KR100893262B1 - Method for controlling the grinding position of roll grinder according to the width of being rolled material - Google Patents

Abstract

The present invention is a contact between the rolled material and the work roll in the process of removing the surface roughness and wear step of the work roll generated during the rolling operation of the material (rolled material) at high temperature in the hot rolling process using an online roll grinding device And a grinding position control method of a roll grinding apparatus in consideration of a rolled material width which can reduce the grinding wheel's left and right roll gap deviations by increasing grinding efficiency by grinding non-contacting parts.

The grinding position control method of the roll grinding apparatus in consideration of the rolling material width of this invention is a method of controlling the on-line roll grinding apparatus which removes the surface roughness and abrasion step formed in the surface of a rolling mill work roll, The roll-wear amount according to a rolling operation Calculating a step amount of the wear part and the wear part in a control computer (PCS) and setting grinding conditions by comparing the set amount of reference wear and the step amount with respect to each; A second step of determining a reference grinding amount and calculating a grinding range and a width grinding amount when a front grinding operation is required; A third step of setting a reference grinding amount and calculating a grinding range and a lateral grinding amount when a step grinding operation is required; And a fourth step of outputting a control signal to the control device PLC to control the on-line roll grinding device in accordance with the grinding range and the widthwise grinding amount set by the second or third step.

Online, grinding equipment, grinding, wear, step, roll gap, work roll, rolling roll

Description

Method for controlling the grinding position of roll grinder according to the width of being rolled material}

1 is a conceptual diagram showing the correlation between the work roll and the plate profile,

2 is a schematic structure and use state diagram of an on-line roll grinding apparatus;

3a and 3b is a cross-sectional view showing a grinding method using a roll grinding device,

4 is a schematic diagram showing a state of occurrence of a grinding work error (deviation) during roll grinding work;

5a and 5b shows a surface grinding and wear step grinding method according to the present invention

Section,

6 is a cross-sectional view showing a deviation occurrence state during the roll grinding operation according to the present invention;

7 is a cross-sectional view showing a front grinding state before and after improvement;

8 is a cross-sectional view showing a step grinding state before and after improvement;

9 is a flowchart illustrating a control method of the present invention.

※ Explanation of symbols about main part of drawing ※

10,10-1: work roll 12: reinforcement roll

14: On-line roll grinding machine 14-1: Grinding wheel

16: PCS 18: PLC                 

20: rolled material 20-1,20-2,20-3,20-4: rolled material

The present invention is a contact between the rolled material and the work roll in the process of removing the surface roughness and wear step of the work roll generated during the rolling operation of the material (rolled material) at high temperature in the hot rolling process using an online roll grinding device And a grinding position control method of a roll grinding apparatus in consideration of a rolled material width which can reduce the grinding wheel's left and right roll gap deviations by increasing grinding efficiency by grinding non-contacting parts.

The work roll (rolling roll) used in the finishing mill of the hot rolling process is composed of a pair of top and bottom, and as the rolling work progresses, the rolling work is continuously made in contact with the hot rolling material passing between the work rolls. Perform. Due to the friction generated during the high temperature contact process, the wear of the work roll is gradually increased, resulting in a rough surface. Also, a rolling step is formed on the surface of the work roll between the roll plate and the non-plate parts to form an almost plate-like rolled material. It has a great influence on the surface and width thickness distribution of the product, causing one of the product defects.

FIG. 1 shows the relationship between the plate profile 10a which shows the wear and width direction thickness distribution of the conventional work rolls 10 and 10-1. The work rolls 10 and 10-1 are constituted by a pair of upper and lower sides, and a rolled material (not shown) passes therebetween. For convenience of explanation, the work roll 10-1 located below will be described as an example.                         

Looking at the profile (10a) showing a partially enlarged state of the work roll (10-1), it can be seen that the center portion (10b) of the profile (10a) is a state of deep wear of the wear step by the continuous rolling operation have. When rolling is performed using the work roll 10 in which the center portion 10b is worn in this way, the rolled material having a width smaller than the step (rolled plate in the drawing) shows a relatively good shape 20-2, but there is no problem. , Rolled material having a width exceeding the step is produced in the edge-up shape 20-1 as indicated at the bottom of the figure.

When the rolled material 20-1 having the edge-up shape is sent to the post-process (cold rolling), wrinkles of the edge part are severely generated, which is a cause of claim, and the work of the rolled material 20-1 is supplied even if supplied to the demand There is a lot of problems that can occur in the product is treated as defective.

