JP2021053673A - Rolling method - Google Patents

Abstract

To provide a rolling method which can widen a rolling width reduced accompanying increase of materials to be rolled without stopping a rolling line.SOLUTION: A rolling method, which is performed using a rolling machine 4 that sequentially rolls a plurality of materials 7 to be rolled having width dimensions different from each other, includes: a rolled-material feeding-in step of feeding the materials 7 to be rolled to the rolling machine 4; a rolling step of rolling the fed-in materials 7 to be rolled with a work-roll R; and a grinding step of grinding a surface of the work-roll R with an inline roll grinding device G. The grinding step includes a step in which the inline roll grinding device G grinds a limited range (δ) that can be ground at a depth equal to a depth of an ablation by the rolled material 7, toward the outside in a work-roll shaft, on the surface of the work-roll R, from at least one width end in a direction of the work-roll shaft of a groove d formed resulting from an abrasion of the work-roll R when one material 7 to be rolled passes on the surface of the work-roll R during rolling processing, without stopping operation of the rolling machine 4.SELECTED DRAWING: Figure 7

Description

The present invention relates to a rolling method.

In rolling, a number of rolled materials mainly composed of metal are intermittently rolled while applying a load so that two work rolls (hereinafter referred to as "rolls") of the rolling mill are sandwiched from above and below. Therefore, the roll gradually wears as the rolled material passes through.

Then, as the wear occurs, grooves having a width corresponding to the width of the passed rolled material are formed on the surface of the roll.

The narrower and deeper the grooves in the roll, the less suitable the roll is for rolling. For example, when a rolled material having a width enough to straddle the groove of a roll in which a deep groove is formed is rolled with the roll, the rolled material after rolling becomes a so-called ear extension state, or the rolled material after rolling meanders. There was a problem that the quality of the rolled material was poor, the rolled material did not wind around the coiler, and the rolling line became inoperable.

Therefore, in order to solve such a problem, the rolls are replaced after rolling an appropriate number of rolled materials. In addition, a method of periodically shifting the roll is also adopted so that the grooves due to wear do not concentrate at the same position on the roll surface. Further, in order to reduce the frequency of roll replacement, the roll surface is ground by an in-line roll grinding device.

In Patent Document 1, while the rolling mill is rolling one rolled material, the roll corresponding to the through portion of the rolled material having the maximum width to be rolled after the rolled material by the in-line roll grinding device. An in-line roll grinding method has been proposed, which is a grinding method for grinding a wear step generated on the inner side of the maximum width on the surface and not grinding a step portion on the outer side thereof. That is, in the in-line roll grinding method shown in Patent Document 1, after the rolling mill has finished rolling one or a plurality of rolled materials, or while the rolling mill is rolling one rolled material, An in-line roll grinder grinds the surface of the roll from the width end of the groove to a width corresponding to the maximum width of the rolled material.

The time required for the rolling mill to roll one rolled material is usually about 30 seconds to 2 minutes. Further, the time (inter-pass time) from rolling one rolled material to starting rolling of the next rolled material is usually about several seconds to several minutes.

Here, assuming that the wear step in which the radial distance of the roll from the groove bottom of the roll groove d is 100 μm is an allowable wear step in terms of rolling quality, the radial distance of the roll from the groove bottom of the roll groove d is assumed. The axial distance between the wear steps where is 100 μm is defined as the “rollable width”.

JP-A-2002-102909

The in-line roll grinding method shown in Patent Document 1 always grinds the surface of a roll with an in-line roll grinding device from the width end of the groove to the width corresponding to the maximum width of the rolled material regardless of the actual width of the groove. Therefore, there is a significant limit to the depth at which grinding can be performed in a limited short time as described above, and in many cases it is not possible to realize a grinding depth that reaches the depth of the groove.

Therefore, in the in-line roll grinding method shown in Patent Document 1, the wear step cannot be sufficiently ground, and the rollable width is limited to the width of the groove formed by the rolled material rolled immediately before.

That is, when the in-line roll grinding method shown in Patent Document 1 is surely carried out, the time between passes must be extremely long, which significantly impairs productivity and is not realistic. In addition, when operating within the normal inter-pass time, the problem that the next rollable width is still limited to the width of the groove formed by the rolled material that has passed through the roll surface has been solved. Absent.

Therefore, an object of the present invention is to provide a rolling method for widening the rollable width, which decreases as the number of rolled rolls increases, without stopping the rolling line.

