WO2020235199A1 - Rolling mill, rolling method, and operation method for work roll - Google Patents

Abstract

This four- to six-stage rolling mill comprises two work rolls vertically disposed with a plate passing line therebetween, the two work rolls each being provided with at least one backup roll, the rolling mill being characterized in that: the two work rolls have the same axial length and the same shapes of roll necks and are thus replaceable with each other; the two work rolls are configured so that one work roll, that is a first work roll, is not rotationally driven and the other work roll, that is a second work roll, is rotationally driven; and the ratio (L₁/D_w1) of the trunk length L₁ and the diameter D_w1 of the first work roll satisfies 4.0≤L₁/D_w1≤7.0, and the ratio (L₂/D_w2) of the trunk length L₂ and the diameter D_w2 of the second work roll satisfies 4.0≤L₂/D_w2≤7.0.

Description

Rolling machine, rolling method and work roll operation method

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

A 4- to 6-stage rolling mill having two work rolls arranged on the upper side and the lower side across a plate passing line and at least one backup roll for each of the two work rolls. It is already well known (for example, Patent Document 1 and Patent Document 2).

In recent years, there has been a demand for a rolling mill capable of rolling harder high-strength steel (high-strength steel having a tensile strength of 1300 MPa or more, etc.) for the purpose of increasing the strength and weight of automobiles and the like. Therefore, by providing a work roll having a smaller diameter than the conventional one, a hard material can be rolled at a higher rolling ratio, and a drive device capable of withstanding a high torque even if the work roll having such a small diameter is used. You need a rolling mill to have.

Japanese Patent No. 3290975 Japanese Patent No. 4928653

As the work roll diameter of the rolling mill becomes smaller, the distance between the work roll centers becomes shorter. Therefore, when both the upper and lower work rolls are rotationally driven, it is necessary to reduce the diameter of each spindle connected to both work rolls. .. Therefore, when a conventional cross-pin type universal joint is used as a spindle for a work roll with a small diameter, there is a limit to increasing the strength of the spindle (increasing the diameter), and the strength of the spindle for high torque drive cannot be secured. ..

When a gear spindle, which is stronger and more expensive than the conventional spindle, is used to secure the strength of the spindle, the cost increases and the tilt angle during operation is about 1.5 ° at the maximum (conventional, the maximum is 8 °). Since only about 10 ° can be obtained, a length is required to secure the roll opening, which is a factor that hinders the compactness of the rolling mill. More importantly, the smaller the diameter of the work roll, the higher the rotation speed, and the longer the spindle length, the larger the vibration, which causes a problem that affects the product accuracy.

Also, if 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. In order to prevent this, strict roll diameter difference control was required.

The present invention has been made in view of the above problems, and an object of the present invention is to have a drive device capable of withstanding a high torque even when a work roll having a small diameter is used, a higher rolling reduction can be realized, and a higher rolling reduction ratio can be realized. The purpose is to provide a rolling mill with reduced cost.

The main invention for achieving the above object includes two work rolls arranged on the upper side and the lower side with the through 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 and can be interchanged with each other. Of the two work rolls, the two work rolls are provided with not the first work roll is one of the work rolls is driven to rotate, the second work roll is the other work roll is configured to be driven to rotate, the barrel length L ₁ and the diameter of the first work roll The ratio of D _w1 (L ₁ / D _w1 ) satisfies 4.0 ≤ L ₁ / D _w1 ≤ 7.0, and the ratio of the body length L ₂ of the second work roll to the diameter D _{w 2} (L ₂ / D). _The rolling mill is characterized in that _w2 ) satisfies 4.0 ≦ L ₂ / D _w2 ≦ 7.0.

Other features of the present invention will be clarified by the description in the present specification and the accompanying drawings.

According to the present invention, it is possible to provide a rolling mill having a drive device that can withstand a high torque even when using a work roll having a small diameter, realizing a higher rolling reduction ratio, and suppressing costs.

It is a side schematic of the rolling mill 1 which concerns on 1st Embodiment. It is sectional drawing for demonstrating the force applied to the work roll 10 at the time of rolling. It is an enlarged view of the X part of FIG. 1, and is the figure which showed the roll neck Rn of the work roll 10. It is a graph which showed the relationship between the maximum plate width of a rolling mill, the one-side drive waste diameter and the nominal diameter of a work roll 10. It is a table which showed each parameter with respect to the work roll new diameter Ds and the work roll waste diameter Dm determined based on the maximum plate width of each equipment specification. The horizontal axis of FIG. 4 is represented by the body length L of the work roll 10, and the new work roll diameter Ds (triangulation point), the work roll waste diameter Dm (round point), and the body length of application examples 1 to 9 shown in FIG. It is the figure which plotted the ratio L / D = 4 and L / D = 7 of the diameter of L and the work roll. It is sectional drawing for demonstrating the force applied to the 1st work roll 10a at the time of rolling which the 1st work roll 10a was offset to the entry side. It is sectional drawing of the offset device 100. It is a figure which showed the offset control unit 130. This is the result of calculating the horizontal force F ₁ and the horizontal force F ₂ under both conditions with and without offset. It is a table which showed each parameter with respect to the determined work roll new diameter Ds and work roll waste diameter Dm in the type rolling mill which shifts a work roll in the axial direction. In a rolling mill of the type that shifts the work roll in the axial direction, the horizontal axis is represented by the body length L of the work roll 10, and the new work roll diameters Ds (triangulation points) of the work rolls 1 to 9 shown in FIG. It is the figure which plotted the return diameter Dm (round point) and the ratio of the body length and the diameter of a work roll L / D = 4 and L / D = 7.

At least the following matters will be clarified by the description in this specification and the attached drawings.

A 4- to 6-stage rolling mill provided with two work rolls arranged on the upper side and the lower side across a plate passing line, and at least one backup roll is provided for each of the two work rolls. The first work roll, which is one of the two work rolls, has the same axial length and roll neck shape and can be interchanged with each other. Is not rotationally driven, and the second work roll, which is the other work roll, is rotationally driven, and the ratio of the body length L ₁ to the diameter D _{w 1} of the first work roll (L ₁ / D _{w 1} ). _Satisfies 4.0 ≤ L ₁ / D _w1 ≤ 7.0, and the ratio (L ₂ / D _{w 2} ) of the body length L ₂ and the diameter D _{w 2} of the second work roll is 4.0 ≤ L ₂ / D. A rolling mill characterized in that _w2 ≤ 7.0 is satisfied.

According to such a rolling mill, it is possible to provide a rolling mill that can withstand a high torque even if a work roll having a small diameter is used and that the cost is suppressed.

It is desirable that such a rolling mill be provided with an electric motor in which a rotating shaft is connected only to the second work roll.

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

In such a rolling mill, it is desirable that the diameters of the two work rolls are in the range of 200 mm to 450 mm.

According to such a rolling mill, a rolling mill having a drive device capable of withstanding a high torque even when a work roll having a small diameter is used when the work roll diameter is between 200 mm and 450 mm and whose cost is suppressed is provided. It becomes possible.

It is desirable that the design maximum plate width of the material to be rolled in such a rolling mill is within the range of 900 mm to 2000 mm.