An online roll grinding device 14 (ORG: Online Roll Grinder) has been introduced to reduce the cause of failure caused by the wear step of the work roll 10. An on-line roll grinding device 14 is installed inside the finishing mill to polish the surface of the work roll 10 or 10-1 during rolling so as to maintain a good state.

2 shows the structure and use state of the on-line roll grinding apparatus 14 installed adjacent to the work roll 10. The on-line roll grinding device 14 is controlled by the PCS 16, PLC 18, and so on, which are upper control units. Reference numeral 14-1 is an abrasive grinding wheel for grinding the work roll. The operating states of the PCS 16 and the PLC 18 are described later.

FIG. 3 shows a method of grinding the roll surface using the on-line roll grinding device 14 as described above. FIG. 3A shows that the surface of the work roll 10 is rough so that the surface of the rolled material 20-3 is not good. The front grinding method is carried out when not in use. The face grinding method uses an on-line roll grinding device 14 to provide a constant thickness of the portion indicated by the double-dotted line over the entire length from the center 10b of the work roll 10 to the both edge portions 10c and 10c-1. Grinding by the wear step (10d) to improve the surface quality of the rolled material (20-3).

In addition, Figure 3b is when the width reversal work of the rolling material 20, that is, when it is necessary to roll a large width of the rolling material 20-4 while rolling a rolling material 20-3 having a small width during the continuous rolling operation The step grinding method to be performed is shown. In this case, PCS (16) (Process Control Computer) calculates (predicts) the amount of wear on the roll surface according to the work load of the rolled material, and sends the appropriate amount of grinding information to the PLC (Program Logic Controller). Accordingly, the grinding operation is performed from the step start portion 10e to the both edge portions 10c and 10c-1 to remove the wear step 10d so that the edge up defective material 20-1 of the plate 20 is caused by the width reversal. Prevent production.

When the work roll 10 is polished by the grinding operation using the conventional on-line roll grinding device 14, regardless of the surface grinding or step grinding, grinding is not always required regardless of the width of the rolled material 20. The parts are also continuously ground, which reduces the grinding efficiency and consumes expensive abrasive grindstones 14-1, thereby increasing the cost.

Further, the grinding operation using the on-line roll grinding device 14 is a precise control operation, and the grinding amount of the surface of the work roll 10 is actually determined in micro units (µm) to perform grinding. However, due to the structure of the equipment, it is not 100% precisely controlled and has an error range of up to ± 20%.

4 shows a grinding error generated in the grinding operation using the conventional on-line roll grinding device 14. For example, the grinding operation was instructed by giving a grinding amount of 10 µm, and the machine error occurred differently on both sides, so that the driving side was ground + 20% (12 µm total), and the working side was -20% (8 µm total). ), The deviation of both ends is 4㎛ (12-8 = 4㎛). When the rolled material 20 is rolled using the rolled roll 10 ground as described above, the angle is deviated while one side 4 μm is in contact with the reinforcing roll 12, and the difference is 8 μm on both sides. When the amount of deviation is added together, a total of 16 μm of deviation occurs.

The deviation as described above is severely affected in the thin rolled material 20 of 2.3 mm or less, the work roll 10 accident due to poor quality or mailing fault, such as meandering or onion or medium wave in the plate-shaped rolling material 20 And cause back.

The grinding operation in the online roll grinding device 14 as described above will be described in detail with reference to FIGS. 3A and 3B as follows.

Grinding by the on-line roll grinding device 14 can set the grinding range according to the coordinate value and set the grinding depth by the number of oscillations (the operation of grinding the grinding wheel 14-1 to the left and right). It is supposed to be. If the surface state of the rolled material 20-3 is bad during the rolling operation, the PCS (16 in FIG. 2) calculates an appropriate grinding amount and gives an instruction to the PLC (18 in FIG. 2) according to the degree of the defect. Is polished according to the instruction information of the PCS 16.

In the case of front grinding, when the number of oscillations is determined only once by the PCS 16 and the work instruction is given to the PLC 18, the PLC 18 ends the grinding start point on one side (e.g., driving side) 10c. ) To the other end (10c-1) to uniformly polish and complete the work.

In the case of step grinding, the PCS determines the oscillation number according to the grinding start point and the amount of wear, and then the PLC 18 moves from the designated starting point (10e in FIG. 3b) to the edge (10c and 10c-1 in FIG. 3b). Grinding will complete the work.

At this time, the grinding range and the amount of grinding applied are determined by the following equation using the wear information of the work roll 10 in the PCS (16).