The rolling method according to the present invention is a rolling method performed by a rolling mill equipped with a work roll and an in-line roll grinding device and sequentially rolling a plurality of rolled materials having different width dimensions. The rolling method includes a rolling material feeding step of feeding the rolled material to the rolling mill, a rolling step of rolling the fed rolled material with the work roll, and in-line roll grinding of the surface of the work roll. Includes a grinding process, which grinds with an apparatus.

Then, the grinding process is formed by wearing the work roll when one of the rolled materials passes through the surface of the work roll during the rolling process without stopping the operating state of the rolling mill. As long as the in-line roll grinding device can grind from at least one width end in the work roll axial direction of the groove toward the outside in the work roll axial direction on the surface of the work roll at the same depth as the wear depth of the rolled material. Includes the step of grinding the rolled area.

According to the rolling method according to the present invention, at least in the work roll axial direction of the groove formed by the wear of the work roll when one of the rolled materials passes through the surface of the work roll during the rolling process. From one width end, the step of grinding a limited range in which the in-line roll grinding device can grind on the surface of the work roll toward the outside in the work roll axial direction at the same depth as the wear depth of the rolled material. Since it is included, the groove is surely widened in the limited range in the work roll axial direction at the same depth as the wear depth of the rolled material. Therefore, since the rollable width allowed in the next rolling is widened, even the next rolled material having a width wider than the width of the previous rolled material can be rolled. Since this step is performed every time the rolled material is rolled without stopping the operating state of the rolling mill, the rollable width, which has decreased as the number of rolled pieces increases, is widened for each rolled material. can do.

The limited range preferably has a length smaller than the difference in width between the rolled material having the minimum width and the rolled material having the maximum width in the work roll axial direction.

By grinding a length smaller than the width difference between the rolled material with the minimum width and the rolled material with the maximum width with an in-line roll grinder, the surface of the work roll is at the same depth as the wear depth of the rolled material. It becomes more reliable to grind. That is, the rollable width can be expanded more reliably.

Further, the limited range is the same depth as the wear depth of the rolled material in the work roll axial direction, after the rolled material has passed through the surface of the work roll and before the next rolled material has passed. It is preferable that the in-line roll grinding device has a length capable of grinding on the surface of the work roll in time.

In the work roll axial direction, the in-line roll grinding device has the same depth as the wear depth of the rolled material, which is the time after the rolled material has passed through the surface of the work roll and before the next rolled material has passed. By grinding the length that can be ground on the surface of the work roll with an in-line roll grinding device, it becomes more reliable to grind the surface of the work roll at the same depth as the wear depth of the rolled material. .. That is, the rollable width can be expanded more reliably.

Therefore, according to the rolling method according to the present invention, it is possible to widen the rollable width, which decreases as the number of rolled rolls increases, without stopping the rolling line.

It is a schematic diagram which shows the whole outline of a hot rolling line. FIG. 1A is a diagram showing the shape of a groove formed by the roll being worn when one rolled material passes through the surface of the roll during rolling. The horizontal axis is the roll axis direction, and the vertical axis is the roll radial direction. In this figure, y represents the amount of wear as a negative value. For example, when the amount of wear is 100 μm, the graph is plotted with y = -100 μm. (B) is a diagram showing a groove of a roll in which a deep groove is formed, and also shows a state of shape defect caused in the rolled material by rolling a rolled material having a width enough to straddle the groove with a roll. It is a figure. It is a figure which shows that the roll axial distance between the wear steps where the radial distance of a roll from the groove bottom of a roll groove is 100 μm is defined as "rollable width". (A) is a figure which shows typically the width end and the wear depth of the groove formed on the surface of a roll when one rolled material is rolled. FIG. 1B is a diagram schematically showing a grinding depth when grinding with an in-line roll grinding device from the width end of a groove to the maximum width of a rolled material by the conventional technique shown in Patent Document 1. It is a schematic perspective view which shows how the in-line roll grinding apparatus grinds the surface of a roll. It is a figure which shows typically the state that the limited range is ground by this invention from the width end of the groove formed on the surface of a roll when one rolled material is rolled. Limited by the present invention from the plurality of groove shapes formed on the roll surface after rolling a plurality of rolled materials in such an order that the plate width of the rolled material is narrowed for each one, and the width end of each groove. It is a figure which shows typically the state that the rolling-rolled area is ground. It is a figure which shows the so-called cyclic shift, and is the figure which shows typically how the two rolls are periodically shifted in the opposite directions in the axial direction. It is a graph which shows the result of having simulated the shape of the groove which changes with the increase of the number of rolled pieces by calculation in the comparative example 1. FIG. It is a graph which shows the result of having simulated the shape of the groove which changes with the increase of the number of rolled pieces by calculation in Comparative Example 2. It is a graph which shows the result of having simulated the shape of the groove which changes with the increase of the number of rolled pieces by calculation in the comparative example 3. FIG. It is a graph which shows the result of having simulated the shape of the groove which changes with the increase of the number of rolled rolls by calculation in the Example which concerns on this invention. It is a graph which shows the calculated rollable width for each number of rolls in Example 1 and Comparative Examples 1, 2 and 3 which concerns on this invention.