According to such a rolling mill, when the work roll body length is between 900 mm and 2000 mm, it is possible to make a drive device that can withstand a high torque even if a work roll having a small diameter is used, and the cost is suppressed. It becomes possible to provide a machine.

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

According to such a rolling mill, it is possible to contribute to extending the life of the work roll and to enhance the effect of reducing the rolling load and torque by one-sided drive different diameter roll rolling.

In such a rolling mill, of the two work rolls, only the first work roll can be offset horizontally to the entry side in the rolling direction of the rolling mill by a predetermined offset amount. It is further desirable to further include a roll offset device and an offset amount control device configured to control the roll offset device so as to offset the first work roll toward the entrance side by the predetermined offset amount.

According to such a rolling mill, the horizontal force can be reduced, so that the work roll can be reduced in diameter and rolled with a higher rolling reduction ratio.

It is desirable that the rolling method using such a rolling mill includes rolling by offsetting the first work roll horizontally to the entry side in the rolling direction of the rolling mill by the predetermined offset amount. ..

According to such a rolling method, the horizontal force can be reduced, so that the work roll can be reduced in diameter and rolled with a higher rolling reduction ratio.

In the method of operating the work rolls of such a rolling mill, a plurality of roll spare parts having the same axial length and roll neck shape as the two work rolls are used in the rolling mill for a certain period of time and then removed. To keep and
Of the multiple roll spare parts that have been removed and stored, two are taken out, one whose diameter ratio to the nominal diameter is larger than the predetermined reference value and the other which is smaller than the predetermined reference value.
Of the two spare rolls taken out, it is desirable to replace the smaller diameter one with the first work roll and the larger diameter one with the second work roll.

According to the work roll operation method of such a rolling mill, different diameter roll rolling can always be performed, so that it is possible to enhance the effect of reducing the rolling load and torque by different diameter roll rolling.

It is desirable that the reference value is 0.9 in the method of operating the work roll of such a rolling mill. Further, it is desirable to _abolish the first work roll when the ratio of the diameter of the first work roll to the nominal diameter (D _w1 / D _w1N ) becomes 0.8.

According to the work roll operation method of such a rolling mill, it is possible to reliably and always perform different diameter roll rolling while suppressing the occurrence of defects due to the smaller diameter of the work roll. Therefore, rolling by different diameter roll rolling is performed. It is possible to enhance the effect of reducing the load and torque, and it is possible to obtain the effect of cost reduction by long-term use (longer life) of the work roll.

=== 1st Embodiment ===
The rolling mill 1 according to the first embodiment is an apparatus for rolling a material 3 to be rolled and producing a strip-shaped (strip-shaped) material 3 to be rolled to a target plate thickness.

FIG. 1 is a schematic side view of the rolling mill 1 according to the first embodiment. In the side view, the horizontal direction (horizontal direction) of the paper surface is referred to as "axial direction", the left side (right side) of the paper surface is referred to as "left (right)", and the vertical direction (vertical direction) of the paper surface is referred to as "vertical direction". The upper side (lower side) of is called "upper (lower side)". The "left" in FIG. 1 corresponds to the drive side in FIG. 9, which will be described later, and the "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 (not shown).

Further, the rolling mill 1 is a four-stage rolling mill 1, in which two work rolls 10 are arranged on the upper side and the lower side of the plate passing line, respectively, with respect to each of the two work rolls 10. A backup roll 12 is provided.

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

A drive unit 7 is connected to the left end of the second work roll 10b via a spindle 5. That is, the rotating shaft of the electric motor 7a is connected only to the second work roll 10b. In other words, of the two work rolls 10, the first work roll 10a, which is one work roll 10, is not rotationally driven, and the second work roll 10b, which is the other work roll 10, is rotationally driven. Has been done.

That is, at the time of rolling, the second work roll 10b is rotated by the drive unit 7 to convey the material 3 to be rolled from the upstream side to the downstream side in the transfer direction, and the first work roll 10a conveys the material 3 to be rolled. It rotates due to the accompanying rotation.

The difference in operation causes a difference in the number of rotations 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 if the first work roll 10a and the second work roll 10b are rolled with the same diameter (same state), depending on the difference in the neutral point (point where the speeds of the roll and the rolled material match) of the upper and lower work rolls. Since there is a region where the shear force due to friction between the roll and the material is canceled up and down, the rolling load and torque are reduced as compared with a general rolling mill driven by a vertical roll.

A body length L ₁ of the first work roll 10a body length L ₂ of the second work roll 10b are the same size, the roll neck Rn shape neck bearing of the right and left end portions is attached (see FIG. 3) is also the same is there. Therefore, it is possible to remove the first work roll 10a (second work roll 10b) and attach it to 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, and can be interchanged 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) comes into contact with the upper side (lower side) of the first work roll 10a (second work roll 10b), and during rolling, the first work roll 10a (second work roll 10a). It is a bending suppressing member for preventing the roll 10b) from bending upward (lower side).

The spindle 5 is a shaft member for transmitting the rotation of the drive unit 7 to the second work roll 10b, is a general cross-pin type universal joint (universal joint), and one end is connected to the drive unit 7. 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 speed reducer 7c. The electric motor 7a is a so-called motor that converts electric power into rotary 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 speed reducer 7c, and the speed reducer 7c is a device that reduces the rotation speed of the electric motor 7a to increase the 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 is rotatably supported via the neck bearing. There is.

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

<<< How to use work roll 10 >>>
Next, how to use the work roll 10 will be described. In the present embodiment, the ratio (L ₁ / D _w1 ) of the body length L ₁ and the diameter D _{w 1} of the first work roll 10a satisfies 4.0 ≦ L ₁ / D _w1 ≦ 7.0, and the second The first work roll 10a and the second work roll so that the ratio (L ₂ / D _{w 2} ) of the body length L ₂ and the diameter D _{w 2} of the work roll 10b satisfies 4.0 ≤ L ₂ / D _{w 2} ≤ 7.0. Use 10b.

As described above, it barrel length L ₂ of the body length L ₁ and the second work roll 10b of the first work roll 10a are the same size, of rolling together the maximum strip width of the specification of the rolling equipment (in the rolling equipment The maximum plate width that can be rolled, which is usually the same as 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 including 150 mm is the value of the body length L ₁ and the body length L ₂ .

Then, the diameter D _w1 of the first work roll 10a and the diameter D _w2 of the second work roll 10b are both worn and reduced during rolling. That is, the value of L ₁ / D _w1 (L ₂ / D _w2 ) at the time of rolling becomes a variable of the diameter D _W1 (diameter D _W2 ) because the body length L ₁ (body length L ₂ ) does not change at the time of rolling. The minimum value is when the work roll 10 is new, and the maximum value is when the work roll 10 is discarded (when it is worn and the diameter becomes small and needs to be discarded).

Therefore, using the first work roll 10a and the second work roll 10b so as to satisfy 4.0 ≤ L ₁ / D _w1 ≤ 7.0 and 4.0 ≤ L ₂ / D _w2 ≤ 7.0 means that the work Use the work roll 10 so that L ₁ / D _w1 (L ₂ / D _{w 2} ) from when the roll 10 is new to when it is discarded is within the above range (that is, 4.0 or more and 7.0 or less). Is. In the following, such matters will be specifically described.

