JP2008238235A - Width press method in hot rolling, and method of manufacturing hot-rolled metal plate by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the consistent operation of a hot rolling line 100 by solving a problem that a material 8 to be rolled cannot be moved in the conveying direction A because a hold roll 98 is non-rotatable while the material 8 is restricted when performing the width press of the material 8 by the hot rolling. <P>SOLUTION: When any slip is detected during the operation of performing the width press or the conveyance of the material 8, the pressing of the hold roll 98 against the material 8 is temporarily opened while performing the conveyance immediately after the operation of performing the next width press. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a width pressing method in hot rolling and hot rolling using the same, in which when a metal material (hereinafter, material to be rolled) is hot-rolled, width pressing is performed while restraining the material to be rolled by a hold roll. The present invention relates to a method for manufacturing a metal plate.

  Hot rolling is generally a slab-like metal material produced by continuous casting, ingot-making, or ingoting, heated in a heating furnace to several hundred to several hundreds of degrees Celsius, and then placed on a hot rolling line. It is a series of processes of extracting and winding thinly and winding it into a coil shape by rotating the roll while pinching with a pair or a plurality of pairs of rolls.

  In FIG. 3, an example of the hot rolling line 100 generally used conventionally is shown. A metal material (hereinafter, material to be rolled) 8 having a thickness of 120 to 270 mm heated to several hundred to several hundreds of degrees Celsius by the heating furnace 10 is rolled to a thickness of 0.8 to 25 mm by a roughing mill 12 and a finishing mill 18. And thinly stretched into a metal strip. Reference numeral 7 denotes a table roll, which conveys the material 8 to be rolled.

  In the case of the hot rolling line 100 shown in FIG. 3, the rough rolling mill 12 is composed of four units and the finishing mill 18 is composed of seven units, but the number of rolling mills (stands) is various. Although there are differences in these various radixes, the roughing mill 12 generally performs a total of 4 to 9 rollings by reciprocating rolling or unidirectional rolling or both, and the material 8 after rough rolling is transferred to it. Then, the steel sheet is supplied to the finishing mill 18, and the finishing mill 18 performs rolling to a predetermined thickness, and the coiler 24 takes up the coil.

  Further, an oxide layer (hereinafter referred to as scale) is formed on the front and back surfaces of the high-temperature rolled material 8. Therefore, on the entry side of each rolling mill of the rough rolling mill 12 and the entry side of the finish rolling mill 18, high pressure water of 10 to 30 MPa is sprayed on the front and back surfaces of the material to be rolled 8 as the supply pressure from the pump. A descaling device 16 is installed to remove the scale.

  50 is a control device, 70 is a process computer, and 90 is a business computer.

  Incidentally, many hot rolling lines 100 as shown in FIG. 3 are provided with a width press 9 on the upstream side of the roughing mill 12. For this width press 9, a part of the drawing described in Patent Document 1 is extracted, the conveying direction of the material to be rolled is reversed for the sake of convenience, and a part of the auxiliary equipment not shown is shown in FIG. Is shown in a bird's eye view. Incidentally, structures such as a housing are omitted.

  The width press 9 disclosed in Patent Document 1 is a width press system called a so-called flying sizing press. In the case of this method, as shown in FIG. 5A, starting from the state of (A), the crank mechanisms 93a and 93b shown in FIG. (B) is moved toward the conveying direction A by a distance corresponding to half of the feed pitch P of the material 8 to be rolled per press operation, while being closed in the width direction of the material 8 to be rolled (b) C) Returning by a distance corresponding to half of the feed pitch P toward the direction opposite to the transport direction A while being separated from the material to be rolled 8 (during this time, the material to be rolled 8 is transported by a distance corresponding to half of the feed pitch P) A separate operation is performed toward A), and (d) a series of operations of closing in the width direction of the material 8 to be rolled is repeated. During this time, the material 8 to be rolled is continuously conveyed on the conveyance table while being restrained by a hold roll 98 (not shown, but also on the lower side of the material 8 to be rolled). In the example of FIG. 4, the crankshaft 91 of the crank mechanism 93a extends in the vertical direction. The hydraulic cylinder 95a and the worm gear 96 are mechanisms for adjusting the opening when the mold 92 is closed.