Preferred embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the description will be made on the premise of hot rolling. However, the present invention is not limited to a rolling method limited to hot rolling, but also includes a rolling method in cold rolling.

A typical hot rolling line is as shown in FIG. The hot rolling line 100 includes a plurality of heating furnaces 1, a plurality of rough rolling mills 2, a crop shear 3, a plurality of finishing rolling mills 4, a cooling zone 5, and a coiler 6. Roll. In the case of FIG. 1, the plurality of heating furnaces 1 are three, and are designated as No. 1, No. 2, and No. 3, respectively. In the case of FIG. 1, the plurality of rough rolling mills 2 are three, and are designated as R1, R2, and R3, respectively. In the case of FIG. 1, there are seven finishing rolling mills 4, and they are designated as F1, F2, F3, F4, F5, F6, and F7, respectively. In the case of FIG. 1, there are two coilers 6, and they are designated as DC1 and DC2, respectively.

One finishing rolling mill 4 (hereinafter referred to as "rolling mill 4") includes a roll R and an in-line roll grinding device G. The rolling mill 4 is a rolling mill that sequentially rolls a plurality of rolled materials 7 having different width dimensions from each other.

The roll R is generally a single tubular metal member. The roll R has a cylindrical barrel surface for contact with the rolled material 7. Two rolls R are provided on the rolling mill 4 so as to be vertically arranged in parallel. Then, the two rolls R apply a load to the rolled material 7 while bringing the rolled material 7 sent to the rolling mill 4 into contact with the barrel surface to roll the rolled material 7.

As the rolled material 7 passes through the surface of the roll R, a groove d having a width corresponding to the width of the passed rolled material 7 is formed on the surface of the roll R. For example, a groove d as shown in FIG. 2A is formed on the surface of the roll R. The shape of the groove d is usually concave in the radial direction of the roll and has a mortar-like shape. The groove d has a width end in the width direction thereof, that is, in the axial direction of the roll. The width end of the groove d is a wear step formed on the surface of the roll R due to the passage of the rolled material 7. The width end of the groove d may be a steep step or a gentle step depending on the rolling method.

As shown in FIG. 2B, when a rolled material 7 having a width enough to straddle the groove d of the roll R in which the deep groove d is formed is rolled by the roll R, the rolled material 7 after rolling is so-called ear extension. It becomes the state. Ear extension means that the edge in the width direction of the rolled material is rolled with a stronger load than the central part in the width direction of the rolled material, so that the extension length becomes longer and the center in the width direction of the rolled material. It is a state in which it rises or swells in the height direction from the part.

Here, from the shape of the roll surface (so-called roll profile), it is possible to define the width of the rolled material (hereinafter, referred to as "rollable width") in which the roll can be rolled without causing quality defects. I will explain it again. In the present specification, as shown in FIG. 3, a wear step in which the radial distance of the roll from the groove bottom of the groove d of the roll R is 100 μm is assumed to be an allowable wear step in terms of rolling quality, and the groove of the roll R is assumed. The axial distance between the wear steps where the radial distance of the roll from the groove bottom of d is 100 μm is defined as the “rollable width” W. That is, the rollable width W is the maximum value of the width allowed in the next rolled material 7 after one rolled material 7 has passed through the surface of the roll R.

The rollable width W is usually the width of the barrel surface of the roll R and maintains a constant width up to a constant number of rolls, and decreases as the number of rolls increases from the constant number. This is because rolling is possible over the entire barrel surface until the depth of the groove d exceeds 100 μm due to wear by the rolled material 7, but when the depth of the groove d exceeds 100 μm, the groove d is shaped like a mortar. This is because the width in the vicinity of the groove bottom becomes narrower as the number of rolled pieces increases due to the shape. Therefore, in order to widen the rollable width W, it is necessary to grind the width end of the groove d toward the outside in the axial direction of the roll.