<Force applied to 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 schematic cross-sectional view for explaining the force applied to the work roll 10 during rolling. In the cross-sectional view, the horizontal direction (horizontal direction) of the paper surface is referred to as the "transportation direction", and one side (the other side) thereof is referred to as "upstream (downstream)" or "inside (outside)", and the vertical direction of the paper surface. (Vertical direction) is called "vertical direction", and the upper side (lower side) is called "upper (lower)".

In the present embodiment, since only the second work roll 10b is driven and the first work roll 10a is not driven, torque due to the rolling reaction force is not generated in the first work roll 10a. That is, as shown in FIG. 2, the rolling reaction force Pr of the first work roll 10a acts from the center of the work roll contact arc length Lp toward the center of rotation of the first work roll 10a.

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 a horizontal component of the rolling reaction force Pr, is supported by the work roll chock via the neck bearing. become.

Since torque is generated in the work roll 10 that is driven and rotated due to the rolling reaction force, the work roll contact arc length is shown as shown by the rolling reaction force (down arrow in FIG. The rolling reaction force acts only in the vertical direction from a certain point between the center of Lp and the outlet of the contact arc length.

Therefore, when both the first work roll 10a and the second work roll 10b are rotationally driven, the above-mentioned horizontal force Ph is not generated. That is, compared to the case of rolling by a general rolling mill in which the upper and lower work rolls 10 are both driven, in the one-sided driving rolling as in the present embodiment, the generation of the horizontal force Ph reduces the diameter of the work roll 10. It becomes a barrier.

Therefore, when the work roll 10 is driven only on one side, the horizontal force Ph of the rolling reaction force Pr is used as a guide when designing the diameter of the work roll 10. 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
Lp = √ ((D _W1 + D _w2 ) / _2/2 · ΔH)
= 1/2 ・ √ ((D _W1 + D _w2 ) ・ ΔH)
ΔH: Reduction amount per pass. Value of entry side plate thickness H1-exit side plate thickness H2.

Rolling reaction force: Pr
Pr = C ・ km ・ b ・ √ (1/2 ・ D _W1・ ΔH)
C: Friction coefficient, rolling force coefficient due to tension, etc. km: Average deformation resistance of the material to be rolled b: Plate width of the material to be rolled 3 (dimensions in the axial direction)
Horizontal force of rolling reaction force Pr: Ph
Ph = 1/2 ・ Lp / D _W1・ 2 ・ Pr
= 1/2 ・ √ ((D _W1 + D _w2 ) ・ ΔH) / D _W1・ Pr
= 1/2 ・ √ ((D _W1 + D _w2 ) ・ ΔH) / D _W1・ C ・ km ・
b ・ √ (1/2 ・ D _W1・ ΔH)
Assuming that 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.

Ph = 1/2 ・ C ・ km ・ b ・ ΔH ・ ・ ・ (1)
As shown in the above equation (1), the horizontal force Ph of the rolling reaction force Pr is simply the rolling force coefficient C, the average deformation resistance km, the plate width b, and the rolling amount, regardless of the diameter of the work roll 10. It can be expressed using ΔH.

<Stress at the weakest part of the work roll 10>
Next, the stress of the weakest part of the work roll 10 is obtained. The weakest portion referred to here is a portion of the work roll 10 during rolling where defects such as cracks are most likely to occur.

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

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

The maximum bending force Fb acting on the roll chock can be expressed by the following equation from the experience value.

Fb = 1/4 · D _w1 ² ... (2)
The resultant force Fc acting on the roll chock can be expressed by the following equation.

Fc = √ ((Ph / 2) ² + Fb ² ) ・ ・ ・ (2-1)
= √ ((Ph / 2) ² + (1/4 · D _w1 ² ) ² )
The stress σ _n acting on the weakest part of the work roll 10 can be expressed by the following equation.

σ _n = α ・ Fc ・ Ln / Zn
= Α ・ √ ((Ph / 2) ² + (1/4 ・ D _w1 ² ) ² ) ・ Ln /
(Π / 32 ・ (kn ・ D _w1 ) ³ ) ・ ・ ・ (3)
α: Stress concentration coefficient of the weakest part Zn: Cross-sectional coefficient of the weakest part kn: Diameter at the time of new work roll (nominal diameter) Ratio of diameter of the weakest part to D _w1N <Calculation of one-sided drive waste diameter and nominal diameter ＞
Next, in designing the diameter of the work roll 10, the one-side drive waste diameter and the nominal diameter as a guideline for the diameter of the work roll 10 are obtained. In the present specification, the nominal diameter of the work roll means the diameter of the work roll when it is new before use, and the waste diameter of the work roll means when the work roll worn by use is discarded. It means the diameter of the work roll.

The one-sided drive waste diameter focuses on the horizontal force Ph generated during one-sided drive, sets the maximum bending force Fb to zero (using the horizontal force Ph during one-sided drive instead of the resultant force Fc in equation (3)). The calculated waste diameter of the work roll 10, and the corresponding nominal diameter is the new diameter of the work roll 10 calculated from the one-side drive waste diameter. That is, the one-side drive waste diameter is calculated only by the horizontal force Ph generated at the time of one-side drive assuming that the maximum bending force Fb does not exist. Therefore, here, for convenience, it is referred to as "one-side drive" waste diameter. It is distinguished from the work roll waste diameter Dm (this waste diameter also considers the maximum bending force Fb), which will be described later.

If the horizontal force Ph is used instead of the resultant force Fc in the formula (3), the following formula is obtained.

σ _n = α · Ph / 2 · Ln / (π / 32 · (kn · D _w1 ) ³ )
= Α ・ 1/4 ・ C ・ km ・ b ・ ΔH ・ Ln /
(Π / 32 ・ (kn ・ D _w1 ) ³ ) ・ ・ ・ (4)
Soshitara, (4) using a formula, and sigma _n of the reference rolling equipment, and sigma _n of a rolling equipment, but when the same value, migraine driving waste却径work roll 10 of the reference rolling equipment And the one-sided drive waste diameter of the work roll 10 of a certain rolling equipment is derived (calculated as a coefficient).

Assuming that the one-side drive waste diameter when the maximum plate width b _{0 in} the specifications of the standard rolling equipment is Dmin ₀ , the stress σ _n0 acting on the weakest part of the work roll 10 can be expressed by the following equation.

σ _n0 = α ・ 1/4 ・ C ・ km ・ b ₀・ ΔH ・ Ln ₀ /
(Π / 32 ・ (k ₀・ Dmin ₀ ) ³ ) ・ ・ ・ (5)
k ₀ : Ratio of the diameter of the weakest part to Dmin _{0 If} the one-sided drive waste diameter at the maximum plate width b _{x in} the specifications of the rolling equipment is Dmin _x , the stress acting on the weakest part of the work roll 10 σ _nx can be expressed by the following equation.