  The width press 9 disclosed in Patent Document 2 is a width press method called a so-called go-stop. In the case of this method, as shown in FIG. 4, there is only one corresponding to the crank mechanism 93a, and there is nothing corresponding to 93b. As shown in FIG. 5 (b), starting from the state (a), the pair of width press dies 92 are closed by the operation of the crank mechanism 93a in the width direction of the material 8 to be rolled (b) C) Separated and (d) When separated, the material to be rolled 8 is pressed from above and conveyed with being held between the table rolls 7 (not shown in FIG. 5 but shown in FIG. 4). A series of operations in which the pinch roll 94 transports in the transport direction A by an amount corresponding to the feed pitch P is repeated.

  Now, during the operation of width-pressing or conveying the material to be rolled 8, the material to be rolled 8 and the die 92 may slip. As shown in FIG. 6, this slip has an inclined portion on the entrance side in the conveyance direction as shown in FIG. 6, and when the width is pressed by closing the die 92 as indicated by the white arrow, Since the force works so that the material to be rolled 8 is pushed back in the direction opposite to the conveying direction, the scale generation condition (thickness etc.) of the surface layer of the material to be rolled 8 and the temperature condition of the mold 92 (higher than a certain level) Etc.) are considered to slip.

In Patent Document 3, in order to make it possible to detect slip by taking the case of the go-stop width press method as an example, the condition of the press load is further added to this, and when the press load is 10% or less of the steady state, the pinch roll is reversed. Slip is detected when a case where the amount is 20% or more of the feed pitch occurs twice or more (determined that slip has occurred), or whether the press load is 10% or less during normal operation It is proposed to further add a condition such that the crank angle is the bottom dead center, that is, the timing when the mold is most closed.
JP 02-127905 A JP 61-245931 A JP 09-122706 A

  The above-mentioned hold roll 98 needs to be pressed against the material 8 to be rolled with a force stronger than a certain degree for the purpose of preventing the material 8 to buckle or twist during width pressing.

  Here, the hold roll 98 is originally non-driven. It is difficult to install a drive actuator in the equipment located in the center of the width of the material 8 to be rolled, such as the hold roll 98, because of problems of utility supply such as water, hydraulic pressure, lubricant, electricity, etc. Because it is virtually impossible.

  By the way, the material to be rolled 8 is thickened by the width pressing. FIG. 7A schematically shows the rolled material 8 in the width press as viewed in the cross section in the width direction from the conveyance direction A, that is, the downstream side. FIG. 7B is the same view from the side. What is indicated by a dotted line is the thickness at the center in the width direction.

  Here, as described above, the thickness of the restraining portion of the hold roll 98 at the center in the width direction of the rolled material 8 is suppressed because the rolled material 8 is pressed with a strong force by the non-driven hold roll 98. Has been. For this reason, by increasing the thickness only before and after the restraining portion by the hold roll 98, the restraining portion at the hold roll 98 becomes slightly concave. As a result, the rolled material 8 on the upstream side in the transport direction protrudes above the lower end of the upper hold roll 98 so as to appear to be circled in FIG. In particular, when the material to be rolled 8 is deformed so as to buckle or twist during width pressing, the tendency becomes remarkable. Although not shown in FIG. 7C, the lower hold roll 98 may protrude downward from the upper end.

  In this way, when the degree of deformation that is likely to buckle or twist becomes more than a certain level, the restraint portion of the hold roll 98 becomes a deep concave shape, so that the material to be rolled 8 is to be transported in the transport direction A. In some cases, the hold roll 98 cannot get over the portion of the material 8 to be circled shown in FIG. As a result, the material to be rolled 8 may remain in a state of being restrained by the hold roll 98 and may cause a trouble that slips between the table roll 7 and the pinch roll 94.