FIG. 4A is a diagram schematically showing the width end and the wear depth of the groove d formed on the surface of the roll R when one rolled material 7 is rolled. The γ shown in FIG. 4A is the wear depth of the groove d formed on the surface of the roll R when one rolled material 7 is rolled.

The wear depth γ can be calculated by the following formula.

_{γ = F × V R × P} × L
Here, F is the advanced rate. V _R is the rotational speed of the rolls R. P is the rolling load per unit width. L is the length of the rolled material 7.

F can be calculated by the following formula.

_{F = (V 1 -V R)} / V R
Here, V ₁ is the exit speed of the rolled material 7 from the roll R.

The in-line roll grinding device G is a device that grinds the surface of the roll R by a grinding machine provided in the rolling mill 4 without replacing the roll. The in-line roll grinding device G is provided on the roll R or in the vicinity of the roll R. As shown in FIG. 5, the in-line roll grinding device G has a rotary grindstone T. The in-line roll grinding device G is a device that grinds the surface of the roll R by moving in the axial direction of the roll R while pressing the rotary grindstone T against the surface of the rotating roll R. The in-line roll grinding device G may grind the surface of the roll R during the time when the rolling mill 4 is rolling the rolled material 7, that is, when the rolled material 7 is passing through the surface of the roll R. The surface of the roll R may be ground in the time from the passage of one rolled material 7 to the time before the next rolled material 7 passes on the surface of the roll R (so-called inter-pass time).

The in-line roll grinding device G has a certain limit capacity with respect to the area and depth that can grind the roll R per unit time, that is, the volume, although it depends on the material of the roll R to be ground. That is, if the in-line roll grinding device G grinds a large area in a certain period of time, the grinding depth becomes shallow. On the other hand, if the in-line roll grinding device G grinds a narrow area in a certain period of time, the grinding depth becomes deeper. Further, in other words, if the in-line roll grinding device G grinds a constant grinding depth, the grinding area is proportional to the grinding time. Here, even if the diameter of the roll R is reduced by grinding to the depth of the groove d by the in-line roll grinding device G, the surface area of the roll R is hardly changed in proportion. That is, if the in-line roll grinding device G grinds a constant grinding depth, the grinding dimension in the axial direction of the roll is proportional to the grinding time.

Hereinafter, in the embodiment according to the present invention, a rolling method in which a plurality of rolled materials 7 having different width dimensions are rolled by the rolling mill 4 will be described.

The rolled material 7 is fed to the rolling mill 4 by a transport means provided in the hot rolling line 100 (rolled material feeding step).

The rolled material 7 sent to the rolling mill 4 is rolled by the roll R (rolling process). During the rolling process, the roll R that comes into contact with the rolled material 7 wears as the rolled material 7 passes through.

The surface of the roll R is ground by the in-line roll grinding device G (grinding process).

This grinding process is performed without stopping the operating state of the rolling mill 4. That is, this grinding step is performed every time the rolling mill 4 rolls a plurality of rolled materials 7. More specifically, this grinding step is performed in a time (so-called inter-pass time) after the specific rolled material 7 has passed through the surface of the roll R and before the next rolled material 7 has passed.

Further, as shown in FIG. 6, this grinding step is performed in the roll axial direction of the groove d formed by the wear of the roll R when one rolled material 7 passes through the surface of the roll R during the rolling step. Includes the step of grinding a limited area from at least one width end.

Here, the limited range is a range in which the in-line roll grinding device G can grind on the surface of the roll R toward the outside in the roll axis direction at the same depth as the wear depth γ of the rolled material 7. The length in the roll axis direction in the limited range is δ shown in FIG.

The length δ in the roll axis direction in a limited range is smaller than the difference in width between the rolled material 7 having the minimum width and the rolled material 7 having the maximum width.

Further, the length δ in the roll axis direction in a limited range has the same depth as the wear depth γ due to the rolled material 7, and the next rolled material 7 passes after the rolled material 7 passes through the surface of the roll R. The length in the roll axial direction that the in-line roll grinding device G can grind on the surface of the roll R before the rolling.

