JP5568261B2 - Rolling mill and tandem rolling mill equipped with the rolling mill - Google Patents

Description

  The present invention relates to a rolling mill capable of reducing the diameter of a work roll and a tandem rolling mill equipped with the rolling mill.

  In a conventional so-called intermediate roll-driven 6-stage rolling mill (hereinafter referred to as a 6-stage mill), the minimum value of the work roll diameter is a support (support) roll inside and outside the roll width of the work roll. Otherwise, it is determined by the work roll deflection rigidity value that can withstand the tangential force of the intermediate roll drive. For example, according to Non-Patent Document 1, it is φ180 to φ380 when driven by a 4-width material (4 feet) and an intermediate roll.

  Here, in the case of the work roll drive, the tangential force does not work, but the differential tension on the entry and exit sides of the rolling mill works. Therefore, the minimum value of the work roll diameter within the allowable strength range of the drive system is determined by the work roll deflection rigidity value that can withstand the differential tension, and at least a work roll diameter equivalent to that described above is possible. Further, in the case of work roll driving, even in a four-stage rolling mill (hereinafter referred to as a four-stage mill), at least a work roll diameter equivalent to the above can be achieved from this viewpoint.

  Further, as a six-stage mill, there is a conventional one having a support roll within the roll width of the work roll, and further provided with a support bearing outside the roll width of the work roll. Patent Document 1 discloses that a work roll is subjected to horizontal bending.

JP-A-5-50109 JP-A-60-238021

"Industrial Machinery" May 1991 (pages 56-60)

  By the way, in order to meet the recent demand, when trying to roll a harder special steel such as stainless steel by a 6-stage mill or a 4-stage mill that does not have a support roll within the width of the work roll that can be rolled, it is described above. There was a problem that the work roll diameter was too large, the load was high, and a necessary reduction amount could not be obtained, and there were problems such as poor gloss.

  On the other hand, a 6-stage mill or a 4-stage mill having a support roll within the roll width of the work roll has a small space for the support roll, and it is difficult to ensure sufficient strength and rigidity, and the work roll can be rolled. Since there is a support bearing for supporting the support roll within the width of the plate, depending on the material, there is a problem that the mark of the support bearing is transferred and generated on the plate via the support roll and the work roll.

  In addition, all rolling mills with support bearings outside the roll width of the work roll that can be rolled are support bearings that are in the same phase in the top and bottom, so large bearings cannot be used, and high loads and high loads that generate large horizontal forces. There is a problem that it cannot be used for rolling of a hard material of torque.

  The present invention has been proposed in view of such circumstances, and its purpose is to make it possible to use a work roll having a smaller diameter for hard material rolling, and to obtain a strip having high productivity and high product quality. It is providing a rolling mill and a tandem rolling mill provided with the rolling mill.

The rolling mill according to the present invention for solving the above problems is as follows.
A pair of upper and lower work rolls for rolling the metal strip, a pair of upper and lower intermediate rolls for supporting the work roll, and a pair of upper and lower reinforcing rolls for supporting the pair of upper and lower intermediate rolls. In a 6-stage rolling mill that does not have a supporting roll inside and outside the rollable sheet width,
The work roll is driven, and the work roll is made of a material having a high longitudinal elastic modulus whose ratio with the longitudinal elastic modulus of the conventional material having a longitudinal elastic modulus of 21,000 kg / mm ² is K = 1.2 to 3.0. The minimum roll diameter of the work roll is between the minimum diameter upper limit Dmax1 and the minimum diameter lower limit Dmin1, and these are expressed by the following formula.
Minimum diameter upper limit Dmax1 = D4max × B / K ^(1/4)
Here, D4max; upper limit of minimum diameter of work roll with conventional plate width of 1,300mm: φ380
B; Board width (mm) / 1,300mm
K: Ratio of high longitudinal elastic material to conventional material
(Longitudinal modulus of high longitudinal elastic material / longitudinal modulus of conventional material (21,000kg / mm ² ))
Minimum diameter lower limit Dmin1 = D4min × B / K ^(1/4)
Here, D4min; Minimum work roll minimum diameter of conventional plate width 1,300mm: φ180

Further, it is composed of a pair of upper and lower work rolls for rolling the metal strip and a pair of upper and lower reinforcing rolls for supporting the work rolls, and has four stages having no support rolls inside and outside the roll width of the work roll. In the type of rolling mill,
The work roll is driven, and the work roll is made of a material having a high longitudinal elastic modulus whose ratio with the longitudinal elastic modulus of the conventional material having a longitudinal elastic modulus of 21,000 kg / mm ² is K = 1.2 to 3.0. The minimum roll diameter of the work roll is between the minimum diameter upper limit Dmax1 and the minimum diameter lower limit Dmin1, and these are expressed by the following formula.
Minimum diameter upper limit Dmax1 = D4max × B / K ^(1/4)
Here, D4max; upper limit of minimum diameter of work roll with conventional plate width of 1,300mm: φ380
B; Board width (mm) / 1,300mm
K: Ratio of high longitudinal elastic material to conventional material
(Longitudinal modulus of high longitudinal elastic material / longitudinal modulus of conventional material (21,000kg / mm ² ))
Minimum diameter lower limit Dmin1 = D4min × B / K ^(1/4)
Here, D4min; Minimum work roll minimum diameter of conventional plate width 1,300mm: φ180

The tandem rolling mill according to the present invention for solving the above problems is
In the tandem rolling mill in which a plurality of rolling mill stands are arranged, at least one of the rolling mills is provided.