  Once such a trouble occurs, the material 8 to be rolled cannot be moved in the conveying direction A, and the width press 9 and thus the entire hot rolling line 100 are stopped.

  The above problem is a problem that can be said to be common to the prior arts relating to all width presses other than Patent Documents 1 to 3 described above.

  The present invention solves the problem of the prior art that the rolled material 8 cannot be moved in the conveying direction A as a result of slipping in a state where the rolled material 8 is restrained by the hold roll 98 as described above. It was made.

  The inventors studied a method for avoiding the occurrence of trouble that the material to be rolled slips in a state where the material to be rolled is restrained by the hold roll 98 as shown in FIGS. 7 (c) and 7 (d).

  In the first place, the purpose of restraining the material 8 to be rolled by the hold roll 98 is to suppress the deformation of the material 8 to be buckled or twisted during width pressing. Therefore, the material to be rolled 8 does not necessarily have to be restrained by the hold roll 98 while the mold 92 is separated from the material to be rolled 8.

  Therefore, the state in which the hold roll 98 constrains the material 8 to be rolled immediately after the die 92 is closed and the operation of width-pressing the material 8 to be rolled, that is, while the die 92 is separated from the material 8 to be rolled. It was thought that the trouble which cannot convey the to-be-rolled material 8 can be prevented by allowing the hold roll 98 to get over the portion shown in FIG. This is the present invention. It does not depend on the flying sizing press method or go-stop method.

That is, the present invention is as follows.
(1) When performing a width press of a material to be rolled in hot rolling, if a slip is detected during the operation of width pressing or conveying the material to be rolled, the conveyance immediately after the operation of performing the next width press is performed. A width pressing method in hot rolling, wherein the restraint of the material to be rolled by the hold roll is temporarily released during the operation to be performed.
(2) When the restraint of the material to be rolled by the hold roll is temporarily released, position control is performed by giving a target value to the deviation from the pressing position of the hold roll against the material to be rolled (1 ) In the hot rolling.
(3) A method for producing a hot-rolled metal plate using the width press method in hot rolling according to either (1) or (2).

  According to the present invention, as a result of the material to be rolled 8 slipping in a state of being restrained by the hold roll 98, the problem of the prior art that the material to be rolled 8 cannot be moved in the transport direction A can be solved. The stable operation of the hot rolling line 100 can be achieved.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 1, taking as an example the case where a width press is performed on a steel material 8.

  FIG. 1A schematically shows a crank mechanism using a width pressing method of a flying sizing press in which the crankshaft is vertical as shown in FIG. As shown in FIG. 1 (a), when the rotation of the crankshaft (normal direction to the paper surface of FIG. 1 (a)) comes to a position 45 ° below the horizontal, the mold 92 is just covered. A case where width pressing is performed on the material 8 to be rolled having such a width as to come into contact with the rolled material 8 is taken as an example.

  Here, if the rotation angle (crank angle) of the crankshaft when the mold 92 is just in contact with the workpiece 8 is newly defined as 0 °, the rotation is further at the bottom dead center, that is, the mold 92 is most closed. After passing through (45 °), when the mold 92 starts to be separated beyond that, it is separated from the material 8 to be rolled. In FIG.1 (c), the area | region of the rotation angle 0-45 degrees shown with the shadow is equivalent during the operation | movement which is performing width press, the metal mold | die 92 contacting the to-be-rolled material 8, and obstruct | occluding.

  In the meantime, FIG. 1B schematically shows a state where the hold roll 98 is viewed from the side, and the upper hold roll 98 is covered with the desired roll pressure by a hydraulic cylinder 95 or the like. Control to press against the rolled material 8 is performed. In the example shown in FIG. 1B, the lower hold roll 98 is not provided with a lift actuator, but is provided with a lift actuator similar to that of the upper hold roll 98 and covered with a desired pressure. You may make it perform control which presses against the rolling material 8. FIG.