Front grinding

Gp (i) = dr × Nosc, (i = 1-jmax),

From here

Gp: grinding amount,

dr: One time grinding reference amount (the amount to be ground by one oscillation)

Nosc: Oscillation frequency (varies according to the amount of wear)

i: The width direction coordinate of a work roll. i is usually set in units of 5 mm (i: start point (drive side edge), jmax: endpoint (work side edge)). 1 to jmax means the entire working roll as the grinding range.

Step grinding

Gp (i) = int (Wc (i) / dr) × dr, (i = 1 ~ jmax)

Here, int () means taking only an integer value among the values in parentheses, and Wc (i) represents the amount of wear for each work roll width direction coordinate. In addition, 1 ~ jmax means the grinding range is covered for the entire work roll.

As described above, in the PLC 18 which directly receives the grinding amount from the PCS 16 and directly drives the on-line roll grinding device 14, it is set under the condition of grinding the entire length (1 to jmax) of the work roll 10 at all times. As a result, even when the PCS 16 is controlled so as not to grind the parts that do not need grinding, there is a problem that the grinding operation is performed on the parts that do not need grinding. Therefore, there is a need to simultaneously control the PCS 16 that calculates and outputs the grinding amount and the PLC 18 that directly performs the grinding.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to use the on-line roll grinding device to reduce the surface roughness and wear step of the work roll generated during the rolling operation of the raw material (rolling material) in a hot state rolling process. In the process of removing and grinding the contact and non-contact parts of the rolling material and the work roll, grinding of the roll grinding device considering the rolling material width, which can increase the grinding efficiency, reduce the amount of grinding grindstone, and reduce the roll gap deviation of the work roll. To provide a grinding position control method.

Another object of the present invention is to provide a grinding position control method of a roll grinding device in consideration of a rolled material width that can improve product quality and resolve consumer complaints by maintaining the surface state of the work roll at an optimum state at all times. .

The grinding position control method of the roll grinding apparatus in consideration of the rolling material width of this invention is a method of controlling the on-line roll grinding apparatus which removes the surface roughness and the abrasion step formed in the surface of a rolling mill work roll, The roll-wear amount according to a rolling operation Calculating a step amount of the wear part and the wear part in a control computer (PCS) and setting grinding conditions by comparing the set amount of reference wear and the step amount with respect to each; A second step of determining a reference grinding amount and calculating a grinding range and a width grinding amount when a front grinding operation is required; A third step of setting a reference grinding amount and calculating a grinding range and a width grinding direction when a step grinding operation is required; And a fourth step of outputting a control signal to the control device PLC to control the on-line roll grinding device according to the grinding range and the widthwise grinding amount set by the second or third step.

Hereinafter, the grinding position control method of the roll grinding apparatus in consideration of the rolled material width of the present invention will be described in detail with reference to the accompanying drawings.

The grinding position control method of the present invention improves the control method of the conventional on-line roll grinding device 14 to perform the work roll grinding to the optimum conditions, thereby increasing the grinding efficiency, the grinding grinding wheel usage, and reducing the left and right roll gap deviation. That's how you can do it. The hardware to which the method of the present invention is applied are conventionally used on-line roll grinding apparatus 14, PCS 16 and PLC 18 as shown in FIG.

9 is a flowchart of the control method of the present invention. First, it is determined whether the surface grinding or the step grinding is performed by using general operation state data for the surface grinding operation of the work roll 10. The operating state data is collected through the PCS 16 to calculate the amount of wear according to the amount of rolling work performed on each mill. The calculation of the amount of wear is performed in the conventional roll grinding operation, and a detailed description thereof will be omitted. Referring to FIG. 9 again, when the condition of "roll wear amount> reference wear amount" is satisfied, the front grinding operation is performed, and if "wear part step amount according to rolling> reference step amount" is set to perform step grinding operation. The step amount is also calculated according to the amount of work as the amount of wear.

As a result of the determination according to the determination condition, when it is determined that the on-line grinding is necessary by the on-line roll grinding apparatus 14, the PCS 16 determines the reference grinding amount dr, sets the grinding range, and calculates the grinding amount in the width direction. The grinding amount is set to 0 in the range other than the grinding range. The reference grinding amount dr is a value already set as the one-time grinding reference amount.

First, calculation of the range (grinding range) which needs grinding at the time of front grinding is calculated | required by the following formula. First, the required grinding range (gf_dis) is

It is calculated by gf_dis = (Width + Margin) / Pitch. From here

gf_dis: The required area for front grinding (calculated in coordinates of the work roll width in the control computer (PCS), that is, the required area for front grinding is the length corresponding to the section to be ground of the work roll measured in mm) ) Is converted to the unit width in the work roll width coordinates (for this, (Width + Margin) in mm is divided by the pitch, which is the distance between the work roll width coordinates).

