JP2012030260A - Method for identifying roll causing rolling flaw - Google Patents

Abstract

An object of the present invention is to provide a method for identifying a roll wrinkle-derived roll that can specify a roll wrinkle due to occurrence of a roll wrinkle in a short time and can determine a roll wrinkle with high accuracy.
In a hot rolling line having a finish rolling mill composed of a plurality of stands, a roll flaw periodically generated on the surface of a steel sheet due to a finish rolling roll is detected, and the detected roll flaw is caused. A method for identifying a roll wrinkle-derived roll that identifies a roll, which compares a roll wrinkle generation condition step, a surface wrinkle detection step, a wrinkle generation pitch calculation step, and an exit side wrinkle cycle and a generated pitch If there is a matching outgoing side dredging cycle with the step, the specified roll identifying step for identifying that the rolling roll is the originating roll of the detected roll trough; Has a non-roll wrinkle determination step for determining that it is a non-roll wrinkle.
[Selection] Figure 1

Description

  The present invention, in a hot rolling line having a finish rolling mill composed of a plurality of stands, detects roll wrinkles periodically generated on the steel sheet surface due to the finish rolling roll, and is the cause of the detected roll wrinkles. The present invention relates to a method of identifying a roll-causing roll that identifies a roll.

  In the steel rolling process and the resin film manufacturing process, rolls are generally used for supporting and transporting strip-shaped products.

  In the hot rolling line for steel, when a roll defect, which is a periodic defect due to a rolling roll, is formed on the surface of the steel sheet, a serious problem arises in product quality. For example, if the diameter of the roll in which an abnormality has occurred is 500 mm, roll wrinkles are continuously generated at a pitch of 500 × π≈1570 mm. Once this roll wrinkle occurs, it may occur over the entire length of the product until treatment such as roll care or roll change is executed.

  For this reason, it is necessary to detect roll wrinkles quickly and take measures such as roll replacement as soon as possible. Conventionally, an operator directly observes or, for example, an operator views an image obtained by a camera to determine the presence or absence of a defect.

  Patent Document 1 discloses a photoelectric sensor with an improved light source, which improves the defect detection rate. Patent Document 2 discloses that the camera angle adjustment is performed when the gray value difference between the image of the defective portion and the formation portion is small, and the threshold value adjustment is performed when the gray value difference is large. A technique is disclosed that can accurately determine the cause of oversight and adjust the surface inspection apparatus in a short time.

  Furthermore, Patent Document 3 discloses a technique in which the detection target is narrowed down to a roll and the processing technique of the inspection apparatus is improved. This technique obtains a signal waveform in which a defect signal portion is emphasized by obtaining a convolution of a specific wave packet signal and an original signal. And by analyzing the obtained signal, it is possible to discriminate periodic defects and detect a weak periodic signal that is as weak as noise even from a very small amount of data of about 3 to 5 cycles. It is what.

JP 2005-134363 A JP 2010-1112846 A JP 2001-281154 A

  However, although the periodic wrinkle signal can be detected with high accuracy by the techniques disclosed in Patent Documents 1 to 3 described above, any of the rolling rolls among the rolling rolls having a plurality of detected periodic wrinkles. There is a problem that the cause of whether it is due to has not yet been investigated.

  FIG. 2 is a diagram showing an image of occurrence of roll wrinkles due to rolling with a rolling roll. (A) has shown the mode that the camera image | photographed the surface of the steel plate rolled with the finish rolling mill with 7 stands in a back | latter stage. And (b) has shown typically the case where roll wrinkles have occurred due to the F5 roll.

  For example, rolls generated due to the final rolling roll (F7-std) having no rolling roll in the subsequent stage are generated at the F7 roll circumferential pitch on the steel plate surface. However, the roll wrinkles generated due to the rolling rolls before the final rolling roll (F7-std) like F5-std shown in (b) pass through F6-std and F7-std and are respectively rolled. Since it is stretched, the wrinkle pitch on the F7-std exit side does not have a period of the F5 roll circumference. Thus, when roll wrinkles occur due to the preceding roll, the roll wrinkle cycle becomes longer due to rolling as the latter rolls.

  Therefore, even if the roll inspection is detected by the surface inspection device installed on the exit side of the rolling mill and the period is accurately known, the roll is composed of a plurality of stages. Is difficult to identify in a short time.

  Further, although a defect candidate having periodicity is detected, there is a possibility of false detection that causes a wrinkle candidate having a period that is impossible from a roll used in operation as a roll flaw.

  The present invention has been made in view of such circumstances, and it is possible to identify the roll that causes the roll wrinkle when the roll wrinkle occurs in a short time, and it is possible to determine the roll wrinkle with high accuracy. It is an object to provide a method for identifying a role.

