JP2009172624A - Method and apparatus for straightening bend in hot rolling stage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for straightening a camber of a hot bar in a hot roughing stage without performing one side reduction. <P>SOLUTION: When the camber is generated on the drive side of the hot bar on the outlet side of a hot rough-rolling stand, solenoid valves 7 of the jetting nozzles 3 on the work side of a valve stand 6 are turned to open and a lubricant is supplied to the work side of the upper and lower back up rolls 2. When the camber is generated on the work side, the solenoid valves 7 of the jetting nozzles 3 of the valve stand are turned to open and the lubricant is supplied to the drive side of the upper and lower back up rolls. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for correcting a bending of a hot bar in the plate width direction (hereinafter referred to as a camber) in a hot rough rolling process.

  One cause of the occurrence of camber is local roughening of the surface of the work roll, and camber tends to occur in the opposite direction to rough skin. For example, when rough skin occurs on the drive side of the work roll, camber occurs on the work side, and when rough skin occurs on the work side, camber occurs on the drive side. When the camber is excessive, the hot bar tip collides with the side guide of the roughing mill and damages the side guide, leading to an increase in repair costs, and loss of opportunity (reduced production) due to rolling stoppage for repair. I will let you. Also, when camber occurs, it becomes easy to induce a narrowing-down accident in a finish rolling mill, and roll replacement work caused by this causes problems such as opportunity loss and roll cost increase. On the other hand, in the quality of the hot coil, when the camber is generated, a telescope is generated when the coil is wound, and a wrinkle is generated at the coil edge portion by contacting the side guide before the winder. Various problems occur when camber occurs.

  As a method of correcting the camber, the operator has been able to recognize the camber by visual observation and change the one-side reduction amount of the reduction device (hereinafter referred to as leveling), but the camber cannot be grasped quantitatively. When a complicated camber in which the camber amount and the camber direction change in the longitudinal direction of the hot bar is generated, it is difficult to properly level the camber, so that the camber has not been completely corrected.

  The method disclosed in Patent Document 1 is also related to a method of correcting the camber by one-sided reduction, and the steel plate is obtained by obtaining the center line of the steel plate from the steel plate image taken by the television camera provided on the exit side of the hot rough stand. Divide in the direction, measure the camber amount for each measurement range, perform arbitrary correction on each camber amount in each measurement range, calculate one leveling amount that has been averaged, and move to the next stage stand Although the amount of reduction is feedforward, this method also cannot correct the camber with high accuracy when a complicated camber that changes the camber amount or camber direction in the longitudinal direction of the hot bar occurs. .

Patent Document 2 discloses a method of correcting the camber with a side guide provided on the exit side of the rolling mill. However, wrinkles are generated in the coil edge portion by contacting the side guide, or excessive in the side guide. There is a risk of equipment damage due to load.
JP-A-11-28510 JP 2002-120005

  An object of the present invention is to correct a camber of a hot bar at a next stand or the stand using a lubricant such as rolling oil sprayed on the roll for protecting the roll.

  The invention according to claim 1 is a method for correcting a camber of a hot bar in a hot rough rolling process, and when a camber is generated on a hot bar on the hot rough rolling stand exit side, the direction opposite to the direction in which the camber is generated. A lubricant is supplied to the rolling roll of the stand or the next stand. For example, when the camber occurs on the drive side, the lubricant is supplied to the work side of the rolling roll of the stand or the next stand, and when the camber occurs on the work side, the lubricant is supplied to the drive side of the rolling roll.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the rolling roll supplied with the lubricant is a backup roll,
The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the supply location and / or supply amount of the lubricant to the rolling roll is adjusted according to the camber amount.