  Here, first, how to control the pressing of the hold roll 98 against the material to be rolled 8 in a steady state where no slip is detected will be described below.

  In the example shown in FIG. 1 (c), the hold roll 98 is operated at a relatively high pressure during the operation in which the die 92 is in contact with the material 8 to be rolled and the width press is performed while closing, as indicated by the shadow. The hold roll 98 is pressed against the material to be rolled 8 with a relatively low pressure while the mold 92 is not pressed from the material to be rolled 8 and is pressed away from the material 8 to be rolled.

  The reason why the hold roll 98 is pressed against the material to be rolled 8 with a relatively high pressure during the operation of performing the width press is to prevent the material to be rolled 8 from buckling or twisting.

  The reason why the hold roll 98 is pressed against the material to be rolled 8 at a relatively low pressure while the die 92 is separated from the material to be rolled 8 is that the die 92 is separated from the material to be rolled 8. Since the material to be rolled 8 is not buckled or twisted during the interval, the force in pressing the hold roll 98 against the material 8 to be rolled is reduced, so that the conveyance in the conveyance direction A can be made as smooth as possible. is there.

  Note that the relatively high pressure (high pressure) is, for example, 3.5 to 8.5 MPa, and is often within or outside that value. The relatively low pressure (low pressure) is, for example, 0.25 to 0.5 MPa, and is often within or outside that value. For example, the diameter of the hold roll 98 is Φ750 to 800 mm, and in many cases, the value is inside or outside the value.

  Whether the die 92 is in contact with the material to be rolled 8 and performing the width press while being closed or whether the die 92 is separated from the material 8 to be rolled is determined by the crank angle. That's fine. The crank angle may be obtained by attaching a pulse generator (not shown) to the crankshaft and counting the pulses generated by the control device 50.

  Incidentally, in the present invention, as shown in FIG. 1 (c), it is not always necessary to switch the holding roll pressing pressure to a high pressure or a low pressure depending on the crank angle. As long as 8 is not buckled or twisted, it can be kept at a low pressure as much as possible, or it can be compared with the low pressure of the limit where the rolled material 8 does not buckle or twist. It is also possible to switch between the low pressure shown in FIG.

  Next, when slip is detected, which is a structural point of the present invention, the restraint of the material 8 to be rolled by the hold roll 98 is temporarily released during the operation of performing the conveyance immediately after the operation of performing the next width press. How to perform the control will be described below.

  In order to carry out the present invention, it is necessary to detect that the material to be rolled 8 and the mold 92 have slipped. As a result of theoretical considerations, the inventors, first of all, as shown in FIG. 2 (a), when viewed as the total during the operation of performing the width press or the operation of performing the transport immediately thereafter, When the slip occurs, the rotational peripheral length of the pinch roll 94 that rotates following the contact with the rolled material 8 is less than the portion corresponding to the feed pitch P in the conveying direction A of the rolled material 8. I came to think.

  Incidentally, as shown in FIG. 2, a pulse generator is attached to the pinch roll 94, and the control device 50 can count the emitted pulses. From the result, the rotation circumference of the pinch roll 94 is determined. And the direction of rotation (reverse rotation) can be detected. Note that the feed pitch P is 400 mm, for example, and in many cases is within or outside of the value.

  In addition, pinch rolls 94 are installed on the entry side and the exit side as viewed in the conveyance direction A across the mold 92, but the rotation circumference takes either one of the values, or takes the average of both, Etc. may be determined as appropriate.

