KR102579271B1 - Rolling mill, rolling method, and work roll operation method - Google Patents

Abstract

It is a 4 to 6-stage rolling mill equipped with two work rolls arranged on the upper and lower sides with a mailing line in between, and at least one backup roll for each of the two work rolls, and the two work rolls are , the axial length and roll neck shape are the same, so they can be replaced. Among the two work rolls, one work roll, the first work roll, is not rotationally driven, and the other work roll, the second work roll, is rotationally driven. It is configured so that the ratio (L ₁ /D _w1 ) of the body length L ₁ and the diameter D _w1 of the first work roll satisfies 4.0≤L ₁ /D _w1 ≤7.0, and the body of the second work roll It is characterized in that the ratio of the length L ₂ and the diameter D _w2 (L ₂ /D _w2 ) satisfies 4.0≤L ₂ /D _w2 ≤7.0.

Description

Rolling mill, rolling method, and work roll operation method

The present invention relates to a rolling mill, a rolling method, and a method of operating a work roll.

A 4- to 6-stage rolling mill equipped with two work rolls arranged on the upper and lower sides with a plate line in between, and at least one backup roll for each of the two work rolls, is already well known (e.g. , Patent Document 1 and Patent Document 2).

And in recent years, for the purpose of increasing the strength and reducing the weight of automobiles, etc., there has been a demand for rolling mills capable of rolling harder high-tensile steel (such as high-strength steel with a tensile strength of 1300 MPa or more). Therefore, by providing work rolls with a smaller diameter than before, hard materials can be rolled at a higher reduction ratio, and also, by having a drive device that can withstand high torque even when using work rolls with such a small diameter. A rolling mill is becoming necessary.

Japanese Patent No. 3290975 Publication Japanese Patent No. 4928653 Publication

As the work roll diameter of the rolling mill becomes smaller, the distance between the centers of the work rolls becomes shorter, so when driving both the upper and lower work rolls to rotate, it is necessary to reduce the diameter of each spindle connected to both work rolls. Therefore, when a conventional crosspin type universal joint is used as a spindle for a small-diameter work roll, there is a limit to increasing the strength of the spindle (increasing the diameter), making it impossible to secure the strength of the spindle for high torque driving. There wasn't.

In order to ensure the strength of the spindle, if a gear spindle that is stronger and more expensive than a conventional spindle is used, the cost increases, and the tilt angle during operation is up to about 1.5° (conventionally, the maximum is about 8° to 10°). ), so length was required to secure the roll opening, which was a factor that hindered the compactization of the rolling mill. More importantly, the smaller the work roll, the higher the rotation speed, and the longer the spindle length, the greater the vibration, which causes problems affecting product precision.

Additionally, when the power of one electric motor is distributed by a distribution reducer to drive both work rolls, torque circulation may occur and excessive torque may be concentrated on one spindle. To prevent this, strict roll diameter difference management has become necessary.

The present invention was made in view of these problems, and its purpose is to have a drive device that can withstand high torque even when using small-diameter work rolls, to achieve a higher reduction ratio, and to reduce costs. The object is to provide a restrained rolling mill.

The main invention for achieving the above object is a 4 to 6-stage work roll comprising two work rolls arranged at the upper and lower sides with a mail order line in between, and at least one backup roll for each of the two work rolls. is a rolling mill, and the two work rolls have the same axial length and the shape of the roll neck, so they can be replaced with each other. Among the two work rolls, the first work roll, which is one work roll, is not driven to rotate, and the other work roll is not driven to rotate. The second work roll, which is the work roll, is configured to be driven in rotation, and the ratio (L ₁ /D _w1 ) of the body length L ₁ and the diameter D _{w 1} of the first work roll satisfies 4.0 ≤ L ₁ /D _{w 1} ≤ 7.0. In addition, the ratio of the body length L ₂ and the diameter D _w2 of the second work roll (L ₂ /D _w2 ) is a rolling mill characterized in that it satisfies 4.0≤L ₂ /D _w2 ≤7.0.

Other features of the present invention will become clear from the description of this specification and the accompanying drawings.

According to the present invention, it becomes possible to provide a rolling mill that has a drive device that can withstand high torque even when using small-diameter work rolls, realizes a higher reduction ratio, and further reduces costs.

1 is a side schematic view of a rolling mill 1 according to the first embodiment.
Figure 2 is a cross-sectional schematic diagram for explaining the force applied to the work roll 10 during rolling.
FIG. 3 is an enlarged view of part X of FIG. 1 and is a view showing the roll neck Rn of the work roll 10.
Figure 4 is a graph showing the relationship between the maximum plate width of the rolling equipment and the single drive closed angle diameter and nominal diameter of the work roll 10.
Figure 5 is a table showing each parameter for the new work roll diameter Ds and the closed work roll diameter Dm determined based on the maximum plate width of each equipment specification.
FIG. 6 shows the horizontal axis of FIG. 4 as the body length L of the work roll 10, and the work roll new diameter Ds (triangular point) and the work roll closed angle diameter Dm (round point) of Application Examples 1 to 9 shown in FIG. 5, This is a diagram plotting the ratio L/D=4 and L/D=7 between the fuselage length L and the diameter of the work roll.
Figure 7 is a cross-sectional schematic diagram for explaining the force applied to the first work roll 10a during rolling with the first work roll 10a offset toward the entry side.
Figure 8 is a cross-sectional view of the offset device 100.
Figure 9 is a diagram showing the offset control unit 130.
Figure 10 shows the results of calculating horizontal force F ₁ and horizontal force F ₂ under both conditions of presence and absence of offset.
Figure 11 is a table showing the parameters for the determined new work roll diameter Ds and work roll closed angle diameter Dm in a rolling mill of a type that shifts the work roll in the axial direction.
Figure 12 shows the type of rolling mill that shifts the work roll in the axial direction, where the horizontal axis is indicated by the body length L of the work roll 10, and the new work roll diameter Ds (triangular point) of Application Examples 1 to 9 shown in Figure 11. This is a diagram plotting the work roll closed diameter Dm (round point), and the ratio L/D=4 and L/D=7 of the fuselage length and the diameter of the work roll.

At least the following matters become clear through the description of this specification and the accompanying drawings.

It is a 4 to 6-stage rolling mill equipped with two work rolls arranged on the upper and lower sides with a mailing line in between, and at least one backup roll for each of the two work rolls, and the two work rolls are , the axial length and roll neck shape are the same, so they can be replaced. Among the two work rolls, one work roll, the first work roll, is not rotationally driven, and the other work roll, the second work roll, is rotationally driven. It is configured so that the ratio (L ₁ /D _w1 ) of the body length L ₁ and the diameter D _w1 of the first work roll satisfies 4.0≤L ₁ /D _w1 ≤7.0, and the body of the second work roll A rolling mill characterized in that the ratio of the length L ₂ and the diameter D _w2 (L ₂ /D _w2 ) satisfies 4.0≤L ₂ /D _w2 ≤7.0.

With such a rolling mill, it is possible to create a driving device that can withstand high torque even when using small-diameter work rolls, and it is also possible to provide a rolling mill with reduced costs.

In such a rolling mill, it is preferable to have an electric motor whose rotating shaft is connected only to the second work roll.

With such a rolling mill, it becomes possible to easily realize a one-side driven rolling mill in which only the second work roll is driven and rotated.

In such a rolling mill, the diameter of the two work rolls is preferably within the range of 200 mm to 450 mm.

According to such a rolling mill, it is possible to provide a rolling mill with a work roll diameter between 200 mm and 450 mm, a drive device that can withstand high torque even when a small diameter work roll is used, and the rolling mill with reduced costs. It becomes.

In such a rolling mill, it is preferable that the maximum design width of the rolled material to be rolled is within the range of 900 mm to 2000 mm.

