the thickness.

Similarly, for the third and subsequent sheets, if the planned finished plate thickness can be realized within the capability range of the running hot plate thickness change control of the continuous hot finish rolling, it is joined and rolled, If it is impossible, it is rolled as an intermittent rolling material.

The ability to control the running thickness change is calculated as follows:
Depending on the speed of response of the speed control system and tension control system to the rate of change of rolling speed (volume speed) (how much can the plate be prevented from breaking or dubbing due to a sudden increase in tension) Decided.

In the above, how to cut off the incompletely joined portion,
The method of rolling the steel slab after cutting was explained, but the next problem is the incomplete joint where the strength is insufficient after the incomplete joint occurs until it is cut. To
It means how to carry without breaking and without causing trouble such as getting stuck.

Therefore, in the present invention, the incompletely joined joining portion of the preceding steel piece and the following steel piece is conveyed in synchronization with the traveling speed of the welding device, and the welding device reaches the most downstream of the running zone. After traveling, the steel billet and the trailing steel billet are not stopped at that time, and are conveyed as they are at the conveyance speed of the preceding steel billet whose tip is already rolled by the finishing mill.

Regarding the operation at this time, here, the joining device proposed in Japanese Patent Laid-Open No. 7-1007 (see FIG. 12 and FIG.
As shown in FIG. 3, when the joining device 40 moves, the elevating type table roller 66 is moved while sequentially pushing down the table pressing guides 45A and 45B on the entrance side and the exit side of the joining device 40). Take for example.

When incomplete joining occurs during the running of the joining apparatus 40 as described above, normal operation is performed if the joining is completed normally (in normal operation, the joining apparatus 40 is temporarily stopped after joining, and the next joining is performed). Returning to the start position in FIG. 8), once the traveling of the joining device 40 is stopped, the joining portion that is only joined incompletely is
It will be conveyed to the downstream side of the joining device 40.

Then, the joining portion 11 starts to move from the joining device 40 toward the immediate downstream thereof, and when the joining portion 11 is broken at that time, the tip 12A of the trailing steel piece after the breaking is As shown in FIG. 14, it falls into the gap G between the lifting table rollers.

The reason why such a gap is formed is that the relative relationship between the traveling stop position of the joining device 40 and the elevating position of the elevating table roller is improper. That is, as shown in FIG.
If the span G of the roller 46 on the joining device 40 and the elevating table roller 66 immediately upstream and downstream of the joining device 40 is stopped at a proper position, the span G of the elevating table roller 66 is changed. The pitch can be about P. However, if this positional relationship is not proper, as shown in FIG. 14, the lifting table roller 66 that does not rise to the rising limit.
If there is A, a span G longer than the pitch P of the lifting table rollers will be formed there.

Theoretically, there is a stop position of the joining device for each pitch for one lifting table roller, which does not require a table gap when the table pressing guide is raised. Therefore, the traveling carriage 42 stops at that position, and the operation of raising the table pressing guides 45A and 45B is performed. However, the tip 12A of the trailing billet may still fall into the table gap during the operation. this is,
This is because the preceding steel piece 10 and the following steel piece 12 are continuously conveyed even during the lifting operation of the table pressing guide.

The traveling carriage 42 stops at the joining device stop position where the table gap is not generated, and the operation of raising the table pressing guides 45A and 45B is sufficiently fast, and the leading end 12A of the trailing steel piece is at that position. If it is possible to close the table gap before coming to the position, as shown in FIG.
The joining device 40 stops at the closest position on the downstream side where it is not necessary to generate a table gap, and at least the downstream side (exit side of the joining device 40) table pressing guide 45.
Increase B.

If the operation for raising the table pressing guide 45B cannot be completed in time before the tip 12A of the trailing steel piece reaches the table gap portion and the table gap cannot be closed, the joining device 40 is incompletely joined. The traveling speed is synchronized with that of the section, travels to the most downstream of the traveling zone, and then stops. At that time, as for the table pressing guide of the welding device 40, at least on the downstream side (for the welding device 40, as shown in FIG. The table pressing guide 45B on the (outgoing side) is lifted, and a span longer than the pitch of one table roller is provided between the roller 46 on the joining device 40 and the uppermost roller 66B in the exit side zone of the joining device running zone. Make sure there are no gaps.