Width: Roll width (measured in mm)

Margin: Margin and width margin (measured in mm)

Pitch means the interval between the work roll width coordinates. (The work roll width coordinates refer to the work roll width coordinates (i) described in the prior art. The gap is usually set in units of 5 mm.)

After calculating the required front grinding range as described above, the grinding start point is calculated. The grinding start point Sp is calculated by Sp = (jmax-gf_dis) / 2 (where jmax corresponds to the length of the work roll converted in coordinates of the work roll width direction, and the work roll width direction). The work roll width coordinate value calculated by subtracting the front grinding required range (gf_dis) converted into coordinates from jmax and dividing in half becomes the grinding start point.) After that, the grinding end point Ep is , Ep = Sp + gf_dis. After the start point and the end point are determined as described above, the grinding amount Gp (i) is calculated. Calculation of grinding amount is classified according to the grinding range, Gp (i) = 0, (i = 1 ~ Sp, Ep ~ jmax) (for front grinding) in the range that does not need grinding, and in the range where grinding is required Gp (i) = dr x Nosc, (i = Sp to Ep). As described above, the soft erased data required when full grinding is required is calculated.

On the other hand, the calculation of the range (grinding range) required for step grinding is similar to that of the starting point and the end point in the case of full-face grinding. Table value should be set. That is, during step grinding, the grinding start point and the end point must be kept constant at all times to prevent the concentrated grinding phenomenon of a specific part depending on the accumulated amount of wear. Margin applied value is larger than the grinding wheel 14-1 in consideration of the contact width of the grinding wheel 14-1 of the on-line roll grinding device 14 and the maximum margin before the riot, unlike front grinding. It is preferable to set.

The calculation of the range required for step grinding is performed by the following formula. First, the step grinding required range (gs_dis) is

Calculated by gs_dis = (Width + Margin) / Pitch (where gs_dis is calculated in coordinates of the work roll width in the control computer (PCS), ie the step grinding required area (gs_dis) is measured in mm The length corresponding to the section of the work roll to be ground is converted into the work roll width coordinate unit used in the control computer (PCS) (for this, (Width + Margin) in mm is converted to the pitch between the work roll width coordinates). It is divided).

Width: The width of the rolled material (measured in mm) is applied to the values in Table 1 according to the size of the width.

Margin (measured in mm): grinding wheel width + maximum roll width (300mm) (where maximum roll width is used for rolling rolls of small width during continuous rolling. The maximum width difference that can be tolerated in rolling reversal operations.

   Roll width   Roll width application value    More than 1200     Unapplied    900-1200      1200     600-900       900

If the width of the rolled material is 1200 or more, it is treated in the same manner as before without applying the method according to the present invention.

In addition, the method of calculating the start point and end point of step grinding is the same as that of face grinding. That is, the grinding start point Sp is calculated by Sp = (jmax-gs_dis) / 2, and the grinding end point Ep is calculated by Ep = Sp + gs_dis. The calculation method of grinding amount is as follows.

Gp (i) = 0 (l = 1 ~ Sp, Ep ~ jmax),

Gp (i) = int (Wc (i) / dr) × dr, (i = Sp ~ Ep)

Here, int () means that only integer values are taken from the values in parentheses, and Wc (i) represents the amount of wear by coordinates in the work roll width direction. As described above, the amount of grinding by the width direction of the work roll 10 calculated in consideration of the width of the rolled material 20 is 0 except for the grinding required section of the work roll 10. The data set for each of the front grinding or the step grinding are output to the PLC 18 as described above. The PLC 18 is a device that actually controls the on-line roll grinding device 14 to determine whether grinding is performed for each position in the width direction of the work roll 10 to perform grinding.

Table 2 shows a brief comparison of the working concept of the roll grinding apparatus according to the control method of the present invention and the conventional control method.

   division       Improvement     After improvement  Grinding start point The first grinding point in the roll center that is greater than zero The first grinding point in the roll center that is greater than zero  Grinding end point Always fix edge of work roll The grinding point is greater than zero and becomes zero

As shown in Table 2, the grinding required range is ground as in the prior art, but the grinding of the section where the grinding of the edge portion of the work roll 10 is not performed. This is shown in the drawings as follows.