According to such a rolling mill, the work roll body length is between 900 mm and 2000 mm, so that a driving device can be used that can withstand high torque even when a small diameter work roll is used, and a rolling mill with reduced costs is provided. It becomes possible to do so.

In such a rolling mill, it is preferable that the ratio of the closed angle diameter of each of the two work rolls to the nominal diameter is 0.8 or more.

Such a rolling mill not only contributes to extending the life of the work roll, but also makes it possible to increase the effect of reducing the rolling load and torque due to single-side drive different-diameter roll rolling.

Such a rolling mill includes a roll offset device configured to offset only the first work roll among the two work rolls by a predetermined offset amount in a horizontal direction on an entrance side in the rolling direction of the rolling mill; and a roll offset device configured to offset the first work roll by a predetermined offset amount. It is preferable to further include an offset amount control device configured to control the roll offset device to offset the first work roll to the entrance side by this amount.

With such a rolling mill, the horizontal force can be reduced, making work rolls smaller in diameter and rolling with a higher reduction ratio possible.

This rolling method using such a rolling mill preferably includes performing rolling by offsetting the first work roll by the predetermined offset amount in a horizontal direction on the entrance side in the rolling direction of the rolling mill.

According to this rolling method, the horizontal force can be reduced, making it possible to reduce the diameter of the work roll and roll with a higher reduction ratio.

This is a work roll operation method of such a rolling mill, in which two work rolls and a plurality of roll spare parts having the same axial length and roll neck shape are separated and stored after being used in the rolling mill for a certain period of time,

Among the plurality of separately stored roll spare parts, take out two roll spare parts, one having a diameter-to-nominal diameter ratio larger than a predetermined standard value and one smaller than the predetermined standard value;

Of the two rolled spare parts taken out, it is preferable to exchange the smaller diameter one with the first work roll and the larger diameter one with the second work roll.

According to this method of operating a work roll of a rolling mill, different-diameter roll rolling can always be performed, making it possible to increase the effect of reducing the rolling load or torque by different-diameter roll rolling.

This is a work roll operation method of such a rolling mill, and it is desirable that the standard value is 0.9. Additionally, it is preferable to discard the first work roll when the ratio (D _w1 /D _w1N ) of the diameter of the first work roll to the nominal diameter reaches 0.8.

According to this method of operating a work roll of a rolling mill, different-diameter roll rolling can be performed reliably at all times while suppressing the occurrence of problems associated with a smaller diameter of the work roll, thereby achieving the effect of reducing the rolling load and torque due to different-diameter roll rolling. In addition to being able to increase the cost, it is possible to obtain the effect of cost suppression through long-term use (longer lifespan) of the work roll.

===First Embodiment===

The rolling mill 1 according to the first embodiment is an apparatus that rolls the rolled material 3 and produces a strip-shaped (belt-shaped) rolled material 3 rolled to a desired plate thickness.

1 is a schematic side view of the rolling mill 1 according to the first embodiment. In the side view, the horizontal direction of the page is referred to as the “axial direction,” the left (right) side of the page is referred to as “left (right),” and the vertical direction (vertical direction) of the page is referred to as the “up and down direction.” The upper (lower) side of the ground is called “upper (lower)”. In addition, “left” in FIG. 1 corresponds to the drive side in FIG. 9 described later, and “right” corresponds to the operation side.

As shown in FIG. 1, the rolling mill 1 includes a work roll 10, a backup roll 12, a spindle 5, a drive unit 7, a housing 8, and a neck bearing (as shown). omitted) is provided.

In addition, the rolling mill 1 is a four-stage rolling mill 1, and two work rolls 10 are disposed on the upper and lower sides across the distribution line, and for each of the two work rolls 10, One backup roll (12) is provided.

The two work rolls 10 are an upper and lower pair of first work rolls 10a and second work rolls 10b, with the first work roll 10a on the upper side and the second work roll 10b on the lower side. It is provided. And, neck bearings are fitted to both left and right ends in the axial direction of the first work roll 10a and the second work roll 10b, respectively, and the first work roll 10a and the second work roll 10b are, It is rotatably supported on a roll chock (not shown) provided in the housing 8 via a neck bearing. The material to be rolled 3 is rolled through the gap between the rotatable first work roll 10a and the second work roll 10b.

A drive unit 7 is connected to the left end of the second work roll 10b via a spindle 5. That is, the rotation shaft of the electric motor 7a is connected only to the second work roll 10b. In other words, among the two work rolls 10, the first work roll 10a, which is the work roll 10 on one side, is not driven to rotate, and the second work roll 10b, which is the work roll 10 on the other side, is not driven to rotate. It is configured to be driven in rotation.

That is, during rolling, the second work roll 10b rotates by the drive unit 7 and conveys the rolled material 3 from the upstream side to the downstream side in the conveyance direction, and the first work roll 10a , it rotates according to the accompanying rotation accompanying the conveyance of the rolled material 3.

This difference in operation causes a difference in the rotation speed of the first work roll 10a and the second work roll 10b during rolling. That is, the rotation speed of the first work roll 10a is smaller than the rotation speed of the second work roll 10b. Therefore, even when the first work roll 10a and the second work roll 10b perform rolling at the same diameter (same state), the neutral point of the upper and lower work rolls (the point where the speeds of the roll and the rolled material match) Due to the difference in position, there is an area where the shear force caused by friction between the roll and the material is canceled out at the top and bottom, so the rolling load and torque are reduced compared to a typical vertical roll driven rolling mill.

The body length L ₁ of the first work roll 10a and the body length L ₂ of the second work roll 10b have the same dimensions, and the shape of the roll neck Rn (see FIG. 3) where the neck bearings at both left and right ends are installed is also the same. do. Therefore, it is possible to separate the first work roll 10a (second work roll 10b) and install it on the second work roll 10b (first work roll 10a). That is, the first work roll 10a and the second work roll 10b have the same axial length and the shape of the roll neck Rn, so they can be replaced with each other.

The backup roll 12 is composed of a first backup roll 12a that backs up the first work roll 10a, and a second backup roll 12b that backs up the second work roll 10b. The first backup roll 12a (second backup roll 12b) contacts the upper (lower) side of the first work roll 10a (second work roll 10b), and during rolling, the first work roll 12a (second backup roll 12b) It is a bending suppression member to prevent the roll 10a (second work roll 10b) from bending upward (lower).

The spindle 5 is a shaft member for transmitting the rotation of the drive unit 7 to the second work roll 10b, and is a general cross pin type universal joint (all-purpose joint), with one end connected to the drive unit 7. They are connected, and the other end is connected to the second work roll 10b.

The drive unit 7 has an electric motor 7a, a gear coupling 7b, and a reducer 7c. The electric motor 7a is a so-called motor that converts electric power into rotational motion, and is a power source that rotates the second work roll 10b during rolling. The gear coupling 7b is a joint member that transmits the rotation of the electric motor 7a to the reducer 7c, and the reducer 7c is a device that reduces the rotational speed of the electric motor 7a and increases torque.

The roll chock (not shown) provided in the housing 8 is a member for supporting the work roll 10 and the backup roll 12, and as described above, the work roll 10 can be rotated via a neck bearing. I am strongly supporting it.

The neck bearing is a member for accurately and smoothly rotating the work roll 10, and is formed to fit only the shape of the roll neck Rn of the work roll 10.

<<<How to use Workroll (10)>>>

Next, how to use the work roll 10 will be described. In this embodiment, the ratio (L ₁ /D _w1 ) between the body length L ₁ and the diameter D _w1 of the first work roll 10a satisfies 4.0≤L ₁ /D _w1 ≤7.0, and also the second work roll 10a The first work roll (10a) and the second work roll (10b) so that the ratio (L ₂ /D _w2 ) of the body length L ₂ and the diameter D _w2 of the roll 10b satisfies 4.0≤L ₂ /D _w2 ≤7.0 ) is used.