As shown in FIG. 6, in the grinding step, by including the step of grinding a limited range as described above, the groove d is surely rolled at the same depth as the wear depth γ of the rolled material 7. It is widened by the limited range (δ) in the axial direction. Therefore, since the rollable width W allowed in the next rolling is widened, even the next rolled material 7 having a width wider than the width of the previous rolled material 7 can be rolled. Since this grinding process is performed every time the rolled material 7 is rolled without stopping the operating state of the rolling mill 4, the rollable width W, which has decreased as the number of rolled pieces increases, is reduced to each rolled material 7. The width can be widened for each rolling.

The length δ in the roll axis direction in a limited range is the minimum because it is smaller than the width difference between the rolled material 7 having the minimum width and the rolled material 7 having the maximum width. The in-line roll grinding device G can grind a length smaller than the width difference between the rolled material 7 having a width and the rolled material 7 having the maximum width. As a result, it becomes more reliable to grind the surface of the roll R at the same depth as the wear depth γ of the rolled material 7. That is, the rollable width W can be widened more reliably.

Further, the length δ in the roll axis direction in a limited range has the same depth as the wear depth γ due to the rolled material 7, and the next rolled material 7 passes after the rolled material 7 passes through the surface of the roll R. Since the in-line roll grinding device G has a length capable of grinding on the surface of the roll R before the rolling material 7, the surface of the roll R is ground at the same depth as the wear depth γ of the rolled material 7. It becomes more certain to do. That is, the rollable width W can be widened more reliably.

Even when the grooves d formed by each of the plurality of rolled materials 7 having different widths overlap to form a stepped groove on the surface of the roll R, the rollable width W is determined by the present embodiment. It is widened. For example, as shown in FIG. 7, when the groove d1 is formed by the plurality of rolled materials 7 whose widths are gradually narrowed, and then the groove d2 is formed, the rollable width W seen from the groove d2 is determined. Before grinding the limited range (δ1), it is W20, but after grinding the limited range (δ1), it is widened to W21 = W20 + δ1 + δ1. Further, when the groove d3 is formed inside the groove d2 by the next rolled material 7, the rollable width W seen from the groove d3 is W30 before grinding in the limited range (δ2). After grinding the limited range (δ2), the width is widened to W31 = W30 + δ2 + δ2. In FIG. 7 and the above description, it is assumed that the rollable width W is defined by the width of the previous groove d, but in the present embodiment, a plurality of rolled materials 7 are used. Since the in-line roll grinding device G grinds a limited range (δ) for each rolling in the above, the rollable width W is the rollable width W regardless of which groove d in the stepped groove defines the rollable width W. It will still be widened.

This leads to the fact that the rollable width W can be widened even in the latter half of the coffin schedule described later, that is, the rolled material 7 wider than the previous rolled material 7 can be rolled in the next rolling order. That is, so-called schedule-free rolling is possible.

(Comparison example)
Next, in order to explain that the present invention is effective in comparison with the above-described embodiment of the present invention, a rolling method conventionally performed in rolling will be described.

(Comparative example 1: Coffin schedule)
There is a coffin schedule as a method for avoiding quality defects of the rolled material 7 after rolling due to the width end of the groove d of the roll R. The coffin schedule is a rolling cycle in which a plurality of rolled materials 7 to be rolled are arranged in chronological order after the roll is exchanged once and then before the next roll exchange. At that time, the rolled material 7 having the maximum width comes slightly before the middle roll of the rolling cycle, and the rolled material 7 having a wider width gradually comes from the first roll before the rolled material 7 having the maximum width. The rolling schedule is such that the rolled material 7 having a narrow width gradually comes after the large rolled material 7.

In the coffin schedule, only the rolled material 7 having a width narrower than the width of the previous rolled material 7 can be rolled after the rolled material 7 having the maximum width. Further, in the coffin schedule, the slabs must be arranged in such an order in the slab yard 10 before the slabs to be rolled materials are charged into the heating furnace 1 of the hot rolling line 100. It takes time and effort.

Therefore, schedule-free rolling is desired. Schedule-free rolling is a method of rolling an arbitrary rolled material regardless of the width of the rolled material 7. That is, in the schedule-free rolling, the rolling order can be liberalized.

(Comparative example 2: Maximum width in-line roll grinding of rolled material)
The in-line roll grinding method described in Patent Document 1, which is a method of grinding the surface of the roll R by the in-line roll grinding device G, is as described above. Patent Document 1 describes that the in-line roll grinding method is performed while the rolling mill 4 is rolling one rolled material 7, but one rolled material 7 is rolled. The time to pass through the machine 4 is about 30 seconds to 2 minutes.