  According to the configuration of the present invention, by using a material having a high longitudinal elastic modulus for the work roll, it is possible to secure the deflection rigidity of the work roll and to reduce the work roll diameter by the amount corresponding to the high rigidity. It is possible to reduce the drop, improve the surface gloss, reduce the minimum rollable plate thickness, and apply to a high-load, high-torque rolling mill for hard materials. In particular, it is suitable for cold rolling.

It is a front sectional view of a 6-stage mill showing Example 1 of the present invention. It is the II-II sectional view taken on the line of FIG. It is explanatory drawing of a composite roll. It is explanatory drawing of the entrance / exit side differential tension | tensile_strength. It is a deflection | deviation explanatory drawing of a work roll. It is a graph which shows the comparison of Example 1 and the conventional work roll minimum diameter upper limit Dmax. It is a graph which similarly shows the comparison of work roll minimum diameter minimum Dmin. It is explanatory drawing of the work roll offset which shows the application example of Example 1. FIG. It is explanatory drawing of the load similarly applied to a work roll. It is explanatory drawing of the intermediate | middle roll offset which shows another application example of Example 1. FIG. It is explanatory drawing of the load similarly applied to a work roll. It is explanatory drawing of the work roll shift of the 6-high mill which shows another application example of Example 1. FIG. It is a front sectional view of a four-stage mill showing Example 2 of the present invention. It is the XII-XII sectional view taken on the line of FIG. It is explanatory drawing of the work roll shift of the 4-step mill which shows the application example of Example 2. FIG. It is application explanatory drawing to the tandem rolling mill of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a rolling mill according to the present invention and a tandem rolling mill equipped with the rolling mill will be described in detail using embodiments with reference to the drawings.

1 is a front sectional view of a 6-stage mill showing Embodiment 1 of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is an explanatory view of a composite roll, and FIG. FIG. 5, FIG. 5 is an explanatory view of the deflection of the work roll, FIG. 6 is a graph showing a comparison between Example 1 and the conventional work roll minimum diameter upper limit Dmax, and FIG. 7 is a graph showing a comparison of the work roll minimum diameter lower limit Dmin. 8A is an explanatory diagram of a work roll offset showing an application example of Example 1, FIG. 8B is an explanatory diagram of a load applied to the work roll, FIG. 9A is an explanatory diagram of an intermediate roll offset showing another application example of Example 1, FIG. 9B is an explanatory view of a load applied to the work roll, and FIG. 10 is an explanatory view of a work roll shift of a 6-stage mill showing still another application example of the first embodiment.
It is.

  As shown in FIGS. 1 and 2, a strip 1 that is a material to be rolled is rolled by a pair of upper and lower work rolls 2. The pair of upper and lower work rolls 2 are each contacted and supported by a pair of upper and lower intermediate rolls 3, and the pair of upper and lower intermediate rolls 3 are each supported by a pair of upper and lower reinforcing rolls 4.

  The upper reinforcing roll 4 is supported by bearing housings 17a and 17c via bearings (not shown). These bearing housings 17a and 17c are pass line adjusting devices 5a such as worm jacks or tapered wedges and stepped rocker plates. , 5b through the housing 7 (7a, 7b). Here, a load cell may be built in the pass line adjusting devices 5a and 5b to measure the rolling load.

  The lower reinforcing roll 4 is supported by bearing housings 17b and 17d through bearings (not shown), and these bearing housings 17b and 17d are supported by housings 7a and 7b through hydraulic cylinders 6 (6a and 6b). Has been.

Here, the pair of upper and lower work rolls 2 uses a material having a high longitudinal elastic modulus. Examples of the material having a high longitudinal elastic modulus include cemented carbide such as tungsten carbide (longitudinal elastic modulus: 53,000 kg / mm ² ) and ceramics (longitudinal elastic modulus: 31,000 kg / mm ² ). In addition, special forged steel (longitudinal elastic modulus: 21,000 kg / mm ² ) or the like has been used as a conventional material.

  The ratio of the high longitudinal elastic material to the conventional material (longitudinal elastic modulus ratio K) is preferably set to K = 1.2 to 3.0.

Moreover, as shown in FIG. 3, a roll composite material using a high longitudinal elastic material for the roll surface layer material 2A and a conventional material for the roll inner layer material 2B may be used as a pair of upper and lower work rolls 2. . In this case, the longitudinal elastic modulus is obtained by multiplying the equivalent longitudinal elastic modulus ratio shown below by the longitudinal elastic modulus of the roll inner layer material (for example, conventional material) .

That is, assuming that the outer diameter of the roll surface layer material 2A is d2, the longitudinal elastic modulus is E2, the outer diameter of the roll inner layer material 2B is d1, and the longitudinal elastic modulus is E1, the equivalent longitudinal elastic modulus ratio Ee is the following (1) It is expressed by a formula.