As described above, the body length L ₁ of the first work roll 10a and the body length L ₂ of the second work roll 10b have the same dimensions, and both have the maximum sheet width according to the specifications of the rolling equipment (the maximum plate width that can be rolled with the rolling equipment). It refers to the maximum plate width that can be rolled, and is usually determined based on the maximum plate width that can be rolled by the rolling mill (1). Generally, it is a value obtained by adding about 100 mm to 150 mm to the maximum plate width. For example, in the case of a maximum plate width of 1250 mm, 1400 mm added by 150 mm becomes the value of the fuselage length L ₁ and the fuselage length L ₂ .

In addition, the diameter D _w1 of the first work roll 10a and the diameter D _w2 of the second work roll 10b are both worn out during rolling and become smaller. In other words, the value of L ₁ /D _w1 (L ₂ /D _w2 ) during rolling is a variable of diameter D _W1 (diameter D _W2 ) since the body length L ₁ (body length L ₂ ) does not change during rolling. , the minimum value when the work roll 10 is new, and the maximum value when the work roll 10 is discarded (when the diameter becomes smaller due to wear and needs to be discarded).

Therefore, using the first work roll 10a and the second work roll 10b to satisfy 4.0≤L ₁ /D _w1 ≤7.0 and 4.0≤L ₂ /D _w2 ≤7.0 means that the work roll 10 The work roll 10 is used so that L ₁ /D _w1 (L ₂ /D _w2 ) from the time of new product to the time of disposal is within the above range (i.e., 4.0 or more and 7.0 or less). Below, these matters will be explained in detail.

<Force applied to the work roll (10)>

In order to calculate the stress at the weakest part of the work roll 10, first, the force applied to the work roll 10 during rolling is calculated. FIG. 2 is a cross-sectional schematic diagram for explaining the force applied to the work roll 10 during rolling. In the cross-sectional view, the transverse direction (horizontal direction) of the paper is called the “conveyance direction”, one side (the other side) is called “upstream (downstream)” or “entrance (outlet)”, and the vertical direction of the paper (vertical) The direction) is referred to as the “up and down direction,” and the upper (lower) side is referred to as “up (down).”

In this embodiment, only the second work roll 10b is driven and the first work roll 10a is not driven, so no torque due to the rolling reaction force is generated in the first work roll 10a. That is, the rolling reaction force Pr of the first work roll 10a acts in the direction from the center of the work roll contact arc length Lp to the rotation center of the first work roll 10a, as shown in FIG. 2.

The vertical component of the rolling reaction force Pr of the first work roll 10a is supported by the first backup roll 12a, and the horizontal force Ph, which is the horizontal component of the rolling reaction force Pr, is supported by the work roll chock through the neck bearing. .

In addition, since torque due to rolling reaction force is generated in the driven and rotating work roll 10, as shown in the rolling reaction force shown in the second work roll 10b in FIG. 2 (lower arrow in FIG. 2), the work roll contact arc The rolling reaction force acts only in the vertical direction from a point between the center of the length Lp and the outlet of the contact arc length.

Accordingly, when both the first work roll 10a and the second work roll 10b are driven to rotate, the above-described horizontal force Ph does not occur. That is, compared to the case of rolling by a general rolling mill in which both the upper and lower work rolls 10 are driven, in rolling with one side drive as in the present embodiment, the generation of the horizontal force Ph is a barrier to reducing the diameter of the work rolls 10. do.

Therefore, when the work roll 10 drives only one side, the horizontal force Ph of the rolling reaction force Pr is used as a standard for designing the diameter of the work roll 10. And, the horizontal force Ph of the rolling reaction force Pr can be expressed by the following equation from the work roll contact arc length Lp and the rolling reaction force Pr.

Work roll contact arc length: Lp

ΔH: Reduction amount per pass. The value of entrance plate thickness H1 - exit plate thickness H2.

Rolling reaction force: Pr

Pr=C·km·b·√(1/2·D _W1 ·ΔH)

C: Coefficient of reduction force due to friction coefficient, tension, etc.

km: average deformation resistance of the rolled material (3)

b: Plate width (axial dimension) of the rolled material (3)

Horizontal force of rolling reaction Pr: Ph

If the diameters of the first work roll 10a and the second work roll 10b are the same (D _w1 = D _W2 ), the horizontal force Ph of the rolling reaction force Pr can be expressed by the following equation.

As shown in the equation (1) above, the horizontal force Ph of the rolling reaction force Pr is simply not limited to the diameter of the work roll 10, and is the coefficient of reduction force C, the average deformation resistance km, the plate width b, and the reduction force. It can be expressed using the quantity ΔH.

<Stress at the weakest part of the work roll (10)>

Next, the stress at the weakest part of the work roll 10 is determined. The weakest part referred to here is the part where problems such as cracks are most likely to occur in the work roll 10 during rolling.

FIG. 3 is an enlarged view of portion X of FIG. 1 and is a view showing the roll neck Rn of the work roll 10. The weakest part of the work roll 10 is present in the roll neck Rn, and is a stepped shoulder round part spaced inward by the distance Ln from the center (Z in FIG. 3) in the axial direction of the neck bearing to the weakest part (in FIG. 3). becomes Y).

And, when the work roll 10 is driven on only one side, half of the horizontal force Ph (half of the work roll 10 is supported by the roll chocks on the left and right) and the maximum bending force Fb (of the work roll 10) The resultant force Fc (force applied to suppress bending during rolling) acts on the weakest part of the work roll 10.

The maximum bending force Fb acting on the roll choke can be expressed by the following equation from empirical values.

The resultant force Fc acting on the roll choke can be expressed by the following equation.

The stress σ _n acting on the weakest part of the work roll 10 can be expressed by the following equation.

α: Stress concentration coefficient at the weakest point

Zn: Section modulus of the weakest part

kn: The ratio of the diameter of the weakest part to the diameter (nominal diameter) D _w1N when the work roll is new.

<Calculation of single drive closed angle diameter and nominal diameter>

Next, in designing the diameter of the work roll 10, the single drive closed angle diameter and the nominal diameter that serve as the standard for the diameter of the work roll 10 are obtained. In this specification, the nominal diameter of the work roll means the diameter of the work roll when it is new before use, and the closed angle diameter of the work roll means the diameter of the work roll when the work roll that has been worn through use is discarded. .

The one-side drive closed angle mirror is a work roll calculated by focusing on the horizontal force Ph generated during one-side drive and setting the maximum bending force Fb to zero (using the horizontal force Ph during one-side drive instead of the resultant force Fc in equation (3)). This is the closed angle diameter of (10), and the nominal diameter corresponding to this is the new diameter of the work roll 10 calculated from the single drive closed angle diameter. In other words, the single-drive closed mirror does not have a maximum bending force Fb and is calculated based only on the horizontal force Ph generated during one-side drive. Therefore, here, for convenience, it is called a “single-driven” closed mirror, and is a work roll closed mirror described later. It is distinguished from Dm (this closed angle diameter also takes into account the maximum bending force Fb).

If the horizontal force Ph is used instead of the resultant force Fc in equation (3), the following equation becomes:

Then, using equation (4), when σ _n of the standard rolling equipment and σ _n of a certain rolling equipment are the same value, the single drive closed angle length of the standard rolling equipment work roll 10 is, The relationship between the single drive closed angle diameter of the work roll 10 of the rolling equipment is derived (calculated as a coefficient).