  The invention according to claim 4 is an apparatus for carrying out the invention according to claim 1, wherein the image pickup means is arranged on the hot rough rolling stand outlet side and picks up an image of a hot bar fed from the rough rolling stand, and the heat The upper and lower rolling rolls of the inter-rough rolling stand, preferably the lubricant injection nozzles arranged on the drive side and work side of the upper and lower backup rolls, and the hot bar image captured by the imaging means are processed to process the camber. It is characterized by comprising a control device for determining the direction to be generated and thereby controlling the opening and closing of the valve of the injection nozzle arranged on the drive side or the work side.

The invention according to claim 5 is the invention according to claim 4, in which the control device obtains the camber amount together with the direction in which the camber is generated from the image of the hot bar, and the control device is one of the upper and lower rolling rolls according to the obtained camber amount. The valve of the injection nozzle is controlled so that the lubricant is supplied to one or both of the
The invention according to claim 6 is the invention according to claim 4 or 5, wherein the control device obtains the camber amount together with the direction in which the camber is generated from the image of the hot bar, and a flow rate adjusting valve is provided in the lubricant supply line, The control device controls the flow rate adjusting valve according to the obtained camber amount, and adjusts the supply amount of the lubricant.

  According to the first aspect of the present invention, it is possible to correct the camber without causing a single pressure reduction, and it is possible to correct even a complicated camber in which the camber amount and the camber direction change in the hot bar longitudinal direction. In addition, the camber can be corrected with a rolling stand, so that a side guide can be dispensed with, or even if a side guide is provided, damage to equipment due to excessive load applied to the side guide can be prevented, and winding can be performed. It is possible to prevent wrinkling of the coil edge portion due to contact with the machine side guide.

  According to the invention according to claim 2, the lubricant is uniformly applied to the work roll required part, and according to the invention according to claim 3, one or both of the upper and lower rolling rolls according to the camber amount, Alternatively, the necessary amount of lubricant is supplied to the entire area of the drive side or the work side or a necessary part of the work side.

  According to the invention of claim 4, the camber can be automatically corrected. According to the invention of claim 5, the lubricant is automatically supplied to the upper and lower rolling rolls according to the camber amount. According to the sixth aspect of the present invention, a necessary amount of lubricant can be supplied according to the camber amount.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following embodiment, an example in which rolling oil is used as the lubricant is shown.
FIG. 1 shows a rolling roll of a hot rough rolling stand composed of upper and lower work rolls 1 and a backup roll 2. The upper and lower backup rolls 2 are provided with rolling oil injection nozzles 3 on the drive side and the work side, respectively. (In the example shown, three pieces are arranged, but one piece or plural pieces other than three pieces may be used.) The rolling oil pressurized by the pump 4 is supplied to each of the flow rate adjusting valve 5 and the valve stand 6. It is supplied to the injection nozzle 3 via the electromagnetic valve 7 and injected to the backup roll 2.

  One method of correcting the camber is performed by the operator visually monitoring the hot bar on the stand exit side. That is, when the operator monitors the presence or absence of the camber and confirms the camber, the operator opens the required electromagnetic valve 7 and closes the other electromagnetic valves according to the direction and amount, and operates the flow rate adjustment valve 5. For example, if the camber is generated in the direction of the drive side and it is determined that the amount is large, the electromagnetic valves 7 of the upper and lower injection nozzles 3 on the work side are opened, the electromagnetic valves 7 of the upper and lower injection nozzles 3 on the drive side are closed, The flow rate adjusting valve 5 is operated so that the flow rate becomes 50% of the flow rate supplied when all the solenoid valves 7 are opened. If it is determined that the camber is generated in the direction of the work side and the amount is large, the solenoid valves 7 of the upper and lower injection nozzles 3 on the drive side are opened, and the solenoid valves 7 of the upper and lower injection nozzles 3 on the work side are closed. The flow rate adjusting valve 5 is operated so that the flow rate becomes 50%.