σ _nx = α ・ 1/4 ・ C ・ km ・ b _x・ ΔH ・ Ln _x /
(Π / 32 ・ (k ₀・ Dmin _x ) ³ )
Here, if β = b _x / b ₀ = Ln _x / Ln ₀ and γ = Dmin _x / Dmin ₀ , the stress σ _{n x} can be expressed by the following equation using b ₀ , Ln ₀ , and Dmin _0. ..

σ _nx = α ・ 1/4 ・ C ・ km ・ βb ₀・ ΔH ・ βLn ₀ /
(Π / 32 ・ (k ₀・ γDmin ₀ ) ³ ) ・ ・ ・ (6)
Then, when the following equation holds, the equations (5) and (6) are the same. That is, the strength of the work roll 10 of the standard rolling equipment and the work roll 10 of a certain rolling equipment (stress of the weakest part of the work roll 10) are equal.

β ² = γ ³
γ = β ^2/3 = (b _x / b ₀ ) ^2/3 ... (7)
Then, the known values of the one-sided drive waste diameter Dmin ₀ of the standard rolling equipment, the maximum plate width b ₀ of the standard rolling equipment, the maximum plate width b _x of a certain rolling equipment, and γ = Dmin _x / From the relational expression of Dmin _{0 and} the equation (7), the one-side drive waste diameter Dmin _x of the work roll 10 in a certain rolling equipment (one-side drive having the same strength as the one-side drive waste diameter Dmin _{0 of the} standard rolling equipment). The waste diameter Dmin _x ) can be calculated. In other words, it can be seen that the basic strength of the work roll can be secured if the work roll waste diameter of each equipment specification of the one-side drive system is determined by the 2/3 power of each maximum plate width ratio.

As a specific numerical value, the maximum plate width b ₀ = 1250 mm of the standard rolling equipment is set, and the allowable stress of a general forged steel roll is set with respect to the pass schedule mainly for hard materials (number of passes, rolling conditions in each pass, etc.). Is 22 kgf / mm ² (216 MPa), and the standard abandonment diameter Dmin ₀ of the rolling mill is calculated by the limit design to be 250 mm. Then, with this as a reference, FIG. 4 shows the one-side drive waste diameter Dmin _x of each rolling equipment obtained from the maximum plate width b _x of each rolling equipment.

FIG. 4 is a graph showing the relationship between the maximum plate width of the rolling equipment and the one-side drive waste diameter and the nominal diameter of the work roll 10. The horizontal axis shows the maximum plate width of the rolling mill, and the vertical axis shows the one-sided drive waste diameter and the nominal diameter when the diameter of the work roll 10 is taken. The one-side drive waste diameter is shown by a solid line and the nominal diameter is shown by a broken line.

The maximum plate width (maximum plate width in the specifications of the rolling equipment) of the material 3 to be rolled to which the present invention is applied is 900 mm at the minimum and 2000 mm at the maximum. Rejection diameter and nominal diameter are calculated and shown. That is, the design maximum plate width of the material 3 to be rolled is in the range of 900 mm to 2000 mm.

Further, in the present embodiment, the ratio of the waste diameter (minimum diameter) to the new diameter (maximum diameter) of the work roll 10 is changed from the conventional 0.9 or more based on the recent improvement results of the work roll surface hardness depth characteristics. Since it has been changed to 0.8 or more, the changed 0.8 is also applied to the ratio of the one-side drive waste diameter to the nominal diameter. That is, the nominal diameter of the work roll 10 is calculated by dividing the value of the one-side drive waste diameter of the work roll 10 obtained earlier by 0.8, and the calculation result is shown as a broken line in FIG.

By changing the ratio between the waste diameter of the work roll 10 and the new diameter in this way, the effect of improving the basic unit of the work roll (suppressing the cost by extending the life of the work roll 10) can be obtained. , Effect of reducing rolling load and torque by single-drive different-diameter roll rolling (Rolling with different diameters of upper and lower work rolls 10 is called different-diameter roll rolling, and single-drive different-diameter roll rolling is same-diameter roll rolling. The rolling load and torque of the work roll 10 are lower with respect to the same reduction amount ΔH).

<Determination of the diameter of the work roll 10>
Next, the work roll waste 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, the allowable stress of a general forged steel roll is set to 22 kgf / mm ² (216 MPa) with respect to the pass schedule mainly composed of hard materials of each rolling equipment, and the maximum of the work roll 10 with respect to the resultant force Fc from the equation (3). The stress σ _{n of the} weak part is obtained, and the work roll waste diameter Dm and the work roll new diameter Ds are determined so that the safety factor becomes a predetermined value or more (1.3 or more in this embodiment).

FIG. 5 is a table showing each parameter for the new work roll diameter Ds and the work roll waste diameter Dm determined based on the maximum plate width of each equipment specification. In the table of FIG. 5, nine examples 1 to 9 are described as application examples. Application example 1 is a rolling mill having a maximum plate width of 1050 mm according to specifications, and application examples 2 to 4 are maximum plate widths according to specifications. 1250 mm rolling equipment, application examples 5 to 7 are rolling equipment having a maximum plate width of 1600 mm according to specifications, and application examples 8 and 9 are rolling equipment having a maximum plate width of 1850 mm according to specifications. In the following, the procedure for determining the work roll waste diameter Dm and the work roll new diameter Ds will be described by taking Application Example 1 as an example.

First, check the one-sided drive waste diameter of the work roll 10. Since the maximum plate width of the material 3 to be rolled that can be rolled in the rolling equipment of Application Example 1 is 1050 mm, the value on the vertical axis of the solid line at the position where the horizontal axis of FIG. It can be seen that it is about 220 mm. Since the work roll waste diameter Dm may be determined so as not to fall below this as a guide, the work roll waste diameter Dm is tentatively determined to be 225 mm. Then, the work roll waste diameter Dm is divided by 0.8 to tentatively determine the new work roll diameter Ds as 280 mm.

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

When the new work roll diameter Ds and the work roll waste diameter Dm of each rolling equipment are determined by this procedure, the diameter of the work roll 10 falls within the range of 200 mm to 450 mm as shown in Application Examples 1 to 9 of FIG. That is, the diameters of the two work rolls 10 are in the range of 200 mm to 450 mm.

Further, (since the cylinder length L ₁ and barrel length L ₂ of the present invention is the same size, or less, the cylinder length L ₁ and barrel length L ₂ also referred to as barrel length L) cylinder length L of the rolling equipment and the work roll When the ratio L / Ds with the new diameter Ds and the ratio L / Dm between the body length L of each rolling equipment and the work roll waste diameter Dm are calculated, the values shown in the two columns on the right side of the table shown in FIG. 5 are obtained. .. The ratio L / D of the body length L and the diameter of the work roll 10 has a minimum value of L / Ds and a maximum value of L / Dm, and is within the range of L / Ds and L / Dm at the time of rolling. ..

In FIG. 6, the horizontal axis of FIG. 4 is represented by the body length L of the work roll 10, and the new work roll diameter Ds (triangulation point) and the work roll waste diameter Dm (round point) of the application examples 1 to 9 shown in FIG. , And the ratio L / D = 4 and L / D = 7 of the body length L and the diameter of the work roll are plotted.