If the single drive closed angle diameter at the maximum sheet width b ₀ according to the standard rolling equipment specifications is set to Dmin ₀ , the stress σ _n0 acting on the weakest part of the work roll 10 can be expressed by the following equation.

k ₀ : ratio of the diameter of the weakest part to Dmin ₀

If the single drive closed angle diameter at the time of the maximum plate width b _x according to the specifications of a certain rolling equipment is Dmin _x , the stress σ _nx acting on the weakest part of the work roll 10 can be expressed by the following equation.

_{Here ,} if _{β = b x / b 0} = _Ln

And, when the following equation is established, equations (5) and (6) become the same. In other words, the strength (stress of the weakest part of the work roll 10) of the work roll 10 of the standard rolling equipment and the work roll 10 of a certain rolling equipment becomes equal.

Then, the relational expression of the single drive closed angle diameter Dmin ₀ of the standard rolling equipment, which is a known value, the maximum sheet width b ₀ of the standard rolling equipment, the maximum sheet width b _x of a certain rolling equipment, and γ=Dmin _x /Dmin ₀ And, from equation ₍ 7), the single drive closed angle diameter Dmin _x of the work roll 10 in a certain rolling equipment (the _single drive closed angle diameter Dmin can be calculated. In other words, it can be seen that the basic strength of the work roll can be secured by determining the work roll closed angle diameter of each equipment specification of the single drive type as 2/3 power of each maximum plate width ratio.

As a specific value, the maximum plate width b ₀ of the standard rolling equipment is set to 1250 mm, and the allowable stress of a general forged steel roll is set to 22 kgf/mm2 ( 216MPa), the closed angle diameter Dmin ₀ of the standard rolling equipment is determined by limit design to be 250 mm. And, based on this, the single drive closed angle diameter Dmin _x of each rolling facility was obtained from the maximum plate width _b

FIG. 4 is a graph showing the relationship between the maximum sheet width of the rolling equipment and the single drive closed angle diameter and nominal diameter of the work roll 10. With respect to the single drive closed angle diameter and the nominal diameter when the maximum sheet width of the rolling equipment is taken on the horizontal axis and the diameter of the work roll 10 on the vertical axis, the single drive closed angle diameter is shown by a solid line and the nominal diameter is shown by a broken line.

In addition, the maximum plate width (maximum plate width according to the specifications of the rolling equipment) of the rolled material 3 to which the present invention is applied is a minimum of 900 mm and a maximum of 2000 mm, so in Figure 4, the single drive closed angle diameter and nominal diameter in this range are calculated. It is indicated as follows. That is, the maximum design width of the rolled material 3 to be rolled is within the range of 900 mm to 2000 mm.

In addition, in this embodiment, the ratio between the closed diameter (minimum diameter) and the new diameter (maximum diameter) of the work roll 10 is changed from 0.9 or more in the past to 0.8 or more based on recent improvements in work roll surface hardness and depth characteristics. Since it has been changed to , the ratio of the single drive closed angle diameter and the nominal diameter is also applied to 0.8 after the change. That is, the nominal diameter of the work roll 10 is calculated by dividing the value of the single drive closed angle diameter of the work roll 10 determined previously by 0.8, and this calculation result is shown as a broken line in FIG. 4.

And, by changing the ratio of the closed angle diameter of the work roll 10 to the new diameter in this way, compared to the past, the effect of improving the work roll basic unit (suppression of costs by extending the life of the work roll 10) and the single drive diameter are achieved. Reduction effect of rolling load and torque by roll rolling (rolling with the upper and lower work rolls 10 having different diameters is called different-diameter roll rolling, and single drive different-diameter roll rolling has the same reduction amount ΔH compared to same-diameter roll rolling) It becomes possible to obtain (the rolling load or torque of the work roll 10 is lowered).

<Determination of the diameter of the work roll (10)>

Next, the work roll closed angle diameter Dm and the work roll new diameter Ds are determined from the stress σ _n of the weakest part of the work roll 10 and the safety factor of the work roll 10. Specifically, with respect to the hard material main pass schedule of each rolling facility, the allowable stress of a general forged steel roll is set to 22 kgf/㎟ (216 MPa), and the weakest part of the work roll 10 with respect to the resultant force Fc is calculated from equation (3). The stress σ _n is determined, and the work roll closed angle diameter Dm and the work roll new diameter Ds are determined so that the safety factor is equal to or greater than a predetermined value (in this embodiment, equal to or greater than 1.3).

Figure 5 is a table showing each parameter for the new work roll diameter Ds and the work roll closed diameter Dm determined based on the maximum plate width of each equipment specification. In the table of Figure 5, nine examples 1 to 9 are listed as application examples, where application example 1 is a rolling facility with a maximum plate width of 1050 mm in specifications, and application examples 2 to 4 are rolling facilities with a maximum plate width of 1250 mm in specifications. , Application Examples 5 to 7 are rolling facilities with a maximum plate width of 1600 mm in specifications, and Application Examples 8 and 9 are rolling facilities with a maximum plate width of 1850 mm in specifications. Below, using Application Example 1 as an example, the procedure for determining the work roll closed diameter Dm and the new work roll diameter Ds will be explained.

First, check the single drive closed angle of the work roll (10). Since the maximum sheet width of the rolled material 3 that can be rolled in the rolling equipment of Application Example 1 is 1050 mm, the value of the vertical axis of the solid line at the position of 1050 mm on the horizontal axis in FIG. 4 (side of the work roll 10) If you look at the driving closed mirror, you can see that it is about 220 mm. Since the work roll closed diameter Dm can be determined not to fall below this standard, the work roll closed diameter Dm is tentatively determined to be 225 mm. Then, the work roll closed diameter Dm is divided by 0.8, and the new work roll diameter Ds is tentatively determined to be 280 mm.

Next, the resultant force Fc is calculated from parameters such as the plate width b (the plate width b of the material to be rolled 3 that is actually rolled) and the reduction amount ΔH, and equations (1), (2), and (2-1). And calculate the stress σ _n of the weakest part of the work roll 10 using equation (3). Then, check whether the stress σ _n of the weakest part of the work roll 10 is more than a predetermined value with respect to the allowable stress of a general forged steel roll of 22 kgf/㎟ (216 MPa), and if the safety factor is more than a predetermined value, it is tentatively determined. It can be said that the new work roll diameter Ds and the work roll closed diameter Dm have no problems in terms of strength.

If the new work roll diameter Ds and the work roll closed angle diameter Dm of each rolling equipment are determined through this procedure, the diameter of the work roll 10 is in the range of 200 mm to 450 mm, as shown in application examples 1 to 9 of Figure 5. Go in. That is, the diameter of the two work rolls 10 is within the range of 200 mm to 450 mm.

In addition, the body length L of each rolling facility (since the body length L ₁ and the body length L ₂ of the present invention have the same dimension, hereinafter, the body length L ₁ and the body length L ₂ are also referred to as the body length L) and the new work roll Calculating the ratio L/Ds with the diameter Ds and the ratio L/Dm between the body length L of each rolling equipment and the work roll closed angle diameter Dm, the values are shown in the second column on the right side of the table shown in FIG. 5. Additionally, the ratio L/D of the body length L and the diameter of the work roll 10 has L/Ds as the minimum value and L/Dm as the maximum value, and is within the range of L/Ds and L/Dm during rolling.

Figure 6 shows the horizontal axis of Figure 4 as the body length L of the work roll 10, and the work roll new diameter Ds (triangular point) and the work roll closed angle diameter Dm (round point) of Application Examples 1 to 9 shown in Figure 5. , and this is a plot of the ratio L/D=4 and L/D=7 between the fuselage length L and the diameter of the work roll.

As shown in Figure 6, if the work roll closed angle diameter Dm is determined in the above-described procedure and the work roll new product diameter Ds is determined so that the ratio between the work roll closed angle diameter Dm and the new work roll diameter Ds is 0.8 or more, all work rolls The new product diameter Ds (triangular point) and the work roll closed angle diameter Dm (round point) fall within the range of L/D=4 to 7 (between the graphs of L/D=4 and L/D=7).