The preceding billet 10 and the following billet 12 are not stopped at that time, but are conveyed as they are at the preceding billet conveying speed at which the tip has already been rolled by the finishing rolling mill group 26.

Whether or not the operation of raising the table pressing guide 45B is in time before the leading end 12A of the trailing steel piece reaches the table gap portion is determined by the table pressing guide 45B.
Capacity of the actuator to raise the temperature and trailing billet 1
It may be determined from the transport speed of 2.

In the case where the post-treatment device 50 is a burr removing device for removing burrs generated at the joint portion, the burr at the joint portion of the incompletely joined preceding steel piece and trailing steel piece is As shown in FIG. 17, if it is attempted to remove as usual, at the time of removal, a tensile force acts from the rotary blade 54 toward the steel piece joining portion 11 in the direction of separating the joining portion, so that the joining portion 11 breaks. there is a possibility. Therefore, it is preferable to stop the removal of the defective joint at the time when it is determined that the joint is incomplete. Specifically, the rotary blades 52 and 54 are retracted to the cutting standby position as shown in FIG. 18, or if possible, the rotary blades 52 and 54 are completely released to open and close as shown in FIG. The expression apron 55 is closed.

The overall structure of this embodiment is shown in FIG.
In the figure, reference numeral 48 is a displacement gauge for detecting the displacement amount of the steel piece when pressing the tail end of the preceding steel piece and the tip end of the following steel piece, 8
Reference numeral 0 indicates a television camera for constantly photographing the state of the joint 11 after joining, and 82 indicates the state of the joint 11 after joining photographed by the television camera 80 as a video image of the operator 86. Monitor to display for
Reference numeral 84 is a push button for cutting a joint for cutting the joint according to the judgment of the operator 86, 88 is a control device, and 90
Is a host computer.

One TV camera 80 is provided at each of the exit side of the joining device 40 and the entrance side of the crop shear 24.
Two units are installed in total, and depending on the transport position of the junction 11,
It is used by appropriately switching.

On the screen of the monitor 82, the joint 11
Scales are written so that the distance from the cutting position to the joint portion 11 can be determined when cutting the.

The controller 88 is connected to all the control target equipment, not shown, other than the bonding apparatus 40, the post-processing apparatus 50, the crop shear 24, the push button 84 for cutting the bonding portion, and the control apparatus. These devices are controlled by 88.

The determination of incomplete joining in this embodiment is
As shown in FIG. 21, a control system is constructed so that the determination can be made by both the logic in the control device 88 (step 130) and the push button input by the operator judgment (step 120).

An example of the logic for automatically determining the cutting of the joining portion in the control device 88 is as follows. For example, in the case of the joining method in which the end surface of the steel piece is heated and then pressed, if the heating temperature is an appropriate temperature. If the temperature is not reached, as a result of insufficient temperature rise, the steel slab will be pressed at a temperature lower than planned in a hard state, and the amount of pressing displacement will be smaller than planned. Therefore, it is possible to make a determination by calculating the pressure displacement amount in advance by predictive calculation and detecting the small displacement amount with the displacement meter 48 (step 130). When it is determined that the joint is incomplete, the joint 11 is cut (step 150).

As an example of the case where the push button input is required by the operator's judgment, for example, the television camera 80 is installed in the joining device 40, and the operator 86 displays the state of the joining portion 11 on the image of the monitor 82. Shall be constantly monitored during operation, and the temperature of the joint 11 should be too high during heating.
This is the case when a hole is found due to melt-through.
In such a case, by pressing the push button 84 for cutting the joint (step 120), the treatment for cutting the joint is performed (step 150).

Next, the subsequent steel piece following the subsequent steel piece may be joined and endless rolled, or may be changed to batch rolling and rolled.
When changing to batch rolling and rolling, it is necessary that the joining device 40 and the post-treatment device 50 be in a state in which the tip of the subsequent steel slab can pass. Hereinafter, a method for allowing the tip of the subsequent steel piece to pass through will be described.

After the joining portion 11 of the preceding steel piece 10 and the following steel piece 12 which have been incompletely joined moves to the downstream side of the traveling zone of the joining device 40, the joining device 40 and the post-treatment device 50.
Enables the subsequent billet to pass.
Taking the joining device 40 as an example, the joining device 40 is as shown in FIG.
After moving to the maintenance position shown in FIG. 13, as shown in FIG. 13, the table pressing guides 45A and 45B are moved up, and the clamps 44A and 44B and the inductor 43 are moved up (opened). In this state, the traveling stop position of the welding device 40 and the lifting table 66
The device group is designed so that the relative relationship between the positions of 1 and 2 becomes an appropriate state as shown in FIG. In this state, the subsequent billets are ready for transportation.