  The present invention for solving the above problems has the following configuration.

[1] In a hot rolling line having a finish rolling mill constituted by a plurality of stands, a roll that is periodically generated on the steel sheet surface due to the finish rolling roll is detected, and the roll that is the cause of the detected roll Is a method for identifying a roll-induced roll,
A roll wrinkle generation condition step for calculating and setting the outgoing side wrinkle cycle in the final finishing mill for the roll flaws assumed to be due to each rolling roll;
Imaging the steel sheet surface with a camera installed at the subsequent stage of the finish rolling mill, performing image processing to detect surface flaws,
A wrinkle generation pitch calculation step for detecting periodic wrinkles from the detected surface wrinkles and calculating the generated pitch of the wrinkles;
A comparison step of comparing the outgoing side wrinkle period and the generated pitch;
In the comparison step, if there is a coincidence of the outgoing side wrinkle cycle, the roll is identified as a causative roll of the roll that has been detected.
In the comparison step, if there is no coincidence of the outgoing side wrinkle cycle, it is determined that the detected roll wrinkle is a non-roll wrinkle;
A method for identifying a roll-derived roll, characterized by comprising:

[2] In the method for identifying a roll wrinkle-derived roll according to [1],
After the identifying role identifying step or the non-roll defect determining step, a result display step of displaying a result of any one of the steps is provided.
In the roll wrinkle generation condition step,
A method for identifying a roll wrinkle-derived roll, wherein the outlet side wrinkle cycle is calculated based on manufacturing conditions such as the diameter of the roll being used, the thickness of the steel sheet, and the plate temperature.

  According to the present invention, the determination of the non-roll wrinkles and the identification of the causative roll are automatically performed, so that the roll wrinkle determination can be performed with high accuracy and the identification of the causative roll can be performed in a short time. As a result, it is possible to respond quickly, such as care for rolls, and it is possible to contribute to an improvement in operating rate.

It is a figure which shows the example of a process sequence in the identification method of the roll wrinkle origin roll which concerns on this invention. It is a figure which shows the generation | occurrence | production image of the roll wrinkle by the rolling with a rolling roll. It is a figure which shows the apparatus structural example for applying this invention. It is a figure which shows the example of roll wrinkle generation | occurrence | production conditions. It is a figure which shows the surface test result about the product A. FIG. 6 is a diagram showing a surface inspection result for product B. It is a figure which shows the surface test result about the product C. FIG.

  FIG. 3 is a diagram showing an example of a device configuration for applying the present invention. In the figure, 1 represents a steel plate, 2 represents a finish rolling mill, 3 represents a camera, 4 represents a host computer, 5 represents a surface inspection apparatus, and 6 represents a display.

  The steel plate 1 finish-rolled by a finishing mill 2 having seven stands is imaged on the respective surfaces by cameras 3 installed on the front side and the back side. The captured image is sent to the surface inspection apparatus 5 to perform the processing described below, and the processing result is sent to the display 6 and used as work guidance for the operator. In addition, the period of the roll roll to generate | occur | produce changes with manufacturing conditions, such as a roll used with the finishing mill 2, a board thickness, and board temperature. Therefore, in order to improve the detection accuracy of the roll wrinkles in the surface inspection device 5, the surface inspection device 5 takes in the roll wrinkle generation conditions obtained from these manufacturing conditions from the host computer 4.

  FIG. 1 is a diagram showing an example of a processing procedure in a method for identifying a roll-caused roll according to the present invention. First, in Step 01, a roll wrinkle generation condition is set. Enter the manufacturing conditions such as the roll diameter, plate thickness, plate temperature, etc. of the F1-F7 stand in use, and based on these, assume that roll wrinkles occur due to each roll. Calculate and set. In addition, since the roll currently used for rolling changes for every roll change and every stand, the roll diameter of each roll is input into a high-order computer after roll exchange implementation. After the roll change, the input value is used until the next roll change.

  An example of the calculation method is represented by the following equation (1), where the F7 exit side saddle cycle of the roll cage caused by the i-th stand Fi is the F7i exit side saddle cycle.

  F7i outlet side wrinkle cycle = i roll diameter × π × Fi outlet side plate thickness / F7 outlet side plate thickness (1)

  For each roll of the stand, the F7 outlet side wrinkle cycle is obtained and sent from the host computer 4 to the surface inspection device 5 as a roll wrinkle generation condition. FIG. 4 is a diagram illustrating an example of roll wrinkle generation conditions. As an example, the used roll diameter for each stand, and the F7 exit side roll wrinkle cycle at the time of the corresponding roll are shown.