In this way, the first work roll 10a and the second work roll 10b are used to satisfy 4.0≤L ₁ /D _w1 ≤7.0 and 4.0≤L ₂ /D _w2 ≤7.0, and by this use, the work roll ( 10) The strength is secured.

<<<How to operate Workroll (10)>>>

Next, the operation method of the work roll 10 will be described. In the first embodiment, the first work roll 10a and the second work roll 10b have the same specifications (at least the dimensions of the body length and the shape of the roll neck Rn are the same) and can be replaced, so the work rolls shown below The operating method of the roll 10 can be applied.

The surface of the work roll of a rolling mill becomes rough as wear progresses through use, so it is necessary to polish the surface every time it is used for a certain period of time. Therefore, rolling mills usually prepare a lot of spare parts for work rolls, and they are assigned a number to each roll and managed in roll shop facilities.

After installing new work rolls as the first work roll (10a) and second work roll (10b) and starting rolling, after a certain period of use, there is a change in roll diameter due to the difference in wear of the work rolls. Occurs. Since the extent to which the work roll will wear out and reduce its diameter in proportion to the time of use is known as an empirical value, the number of each work roll (roll spare part) and the time of use are linked to form a database, and this results in a database for each work roll (roll spare part). The diameter of the roll spare parts) is managed.

After the operation period, at the point where the rolls were widely distributed from new products to rolls near the closed diameter, among the plurality of roll spare parts, two rolls, one with a diameter ratio to the nominal diameter larger and one with a smaller diameter than the predetermined standard value, were taken out, and the two rolls taken out were taken out. Among the spare parts, the one with a smaller diameter is replaced with the first work roll (10a), and the one with a larger diameter is replaced with the second work roll (10b). It is desirable that this standard value is around 0.9.

In addition, it is preferable to discard the first work roll 10a when _the ratio (D _w1 /D _w1N ) between the diameter D _w1 and the nominal diameter D w1N reaches 0.8. It is preferable to calculate the diameter of each roll including the first and second work rolls and the roll spare parts based on the relationship (experience value) between the usage time and the degree of wear, because it avoids equipment complexity. However, the present invention is not limited to this method, and the diameter of the first work roll may be directly measured to determine that the ratio (D _w1 /D _w1N ) between the diameter D _w1 and the nominal diameter D _w1N is 0.8.

===About the effectiveness of the first embodiment===

As described above, the rolling mill 1 according to the first embodiment is provided with two work rolls 10 disposed on the upper and lower sides with a plate line in between, and each of the two work rolls 10 has In relation to this, it is a four-stage rolling mill (1) equipped with one backup roll (12), and the two work rolls (10) have the same axial length and the shape of the roll neck Rn, so they can be replaced with each other, and the two work rolls (10) are interchangeable with each other. 10), the first work roll 10a, which is the work roll 10 on one side, is not driven to rotate, and the second work roll 10b, which is the work roll 10 on the other side, is configured to be driven to rotate. The ratio (L ₁ /D _w1 ) of the body length L ₁ and the diameter D _w1 of the first work roll (10a) satisfies 4.0≤L ₁ /D _w1 ≤7.0, and also the body length of the second work roll (10b) The ratio of L ₂ to the diameter D _w2 (L ₂ /D _w2 ) is characterized in that 4.0≤L ₂ /D _w2 ≤7.0. Therefore, it is possible to provide a driving device that can withstand high torque even when using a small-diameter work roll 10, and also to provide a rolling mill 1 with reduced costs.

In recent years, for the purpose of increasing the strength and reducing the weight of automobiles, etc., there has been a demand for rolling mills that can drive small-diameter work rolls 10 with a smaller diameter than before even at high torque. However, in the conventional method, problems such as insufficient strength of the spindle, enlargement of the rolling mill, vibration during high-speed rolling, and torque circulation problems occurred.

On the other hand, in the rolling mill 1 according to the first embodiment, first, generally, both upper and lower work rolls 10 are driven and rotated, and one side of the work roll 10 (second work roll 10b )) was allowed to drive and rotate only. As a result, interference between spindles at the top and bottom is eliminated, creating a space to increase the spindle diameter, making it possible to increase the spindle strength by increasing the diameter, and a spindle that can withstand large torque and rotate at high speeds. It becomes possible to do so.

In addition, since an inexpensive general crosspin type universal joint can be used rather than an expensive special gear spindle type to ensure the strength of the spindle, it is possible to keep costs down.

In addition, since the tilt angle of the universal joint is larger than that of the gear spindle (tilt angle of up to 1.5°), at a maximum of about 8° to 10°, a long spindle such as a gear spindle is not needed to secure the roll opening. It becomes possible to suppress the enlargement of rolling mills.

Additionally, since rolling is performed by driving only the second work roll 10b, torque circulation does not occur, making strict management of the diameter difference between the upper and lower work rolls unnecessary.

Second, the first work roll 10a and the second work roll 10b were work rolls 10 with the same specifications. That is, even with the same specification (diameter), the wear amount of the upper and lower work rolls 10 is different, so it is possible to obtain the effect of the above-described different diameter roll rolling. In addition, since the specifications are the same, operation spare parts (consumable parts) such as work rolls, neck bearings, and neck seals are available compared to the general different diameter roll rolling mill (the specifications of the upper and lower work rolls are different) disclosed in Patent Document 1 (Japanese Patent No. 3290975). The type and number of can be reduced.

Third, the work roll 10 was used in the range of 4.0≤L ₁ /D _w1 ≤7.0 and 4.0≤L ₂ /D _w2 ≤7.0. As with the rolling mill 1 according to the first embodiment, if rolling is performed by driving only the second work roll 10b, a large horizontal force Ph is generated and insufficient strength of the work roll 10 becomes a problem, but the work roll 10 By using to satisfy 4.0≤L _1/ D _w1 ≤7.0 and 4.0≤L ₂ /D _w2 ≤7.0, it becomes possible to secure sufficient strength for the work roll 10 in any rolling equipment.

Additionally, in the first embodiment, the ratio of the closed diameter (minimum diameter) of each work roll to the nominal diameter (maximum diameter, new diameter) was set to 0.8 or more.

In other words, it is possible to contribute to extending the life of the work roll and to increase the effect of reducing the rolling load and torque by single-side driven different-diameter roll rolling.

Additionally, in the first embodiment, the diameters of the two work rolls 10 were within the range of 200 mm to 450 mm.

In other words, the diameter of the work roll 10 is within the range of 200 mm to 450 mm, so that a driving device can be used that can withstand high torque even when a small diameter work roll 10 is used, and furthermore, the rolling mill is cost-suppressed. It becomes possible to provide (1).

In addition, in the first embodiment, the maximum design width of the rolled material 3 to be rolled is within the range of 900 mm to 2000 mm.

In other words, since the rolling equipment is designed within the range of 900 mm to 2000 mm for the maximum plate width of the material to be rolled (3), a driving device that can withstand high torque even when using a small diameter work roll (10) within this range. Moreover, it becomes possible to provide the rolling mill 1 with reduced costs.

Furthermore, in the first embodiment, the diameter D _w1 of the first work roll 10a is rolled to a smaller diameter than the diameter D _w2 of the second work roll, and the diameter D _w2 of the second work roll 10b is, The ratio (D _w2 /D _w2N ) of the nominal diameter (new diameter) D _w2N of the second work roll (10b) is greater than or equal to the standard value and it is used at the second work roll position, and the diameter of the first work roll (10a) D _w1 The ratio (D _w1 /D _w1N ) of the nominal diameter (new diameter) D _w1N of the first work roll (10a) is less than the standard value and the work roll operation method is used from the first work roll position to the closed angle diameter. The standard value can be appropriately set to a value of about 0.85 to 0.95, but from the viewpoint of using the roll for a longer period of time compared to the conventional method, which was discarded when the ratio of the diameter to the nominal diameter reached about 0.9, the standard value was set to 0.9. In addition, it is desirable to use roll spare parts worn to a diameter smaller than this.