On the other hand, taking the post-processing device 50 as an example,
After a certain amount of time has passed from the cutting standby position (cutting preparation state) as shown in FIG. 17, the pressure reducing device 51 and the pressure raising device 53 are released as shown in FIG. 18, and the opening / closing apron 55 as shown in FIG. Move to the closed state. Regarding the rotation of the rotary blades 52 and 54, the rotary blades that were rotating in the opposite direction to the transport direction in the cutting preparation state were rotated in the same forward direction as the material transport in a speed substantially equal to the material transport speed (rotary blade diameter 95
It is more preferable to rotate at 0 mm and 180 mpm when the rotation speed is 60 rpm. This is because the trailing steel slab is warped so that the tip can be sent in the transport direction and passed even if the rotary blade should be hit. By the way, the conveying speed of the succeeding billet until the biting of the finish rolling mill is 150mp.
set to m.

Here, when the post-processing apparatus 50 has already been operated up to the state of FIG. 19 when the joining portion is passed through the post-processing apparatus 50, the post-processing apparatus 50 may be left as it is. Good.

As described above, the succeeding steel piece may be passed at the timing when the joining device group completes the transition to the state where the leading end of the succeeding steel piece can pass. At the timing when the welding equipment group completes the transition to the state where the leading edge of the succeeding billet can pass, the succeeding billet may be restarted to be conveyed, or at a timing when it is expected that the succeeding billet will be able to pass by the passing time The transportation may be restarted. Subsequent bills may be temporarily stopped until conveyance is restarted, or only the part in contact with the roller may be moved back and forth so that the temperature does not locally drop, and it may be on standby for oscillation. .

[0070]

[Examples] Now, continuous hot rolling with four joints (first low carbon steel 1.2 × 1000 mm, second low carbon steel 1.0 ×)
1000 mm, the third is low carbon steel 1.0 x 1000 m
It is assumed that joining of the tail end of the second end and the tip end of the third end is incomplete during the execution of the low carbon steel 1.2 × 1000 mm for the fourth end.

When incomplete joining is performed, the running of the joining device 40 is stopped after running to the most downstream of the running zone in synchronization with the conveying speed of the preceding steel piece 10 and the following steel piece 12. Further, the control device 88 issues a command to the post-processing device 50 so as to stop the removal of the defective joint portion (burr). By this command,
The post-processing device 50 does not perform cutting in the cutting preparation state (state of FIG. 18). Continuing to this, the crop shear 24 on the finish rolling mill side automatically cuts once at a position of 500 mm on the finish rolling mill side (the preceding steel strip side) with respect to the joint portion 11, and after cutting, the trailing steel strip 12 is cut. The transportation of is temporarily stopped. At this point, the operator 86 has the monitor 82
From the image of, the number of meters behind the first cut end is visually confirmed. As a result, if it is confirmed that the joint portion 11 is located 600 mm behind the first cut end, the operator determines that the crop shear 24 should be cut twice more.

The rationale is that when the push button 84 is pressed once, the trailing billet 12 advances 500 mm and stops, and the crop shear 24 cuts once. It is designed to be performed in sequence, and as shown in FIG.
This is because the cutting position shifts backwards.

Therefore, 500 mm each, two more times, a total of 10
If 00 mm is cut and removed by the crop shear 24, the joint portion 11 that has been incompletely joined can be reliably removed. By the way, the automatic cutting once and the second cutting are performed by the operator 86 pressing the push button 84 twice.

It should be noted that, with respect to the first cutting target position, which is 500 mm from the finish rolling mill from the joining portion 11, the actually cut position is 600 mm from the finishing rolling mill from the joining portion 11. The reason is that the tracking error of the joint portion 11 is caused. In this case, the tracking error is caused by the finish rolling mill group 26 with respect to the joint position.
It means that 100 mm is generated on the opposite side.