As shown in FIG. 6, the work roll waste diameter Dm is determined by the above-mentioned procedure, and the work roll new diameter Ds is set so that the ratio of the work roll waste diameter Dm and the work roll new diameter Ds is 0.8 or more. Once determined, all work roll new diameters Ds (triangular points) and work roll waste diameters Dm (round points) are within the range of L / D = 4 to 7 (L / D = 4 and L / D = 7). It fits in between).

In this way, the first work roll 10a and the second work roll 10b are used so as to satisfy 4.0 ≤ L ₁ / D _w1 ≤ 7.0 and 4.0 ≤ L ₂ / D _w2 ≤ 7.0. By such use, the strength of the work roll 10 is ensured.

<<< Operation method of work roll 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 body length and the shape of the roll neck Rn are the same) and can be replaced. Ten operation methods can be applied.

The surface of the work roll of the rolling mill becomes rough as it wears, so it is necessary to polish the surface after each use for a certain period of time. Therefore, in a rolling mill, many spare parts for work rolls are usually prepared, and they are numbered for each roll and managed by a roll shop facility.

After a new work roll was attached as the first work roll 10a and the second work roll 10b and rolling was started, after a certain period of use, the roll diameter varies due to the difference in the degree of wear of the work roll. Since it is known as an empirical value how much the work roll wears and the diameter decreases in proportion to the usage time, the number of each work roll (roll spare part) is associated with the usage time and a database is created. , The diameter of each work roll (roll spare part) is controlled by this.

When the rolls are widely distributed from new products to rolls with a diameter near the abandoned diameter after the operation period, two of the multiple roll spare parts, one with a diameter ratio to the nominal diameter larger than the predetermined reference value and the other with a smaller diameter, are selected. Of the two roll spare parts taken out, the one having the smaller diameter is replaced with the first work roll 10a, and the one having the larger diameter is replaced with the second work roll 10b. The reference value is preferably about 0.9.

Further, it is preferable to _{dispose of} the first work roll when the ratio (D _w1 / D _w1N ) of the diameter D _w1 of the first work roll 10a to the nominal diameter D _w1N becomes 0.8. It is preferable to calculate the diameter of each roll including the first and second work rolls and roll spare parts based on the relationship (experience value) between the usage time and the degree of wear because the complexity of the equipment can be avoided. However, the present invention is not limited to this method, and it is determined that the ratio (D _w1 / D _w1N ) of the diameter D _w1 to the nominal diameter D _w1N is 0.8 by directly measuring the diameter of the first work roll. You may.

=== About the effectiveness of the first embodiment ===
As described above, the rolling mill 1 according to the first embodiment includes two work rolls 10 arranged on the upper side and the lower side of the plate passing line, and 1 for each of the two work rolls 10. It is a four-stage rolling mill 1 provided with a book backup roll 12, and the two work rolls 10 have the same axial length and the shape of the roll neck Rn and can be interchanged with each other. Of the work rolls 10, the first work roll 10a, which is one work roll 10, is not rotationally driven, and the second work roll 10b, which is the other work roll 10, is rotationally driven. The ratio (L ₁ / D _w1 ) of the body length L ₁ of the roll 10a to the diameter D _{w 1} satisfies 4.0 ≦ L ₁ / D _w1 ≦ 7.0, and the body length L ₂ of the second work roll 10b. It is characterized in that the ratio of diameters D _w2 (L ₂ / D _{w 2} ) satisfies 4.0 ≦ L ₂ / D _w2 ≦ 7.0. Therefore, it is possible to provide a rolling mill 1 that can withstand a high torque even if a work roll 10 having a small diameter is used and whose cost is suppressed.

In recent years, for the purpose of increasing the strength and weight of automobiles and the like, there has been a demand for a rolling mill capable of driving a work roll 10 having a smaller diameter than the conventional one with a high torque. However, in the conventional method, problems such as insufficient strength of the spindle, upsizing of the rolling mill, vibration during high-speed rolling, and torque circulation have occurred.

On the other hand, in the rolling mill 1 according to the first embodiment, first, in general, when both the upper and lower work rolls 10 are driven and rotated, only one side of the work roll 10 (second work roll 10b) is driven and rotated. Was to be driven and rotated. This eliminates the interference between the spindles at the top and bottom, creating a space to increase the spindle diameter, making it possible to increase the diameter and increase the spindle strength, withstand large torque, and rotate at high speed. It becomes possible to.

Also, since it is possible to use an inexpensive general cross-pin type universal joint instead of the expensive special gear spindle type for ensuring the strength of the spindle, it is possible to suppress the cost.

Further, since the tilt angle of the universal joint is about 8 ° to 10 ° at the maximum, which is larger than that of the gear spindle (tilt angle of about 1.5 ° at the maximum), a long spindle such as a gear spindle is used to secure the roll opening. Is no longer necessary, and it is possible to suppress the increase in size of the rolling mill.

Further, since only the second work roll 10b is driven for rolling, torque circulation does not occur and strict diameter difference management between the upper and lower work rolls becomes unnecessary.

Second, the first work roll 10a and the second work roll 10b are set to work rolls 10 having the same specifications. That is, even if the specifications (diameter) are the same, the amount of wear of the upper and lower work rolls 10 is different, so that the above-mentioned effect of different diameter roll rolling can be obtained. Since the specifications are the same, the work roll, neck bearing, and neck seal are more than those of the general different diameter roll rolling mill (the specifications of the upper and lower work rolls are different) shown in Patent Document 1 (Patent No. 3290975). It is possible to reduce the types and number of spare parts (consumables) for operation such as.

Thirdly, it was decided to use the work roll 10 in the range of 4.0 ≤ L ₁ / D _w1 ≤ 7.0 and 4.0 ≤ L ₂ / D _w2 ≤ 7.0. When rolling is performed by driving only the second work roll 10b as in the rolling mill 1 according to the first embodiment, a large horizontal force Ph is generated and the strength of the work roll 10 is insufficient. By using it so as to satisfy 4.0 ≤ L ₁ / D _w1 ≤ 7.0 and 4.0 ≤ L ₂ / D _w2 ≤ 7.0, the work roll 10 has sufficient strength in any rolling equipment. It becomes possible to secure.

Further, in the first embodiment, the ratio of the waste diameter (minimum diameter) of each work roll to the nominal diameter (maximum diameter, new diameter) is 0.8 or more.

That is, it is possible to contribute to extending the life of the work roll and to enhance the effect of reducing the rolling load and torque by one-sided drive different diameter roll rolling.

Further, in the first embodiment, the diameters of the two work rolls 10 are set to be within the range of 200 mm to 450 mm.

That is, there is provided a rolling mill 1 in which the diameter of the work roll 10 is in the range of 200 mm to 450 mm, the drive device can withstand a high torque even if a small diameter work roll 10 is used, and the cost is suppressed. It becomes possible to do.

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

That is, since the rolling equipment is designed within the range where the maximum plate width of the material 3 to be rolled is in the range of 900 mm to 2000 mm, the drive device should be able to withstand high torque even if the work roll 10 having a small diameter is used in such a range. It is possible to provide a rolling mill 1 whose cost is suppressed.