According to this method of operating the work roll 10, rolling is always performed in a state where the diameter of the first work roll 10a is smaller than that of the second work roll 10b (different diameter roll rolling state).

That is, according to the operating method of the work roll 10 according to the present embodiment, single-driven, different-diameter roll rolling can always be performed, making it possible to increase the effect of reducing the rolling load by single-driven, different-diameter roll rolling.

===Second Embodiment===

In the first embodiment, there was no offset (the positions of the rotation center of the work roll 10 and the rotation center of the backup roll 12 in the conveyance direction were the same; the positional relationship shown in FIG. 2), but in the second embodiment, there was no offset. In the embodiment, as shown in FIG. 7, there is an offset (at least one of the rotation center of the first work roll 10a and the rotation center of the second work roll 10b is the rotation center of the backup roll 12). Rolling is performed at a position (different from the position in the conveyance direction).

FIG. 7 is a diagram corresponding to FIG. 2 and is a cross-sectional schematic diagram for explaining the force applied to the work roll 10 during offset rolling. In addition, details will be described later using calculation formulas, but by performing rolling with the work roll 10 offset, it becomes possible to reduce the horizontal force generated on the work roll 10.

The rolling mill 150 according to the second embodiment has an offset amount in order to stably generate an optimal horizontal force on the work roll 10 for a wide range of pass schedules from soft materials to hard materials in each sheet width. An offset device 100 (corresponding to a roll offset device) and an offset control unit 130 (corresponding to an offset amount control device) that can change are provided on the non-driven first work roll 10a of the rolling mill 1.

That is, in the rolling mill 150, in addition to the rolling mill 1, only the first work roll 10a among the two work rolls 10 is installed at a predetermined level in the horizontal direction on the entry side in the rolling direction of the rolling mill 1. A roll offset device (offset device 100) configured to offset by an offset amount, and a roll offset device (offset device 100) controlled to offset the first work roll 10a to the entry side by a predetermined offset amount. It is further provided with an offset amount control device (offset control unit 130) configured to do so.

FIG. 8 is a cross-sectional view of the offset device 100, and FIG. 9 is a diagram showing the offset control unit 130. In Fig. 9, one side in the axial direction is called the driving side, and the other side is called the operating side.

As shown in FIG. 9, the offset device 100 includes a first offset device 100a on the exit operation side of the first work roll 10a, a second offset device 100b on the entry operation side, and an exit drive side. It has a third offset device 100c, and a fourth offset device 100d on the entrance drive side. And, the first offset device 100a to the fourth offset device 100d are devices of the same type.

Therefore, in the following, when the descriptions of the first offset device 100a to the fourth offset device 100d overlap, the first offset device 100a will be described, and descriptions of other devices will be omitted (numbers in the drawings) (also omitted). 8 shows the offset device 100 as seen from the operating side, and among the offset devices 100, the first offset device 100a and the second offset device 100b are shown.

The first offset device 100a includes a first position adjustment cylinder 102a, a first position detection sensor 104a, a first upper bending block 106a, a first projecting block 108a, and a first It has a bending cylinder 110a and a first lower bending block 112a.

The first position adjustment cylinder 102a presses the roll chock 9 of the rolling mill 1 at the first cylinder tip 102ae, thereby moving the first work roll 10a supported on the roll chock 9 in the conveyance direction. Move it to the entrance side (offset it). In addition, the first position adjustment cylinder 102a is provided in the first upper bending block 106a (may be provided in the first project block 108a), and on the opposite side of the first cylinder tip 102ae, a first A position detection sensor 104a is provided.

The first position detection sensor 104a is a sensor for detecting the position of the first position adjustment cylinder 102a, and is used to control the position of the first cylinder tip 102ae in the conveyance direction.

The first upper bending block 106a is provided to be movable in the vertical direction on the first project block 108a. And the roll chock 9 side of the first upper bending block 106a has a concave shape and is fitted with the convex shape of the opposing roll chock 9. That is, the first upper bending block 106a restrains the roll chock 9 in the vertical direction, and when the first upper bending block 106a moves in the vertical direction, the first workpiece is moved through the roll chock 9. The roll 10a moves in the vertical direction.

In addition, the first upper bending block 106a is connected to the first bending cylinder 110a provided in the first lower bending block 112a, and the first bending cylinder 110a is connected to the first lower bending block 112a. ), it is possible to move in the up and down directions.

That is, when the first bending cylinder 110a moves in the vertical direction, the first work roll 10a moves in the vertical direction through the first upper bending block 106a and the roll chock 9.

And, during rolling, the first bending cylinder 110a moves the work roll 10 to counter the bending of the work roll 10. Therefore, the maximum bending force Fb described above is generated in the work roll 10.

Next, the effect of reducing the horizontal force in rolling with offset will be explained using FIG. 7. As shown in FIG. 7, in the second embodiment, the rotation center of the non-driven first work roll 10a is the rotation center of the roll with which it is in contact (the first backup roll 12a and the second work roll 10b). Rolling is performed in a state offset toward the entry side with respect to the rotation center of .

And, the horizontal force Fh ₁ of the first work roll 10a generated by the offset can be expressed by the following equation.

Db ₁ : Diameter of the first backup roll (12a)

e1: Offset amount between the first work roll (10a) and the first backup roll (12a)

e2: offset amount of the first work roll (10a) and the second work roll (10b)

Tension, inertial force from contacting rolls, frictional force, etc. also act on the work roll 10, but the horizontal force Ph of the above-described rolling reaction force Pr and the horizontal force Fh ₁ due to offset mainly act on the first work roll 10a. The horizontal force F ₁ can be expressed as the following equation by summing equations (1) and (8).

Additionally, the horizontal force Fh ₂ of the second work roll 10b generated by offset can be expressed by the following equation.

Db ₂ : Diameter of the second backup roll (12b)

Since the horizontal force Ph and horizontal force Fh ₂ are the main forces acting on the second work roll 10b, the horizontal force F ₂ acting on the second work roll 10b is obtained by adding up equations (1) and (10). It can be expressed as follows:

Figure 10 shows the results of calculating the horizontal force F ₁ and horizontal force F ₂ under both conditions of presence and absence of offset using the above equation. The table on the left of FIG. 10 is the result of calculation under the condition of no offset, and the table on the right of FIG. 10 is the result of calculation under the condition of presence of offset. 10 is an example of using a cold reversible rolling mill (a rolling mill that rolls from the entrance side to the exit side, and the next pass rolls from the exit side to the entrance side).

As shown in the table on the left of FIG. 10, under the condition of no offset, a large horizontal force that reverses positive and negative occurs in odd passes (rolling from the entry side to the exit side) and even passes (rolling from the exit side to the entry side). I'm doing it.

On the other hand, as shown in the table on the right side of FIG. 10, in the condition with offset in which the offset amount of the first work roll 10a is changed for each pass, the horizontal forces F ₁ and F ₂ are less than half compared to those without offset. It is reducing.

That is, by offsetting the first work roll 10a at an appropriate position on the entry side during each pass of rolling, the horizontal forces F ₁ and F ₂ can be reduced to half or less compared to the case where no offset is performed. And, the resultant force Fc with the maximum bending force Fb = 26.4 tons (259kN) shown in equation (2) is √(26.4 ² + (11.0/2) ² ) = 27.0 tons (265kN) from equation (2-1). , it becomes possible to suppress the increase in resultant force Fc to an increase of about 2% of the maximum bending force Fb.