If the surface of the roll R corresponding to the width difference between the rolled material 7 at that time and the rolled material 7 having the maximum width thereafter is to be ground in such a short time, the grinding ability of the in-line roll grinding device G is limited. , As shown in FIG. 4, _{it is possible to grind only to a depth of up to γ Gm} , and grinding is performed to reach the wear depth γ of the roll R when one rolled material 7 is rolled. I can't.

In other words, from the width end of the groove d formed by rolling a specific rolled material 7, the width of the rolled material 7 having the largest width among the subsequent rolled materials 7 (hereinafter, "rolled material maximum"). If the rolling mill 4 grinds the specific rolled material 7 with the in-line roll grinding device G while the rolling mill 4 is rolling the specific rolled material 7, the grinding capacity of the in-line roll grinding device G limits the grinding ability. The depth reaches only up to _{γ Gm} , as shown in FIG. 4 (b). That is, γ _Gm <γ, and the rollable width W is not widened.

This is the time from the time after the previous rolling material 7 is rolled to the time before the next rolling material 7 is rolled by the in-line roll grinding device G in the rolling mill 4 by applying the in-line roll grinding method shown in Patent Document 1. The same applies to grinding at (so-called inter-pass time). This is because the time between passes is also about several seconds to several minutes.

Therefore, in the in-line roll grinding method shown in Patent Document 1, the rollable width W of the next rolled material 7 is still limited to the width of the groove d formed by the rolled material 7 that has passed through the surface of the roll R. The problem of being rolled has not been solved.

Hereinafter, the rolling method including the in-line roll grinding method shown in Patent Document 1 is referred to as "rolled material maximum width in-line roll grinding" in the present specification. As described above, the rolled material maximum width in-line roll grinding could not sufficiently grind the wear step as shown in FIG. 4, and the rollable width W was formed by the rolled material 7 rolled immediately before. It is limited to the width of the groove d.

(Comparative example 3: Cyclic shift)
There is a cyclic shift as a method of dispersing the groove d formed by the rolled material 7 that has passed through the surface of the roll R in the width direction (axial direction of the roll). As shown in FIG. 8, the cyclic shift is a method of periodically shifting the two rolls R held up and down by one rolling mill 4 in the roll axis direction and in opposite directions to each other. By cyclic shift, the groove d formed by the rolled material 7 that has passed through the surface of the roll R can be dispersed in the width direction (roll axis direction), and the wear step can be changed from a steep shape to a gentle shape. Can be done.

However, even in the cyclic shift, the rolled material 7 passes through a certain range on the surface of the roll R for each rolling, and there is a problem that the rollable width W cannot be greatly expanded from the range.

(simulation result)
Hereinafter, the results of simulating the embodiments according to the present invention (hereinafter referred to as “Examples”) and the above Comparative Examples 1, 2 and 3 based on calculations will be described with reference to the drawings. In the simulation in the example, the calculation was made assuming that the rolling method of the example was performed after performing the coffin schedule and the cyclic shift.

FIG. 9 shows the shape of the groove d in Comparative Example 1 in relation to the number of rolled rolls, the wear depth (wear amount), and the roll axial direction. From FIG. 9, it can be seen that in the coffin schedule, the groove d becomes deeper as the number of rolled pieces increases, and the width end of the groove d becomes steep.

FIG. 10 shows the shape of the groove d in Comparative Example 2 in relation to the number of rolled rolls, the wear depth (wear amount), and the roll axial direction. From FIG. 10, in the in-line roll grinding with the maximum width of the rolled material, the groove d becomes deeper as the number of rolled pieces increases, and the width end of the groove d becomes stepped in the latter half of the number of rolled pieces, so that the wear step cannot be sufficiently ground. Understand.

FIG. 11 shows the shape of the groove d in Comparative Example 3 in relation to the number of rolled rolls, the wear depth (wear amount), and the roll axis direction. From FIG. 11, it can be seen that in the cyclic shift, the groove d becomes deeper in a certain range as the number of rolling rolls progresses, and the width end of the groove d has a gentle shape.