In the first embodiment, the diameter _{D w1} of the first work roll 10a is a method comprising rolling a smaller diameter than the diameter _{D w2} of the second work roll, the diameter _{D w2} of the second work roll 10b, the second work The roll 10b is used at the second work roll position when the ratio (D _w2 / D _w2N ) to the nominal diameter (new diameter) D _w2N is equal to or higher than the reference value, and the diameter D _w1 of the first work roll 10a is the first work roll 10a. When the ratio (D _w1 / D _w1N ) to the nominal diameter (new diameter) D _w1N is less than the standard value, the work roll is used up to the discarded diameter at the first work roll position. The reference value may be appropriately set at a value of about 0.85 to 0.95, but it is better than the conventional method that was abolished when the ratio of the diameter to the nominal diameter became about 0.9. From the viewpoint of using the roll for a long time, it is preferable to set the reference value at 0.9 and use a roll spare part worn to a diameter smaller than this.
According to the operation method of the work roll 10, the first work roll 10a is always rolled in a state where the diameter is smaller than that of the second work roll 10b (different diameter roll rolling state).
That is, according to the operation method of the work roll 10 according to the present embodiment, one-sided drive different-diameter roll rolling can always be performed, so that the effect of reducing the rolling load by one-side drive different-diameter roll rolling can be enhanced.

=== 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 transport direction are the same. The positional relationship shown in FIG. 2), but in the second embodiment, , As shown in FIG. 7, rolling is performed with 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 different from the position of the rotation center of the backup roll 12 in the transport direction). Will be done.

FIG. 7 is a diagram corresponding to FIG. 2, and is a schematic cross-sectional view for explaining the force applied to the work roll 10 during offset rolling. Although the details will be described later using a calculation formula, it is possible to reduce the horizontal force generated in the work roll 10 by rolling the work roll 10 in an offset state.

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

That is, the rolling mill 150, in addition to the rolling mill 1, offsets only the first work roll 10a of the two work rolls 10 horizontally to the entry side in the rolling direction of the rolling mill 1 by a predetermined offset amount. It is configured to control the roll offset device (offset device 100) configured to enable the operation and the roll offset device (offset device 100) so as to offset the first work roll 10a to the entry side by a predetermined offset amount. It further includes an offset amount control device (offset control unit 130).

FIG. 8 is a cross-sectional view of the offset device 100, and FIG. 9 is a view showing the offset control unit 130. Further, in FIG. 9, one side in the axial direction is referred to as a drive side, and the other side is referred to as an operation side.

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

Therefore, in the following, when the description of the first offset device 100a to the fourth offset device 100d is duplicated, the first offset device 100a will be described and the description of the other devices will be omitted (the reference numerals of the drawings are also omitted). Note that FIG. 8 is an offset device 100 viewed from the operation 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 adjusting cylinder 102a, a first position detection sensor 104a, a first upper bending block 106a, a first project block 108a, a first bending cylinder 110a, and a first lower bending. It has a block 112a and.

The first position adjusting cylinder 102a moves (offsets) the first work roll 10a supported by the roll chock 9 to the entry side in the transport direction by pushing the roll chock 9 of the rolling mill 1 at the tip 102ae of the first cylinder. Further, the first position adjusting cylinder 102a is provided in the first upper bending block 106a (may be provided in the first project block 108a), and the first position adjusting cylinder 102a is on the opposite side of the first cylinder tip 102ae. A one-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 for controlling the position of the tip 102ae of the first cylinder in the transport direction.

The first upper bending block 106a is provided on the first project block 108a so as to be movable in the vertical direction. 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 opposite 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 work roll 10a moves in the vertical direction via the roll chock 9. ..

Further, 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 in the first lower bending block 112a. It can move up and down.

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

Then, at the time of rolling, the first bending cylinder 110a moves the work roll 10 so as to oppose the bending of the work roll 10. Therefore, the above-mentioned maximum bending force Fb is generated in the work roll 10.

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

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

Fh ₁ = Pr · (2 · e1 / (Db ₁ + D _w1 ))
-2 ・ e2 / (D _w1 + D _w2 )) ・ ・ ・ (8)
Db ₁ : Diameter of the first backup roll 12a e1: Offset amount of 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 The work roll 10 has tension. Inertial force, frictional force, etc. from the contacting rolls also work, but since the horizontal force Ph _{1 of} the rolling reaction force Pr and the horizontal force Fh ₁ due to the offset mainly work, the horizontal force F ₁ acting on the first work roll 10a. Can be expressed by the following equation by summing the equations (1) and (8).

F ₁ = Ph + Fh ₁
= 1/2 ・ C ・ km ・ b ・ ΔH + Pr ・ (2 ・ e1 / (Db ₁ + D _w1 ))
-2 ・ e2 / (D _w1 + D _w2 )) ・ ・ ・ (9)
Further, the horizontal force Fh ₂ of the second work roll 10b generated by the offset can be expressed by the following equation.

Fh ₂ = Pr · (2 · (e1 + e2) / (Db ₂ + D _w2 ))
+2 ・ e2 / (D _w1 + D _w2 )) ・ ・ ・ (10)
Db ₂ : Diameter of the second backup roll 12b Even in the second work roll 10b, the horizontal force Ph and the horizontal force Fh ₂ are mainly acting forces, so that the horizontal force F ₂ acting on the second work roll 10b is ( The equations 1) and (10) can be summed up and expressed by the following equation.

F ₂ = -Ph + Fh ₂
= -1 / 2 ・ C ・ km ・ b ・ ΔH + Pr ・ (2 ・ (e1 + e2) /
(Db ₂ + D _w2 ) + 2 · e2 / (D _w1 + D _w2 )) ・ ・ ・ (11)
FIG. 10 shows the results of calculating the horizontal force F ₁ and the horizontal force F ₂ under both conditions with and without offset using the above equation. The left table of FIG. 10 is the result of calculation under the condition without offset, and the right table of FIG. 10 is the result of calculation under the condition with offset. In addition, FIG. 10 is an example using a cold reversible rolling mill (a rolling mill that rolls from the entry side to the exit side and then rolls the next pass from the exit side to the entry side).

As shown in the table on the left of FIG. 10, under the condition without offset, a large horizontal force in which the positive and negative directions are reversed in odd-numbered passes (rolling from the entry side to the exit side) and even-numbered passes (rolling from the exit side to the entry side). Is occurring.

On the other hand, as shown in the right table of FIG. 10, under 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 higher than those without offset. It has been reduced to less than half.

That is, by offsetting the first work roll 10a to an appropriate position on the entry side in the rolling of each pass, the horizontal forces F ₁ and F ₂ can be reduced to half or less as compared with the case where the offset is not performed. Then, the resultant force Fc with the maximum bending force Fb = 26.4 tons (259 kN) shown in the equation (2) is √ (26.4 ² + (11.0 / 2) ² ) from the equation (2-1). = 27.0 tons (265 kN), and it is possible to suppress the increase in the resultant force Fc to an increase of about 2% of the maximum bending force Fb.

