KR100832434B1 - Method for automatically controling o.r.g with the surface defect of strip - Google Patents

Abstract

The present invention detects and analyzes various roll mark defects caused by rolling rolls that are rolled down during hot rolling operation by a surface defect detector (SDD), and then measures corresponding to the rolls causing the defects according to the results. ORG automatic control method according to the surface defects of the hot rolled steel sheet which can improve the surface quality and the error rate of products by speeding up the early detection and measures of fatal defects and preventing further occurrences. Using defect information obtained from flaw flaw detectors, defects generated on the surface of the rolls are removed by ORG according to the grading grade of the defects at the same time as the defects are generated, or surface replacement is continuously generated by performing roll replacement. There is a practical effect that can improve the product surface quality and error rate by preventing.

Hot rolled, surface flaw detector, ORG, surface defect, scale, roll mark

Description

Automatic control of false paper according to the surface defect of hot rolled steel sheet {METHOD FOR AUTOMATICALLY CONTROLING O.R.G WITH THE SURFACE DEFECT OF STRIP}

1 is a schematic diagram of a conventional hot rolled steel sheet manufacturing process;

Figure 2 is a schematic diagram of a hot rolled steel sheet manufacturing process of the O.R.G automatic control method according to the surface defects of the hot rolled steel sheet according to the present invention;

3 is a hot rolled product surface defect rating criteria table;

Figure 4 is a process flow diagram showing the O.R.G automatic control method according to the surface defects of the hot rolled steel sheet according to the present invention.

♣ Explanation of symbols for main part of drawing ♣

22: slab 14: heating furnace 24: crude rolling mill 26: sand mill 18: winding machine

10, 12: SCC 100: Surface flaw flaw detector

The present invention relates to a method for automatically controlling ORG according to surface defects of hot rolled steel sheet, and more particularly, to detect various roll mark defects caused by rolling rolls that are reduced during hot rolling in a surface defect detector (SDD). After the analysis, it is possible to take action corresponding to the roll causing the defect according to the result, so that the early detection and action of the fatal defect can be promptly detected and no further occurrences can be made to improve product surface quality and error rate. The present invention relates to an ORG automatic control method according to the surface defect of the hot rolled steel sheet which can be improved.

In general, as shown in Figure 1, the hot rolling process for producing a hot rolled steel sheet is extracted after reheating the slab (22) supplied from the continuous casting machine of the steelmaking process to a temperature suitable for rolling in the furnace (14) The rolling mill 24 performs the width rolling and the thickness rolling, and in the finishing mill 26, the final thickness rolling is performed to the product having the desired thickness to roll the strip STRIP rolled up in the winding machine 18 to the coil COIL 20. After winding the product in the form of a surface inspection in the inspection panel 30 to complete the work, the process computer that controls the operation of the furnace 14 is SCC1 (Supervisorial Control Computer) 10 and the rough rolling machine ( The SCC2 12 is in charge of the process computer for controlling the operation of the coil 24 and the winding mill 26.

In the above process, the slab 14 extracted from the heating furnace 14 usually generates a defect called scale because the work is performed at a high temperature of 1100 to 1200 ° C. The scale (Sand, Banchu, Rolled) is a roll surface. Minute defects are generated in the steel sheet and printed on the steel sheet to generate the defects.

In addition, foreign matters are introduced into the rolling rolls 16 through mechanical devices such as the rough rolling mill 24 and the finishing mill 26, or damage to the rolling rolls 16 due to poor sheet flow. Damaged roll 16 will cause a fatal surface defect called a roll mark on the hot rolled product surface.

Products that have surface defects due to roll mark and scale (Sand, Banchu, Rolled) defects may be products depending on the usage of the demand and the occurrence of surface defects. As a result, when the roll 16 is damaged once due to the working characteristics of the hot rolling process, surface defects are generated in the product until proper measures are taken.