  However, it is not necessary to use a lever ruler so that the rotation is determined by, for example, 1 mm less than the feed pitch P corresponding to the conveyance direction in the conveyance direction, and an allowable range of, for example, plus or minus 50 mm is provided. Or, as described in Patent Document 4 above, conditions such as a press load and a crank angle may be further added, and the specific method for detecting slip is uniquely described above. It is not limited to.

  In any case, for example, when slip is detected by the method described above or other methods, in the present invention, as shown in FIG. In contrast to the operation to be performed, the pressing of the hold roll to the material to be rolled is temporarily released during the operation of performing the conveyance immediately after the operation of performing the next width press.

  In FIG.1 (c), the place which is set to raise / lower of a hold roll corresponds to the timing which presses the hold roll to the to-be-rolled material temporarily.

  At this time, the hydraulic cylinder may be controlled by any control as long as the pressing of the hold roll against the material to be rolled can be temporarily released.

(Second Embodiment)
Further, in the present invention, as shown in FIG. 1C, when the pressing of the hold roll 98 against the material 8 to be rolled is temporarily released, the position (the oil in the hydraulic cylinder) is controlled from the constant pressure control for controlling the pressure. It is preferable to control the hold roll height by switching to the fixed position control for controlling the column length). Here, the deviation from the position where the hold roll 98 is pressed against the material 8 to be rolled is given a deviation target, for example, in the example in FIG. It is more preferable to use position control. Here, it is preferable to use a value such as the thickness of the material to be rolled 8 before performing the width press, for example, a value such as 250 mm as the set material thickness to be rolled. Further, the value to be added to the set material thickness (+10 mm in the example of FIG. 1C) may be appropriately determined in consideration of the depth of the concavity of the restraint portion by the hold roll, the operating speed of the hydraulic cylinder, and the like. .

  As described above, the position control in which the deviation from the pressing position of the hold roll 98 against the material to be rolled 8 has a target value is not given the target value at all unless the hold roll 98 is rolled. When the constrained portion of the material 8 cannot be overcome or the hydraulic cylinder rises excessively, the hold roll 98 is again attached to the material 8 when the next material 8 is subjected to width press. This is because the pressing operation may not be in time.

  According to the present invention, when performing the width press of the material to be rolled by hot rolling, the material to be rolled 8 slips in a state of being restrained by the hold roll 98, and the material to be rolled 8 cannot be moved in the conveying direction A. The problem of the prior art can be solved, and stable operation of a hot rolling line that hot-rolls not only steel but all metals can be achieved.

Diagram for explaining an embodiment of the present invention Diagram for explaining an embodiment of the present invention The diagram which shows an example of the conventional hot rolling line which should apply this invention Perspective view for explaining the principle of width press Plan view for explaining the principle of width press Plan view for explaining the reason why the material to be rolled and the die slip Diagram for explaining problems of the prior art

Explanation of symbols

7 Table Roll 8 Rolled Material 9 Width Press 91 Crankshaft 92 Die 93, 93a, 93b Crank Mechanism 94 Pinch Roll 95, 95a Hydraulic Cylinder 96 Worm Gear 98 Hold Roll 10 Heating Furnace 12 Rough Rolling Machine 15 Finishing Input Thermometer 16 Descaling device 18 Finishing mill 23 Runout table 24 Coiler 50 Control device 70 Process computer 90 Business computer 100 Hot rolling line A Conveying direction

Claims (3)

  During hot rolling, during the width press of the material to be rolled, during the operation of width pressing or conveying the material to be rolled, when slip is detected, during the operation of conveying immediately after the operation of performing the next width press A width pressing method in hot rolling characterized by temporarily releasing the restraint of the material to be rolled by the hold roll.   2. The heat according to claim 1, wherein, when the restraint of the material to be rolled by the hold roll is temporarily released, position control is performed by giving a target value to a deviation from a position where the hold roll is pressed against the material to be rolled. The width press method in hot rolling.   The manufacturing method of the hot-rolled metal plate using the width press method in the hot rolling in any one of Claim 1 or 2.

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