In other words, the non-driving work roll 10 (first work roll 10a) of the work roll 10 is provided with an offset device 100 capable of changing the offset amount, and the non-driving work roll 10 (first work roll 10a) is provided. By rolling by offsetting the rotation center of the roll that contacts the rotation center of 10a) to an appropriate position on the entry side with respect to the rotation center of the roll (the rotation center of the first backup roll 12a and the second work roll 10b in the present embodiment). The external force of the work roll 10 can be suppressed in each pass, and stable rolling becomes possible.

Further, if the horizontal force F ₁ becomes smaller, the reduction amount ΔH per pass can be increased. That is, in one-sided driving rolling, the rolling reduction ratio (rolling amount ΔH / entry side plate thickness H1) can be increased by offsetting.

When the offset amounts e1 = −4.5 mm and e2 = 4.5 mm, only the first work roll 10a is moved 4.5 mm to the entry side, and the second work roll 10b is the center of rotation with the backup roll 12 in the transport direction. Indicates that they are in the same position (not offset).

Next, a rolling method (rolling control) for offset rolling will be described with reference to FIGS. 8 and 9. Specifically, a rolling method (rolling control) in which the first work roll 10a is offset horizontally by a predetermined offset amount to the entry side in the rolling direction of the rolling mill 1 by using the rolling mill 150 will be described. To do. In the following description, the material 3 to be rolled is conveyed and rolled from the entry side (left side) to the exit side (right side) shown in FIGS. 8 and 9.

The offset control unit 130 includes a PI controller provided on the offset position control panel 132 corresponding to each of the first offset device 100a to the fourth offset device 100d, a control valve, and a cylinder pressure detection sensor. The same control is performed on the first offset device 100a to the fourth offset device 100d. Therefore, in the following, when the description of the first offset device 100a to the fourth offset device 100d is duplicated, only the first offset device 100a will be described, and the description of the other devices will be omitted (the reference numerals of the drawings are also omitted). ..

First, before the start of rolling, the first position adjusting cylinder 102a of the first offset device 100a on the output side operation side and the third position adjustment cylinder 102c of the third offset device 100c on the output side drive side are subjected to the first work roll. The 10a is pushed toward the entry side, and the first work roll 10a is offset (moved) so as to be at a predetermined position on the entry side from the rotation center of the backup roll 12.

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

Then, after the above setting, rolling is started, and at the time of rolling, the offset amount of the first work roll 10a is controlled to be a constant value. Specifically, the first PI controller 134a provided on the offset position control panel 132 has a position actual value (offset position) detected by the first position detection sensor 104a corresponding to the first position adjustment cylinder 102a, and a path schedule. Compares with the offset command value determined in advance from, and calculates whether the offset position deviates from the offset command value.

When the offset position deviates from the offset command value, the position of the first position adjusting cylinder 102a is set by the first PI controller 134a via the first control valve 120a so that the deviation between the offset command value and the actual position value becomes zero. Control so that it becomes the offset command value. The pressure detection sensor 122a functions as a monitor for monitoring whether or not the previously calculated horizontal force is correct, and is useful for correcting the offset command value.

The offset command value rolling load, not only horizontal force F _1, F _2, the difference in tension of the rolled material 3 side out and entry side, the transmission force from the bearing friction torque of the backup roll 12, acceleration and deceleration It is determined in consideration of the inertial force of the backup roll 12 at that time.

=== About the effectiveness of the second embodiment ===
As described above, in the rolling mill 150 according to the second embodiment, of the two work rolls 10, only the first work roll 10a is offset horizontally to the entry side in the rolling direction of the rolling mill 1 by a predetermined offset amount. It is configured to control the roll offset device (offset device 100) configured to be able to perform the rolling and the roll offset device (offset device 100) so as to offset the first work roll 10a to the entry side by a predetermined offset amount. An offset amount control device (offset control unit 130) is further provided, and the first work roll 10a is rolled by being offset horizontally by a predetermined offset amount on the entry side of the rolling mill 1 in the rolling direction. I decided.

Therefore, the offset amount of the first work roll 10a can be changed for rolling, and the horizontal forces F ₁ and F ₂ can be reduced, so that the bending is suppressed and the diameter of the work roll 10 is reduced. Is possible. Further, as can be seen from the equations (9) and (11), if the horizontal forces F ₁ and F ₂ become smaller, the reduction amount ΔH per pass can be increased. That is, in one-sided driving rolling, the reduction rate (rolling amount ΔH / input side plate thickness H1) can be increased by offsetting the first work roll 10a to the entry side by a predetermined offset amount.

In cold rolling, especially in a tandem mill, rolling is performed according to a wide range of pass schedules depending on the material, plate thickness, and plate width b of the material 3 to be rolled. It is necessary to increase the rolling amount ΔH of. That is, conventionally, when rolling by driving only one side of the work roll 10, a large horizontal force Ph is generated in the work roll 10, so that it is difficult to reduce the diameter of the work roll 10.

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

Further, by making the offset amount changeable, the first work roll 10a can be adjusted to an appropriate offset position according to each path schedule, so that the horizontal forces F ₁ and F ₂ can be further reduced, and the work can be further reduced. The diameter of the roll 10 can be further reduced, and the roll 10 can be rolled at a higher reduction rate.

In addition, by reducing the horizontal forces F ₁ and F ₂ , the strength of the work roll 10 and the strength of the neck bearing are relatively increased, so it is expected that the life of the work roll 10 and the neck bearing will be extended. Can be done.

Further, in the one-sided driving rolling mill 150 in which only the second work roll 10b is driven as in the second embodiment, a horizontal force Ph acts on the first work roll 10a in the same direction as the rolling direction, and the second work roll 10b Since a horizontal force Ph in the direction opposite to the rolling direction acts on the first work roll 10a, it is effective to offset only the first work roll 10a in the direction opposite to the rolling direction (entry 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 between the first work roll 10a and the second work roll 10b becomes zero, so that the horizontal forces F ₁ and F ₂ The horizontal force F ₂ of the second work roll 10b increases because the effect of reducing the amount is small.

Further, when the first work roll 10a is offset to the opposite side (entry side) of the rolling direction and the second work roll 10b is offset to the rolling direction (outside), the effect of reducing the horizontal forces F ₁ and F ₂ is high. Since it is necessary to provide the offset device on the second work roll 10b side as well, the equipment cost and the maintenance cost of the equipment are increased, and the control system of the offset device is also complicated.

=== Other embodiments ===
Although the rolling mill 1 and the rolling mill 150 according to the present invention have been described above based on the above-described embodiment, the above-described embodiment of the present invention is for facilitating the understanding of the present invention, and the present invention is the above-described embodiment. It is not limited to the form. The present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes an equivalent thereof.

In the above embodiment, the non-driven work roll 10a is shown as an upper roll and the driven work roll 10b is shown as a lower roll, but the non-driven work roll 10a may be a lower roll and the driven work roll 10b may be an upper roll. Further, the rolling mill 1 has a four-stage configuration, but the present invention is not limited to this, and for example, a six-stage rolling mill in which an intermediate roll is provided between the work roll 10 and the backup roll 12 may be used. .. For the offset amount in such a case, the offset amount between the work roll 10 and the intermediate roll may be calculated instead of the work roll 10 and the backup roll 12.

