JP2014113630A - Method and apparatus for cooling sheet bar joining part in hot rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely cool only the immediate vicinity of a joining part of a traveling sheet bar, and accurately control the cooling without excessively cooling the front and rear spaced apart from the joining part.SOLUTION: Prior to hot finish rolling, a rear end of a preceding sheet bar (10a) and a tip of a following sheet bar (10b) are subjected to heating, temperature rise and pressing, and to butt joining. Then, the luminance of the sheet bar is detected when cooling a sheet bar joining part 10c. The sheet bar joining part 10c is detected by using a luminance difference of the joining part and a non-joining part of the sheet bar, and a portion of high luminance is cooled in a concentrated manner.

Description

  The present invention relates to a method and apparatus for cooling a sheet bar joint in hot rolling of steel, and in particular, prior to hot finish rolling, the leading end of the preceding sheet bar and the trailing sheet bar are heated. -The present invention relates to a method and apparatus for cooling a sheet bar joint in hot rolling, in which, after temperature rising, pressing and butt joining, only the vicinity of the joined sheet bar joint is cooled to achieve stable rolling. Is.

  In the hot finish rolling of steel, the sheet bars extracted from the heating furnace are not rolled one by one, but in the inlet side conveying line of the hot finish rolling mill, the sheet that follows the trailing end of the preceding sheet bar A continuous rolling method has been proposed and put into practical use, in which the tip of the bar is sequentially joined and then used for finish rolling.

  In this continuous rolling, in order to accurately cool the joined sheet bar joint, Patent Document 1 combines a cooling means and a masking means that travel in synchronization with the sheet bar traveling speed, and only the traveling seat bar joint. A technique for cooling is proposed.

JP-A-10-272510

  However, conventionally, when the sheet bar is cooled after bonding, the distance from the position when the bonding is completed by the bonding apparatus to the bonded portion cooling apparatus is measured by measuring with a measuring roll that measures the length by contacting the sheet bar. However, since the distance from the completion of joining to the start of cooling is as long as about 25 m, tracking of the joining point is deviated, which may cause variation in the cooling position, resulting in overcooling in front of or behind the joint. . Further, when the cooling position is shifted, the strength of the strip is lowered due to the high temperature of the sheet bar joint, and there is a problem that the sheet bar breaks during finish rolling.

  The present invention has been made to solve the above-described conventional problems, and it is an object of the present invention to accurately cool only the vicinity of the joint portion of the traveling seat bar.

  In the present invention, prior to hot finish rolling, the rear end portion of the preceding sheet bar and the front end portion of the succeeding sheet bar are heated, heated, pressed, butt-joined, and then the sheet bar joint portion is cooled. In addition, the brightness of the seat bar is detected, and the sheet bar joint is detected using the brightness difference between the joined portion and the non-joint portion of the seat bar, and the high brightness portion is concentrated and cooled, thereby It has been solved.

  Here, a cooling means for cooling the seat bar joint portion can be mounted on the traveling carriage.

  In addition, prior to hot finish rolling, the present invention heats, raises and presses the trailing end of the preceding sheet bar and the leading end of the succeeding sheet bar, and then cools the sheet bar joining portion. A cooling device for detecting the brightness of the seat bar, means for detecting the seat bar joint using the brightness difference between the joint and non-joint of the seat bar, and a portion with high brightness. The above-mentioned problem is also solved by providing a cooling means for cooling in a concentrated manner.

  Here, the cooling means can be mounted on a traveling carriage.

  According to the present invention, the brightness of the seat bar is detected, the brightness difference between the joined portion and the non-joined portion of the seat bar is detected, and the high brightness portion is concentrated and cooled. Therefore, it is possible to accurately cool only the vicinity of the joint portion of the traveling seat bar, and to perform accurate cooling control without supercooling the front and rear portions away from the joint portion. As a result, good continuous rolling can be continued without breaking the sheet bar joint at the time of finish rolling after joining.

The diagram which shows typically the entrance side conveyance line of the finishing mill in which embodiment of the junction part cooling device which concerns on this invention was integrated. The side view which shows the structure of the junction cooling device based on this invention used with the said entrance side conveyance line. Diagram for explaining the operation of the joint cooling device The diagram which shows an example of the output change of the sheet | seat bar junction part vicinity of the brightness sensor used with the said junction part cooling device

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  An entry side conveyance line of a finishing mill incorporating the embodiment of the present invention is schematically shown in FIG.