In the above-described embodiment, the first cut is automatically performed, and the other two cuts are performed by the judgment operation of the operator 86. However, the maximum amount of tracking error of the joint 11 is estimated. In any case, if the tracking error is automatically cut to a length equal to or more than the length when the maximum amount of tracking error occurs, the operator's judgment and operation can be eliminated. For example, if the variation in the recognition of the joining point position due to the tracking error is 400 mm at the maximum as a result of the actual statistics, it is the target of the first cutting position, that is, the finish rolling mill side 500 m.
With respect to m, the actual cutting position may vary from a position of 400 mm on the finish rolling mill side of the joining point to a position of 400 mm on the opposite side due to a tracking error. Therefore, in any case, in order to surely remove the joint portion 11, it is sufficient to cut the joint portion 2 more times automatically for a total of 1000 mm.

After the finish rolling of the preceding billet 10 is completed, according to the procedure shown in FIG. 22, recalculation (step 440) and resetting (step 450) for trailing billet rolling of the finish rolling mill are performed by the operator's judgment. This is done by pressing a button.

As proposed by the applicant in Japanese Patent Application No. 9-333801, the recalculation of step 440 is not necessary when preset calculation is performed for both endless rolling and batch rolling.

Further, when it is determined that the joining portion 11 of the preceding steel piece 10 and the trailing steel piece 12 which have been incompletely joined has moved to the downstream of the traveling zone of the joining device 40, the joining device 40
After moving to the maintenance position shown in FIG.
As shown in FIG. 3, the table pressing guides 45A and 45B are moved up so that the clamps 44A and 44B and the inductor 43 are moved up (opened). In this state, the relative relationship between the traveling stop position of the joining device 40 and the position of the lifting table roller 66 is designed to be in an appropriate state as shown in FIG. In this state, the leading edge of the succeeding billet following the trailing billet is ready for transportation.

Further, in the post-processing device 50, after the joint portion 11 has passed, the upper and lower rotary blades 5 are moved by the pressing device 51 and the pressing device 53 according to the procedure shown in FIG. 23 as shown in FIG.
2, 54 are opened (step 320), the retractable apron 55 is closed (step 330), and the rotary blades 52, 54 are
180 mpm (rotary blade diameter: 950 mm, number of revolutions: 60), which is almost equal to the material transport speed in the same forward direction as the material transport
Rotate at rpm (steps 340, 35)
0). By the way, after the joining portion is cut, the conveying speed of the succeeding steel bill 12 from the restart of conveyance to the biting of the finish rolling mill is set to 150 mpm. In this state, the post-treatment device 50 is also ready to carry the leading end of the subsequent steel slab.

In the present embodiment, the third steel piece, which is the trailing steel piece after cutting the joint portion, is 2.6 m when the planned plate thickness is 1.0 mm.
The treatment was performed by rolling at m to prevent the tip of the side guide from being caught. FIG. 24 shows the planned rolling schedule before cutting the third joint and the rolling schedule after cutting the joint.

Further, the first to fourth scheduled finish plate thicknesses and 2
The finish plate thicknesses (actual results) of the first to fourth pieces when the joint portion between the third piece and the third piece is cut are shown in comparison with FIG. 25.

As is apparent from FIG. 25, the fourth continuous hot rolling, which is the final rolling, was changed to batch rolling to 1.2.
I try to deal with it by rolling in mm.

Further, by pressing the stop release button according to the operator's judgment (step 46 in FIG. 23).
0), the conveyance of the trailing billet and the following billet is restarted (step 470).

In the above description, the present invention was applied to the hot rolling of steel slabs, but the application of the present invention is not limited to this, and the same applies to the hot rolling of metal strips in general. Clearly applicable.

[0085]

EFFECTS OF THE INVENTION According to the present invention, in hot continuous rolling, when any abnormality occurs, the joint is cut,
The joining-related equipment was operated so as not to interfere with the subsequent passage of metal pieces, and the residual metal pieces after cutting the joint were intermittently supplied to the finish rolling mill to enable finish rolling. , Even if joining is not completed, it is not necessary to stop the operation of the line.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a continuous hot rolling line suitable for applying the present invention.

FIG. 2 is a front view showing a modified example of the continuous hot rolling line.

FIG. 3 is a front view showing a material conveyance state in a finishing rolling mill group.

FIG. 4 is a cross-sectional view showing a joint where a joint failure occurs.

FIG. 5 is a cross-sectional view showing a completely joined joint.