Further, in the above embodiment, the rolling equipment in which the material 3 to be rolled is rolled by one rolling mill has been described, but the present invention is not limited to this, and the reversing rolling equipment consisting of one or a plurality of stands, one or a plurality of stands. It can be applied to both a non-reversing rolling mill consisting of one and a tandem rolling mill consisting of one or more stands.

Further, in the above embodiment, the work roll 10 of the rolling mill 1 is a type of rolling mill that does not shift in the axial direction, but a shift type rolling mill in which the work roll 10 shifts in the axial direction may also be used.

FIG. 11 is a diagram corresponding to FIG. 5, and is a table showing each parameter for the new work roll diameter Ds and the work roll waste diameter Dm determined in the shift type rolling mill, and FIG. 12 is a diagram. 6 is a diagram corresponding to FIG. 6, in which the horizontal axis is represented by the body length L of the work roll 10 in the shift type rolling mill, and the new work roll diameter Ds (triangulation point) and the work roll of the application examples 1 to 9 shown in FIG. It is the figure which plotted the waste diameter Dm (round point) and the ratio L / D = 4 and L / D = 7 of the body length and the diameter of a work roll. In the shift type rolling mill, the body length L of the work roll 10 is a value obtained by adding about (maximum plate width × 0.12 to 0.14) to the maximum plate width (3 from the right in the table shown in FIG. 11). The shift amount of the column).

Also in the shift type rolling mill, the work roll waste diameter Dm is determined in the same manner as in the above embodiment, and the work roll new work roll is made so that the ratio of the work roll waste diameter Dm and the work roll new diameter Ds is 0.8 or more. Determine the diameter Ds. Then, even in the shift type rolling mill, as shown in FIG. 12, the work roll waste diameter Dm and the work roll new diameter Ds are within the range of the ratio L / D = 4 to 7 of the body length and the work roll diameter. Will fit in.

1 Roller 3 Rolled material 5 Spindle 7 Drive 7a Electric motor 7b Gear coupling 7c Reducer 8 Housing 9 Roll chock 10 Work roll 10a 1st work roll 10b 2nd work roll 12 Backup roll 12a 1st backup roll 12b 2nd backup Roll D _w1 Diameter of the first work roll D _w2 Diameter of the second work roll Ds (D _w1N ) New diameter of the work roll Dm Waste diameter of the work roll L Body length of the work roll L ₁ Body length of the first work roll L ₂ No. 2 Work roll body length Lp Work roll contact arc length b Plate width km Average deformation resistance Fb Maximum bending force (bending force)
Fc resultant force σ _n Weakest stress L / D Body length to diameter ratio L / Ds Body length to diameter ratio minimum value L / Dm Body length to diameter ratio maximum value Db ₁ Diameter of first backup roll Db ₂ Diameter of the second backup roll H1 Inlet side plate thickness H2 Outer side plate thickness ΔH Reduction amount Pr Rolling reaction force Ph Horizontal force by one-side drive method Fh ₁ Horizontal force by offset acting on the first work roll Fh _{2 For} the second work roll Horizontal force due to the offset acting F ₁ Horizontal force acting on the first work roll F ₂ Horizontal force acting on the second work roll Ln Roll neck Distance from the center to the weakest part kn Diameter of new work roll (nominal diameter) Rn roll neck e1 offset amount of the first work roll and the first backup roll e2 offset amount of the second work roll and the second backup roll 100 offset device (roll offset device)
100a 1st offset device 100b 2nd offset device 100c 3rd offset device 100d 4th offset device 102a 1st position adjustment cylinder 102b 2nd position adjustment cylinder 102c 3rd position adjustment cylinder 102d 4th position adjustment cylinder 102ae 1st cylinder tip 104a 1st position detection sensor 106a 1st upper bending block 108a 1st project block 110a 1st bending cylinder 112a 1st lower bending block 120a 1st control valve 122a 1st cylinder pressure detection sensor 130 Offset control unit (offset amount control device)
132 Offset position control panel 134a 1st PI controller 150 Roller

Claims (10)

1. A 4- to 6-stage rolling mill provided with two work rolls arranged on the upper side and the lower side across the plate passing line, and at least one backup roll is provided for each of the two work rolls. And
   The two work rolls have the same axial length and roll neck shape and can be interchanged with each other.
   Of the two work rolls, the first work roll, which is one work roll, is not rotationally driven, and the second work roll, which is the other work roll, is rotationally driven.
   The ratio (L ₁ / D _w1 ) of the body length L ₁ of the first work roll to the diameter D _{w 1} satisfies 4.0 ≦ L ₁ / D _w1 ≦ 7.0, and the body length L of the second work roll A rolling mill characterized in that the ratio of ₂ to the diameter D _w2 (L ₂ / D _{w 2} ) satisfies 4.0 ≤ L ₂ / D _{w 2} ≤ 7.0.
2. The rolling mill according to claim 1.
   A rolling mill comprising an electric motor in which a rotating shaft is connected only to the second work roll.
3. The rolling mill according to claim 1 or 2.
   A rolling mill characterized in that the diameters of the two work rolls are in the range of 200 mm to 450 mm.
4. The rolling mill according to any one of claims 1 to 3.
   A rolling mill characterized in that the design maximum plate width of the material to be rolled is in the range of 900 mm to 2000 mm.
5. The rolling mill according to any one of claims 1 to 4.
   A rolling mill characterized in that the ratio of the waste diameter of each of the two work rolls to the nominal diameter is 0.8 or more.
6. The rolling mill according to any one of claims 1 to 5.
   Of the two work rolls, only the first work roll is configured to be offset horizontally to the entry side in the rolling direction of the rolling mill by a predetermined offset amount, and a roll offset device.
   An offset amount control device configured to control the roll offset device so as to offset the first work roll to the entry side by the predetermined offset amount.
   A rolling mill characterized by further providing.
7. The rolling method using the rolling mill according to claim 6.
   A rolling method comprising rolling the first work roll horizontally offset to the entry side in the rolling direction of the rolling mill by the predetermined offset amount.
8. The method for operating a work roll of a rolling mill according to any one of claims 1 to 6.
   A plurality of roll spare parts having the same axial length and roll neck shape as the two work rolls are used in the rolling mill for a certain period of time, and then removed and stored.
   Of the plurality of spare roll parts that have been removed and stored, two of the spare parts having a diameter ratio to a nominal diameter larger than or smaller than a predetermined reference value are taken out.
   Of the two spare rolls taken out, the one having the smaller diameter is replaced with the first work roll, and the one having the larger diameter is replaced with the second work roll.
   Work role operation method including.
9. The work role operation method according to claim 8.
   A work roll operation method characterized in that the predetermined reference value is 0.9.
10. The work roll operation method according to claim 8 or 9.
    A work roll characterized by further including _abolishing the first work roll when the ratio of the diameter to the nominal diameter (D _w1 / D _w1N ) of the first work roll becomes 0.8. Operation method.

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