  In FIG. 1, 10a and 10b are the preceding and succeeding seat bars, 12 is a coil box for winding and storing the sheet bar heated in a heating furnace (not shown), and 14, 20 and 24 are , A pinch roll for conveying the sheet bar, 16 is a leveler for straightening the sheet bar that has been rewound from the coil box 12, and 18 is a crop of the front and rear ends of the sheet bar before joining, A joining crop shear 22 for shaping into a shape suitable for joining, for example, a joining device for joining the rear end of the preceding sheet bar 10a and the leading end of the succeeding sheet bar 10b between runs, The joint cooling device according to the invention, 28 is a descaler for removing scales, and 30 is a finishing mill first stand. In FIG. 1, as the joining device 22, a case where the heating and joining processes are performed between runs in synchronization with the running of the seat bar is illustrated.

  As shown in detail in FIG. 2, the joint cooling device 26 cools the sheet bar joint 10c, which is provided with a plurality of nozzles 42 in the width direction of the sheet bar perpendicular to the paper surface, by applying water from above and below. The upper and lower nozzle headers 40a and 40b, the valve 44 for turning on and off the cooling water supplied from the nozzle headers 40a and 40b, and the traveling carriage for running the nozzle headers 40a and 40b for cooling between runnings 50 and during acceleration / deceleration when the traveling speed of the traveling carriage 50 is synchronized with the traveling speed of the seat bar, the upper and lower acceleration masking devices 60a and 60b and the decelerating mechanism are used to prevent the coolant from being applied to the seat bar Masking devices 62a and 62b are provided.

  The upper and lower nozzle headers 40 a and 40 b are connected to the traveling carriage 50 via a connecting member 46 so as to move at the same speed as the traveling carriage 50.

  The traveling carriage 50 includes a wheel 54 driven by a drive motor 52 and a body 56 that supports the wheel 54 and the nozzle headers 40a and 40b. The vehicle travels on the arranged rail 58 by a travel distance C.

  A luminance sensor 68 for carrying out the present invention is mounted on the connecting member 46. The luminance sensor 68 is also called a luminance camera, and has a function of photographing a monitoring area and deriving a luminance distribution in the photographed screen. An example of such a brightness sensor is a commercially available line scan camera.

  Hereinafter, the operation of the embodiment will be described.

  First, the joining crop shear 18 shown in FIG. 1 cuts the rear end portion of the preceding sheet bar 10a and the front end portion of the succeeding sheet bar 10b.

  Next, at the joining device 22, the rear end portion of the preceding sheet bar 10a and the front end portion of the succeeding sheet bar 10b are opposed to each other with a predetermined gap.

  Next, the rear end portion of the preceding preceding sheet bar 10a and the front end portion of the succeeding sheet bar 10b are heated across the width direction of the sheet bar.

  The sheet bar heated and bonded by the bonding device 22 is cooled only by the bonding portion cooling device 26 in the immediate vicinity of the bonding portion. FIG. 3 shows an example of the relationship between the seat bar speed (broken line H) and the traveling carriage speed (solid line I) when the speed of the seat bar is constant. Specifically, the traveling cart 50 of FIG. 2 has a predetermined position of the seat bar joint 10c detected as a portion where the output brightness of the brightness sensor 68 is high as shown in FIG. 4 at the standby position D of FIG. It stops until it approaches the position. When the seat bar joint portion 10c arrives at a predetermined position, the traveling carriage 50 starts acceleration as shown by the solid line I, reaches the seat bar speed (dashed line H) within the acceleration masking range, and is out of the acceleration masking range. At position E, the upper and lower nozzle headers 40a and 40b are moved so as to be positioned above and below the sheet bar joint 10c. The traveling carriage 50 moves in a predetermined range indicated by positions E to F in FIG. 3 in synchronization with the speed of the seat bar, and then decelerates within the deceleration masking range and stops at the predetermined position G.