In other words, an offset device 100 capable of changing the offset amount is provided on the work roll 10 (first work roll 10a) on the non-driven side of the work roll 10, and the non-driven work roll 10 (In this embodiment, the rotation centers of the first backup roll 12a and the second work roll 10b) of the roll contacting the rotation center of the first work roll 10a) at an appropriate position on the entrance side. By rolling with offset, the external force of the work roll 10 can be suppressed in each pass, enabling stable rolling.

Additionally, when the horizontal force F ₁ decreases, the reduction amount ΔH per pass can be increased. That is, in rolling with one side drive, the reduction ratio (reduction amount ΔH/entrance plate thickness H1) can be increased by offsetting.

In addition, the offset amounts e1 = -4.5 mm and e2 = 4.5 mm move only the first work roll 10a 4.5 mm toward the entry side, and the second work roll 10b moves the backup roll 12 in the conveyance direction. It indicates that the center of rotation is at the same location (not offset).

Next, the rolling method (rolling control) of rolling with offset is explained using FIGS. 8 and 9. Specifically, a rolling method (rolling control) that uses the rolling mill 150 to offset the first work roll 10a by a predetermined offset amount horizontally to the entrance side in the rolling direction of the rolling mill 1. ) is explained. In the following description, the rolled material 3 is conveyed and rolled from the entry side (left side) shown in Figs. 8 and 9 toward the exit side (right side).

The offset control unit 130 has a PI controller provided in the offset position control panel 132, corresponding to each of the first offset devices 100a to 4th offset devices 100d, a control valve, and a cylinder pressure detection sensor. And similar control is performed on the first offset device 100a to the fourth offset device 100d, respectively. Therefore, in the following, when the descriptions of the first offset device 100a to the fourth offset device 100d overlap, only the first offset device 100a will be described, and descriptions of other devices will be omitted (numbers in the drawings) (also omitted).

First, before starting rolling, the first position adjustment cylinder 102a of the first offset device 100a on the exit operation side and the third position adjustment cylinder 102c of the third offset device 100c on the exit drive side are, The first work roll 10a is pressed in toward the entry side, and the first work roll 10a is offset (moved) so that it is at a predetermined position toward the entry side relative to the rotation center of the backup roll 12.

Then, the gap between the second position adjustment cylinder 102b of the second offset device 100b on the entry operation side and the roll chock 9 (Gap shown in FIG. 8) and the fourth offset device on the entry drive side ( A gap between the fourth position adjustment cylinder 102d and the roll choke 9 of 100d is set. This gap is provided so that the offset device 100 does not excessively restrain the rolling mill 1 during rolling, so for example, based on a signal from the pressure detection sensor 122a of the piping system, a certain light force is applied. It may be in contact with the roll choke (9).

Then, after the above setting, rolling is started, and during rolling, the offset amount of the first work roll 10a is controlled to be a constant value. Specifically, the position performance value (offset position) detected by the first PI controller 134a provided in the offset position control panel 132 from the first position detection sensor 104a corresponding to the first position adjustment cylinder 102a. By comparing the offset command value predetermined from the pass schedule, it is calculated whether the offset position is deviated from the offset command value.

When the offset position deviates from the offset command value, the first PI controller 134a controls the first position adjustment cylinder 102a through the first control valve 120a so that the deviation between the offset command value and the position actual value becomes zero. Control the position of to become the offset command value. The pressure detection sensor 122a functions as a monitor to monitor whether the previously calculated horizontal force is accurate and helps correct the offset command value.

In addition, the offset command value is not only the rolling load and horizontal force F ₁ and F ₂ , but also the difference in tension between the rolled materials 3 on the entry and exit sides, the transmission force from the bearing friction torque of the backup roll 12, and the time of acceleration and deceleration. It is determined by considering the inertial force of the backup roll 12, etc.

===About the effectiveness of the second embodiment===

As described above, in the rolling mill 150 according to the second embodiment, among the two work rolls 10, only the first work roll 10a is predetermined in the horizontal direction on the entry side in the rolling direction of the rolling mill 1. A roll offset device (offset device 100) configured to offset by an offset amount of It is further provided with an offset amount control device (offset control unit 130) configured to control, and offsets the first work roll 10a by a predetermined offset amount in the horizontal direction on the entry side in the rolling direction of the rolling mill 1. It was decided that rolling would be carried out.

Therefore, rolling can be performed by changing the offset amount of the first work roll 10a, and the horizontal forces F ₁ and F ₂ can be reduced, so that bending is suppressed and the work roll 10 can be reduced in diameter. . Additionally, as can be seen from equations (9) and (11), when the horizontal forces F ₁ and F ₂ become small, the reduction amount ΔH per pass can be increased. That is, in one-side drive rolling, the reduction ratio (reduction amount ΔH/entrance plate thickness H1) can be increased by offsetting the first work roll 10a toward the entry side by a predetermined offset amount.

In cold rolling, especially in tandem mills, rolling is carried out in a wide range of pass schedules depending on the material, plate thickness, and plate width b of the material to be rolled (3). Additionally, since the number of passes is small, the work roll is reduced in diameter and the number of passes per pass is reduced. It is necessary to increase the reduction amount ΔH. That is, conventionally, when only one side of the work roll 10 is driven and rolled, a large horizontal force Ph is generated in the work roll 10, making it difficult to reduce the diameter of the work roll 10.

On the other hand, the rolling mill 150 can roll the first work roll 10a by offsetting it to the side opposite to the rolling direction (entry side) by the offset device 100 and the offset control unit 130, so that the horizontal force F ₁ , F ₂ can be made small, and the work roll 10 can be reduced in diameter. It becomes possible to roll at a higher reduction ratio.

In addition, by making this offset amount changeable, the first work roll 10a can be adjusted to an appropriate offset position according to each pass schedule, and the horizontal forces F ₁ and F ₂ can be reduced, and the work roll 10 It becomes possible to further reduce the diameter and roll at a higher reduction ratio.

In addition, by reducing the horizontal forces F ₁ and F ₂ , the strength of the work roll 10 and the neck bearing are relatively increased, so the lifespan of the work roll 10 and the neck bearing can be extended.

In addition, in the single-side driven rolling mill 150 in which only the second work roll 10b is driven as in the second embodiment, the horizontal force Ph acts on the first work roll 10a in the same direction as the rolling direction, and the second work roll 10a is driven by a horizontal force Ph in the same direction as the rolling direction. Since the horizontal force Ph in the direction opposite to the rolling direction acts on the work roll 10b, it is effective to offset only the first work roll 10a in the direction opposite to the rolling direction (entrance side).

For example, when the first work roll (10a) and the second work roll (10b) are offset at the same time, the offset amount e2 of the first work roll (10a) and the second work roll (10b) becomes zero, The reduction effect of the horizontal forces F ₁ and F ₂ is small, and the horizontal force F ₂ of the second work roll 10b increases.

In addition, when the first work roll 10a is offset to the side opposite to the rolling direction (entry side) and the second work roll 10b is offset to the rolling direction (outlet side), the effect of reducing the horizontal forces F ₁ and F ₂ is high, but 2 Since it is necessary to provide an offset device on the work roll 10b side, the equipment cost and maintenance cost of such equipment increase, and the control system for the offset device also becomes complicated.

===Other embodiments===

Above, the rolling mill 1 and the rolling mill 150 according to the present invention have been described based on the above-mentioned embodiments. However, the above-described embodiments of the invention are intended to facilitate understanding of the present invention, and the present invention is based on the above-described embodiments. It is not limited to. The present invention can be changed and improved without departing from its spirit, and it goes without saying that equivalents thereof are included in the present invention.