FIG. 6 is a front view showing a state in which a joint portion is broken in a finishing rolling mill group.

7 is an enlarged front view of the continuous hot rolling line of FIG. 2 from the rough rolling mill exit side to the finish rolling mill entrance side.

FIG. 8 is a front view showing a stop position of a joining device used in the continuous hot rolling.

FIG. 9 is a front view showing a state in which a region sandwiching the joint is cut off by a crop shear.

FIG. 10 is a perspective view showing a state in which the tip of the steel piece hits the side guide.

FIG. 11 is a diagram showing an example of plate thickness change control capability in changing the running plate thickness.

FIG. 12 is a front view showing the joining device in a state where joining and rolling are normally performed.

FIG. 13 is a front view showing a normal state of the joining device when the trailing steel piece tip is conveyed through when the joining portion is cut.

FIG. 14 is a front view showing a state in which the trailing steel strip leading edge is conveyed when the stop position of the welding device is not appropriate.

FIG. 15 is a front view showing a state immediately before transferring the joining portion to the table on the exit side of the joining device without any trouble.

FIG. 16 is likewise a front view showing a state of transferring

FIG. 17 is a front view showing the post-treatment device in a state where joining and rolling is normally performed.

FIG. 18 is a front view showing the post-processing device in a cutting preparation state.

FIG. 19 is a front view showing the post-treatment device in a state where the leading edge of the trailing steel piece is passed after the joint is cut.

FIG. 20 is a front view including the partial block diagram showing the overall configuration of the embodiment of the present invention.

FIG. 21 is a flowchart showing a procedure for determining incomplete joining in the embodiment.

FIG. 22 is a flow chart showing the procedure of recalculation and resetting for calculation of trailing billets of the finish rolling mill.

FIG. 23 is a flow chart showing an operation procedure of the post-treatment apparatus when the joint portion is similarly cut.

FIG. 24 is a diagram showing a comparison of rolling schedules of trailing steel slabs before and after cutting a joint.

FIG. 25 is a diagram showing a comparison of target strip thicknesses of rolled materials in hot continuous rolling.

[Explanation of symbols]

10 ... Leading steel slab 10B ... tail end 12 ... Trailing billet 12A ... Tip 22 ... Rough rolling mill group 24 ... Crop shear 32, 34 ... Steel slab detection device 26 ... Finishing mill group 40 ... Joining device 42 ... Truck 43 ... Inductor 44A, 44B ... Clamp 45A, 45B ... Table pressing guide 50 ... Post-processing device 52, 54 ... rotary blade 80 ... TV camera 82 ... Monitor 84 ... push button 88 ... Control device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B23K 20/02 B23K 20/02 31/00 31/00 L (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (56) Reference JP-A-11-169937 (JP, A) JP-A-10-225706 (JP, A) JP-A-10-211503 (JP, A) JP-A-11- 169926 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21B 1/00-1/46 B21B 15/00 B21B 39/12 B21B 39/14 B23K 20/00 B23K 20/02 B23K 31/00

Claims (13)