  When the amount of the camber is small, only one of the upper and lower injection nozzles 3 or, in the example shown in FIG. ˜5 injection nozzles 3 are selected, the solenoid valve 7 of the nozzle 3 is opened, and the others are closed. Then, the flow rate adjusting valve 5 is narrowed down by the number of electromagnetic valves 7 that are closed. For example, when the upper three injection nozzles 3 are opened and the others are closed, the flow rate is reduced to 25%.

  Another method of correcting the camber is to automatically correct the camber. FIG. 2 shows an example thereof. The image pickup means 11 is composed of a CCD camera or a television camera, and is arranged on the exit side of the hot rough rolling stand so that the hot bar 10 fed from the stand can be photographed. The image of the hot bar 10 captured by the imaging unit 11 is output to the image processing unit 13 of the control device 12. The image processing unit 13 has a known structure, and a detailed description thereof will be omitted. However, the image signal of the analog signal captured by the imaging unit 11 is subjected to a filtering process such as smoothing, and then binarized to obtain a digital signal. The background and noise data other than the hot bar are removed.

  The camber amount calculation unit 14 calculates the camber amount from the digital image of the hot bar 10 obtained by the image processing unit 13 as follows.

  As for the camber amount of the hot bar 10, in the digital image photographed and processed by the image pickup means 11, the coordinate X of the central portion in the hot bar width direction is set to Xn, Xn + 1, Xn + 2,. And the camber amount at an arbitrary position in the hot bar longitudinal direction is calculated from the amount of change between two adjacent X coordinates.

  The control unit 15 determines from the camber amount calculated by the calculation unit 14 that the camber is generated on the drive side when the camber amount is, for example, and on the work side when the camber amount is +, and the camber amount is shown in FIG. The opening and closing of each solenoid valve 7 of the valve stand 6 shown and the flow rate adjustment valve 5 are controlled, and the flow rate of the rolling oil supplied by the pump 4 is controlled by the control of the flow rate adjustment valve 5, for example, when all the solenoid valves 7 are opened. The flow rate is adjusted in steps of 50%, 25%, and 0%. Specifically, camber amount set values ± a, ± b, ± c (where a <b <c) are set. When the camber amount is ± a or less, each solenoid valve 7 is kept closed. The rolling oil is not supplied to the injection nozzle 3. When the camber amount exceeds ± a and is less than ± b, depending on the camber amount + or-, for example, when the camber amount is + or the camber is generated on the work side, either the upper or lower side of the drive side in the example shown in FIG. Three solenoid valves 7 of one injection nozzle 3 are controlled to open (the other solenoid valves 7 remain closed), and the flow rate adjusting valve 5 is controlled to adjust the flow rate to 25% of the fully opened flow rate. To do. When the camber amount is-, conversely, three electromagnetic valves 7 of the injection nozzle 3 on either the upper or lower side of the work side are controlled to be opened. (Other solenoid valves 7 remain closed.) The flow rate is also adjusted to 25% of the flow rate when fully opened.

  When the camber amount exceeds ± c, all six solenoid valves 7 of the upper and lower injection nozzles 3 on the drive side or work side are controlled to be opened, so that the flow rate adjustment valve 5 is 50% of the fully opened flow rate. To control.

  Each hot bar made of low carbon steel with the components shown in Table 1 below, with a plate thickness of 1.99 mm or less and a plate width of 1150 to 1399 mm is monitored immediately after being sent out from the rough rolling stand. 1, a total of six solenoid valves 7 of the work side injection nozzles 3 of the valve stand 6 shown in FIG. 1 are opened by an operator operation, and supplied from the injection nozzles 3 to the upper and lower backup rolls 2 on the work side. The flow rate of the rolling oil was reduced to 50% by the flow rate adjusting valve 5 and sprayed at 75 cc / min. Conversely, when the hot bar is cambered to the work side, a total of six solenoid valves 7 of the drive side injection nozzle 3 are opened, and the rolling oil supplied from each injection nozzle 3 to the upper and lower backup rolls 2 on the drive side is opened. The flow rate was squeezed and injected to the same amount of 75 cc / min. The amount of camber before and after using rolling oil is shown in FIG.