  For example, when roll wrinkles occur due to F1, as a result of calculating the rolling reduction from the roll cycle of the F1 roll to the final F7 roll, the roll wrinkle cycle on the outlet side is calculated as 1790.5 mm. The same applies to the following, but when roll wrinkles occur due to F7, since there are no rolling rolls after F7, “roll cycle = exit side wrinkle cycle”, so the roll wrinkle cycle on the plate surface is 1633. 3 mm.

  Next, in Step 02, surface wrinkles are detected. The image from the camera 3 installed on each of the front side and the back side is subjected to image processing to detect surface defects. As a specific detection method, the method described in Patent Document 2 described above may be used.

  In Step 03, the roll wrinkles are detected from the surface wrinkles detected in Step 02, and the steel roll longitudinal interval of the detected roll wrinkles, that is, the generation pitch of the roll wrinkles is calculated. As a specific calculation method, the method described in Patent Document 3 described above may be used.

  Then, in the next Step 04, the wrinkle generation pitch calculated in Step 03 is compared with the F7 outgoing side wrinkle cycle of the roll wrinkle generation condition described above to determine whether there is a match.

  If there is a match, it is specified that the matched roll is the origin of the roll defect (Step 05). For the coincidence determination, it is preferable to give an upper and lower limit range to the value of the F7 outgoing side wrinkle period in FIG. 4 and determine whether or not the wrinkle pitch obtained from the image is within that range. 5-7 is a figure which shows the surface test result about products AC, respectively.

  From the surface inspection result for the product A in FIG. 5, the wrinkle pitch is 1633 mm, and the F7 roll has the same period in the F7 outlet side wrinkle period in FIG. For this reason, this roll wrinkle is determined to be caused by the F7 roll.

  Similarly, from the surface inspection result for the product B in FIG. 6, the heel pitch is 1790 mm, and the roll of F1 has the same period in the F1 exit side heel period of FIG. For this reason, this roll wrinkle is determined to be caused by the F1 roll.

  However, from the surface inspection result for the product C in FIG. 7, the wrinkle pitch is 1570 mm, and there is no corresponding one in the F1 outlet side wrinkle cycle in FIG. Therefore, it is determined that this roll wrinkle has been detected as a periodic wrinkle accidentally, and is determined as a non-roll wrinkle. The process here describes Step 06 in FIG. In this way, it is possible to exclude defects of the period detected accidentally that do not occur from the roll to be rolled.

  In the final Step 07, the result of Step 05 or Step 06 is displayed on the display 6 and used as the operator's work guidance. It is possible to exclude defects with a period detected accidentally that do not occur from the roll to be rolled, and it is possible to improve the accuracy of the roll defect determination result in the surface inspection apparatus. Further, when a roll wrinkle is detected from the above result, the roll wrinkle cycle and the resulting roll can be displayed on the screen on the display unit of the surface inspection apparatus, and an abnormal roll can be recognized in a short time.

DESCRIPTION OF SYMBOLS 1 Steel plate 2 Finishing mill 3 Camera 4 Host computer 5 Surface inspection apparatus 6 Display

Claims (2)

In a hot rolling line having a finish rolling mill composed of a plurality of stands, the rolls periodically generated on the surface of the steel sheet due to the finish rolling roll are detected, and the roll that is the cause of the detected roll is identified , A method for identifying a roll-induced roll,
A roll wrinkle generation condition step for calculating and setting the outgoing side wrinkle cycle in the final finishing mill for the roll flaws assumed to be due to each rolling roll;
Imaging the steel sheet surface with a camera installed at the subsequent stage of the finish rolling mill, performing image processing to detect surface flaws,
A wrinkle generation pitch calculation step for detecting periodic wrinkles from the detected surface wrinkles and calculating the generated pitch of the wrinkles;
A comparison step of comparing the outgoing side wrinkle period and the generated pitch;
In the comparison step, if there is a coincidence of the outgoing side wrinkle cycle, the roll is identified as a causative roll of the roll that has been detected.
In the comparison step, if there is no coincidence of the outgoing side wrinkle cycle, it is determined that the detected roll wrinkle is a non-roll wrinkle;
A method for identifying a roll-derived roll, characterized by comprising: In the identification method of the roll wrinkle origin roll of Claim 1,
After the identifying role identifying step or the non-roll defect determining step, a result display step of displaying a result of any one of the steps is provided.
In the roll wrinkle generation condition step,
A method for identifying a roll wrinkle-derived roll, wherein the outlet side wrinkle cycle is calculated based on manufacturing conditions such as the diameter of the roll being used, the thickness of the steel sheet, and the plate temperature.