  In the nozzle 42, the valve 44 is opened in advance so as to start injection of cooling water within the acceleration masking range. Therefore, when the nozzle 42 is out of the acceleration masking range, the upper and lower nozzles 42 are positioned above and below the seat bar joint 10c, so that cooling water is directly poured only into the sheet bar joint 10c, Only the immediate vicinity of the sheet bar joint 10c is cooled. Since traveling vehicle 50 moves between predetermined ranges E to F in synchronization with the speed of the seat bar, the cooling water is injected only to seat bar joint 10c.

  When the traveling carriage 50 enters the masking range during deceleration, the valve 44 is closed and the cooling water injection is stopped.

  The cooling water sprayed within the acceleration / deceleration masking range is received and discharged by the masking devices 60a, 60b, 62a, 62b without cooling the seat bar.

  In the above description, the seat bar is cooled from the up and down direction. However, the seat bar may be cooled only from the up or down direction. For example, when cooling only from above, the lower nozzle header 40b, the connecting member 46, and the lower masking devices 60b and 62b are unnecessary. On the other hand, when cooling from the lower direction only, the upper nozzle header 40a and the upper masking devices 60a and 62a are not necessary.

  Further, since it takes time until the valve 44 is stably discharged after being opened, it is desirable that the valve 44 be in the immediate vicinity of the nozzle 42. However, in the present invention, there is a masking means, and water is discharged in advance. Therefore, the valves 44 may be provided on the upper and lower nozzle headers 40a and 40b.

  In the present embodiment, since the brightness sensor 68 is disposed on the connecting member 46 of the joint cooling device 26, the brightness can be detected with high accuracy near the seat bar. The position where the brightness sensor 68 is provided is not limited to this. For example, when cooling water is discharged only from the upper nozzle 42, the brightness sensor can be provided so as to detect the brightness from the lower side of the seat bar.

  In addition, in the said embodiment, although this invention was applied to cooling of the sheet bar joint part of a steel piece, the application object of this invention is not limited to this, The sheet | seat of general metal pieces other than a steel piece Obviously, it is equally applicable to the cooling of the bar joint. The coolant is not limited to water.

  For example, as a preceding sheet bar 10a and a succeeding sheet bar 10b, low carbon steel sheet bars each having a width of 1000 mm and a thickness of 30 mm are subjected to the line shown in FIG. Using the luminance sensor 68 arranged in the immediate vicinity of the device 26, the point having the largest luminance difference was intensively cooled.

  As a result, in the conventional cooling position control by tracking, the error variation in the cooling position is 50 mm standard deviation, whereas according to the present invention, the error variation in the cooling position is about 10 mm standard deviation, and the cooling position is not shifted. It was confirmed that good continuous rolling could be continued without breaking the sheet bar joint during finish rolling after joining.

DESCRIPTION OF SYMBOLS 10a ... Preceding sheet bar 10b ... Subsequent sheet bar 10c ... Sheet bar joining part 22 ... Joining device 26 ... Joining part cooling device 30 ... Finishing rolling mill first stand 42 ... Nozzle 46 ... Connecting member 50 ... Traveling carriage 52 ... Drive motor 68. Luminance sensor

Claims (4)

Prior to hot finish rolling, when the sheet bar joint is cooled after heating and raising the temperature, pressing the butt joint of the leading end of the preceding sheet bar and the trailing sheet bar,
Detect the brightness of the seat bar,
Detecting the seat bar joint using the brightness difference between the joint and non-joint of the sheet bar,
A method for cooling a sheet bar joint in hot rolling, characterized by concentrating and cooling a portion with high brightness.   The method for cooling a sheet bar joint in hot rolling according to claim 1, wherein a cooling means for cooling the sheet bar joint is mounted on a traveling carriage. Prior to hot finish rolling, in the cooling device for cooling the sheet bar joint after heating and raising the temperature, pressing the butt joint of the trailing end of the preceding sheet bar and the leading end of the following sheet bar ,
A brightness sensor for detecting the brightness of the seat bar;
Means for detecting the seat bar joint using the brightness difference between the joint and non-joint of the sheet bar;
A cooling means for concentrating and cooling the portion with high brightness;
An apparatus for cooling a sheet bar joint in hot rolling.   The said cooling means is mounted in the traveling trolley | bogie, The cooling apparatus of the sheet-bar junction part in the hot rolling of Claim 3 characterized by the above-mentioned.

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