  Incidentally, as shown in FIG. 4, the camber amount is corrected to -5 to 5 mm for the hot bar cambered by 36 mm or more on the work side, and the camber amount is corrected to -15 to -6 mm for the hot bar having the camber amount of 26 to 35 mm. It was done.

  On the other hand, as shown in FIG. 5, the camber amount is corrected to −5 to 5 mm for a hot bar with −36 to −45 mm camber on the drive side, and the camber amount is − for a hot bar with a camber amount of −46 mm or less. It was corrected to 6 to -15 mm.

  FIG. 6 shows the incidence rate of holding by a telescope in the conventional method of correcting one camber and correcting the camber, and the occurrence rate of holding by the telescope in a method of correcting the camber using rolling oil without performing one-sided pressing. In comparison with the conventional method using a single pressure, the incidence rate of holding by a telescope was 2.1%, whereas this method was 1.2%.

  As shown in the figure, the camber was corrected by simply supplying rolling oil to the backup roll, the amount of camber could be greatly reduced, and the occurrence of a telescope could be prevented.

A rolling roll of a hot rough rolling stand equipped with a rolling oil supply mechanism. The schematic diagram of a camber correction apparatus. The graph which shows the relationship between the camber amount of a hot bar tip, and the incidence. The graph which shows the relationship between the camber amount at the time of cambering to a work side (WS), and an incidence rate. The graph which shows the relationship between the camber amount at the time of cambering to drive side (DS), and the incidence. The figure shown about the incidence rate of the holding | maintenance by a telescope in the case of this invention method which injects a conventional method and rolling oil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Work roll 2 ... Backup roll 3 ... Injection nozzle 4 ... Pump 5 ... Flow control valve 6 ... Valve stand 7 ... Solenoid valve 10 ... Hot bar 11 ... Imaging means 12 ... Control device 13. Image processing unit 14 Calculation unit 15 Control unit

Claims (6)

  A method of correcting the bending in the plate width direction of the hot bar in the hot rough rolling step, and detecting the bending in the plate width direction on the hot bar on the hot rough rolling stand exit side, opposite to the direction in which the bending occurs. A bending correction method in a hot rough rolling process, characterized in that a lubricant is supplied to a work side or a drive side of a rolling roll of the stand or the next stand.   2. The method for correcting bending in a hot rough rolling process according to claim 1, wherein the rolling roll supplied with the lubricant is a backup roll.   The supply location of the lubricant to the rolling roll and / or the supply amount thereof is adjusted according to the bending amount of the hot bar in the plate width direction, and the bending in the hot rough rolling process according to claim 1 or 2 Correction method.   An image pickup means that is arranged on the hot rough rolling stand outlet side and picks up an image of a hot bar fed from the rough rolling stand, and a lubricant that is arranged on the drive side and work side of the upper and lower rolling rolls of the hot rough rolling stand. Processing the image of the injection nozzle and the hot bar imaged by the imaging means to determine the direction in which the bending in the plate width direction occurs, thereby controlling the opening and closing of the valve of the injection nozzle arranged on the drive side or work side The bending correction apparatus in the hot rough rolling process which implements the bending correction method of Claim 1 characterized by comprising the control apparatus which performs.   An injection nozzle that obtains the amount of bending along with the direction of occurrence of bending in the plate width direction from the image of the hot bar, and the control device supplies lubricant to one or both of the upper and lower rolling rolls according to the obtained amount of bending. The bending correction apparatus in the hot rough rolling process according to claim 4, wherein the valve control is performed.   The flow rate adjustment valve is provided in the lubricant supply line, and the control device controls the flow rate adjustment valve in accordance with the amount of bending obtained from the image of the hot bar to adjust the supply amount of the lubricant. The bending correction apparatus in the hot rough rolling process of 4 or 5.

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