FIG. 12 shows the shape of the groove d in the example in relation to the number of rolled rolls, the wear depth (wear amount), and the roll axis direction. From FIG. 12, it can be seen that in the rolling method of the embodiment, the groove d becomes deeper in a certain range as the number of rolled pieces increases, and the width end of the groove d has a gentle shape. In particular, it can be seen that the example has a wider range than that of the comparative example 3 with respect to a certain range forming the groove bottom. This indicates that the rollable width W is wider than that of Comparative Example 3 in the examples.

From the above calculation results for the shapes of the grooves d of Comparative Examples 1, 2, 3 and Examples, the results of calculating the rollable width W of Comparative Examples 1, 2, 3 and Examples in relation to the number of rolls are obtained. It is shown in FIG.

As shown in FIG. 13, in the first half of the rolling cycle in which the amount of wear is small and smaller than the allowable wear step, the rollable width coincides with the roll barrel width regardless of the rolling method. On the other hand, in the latter half of the rolling cycle in which the number of rolls increases and the amount of wear becomes larger than the allowable wear step, the rollable width W is widened for all of Comparative Examples 1, 2 and 3. You can see that.

(Modification example)
The above is the description of the present embodiment, but the technical scope of the present invention is not limited to the present embodiment. That is, various changes are allowed in the present embodiment, and some examples of the changes are described below.

In the above description, the in-line roll grinding device G is used to grind the width ends located on both sides of the groove d. However, even if either one of the width ends of the groove d is ground, the rollable width W Is widened. Further, even when the width ends located on both sides of the groove d are ground by the in-line roll grinding device G, the area of a limited range to be ground on one end side and the limit to be ground on the other end side. The area of the specified range does not necessarily have to be the same.

The limited area does not have to be the same area for each rolling. That is, the length δ in the roll axis direction in a limited range does not have to be constant for each rolling.

In the above, the length δ in the roll axis direction in a limited range has the same depth as the wear depth γ due to the rolled material 7, and the next rolled material 7 after the rolled material 7 has passed through the surface of the roll R. Although it is assumed that the in-line roll grinding device G has a length in the roll axial direction capable of grinding on the surface of the roll R in the time before passing, the length may be even smaller than that length. ..

In the above description, it has been described that the grinding process is performed after the specific rolled material 7 has passed through the surface of the roll R and before the next rolled material 7 has passed. However, the grinding process is performed by the rolling mill. 4 may be performed while the rolled material 7 is being rolled. That is, it may be performed during the time when the rolled material 7 is passing through the surface of the roll R.

Further, the grinding step may be performed at a time from when the specific rolled material 7 is fed to the rolling mill 4 until when the next rolled material 7 is fed.

The present invention is not limited to rolling methods in hot rolling. That is, the present invention is also effective in the rolling method in cold rolling.

1 Heating furnace 2 Rough rolling mill 3 Crop shear 4 (Finishing) rolling mill 5 Cooling zone 6 Koyler 7 Rolled material 10 Slab yard 100 Rolling line d Groove R (Work) Roll G In-line roll grinding device T Rotating grindstone γ 1 rolling Abrasion depth of grooves formed on the surface of the roll when the material is rolled γ _Gm Grinding depth when the roll surface corresponding to the width difference between the rolled material at that time and the rolled material with the maximum width thereafter is ground. δ Length in the roll axis direction in a limited range W Rollable width

Claims (3)

In a rolling method performed by a rolling mill equipped with a work roll and an in-line roll grinding device and sequentially rolling a plurality of rolled materials having different width dimensions from each other.
The rolling method is
The rolling material feeding process of feeding the rolled material to the rolling mill, and
A rolling process in which the fed rolled material is rolled with the work roll, and
A grinding process in which the surface of the work roll is ground by the in-line roll grinding device, and
Including
The grinding step is a groove formed by the work roll being worn when one of the rolled materials passes through the surface of the work roll during the rolling step without stopping the operating state of the rolling mill. Limited that the in-line roll grinder can grind from at least one width end in the work roll axial direction toward the outside in the work roll axial direction on the surface of the work roll at the same depth as the wear depth of the rolled material. Including the process of grinding the area,
Rolling method. The limited range has a length smaller than the width difference between the rolled material having the minimum width and the rolled material having the maximum width in the work roll axial direction.
The rolling method according to claim 1. The limited range is the same depth as the wear depth of the rolled material in the work roll axial direction, from the time when the rolled material passes through the surface of the work roll to the time before the next rolled material passes. The in-line roll grinding device has a length capable of grinding on the surface of the work roll.
The rolling method according to claim 1 or 2.

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