In the hot rolling process, in order to prevent a large amount of surface defects, the inspection panel 30 inspects the surface of the product, and when there is an abnormality, the work is stopped and ORG (On Line Roll Grinding) is performed or the roll 16 It is determined whether or not to replace, which is not the full-length test, but the sample test (product end: 3 ~ 4m) is less accurate, it is difficult to accurately and quickly recognize the surface defects.

In addition, the criteria for judging defects are different according to the proficiency among inspectors, and since the inspection results are processed based on the inspector's knowledge and experience, there is always a possibility of not finding a defect or judging it incorrectly.

In particular, since the inspection of the surface of the coil 20 after the rolling is carried out in the state that the hot rolling continues, it is not a problem if a defect does not occur in the product, but if the defect is generated, the coil is completed winding Since the product of (20) is inspected, while the inspection is in progress, the rolling work is performed while the same defect is generated in other products, and the inspection is completed. Thus, there is a problem that the defect is continuously generated until it is transmitted to the finishing rolling 26 driver to determine whether or not to perform the ORG or replace the roll.

In order to solve the above problems, the present invention provides a surface flaw flaw detector on the front of the winder, using the defect information obtained from the surface flaw flaw detection and generated on the surface of the roll according to the grade of the defect at the same time It is an object of the present invention to provide an automatic ORG control method according to surface defects of a hot rolled steel sheet which can prevent the occurrence of defects by performing an ORG or by performing a roll replacement to prevent surface defects from occurring continuously.

In order to achieve the above object, the present invention is to calculate the grade for each grade of defects to determine whether or not continuous operation, online roll polishing, roll replacement when the surface defects detected by the surface flaw flaw detection, According to the present invention, the step of stopping the rolling work by immediately determining whether the removal is possible by ORG, and the rolling work is carried out after performing the ORG or the roll replacement according to the grade for each grade. It provides ORG automatic control method according to surface defect of hot rolled steel sheet.

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

Figure 2 is a schematic diagram of a hot rolled steel sheet manufacturing process of the O.R.G automatic control method according to the surface defects of the hot rolled steel sheet according to the present invention.

As shown in FIG. 2, in the hot rolling process, the slab 22 supplied from the continuous casting machine 8 of the steelmaking process is reheated in the heating furnace 14 to pass through the roughing mill 24 and the finishing mill 26. The strip is wound in the form of a coil in the winder 18, and an online surface defect detector 100 is installed just before the winder 18.

Figure 4 is a process flow diagram showing the O.R.G automatic control method according to the surface defects of the hot rolled steel sheet according to the present invention.

As shown in FIG. 4, the slab 22 extracted 50 from the heating furnace 14 is subjected to width and thickness rolling 52 in the roughing mill 24, and the final thickness rolling in the finishing mill 26. When the winding is completed (58) by the surface flaw flaw detector (100) installed just before the winder (18) to wind the winder (18), the control is terminated. The process computer controlling the operation of the SCC 1 (10) and the process computer controlling the operation of the roughing mill 24, the finishing mill 26, and the winding machine 18 are SCC 2 (12). The information is transmitted to the surface flaw flaw detector 100 by the SCC 1 (10) and the SCC 2 (12), and the information of the surface flaw flaw detector 100 is also transmitted to the SCC 1 (10) and the SCC 2 (12).

Thereafter, with the collected flaw flaw detection result when passing through the surface flaw flaw detector 100, and it is determined whether or not the surface flaw detection (60), if the surface flaw is not detected, rolling is made continuously, the surface flaw If it is detected, it is determined whether the defect is capable of continuous rolling again (62). If the defect is in the range where rolling is possible, rolling is continuously performed. If the defect is in the range where rolling is impossible, it is determined whether rolling after ORG polishing is possible (64). If it is judged that rolling is impossible even if ORG polishing is performed, extraction of the slab which is a rolling material is stopped (70) in the heating furnace 14, and roughing rolling (26) in which the rough rolling (24) and the rough rolling completed are completed. After rolling the entry atmospheric material (70), the roll replacement is carried out (80), and then continuous rolling is performed.