First, referring to FIGS. 5A and 5B, FIG. 5 is a concept of front grinding and step grinding according to the method of the present invention, and FIG. 5A is a grinding state in which a margin 20a is given during front grinding. 5B shows a grinding state in a state where a margin 20b is given during step grinding. The margin 20a in FIG. 5A is applied when the width of the rolled material 20 is small, and the margin 20b in FIG. 5B is applied when the width of the rolled material 20 is large. The reason for giving such margins (20a, 20b) is to give operational stability due to the width change of the rolled material (20).                     

7 and 8 show the grinding position before and after improvement for the front grinding and step grinding, respectively. Referring to Figure 7, it can be seen that the grinding interval is set over the entire section from 1 to 401 (jmax) the grinding amount by 2㎛ by the conventional method. On the other hand, according to the control method of the present invention, the grinding amount is the same as 2㎛, it can be seen that the grinding for a length (including margin amount) slightly larger than the size of the rolled material. In addition, it can be seen that in the case of step grinding, the grinding section is reduced after the improvement compared to the grinding section before the improvement.

In addition, referring to Figure 6 of the roll gap of the work roll 20 controlled by the grinding position control method of the present invention as described above, the gap of the roll gap is up to 8㎛, the roll gap deviation is significantly improved compared to Figure 4 You can see that.

According to the present invention, it is possible to selectively work only the parts that need grinding in consideration of the width of the rolled material, and thus, the grinding efficiency can be increased, and the amount of grinding stones used during the conventional unnecessary grinding can be reduced, thereby reducing the cost. have. In addition, since the grinding operation is performed except for the two edges, there is an effect of preventing the faulty mailing ability by eliminating the left and right roll gap deviation factors caused by the on-line roll grinding device.

Claims (4)

In the method for controlling the on-line roll grinding device to remove the surface roughness and wear step formed on the surface of the rolling mill work roll, The amount of roll wear according to the rolling work and the step amount of the abrasion part are calculated by the control computer (PCS), and the standard grinding amount and the standard step amount and size set for each of them are compared to set whether to perform the front grinding operation or the step grinding operation. First step; A second step of determining a reference grinding amount and calculating a grinding amount to be ground along the grinding range and the width direction of the work roll when the front grinding operation is required; A third step of setting a reference grinding amount and calculating a grinding amount to be ground along the grinding range and the width direction of the work roll when a step grinding operation is required; And a fourth step of outputting a control signal to the control device PLC so as to control the on-line roll grinding device according to the grinding range set by the second or third step and the amount of grinding ground along the width direction of the work roll. Grinding position control method of the roll grinding apparatus in consideration of the width of the rolled material comprising a. The method of claim 1, In the second step, the calculation of the grinding range and the grinding amount for the front grinding calculates the front grinding required range gf_dis, calculates the grinding start point Sp and the grinding end point Ep, and calculates the grinding amount Gp. (i)), GF_dis needs to be ground grinding, gf_dis = (Width + Margin) / Pitch, (Here, gf_dis: required surface grinding, Width: width of rolled material, Margin: margin value considering meandering and width margin, and Pitch: distance between working roll width coordinates) The grinding start point Sp is Sp = (jmax-gf_dis) / 2, Grinding endpoint Ep, Ep = Sp + gf_dis, The grinding amount Gp (i) is calculated by Gp (i) = 0, (i = 1 to Sp, Ep to jmax), and Gp (i) = dr × Nosc (i = Sp to Ep), respectively. Grinding position control method considering the rolling material width to be considered. The method of claim 1, In the third step, the calculation of the grinding range and the widthwise grinding amount for the step grinding calculates the step grinding required range gs_dis, calculates the grinding start point Sp and the grinding end point Ep, and the grinding amount. (Gp (i)), The step grinding required range (gs_dis) is gs_dis = (Width + Margin) / Pitch, (Here, Width: rolled material width, Margin: grinding wheel width + rolled material width range maximum value (300mm)) Grinding start point Sp is Sp = (jmax-gs_dis) / 2, Grinding endpoint Ep, Ep = Sp + gs_dis, Grinding amount Gp (i) is Gp (i) = 0, (i = 1 to Sp, Ep to jmax), Gp (i) = int (Wc (i) / dr) × dr, (i = Sp to Ep Considering the width of the rolled material, wherein int () means to take only integer values among the values in parentheses, and Wc (i) represents the amount of wear for each coordinate in the width direction of the work roll. Grinding position control method of roll grinding device. The method of claim 3, If the width of the rolled material used to calculate the step grinding required range is 1200 mm or more according to the width of the rolled material to be rolled, the rolled material width applied value is not applied, and the If the width is 900 ~ 1200mm, the grinding position control method of the roll grinding device considering the width of the rolling material, characterized in that 1200mm, if the width of the rolling material is 600 ~ 900mm is applied.

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