(57) [Claims] 1. A hot rolling method for a metal strip, which comprises removing an endless rolling joint and switching a rolled material after the joining is removed to a batch rolled material. 2. A joining device installed on the entrance side of a finishing rolling mill, which joins the front end of the material to be rolled to the tail end of the front material and continuously finish-rolls the material to be rolled and the front material. In the method for hot rolling a metal strip by a hot rolling facility capable of performing the above, it is determined whether or not the joining has been normally performed, and when the result of the determination is abnormal, the both sides of the joining portion are connected to the joining device. And a finish rolling mill, and the leading end of the material to be rolled is set in a finish rolling mill for batch rolling, and the hot rolling method for a metal strip is performed. 3. The method of hot rolling a metal strip according to claim 1, wherein a range of plate thickness capable of batch rolling is set in advance, and the planned finish plate thickness of the material to be rolled is the plate. When it is not within the thickness range, the finish plate thickness of at least the tip of the material to be rolled is changed to a value within the range, and finish rolling is performed so as to obtain the finished plate thickness after the change of the plate thickness. Method for hot rolling a metal strip. 4. The method for hot rolling a metal strip according to claim 1, wherein the rolled material following the rolled material after cutting is joined to the rolled material after cutting. A method for hot rolling a metal strip, which comprises rolling and rolling. 5. The method of hot rolling a metal strip according to claim 3 , wherein the succeeding rolled material following the rolled material after cutting is subjected to pressure treatment after the cutting.
When joining and rolling the rolled material, the amount of change in thickness from the finished thickness of the rolled material after the thickness change to the planned finished thickness of the next succeeding rolled material is within the range in which the thickness can be changed. It is determined whether there is, if it is not within the plate thickness changeable range, the finished plate thickness of at least the tip of the subsequent rolled material, the plate thickness change amount to a value within the plate thickness changeable range A hot-rolling method for a metal strip, which is modified and finish-rolled. 6. The hot rolling method for a metal strip according to claim 5, wherein the rolled material after the succeeding rolled material is within the range in which the sheet thickness can be changed, up to the final planned material for continuous hot rolling. A hot rolling method for a metal strip, characterized in that a process of changing at least the tip of the unrolled material to a value within the range in which the thickness can be changed is sequentially repeated until the intended finished thickness is reached. 7. The hot rolling method for a metal strip according to claim 3, wherein the plate thickness from the finished plate thickness of the rolled material after the plate thickness change to the planned finished plate thickness of the next succeeding rolled material. It is determined whether or not the change amount is within the plate thickness changeable range, and if it is not within the plate thickness changeable range, the succeeding rolled material is switched to a batch rolled material and rolled. Hot rolling method. 8. A hot rolling method for metal strip according to any one of claims 1 to 7, mounted on the joining device is installed in base vehicle, the bonding apparatus,
When the trolley is traveling, the joining is completed when the elevator table roller is a joining device that moves while sequentially pushing down the entrance-side table pressing guide and the exit-side table pressing guide of the joining device in a lowered state. After that, the carriage is stopped at a position where the relative relationship between the position of the joining device and the position of the lifting type table roller is in an appropriate state when the output side table pressing guide is at the upper limit, and the output side table pressing is stopped. A method for hot rolling a metal strip, characterized in that the guide is raised to the upper limit and the joint is conveyed downstream of the joining device. 9. A hot rolling method for metal strip according to claim 7, mounted on the joining device is installed in base vehicle, the bonding apparatus,
When the trolley is traveling, the joining is completed when the elevator table roller is a joining device that moves while sequentially pushing down the entrance-side table pressing guide and the exit-side table pressing guide of the joining device in a lowered state. After that, the carriage is stopped at a position where the relative relationship between the position of the joining device and the position of the lifting-type table roller is in an appropriate state when the output-side table pressing guide is at the upper limit, and the carriage is stopped. A hot rolling method for a metal strip, characterized in that the side table pressing guide is set to the upper limit, and the succeeding rolled material following the rolled material after cutting is finish-rolled as a batch rolled material. 10. A hot rolling method for metal strip according to any one of claims 1 to 9, junction device is installed, the bonding apparatus, said material to be rolled tip and the front member The material to be rolled and the front material are clamped so that a predetermined gap is opened between the rear end portion and the front end portion and the rear end portion after heating the front end portion and the rear end portion in this state. In the case of a joining device that joins by pressing the end portion, the hot rolling of the metal strip characterized by determining whether or not the joining is normally performed based on the displacement amount associated with the pressing. Method. 11. The method for hot rolling a metal strip according to claim 1, wherein a joining device is installed , and the joining device and the finish rolling mill are provided.
To, the post-processing apparatus for processing a junction have been installed
In this case, the method for hot rolling a metal strip is characterized in that the post-treatment device is caused to pass through the joint portion in a state when the joint portion is not treated. 12. The method according to any one of claims 1 to 10.
In the hot rolling method of the metal strip of,Contact Integrated deviceIs installed between the joining device and the finish rolling mill.
In the opposite direction to the rolled material placed above and below the pass line
Insert the joint with a rotating blade that rotates
Deburring device that removes burrs generated at jointsButInstallationDonehand
IfDetermine whether the joining was done normally, Judgmentofresult
Is abnormal, the burr removal device is in the middle of removing burr.
A method for hot rolling a metal strip, which comprises stopping. 13. If the joining is not successful, the
Change dress rolling to batch rolling and change to batch rolling
The succeeding rolled material that follows the leading rolled material after the
Hot rolling of metal strip characterized by being joined to rolled material and rolled
Rolling method.