If it is determined that rolling is possible after the ORG polishing (64), and it is determined that rolling is possible, the slab extraction is stopped in the heating furnace 14, and the waiting material is oscillated from the current position (66, OSCILLATION: back and forth in place). The surface flaw flaw detection apparatus 100 of FIG. 4 according to the hot-rolled product surface defect reference table (TABLE) value of FIG. 3 by performing online roll grinding (ORG) by a flaw and a rating in finishing rolling 26. The ORG polishing operation is performed according to the input value by applying the data conversion value from the above, and some examples of the data conversion value from the surface flaw flaw detector 100 of FIG. 4 will be described.

① if (defect.class == 1) // rollmark id is "roll mark" if defect name is "1",

② else if ((feature.A <= 43) && (feature.w_sbox> 17) && (feature.w_sbox <= 24)) defct.grade = 1; Is 43 or less pixels (feature.A <= 43) where defects are recognized, 17 or more width defects (feature.w_sbox> 17), or 24 or less width defects (feature.w_sbox <= 24) ) Is 1 point (defct.grade = 1).

Else if ((feature.A> 43) && (feature.A <= 59) && (feature.h_sbox> 8)) defect.grade = 2; If the number of detected defects is 43 or more (feature.A> 43), 59 or less (feature.A <= 59), or 8 or more height defects (feature.h_sbox> 8), the rating is 2 Point (defect.grade = 2).

④ else if ((feature.A> 82) && (feature.A <= 276) && (feature.w_sbox> 41) && (feature.w_sbox <= 82) && (feature.h_sbox <= 25)) defect.grade = 3; means that the number of detected pixels is 82 or more (feature.A> 82), 276 or less (feature.A <= 276), or 41 or more width defects (feature.w_sbox> 41), If it is 82 or less (feature.w_sbox <= 82) or if there are 25 or less height direction defects (feature.h_sbox <= 25), the rating is 3 points (defect.grade = 3).

Else if ((feature.A> 350) && (feature.w_sbox <= 126) && (feature.h_sbox> 20) && (feature.h_sbox <= 84)) defect.grade = 4; 350 or more (feature.A> 350), 126 or less width defects (feature.w_sbox <= 126), or 20 or more height defects (feature.h_sbox> 20), 84 or less ( If feature.h_sbox <= 84), the rating is 4 points (defect.grade = 4).

⑥ else if ((feature.A> 276) && (feature.A <= 350) && (feature.h_sbox> 20)) defect.grade = 5; Is 5 if there are more than 276 pixels (feature.A> 276), 350 or less (feature.A <= 350) or 20 or more height defects (feature.h_sbox> 20) Point (defect.grade = 5).

⑦ else if (defect.class == 2) // bangchu_scale id is "church scale" if defect name is "2",

⑧ if ((feature.A <= 66)) defect.grade = 1; Is a score of 1 (defect.grade = 1) if the number of detected pixels is less than 66 (feature.A <= 66).

⑨ else if ((feature.A> 66) && (feature.A <= 183) && (feature.A_sbox <= 17608)) defect.grade = 2; means that there are more than 66 pixels where the defect is recognized. A> 66), 183 pieces or less (feature.A <= 183), or the area of a defect is 17608 or less (feature.A_sbox <= 17608), and a grade | grade is 2 points (defect.grade = 2).

If else if ((feature.A> 183) && (feature.A_sbox <= 17608)) defect.grade = 3; is 183 or more pixels (feature.A> 183) where the defect was recognized, or the area of the defect If it is less than 17608 (feature.A_sbox <= 17608), the rating is 3 points (defect.grade = 3).

If else if ((feature.A <= 614) && (feature.A_sbox> 21423) && (feature.A_sbox <= 56034)) defect.grade = 4; means that the number of detected pixels is less than or equal to 614 (feature. If A <= 614, or the defect area is 21413 or more (feature.A_sbox> 21423) and 56034 or less (feature.A_sbox <= 56034), the rating is 4 points (defect.grade = 4).