In the above embodiment, the non-driven work roll 10a is shown as the upper roll and the driven work roll 10b is shown as the lower roll. However, the non-driven work roll 10a is shown as the lower roll, and the driven work roll 10b is shown as the upper roll. You can do it. In addition, although the rolling mill 1 has a four-stage configuration, it is not limited to this, and for example, it may be a six-stage rolling mill with an intermediate roll provided between the work roll 10 and the backup roll 12. In this case, the offset amount can be calculated not by the work roll 10 and the backup roll 12, but by calculating the offset amount of the work roll 10 and the middle roll.

In addition, in the above embodiment, a rolling facility in which the material to be rolled 3 is rolled by a single rolling mill has been described, but it is not limited to this, and a reverse rolling facility consisting of one or more stands, one or more stands It can be applied to any of non-reversing rolling equipment consisting of and tandem rolling equipment consisting of one or multiple stands.

In addition, in the above embodiment, the rolling mill 1 is a type rolling mill in which the work roll 10 does not shift in the axial direction, but it may be a shift type rolling mill in which the work roll 10 shifts in the axial direction.

FIG. 11 is a diagram corresponding to FIG. 5 and is a table showing each parameter for the determined work roll new diameter Ds and work roll closed diameter Dm in a shift type rolling mill, and FIG. 12 is a diagram corresponding to FIG. 6 In the shift type rolling mill, the horizontal axis is expressed as the body length L of the work roll 10, and the work roll new diameter Ds (triangular point) and the work roll closed angle diameter Dm (round) of Application Examples 1 to 9 shown in Figure 11 point), and the ratio of the fuselage length and the diameter of the work roll, L/D=4 and L/D=7, are plotted. In addition, in the shift type rolling mill, the body length L of the work roll 10 is the maximum sheet width plus approximately (maximum sheet width x 0.12 to 0.14) (shift amount in the third row from the right in the table shown in FIG. 11) It becomes.

Also in the shift type rolling mill, the work roll closed shell diameter Dm is determined similarly to the above embodiment, and the work roll new product diameter Ds is determined so that the ratio between the work roll closed shell diameter Dm and the work roll new product diameter Ds is 0.8 or more. Then, even in the shift type rolling mill, as shown in Fig. 12, the work roll closed diameter Dm and the work roll new diameter Ds are within the range of the ratio L/D of the body length and the diameter of the work roll = 4 to 7. I go in.

1: rolling mill
3: Rolled material
5: spindle
7: Drive part
7a: electric motor
7b: Gear coupling
7c: Reducer
8: Housing
9: Roll Choke
10: Workroll
10a: First work role
10b: Second work role
12: Backup roll
12a: 1st backup roll
12b: Second backup roll
D _w1 : Diameter of the first work roll
D _w2 : Diameter of the second work roll
Ds(D _w1N ): Workroll Shin Pum-kyung
Dm: Walkroll Closed Mirror
L: Body length of work roll
L ₁ : Body length of the first work roll
L ₂ : Body length of the second work roll
Lp: Work roll contact arc length
b: plate width
km: average deformation resistance
Fb: Maximum bending force (bend force)
Fc: resultant force
σ _n : Stress at the weakest point
L/D: ratio of fuselage length and diameter
L/Ds: Minimum ratio of fuselage length to diameter
L/Dm: Maximum value of ratio between fuselage length and diameter
Db ₁ : Diameter of the first backup roll
Db ₂ : Diameter of the second backup roll
H1: Inlet plate thickness
H2: Outgoing plate thickness
ΔH: Reduction amount
Pr: rolling reaction force
Ph: Horizontal force by single drive method
Fh ₁ : Horizontal force due to offset acting on the first work roll
Fh ₂ : Horizontal force due to offset acting on the second work roll
F ₁ : Horizontal force acting on the first work roll
F ₂ : Horizontal force acting on the second work roll
Ln: Distance from the center of the roll neck bearing to the weakest point
kn: Ratio of the diameter of the weakest part to the diameter of the new work roll (nominal diameter)
Rn: roll neck
e1: Offset amount between the first work roll and the first backup roll
e2: Offset amount between the second work roll and the second backup roll
100: Offset device (roll offset device)
100a: first offset device
100b: second offset device
100c: third offset device
100d: fourth offset device
102a: first position adjustment cylinder
102b: second position adjustment cylinder
102c: Third position adjustment cylinder
102d: fourth position adjustment cylinder
102ae: first cylinder tip
104a: first position detection sensor
106a: first upper bending block
108a: first project block
110a: first bending cylinder
112a: first lower bending block
120a: first control valve
122a: First cylinder pressure detection sensor
130: Offset control unit (offset amount control device)
132: Offset position control panel
134a: first PI controller
150: rolling mill

Claims (10)

It is a 4 to 6-stage rolling mill equipped with two work rolls arranged on the upper and lower sides with a plate line in between, and at least one backup roll for each of the two work rolls,
The two work rolls have the same axial length and roll neck shape, so they can be replaced with each other.
Among the two work rolls, the first work roll, which is the work roll on one side, is not rotationally driven, but rotates according to the accompanying rotation accompanying the conveyance of the rolled material, which is the object of rolling, and only the second work roll, which is the work roll on the other side, is rotationally driven. It consists of
The ratio (L ₁ /D _w1 ) of the body length L ₁ and the diameter D _w1 of the first work roll satisfies 4.0≤L ₁ /D _w1 ≤7.0, and also the body length L ₂ and the diameter of the second work roll The ratio of D _w2 (L ₂ /D _w2 ) satisfies 4.0≤L ₂ /D _w2 ≤7.0,
A rolling mill, characterized in that the diameter of the first work roll is smaller than the diameter of the second work roll. According to paragraph 1,
A rolling mill, characterized in that it has an electric motor whose rotation shaft is connected only to the second work roll. According to claim 1 or 2,
A rolling mill, characterized in that the diameter of the two work rolls is within the range of 200 mm to 450 mm. According to claim 1 or 2,
A rolling mill characterized in that the maximum design width of the rolled material to be rolled is within the range of 900 mm to 2000 mm. According to claim 1 or 2,
A rolling mill, characterized in that the ratio of the closed angle diameter of each of the two work rolls to the nominal diameter is 0.8 or more. According to claim 1 or 2,
Of the two work rolls, a roll offset device configured to offset only the first work roll by a predetermined offset amount with respect to the rotation center of the contacting backup roll in a horizontal direction on the entrance side in the rolling direction of the rolling mill; ,
Further comprising an offset amount control device configured to control the roll offset device to offset the first work roll toward the entry side by the predetermined offset amount,
The rolling mill, wherein the offset amount control device is configured to control the roll offset device based on an offset command value that is predetermined based on at least a rolling load and a horizontal force from a pass schedule. A rolling method using the rolling mill described in paragraph 6,
A rolling method comprising performing rolling by offsetting the first work roll by the predetermined offset amount in a horizontal direction on an entrance side in the rolling direction of the rolling mill. A method of operating the work roll of the rolling mill described in paragraph 1 or 2,
A plurality of roll spare parts having the same axial length and roll neck shape as the two work rolls are separated and stored after being used in the rolling mill for a certain period of time;
Taking out two of the plurality of roll spare parts stored separately, one having a diameter-to-nominal diameter ratio larger than a predetermined reference value and one having a smaller diameter;
Of the two rolled spare parts taken out, the one with a smaller diameter is exchanged with the first work roll, and the one with a larger diameter is exchanged with the second work roll.
Method of operating work roles including. According to clause 8,
A method of operating a work role, characterized in that the predetermined standard value is 0.9. According to clause 8,
A method of operating a work roll, further comprising discarding the first work roll when the ratio (D _w1 /D _w1N ) between the diameter and the nominal diameter of the first work roll reaches 0.8.

Images