Else if ((feature.A_sbox> 56034)) defect.grade = 5; has a score of 5 (defect.grade = 5) if the defect area is more than 56034 (feature.A_sbox> 56034).

According to the rating of the data conversion value from the surface flaw flaw detector 100 as described above, if the defect is a scalability defect 72 according to which defect 68 is the defect, the rolling is continuously performed if the rating is within 4 points 76. Otherwise, if the rating is 4 points (84), the ORG polishing operation is performed for 1 minute (94). If the rating is 5 points (86), the ORG polishing operation is performed for 3 minutes (95). In the case of the defect 74, if the rating is within 3 points (78), rolling is continuously performed. Otherwise, if the rating is 3 points (88), ORG polishing is performed for 1 minute (95), and the rating is 4 points ( 90), the ORG polishing operation is carried out for 3 minutes (97), and if the rating is 5 points (92), the roll rolling (99) is carried out and then the continuous rolling operation is performed. If the defect is not removed by determining whether the surface is removed 98, the roll replacement 99 is performed, and the removal of the defect is completed. Continuous rolling operation is started after the surface atmospheric material rolling 82 is performed.

 After the rolled material is inspected by the surface flaw flaw detector 100 again, if there is a defect on the surface of the roll, the control system is again performed, and when the flaw removal is completed, the normal rolling operation is performed.

 If there is a product that has already been subjected to finishing rolling 26 in the control process, the intermediate inspector 30 causes the product to take the necessary measures in the correction line, which is a post-process.

Hereinafter, the measures according to the hot rolled product surface defect reference table values of FIG. 3 will be described in summary.

① Roll Mark Rating: 1, 2 / Scale Rating: 1, 2, 3

→ Continue rolling operation, no online roll polishing machine, no rolling roll replacement

② roll mark rating is 3

 → Stop rolling work, start online roll grinding machine, no rolling roll replacement

③ roll mark rating: 4                     

→ Stop rolling work, start online roll grinding machine, no rolling roll replacement

④ roll mark rating: 5

→ Stop rolling, deactivate online roll grinding machine, replace rolling roll

⑤ scale rating: 4

→ Stop rolling work, start online roll grinding machine, no rolling roll replacement

⑥ Scale Rating: 5

→ Stop rolling work, start online roll grinding machine, no rolling roll replacement

As described above, according to the present invention, by using the defect information obtained from the surface flaw flaw detector, at the same time as the occurrence of the defect, the cause of the defect generated on the surface of the roll according to the grade of the defect rating is performed by performing an ORG or removing the roll replacement. By preventing the occurrence of surface defects continuously, there is a practical effect that can improve the product surface quality and error rate.

Claims (3)

Calculating grades for each grade of defects to determine whether continuous work, on-line roll polishing (O.R.G), or roll replacement are performed when surface defects are detected by the surface flaw flaw detector 100; Stopping the rolling operation by immediately determining whether removal by online roll polishing (O.R.G) is possible according to the grade; When the rolling operation is stopped, O.R.G automatic control method according to the surface defects of the hot-rolled steel sheet, characterized in that consisting of the step of performing an online roll polishing (O.R.G) or rolling after performing a roll replacement depending on the grade for each grade. The method of claim 1, The step of calculating the grade for each grade of the defect is the ORG according to the surface defect of the hot-rolled steel sheet, characterized in that the scale and the roll mark of the surface of the hot-rolled steel sheet is detected by the surface flaw flaw detector 100 and divided into five grades Automatic control method. The method of claim 1, According to the grade-by-grade grades to perform the online roll polishing (ORG) or roll replacement after the rolling operation is carried out if the roll mark rating is 1, 2 and the scale rating is 1, 2, 3, the rolling operation continues, If the roll mark rating is 3 to 4, the rolling work is started by stopping the rolling work.If the roll mark rating is 5, the rolling work is replaced by stopping the rolling work. An ORG automatic control method according to a surface defect of a hot rolled steel sheet, wherein the apparatus is operated and the rolling operation is stopped by stopping the rolling operation when the scale rating is 5.

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