Ee = (d1 ⁴ + (d2 ⁴ −d1 ⁴ ) × E2 / E1) / d2 ⁴ (1)

  Furthermore, bearing boxes 13a to 13d are attached to the roll neck portion of the pair of upper and lower work rolls 2 via bearings (not shown). These bearing boxes 13a to 13d are provided with bending cylinders 14a to 14d for applying roll bending. This gives roll bending to the work roll 2.

  Here, the rolling load is applied by the hydraulic cylinders 6a and 6b, and the rolling torque is transmitted to the work roll 2 from a spindle (not shown). The pair of upper and lower intermediate rolls 3 have roll shoulders 3a each having a roll diameter decreasing at a roll barrel end position symmetrical with respect to the upper and lower points with respect to the center of the width of the band plate 1.

  The pair of upper and lower intermediate rolls 3 are supported by bearing boxes 15a to 15d via bearings (not shown). The pair of upper and lower intermediate rolls 3 can be moved in the axial direction by a shift device (not shown) via drive-side bearing boxes 15c and 15d. Further, these bearing boxes 15a to 15d are provided with bending cylinders 16a to 16d for applying roll bending. This gives roll bending to the intermediate roll 3.

  Here, the deflection of the work roll due to the differential tension at the entrance and exit of the rolling mill will be described with reference to FIGS. 4 and 5.

First, as shown in FIG. 4, assuming that the entry side tension of the rolling mill is Tb and the exit side tension is Tf, a differential tension that is a difference between these is applied to the work roll 2. Since the work roll has one bearing on each of the operation side and the drive side, the support conditions for simple support shown in FIG. 5 are satisfied. The horizontal deflection δs of the work roll in this case is expressed by the following equation (2). Here, the differential tension per unit length is F, the support interval is L, the diameter of the conventional work roll 2 is Dc, the cross-sectional secondary moment of the conventional work roll diameter is Ic, the material of the conventional work roll (special forged steel ) Is the elastic modulus of elasticity (21,000kg / mm ² ).

^{δs = 5 × F × L 4} / (384 × Ec × Ic) (2) where ^{formula, Ic = π × Dc 4/} 64
F = (Tf−Tb) / L / 2

Here, a material having a high longitudinal elastic modulus is used for the pair of upper and lower work rolls 2. In this case, the horizontal deflection δr of the work roll 2 is expressed by the following equation (3). The diameter of the work roll 2 of the embodiment is Dr, the cross-sectional secondary moment of the work roll diameter of the embodiment is Ir, and the longitudinal elastic modulus of the material of the work roll of the embodiment is Er.

^{δr = 5 × F × L 4} / (384 × Er × Ir) (3) where ^{equation, Ir = π × Dr 4/} 64
Here, if δr = δs, Dr is expressed by the following equation (4).

Dr = Dc / K ^(1/4) (4) Formula

On the other hand, the minimum roll diameter of the work roll is similarly between the minimum diameter upper limit Dmax1 and the minimum diameter lower limit Dmin1, and these are expressed by the following equation (5).

Minimum diameter upper limit Dmax1 = D4max × B / K ^(1/4) (5) where D4max; Conventional work roll minimum diameter upper limit of 1,300 mm: φ380
B; Plate width (mm) / 1,300mm
K: Ratio of high longitudinal elastic material to conventional material
(Longitudinal modulus of high longitudinal elastic material / longitudinal modulus of conventional material (21,000kg / mm ² ))

FIG. 6 shows the minimum diameter upper limit Dmax1 for each plate width of this embodiment. However, the work roll material was K = 2.5 in the case of cemented carbide.

Minimum diameter lower limit Dmin1 = D4min x B / K ^(1/4) (6) where D4min; Minimum roll diameter lower limit for conventional rolls of 1,300 mm: φ180

FIG. 7 shows the minimum diameter lower limit Dmin1 for each plate width in this example. However, the work roll material was K = 2.5 in the case of cemented carbide.

  Thus, in this embodiment, the work roll 2 made of a cemented carbide or ceramic material of a high longitudinal elastic material is used in a 6-stage mill having no support roll inside and outside the roll width of the work roll 2. Therefore, the bending rigidity of the work roll is ensured, and the work roll diameter can be reduced by the high rigidity, and the strip 1 having high productivity and high product quality can be obtained in the hard material rolling.

  Further, as shown in FIGS. 8A and 8B, the work roll 2 made of a high longitudinal elastic material is offset in the horizontal rolling direction on the input side in accordance with the magnitude of the input / output differential tension (Tf−Tb) / 2. (See offset amount α in FIG. 8A). Thereby, the input / output side differential tension (Tf−Tb) / 2 is reduced by the offset horizontal component Fa of the rolling load Q, and the total horizontal force applied to the work roll 2 is reduced. In FIG. 8B, Fb represents the offset vertical component force.

As a result, there is an advantage that the deflection of the work roll 2 can be further reduced.
The total horizontal force applied to the work roll 2; Fw is expressed by the following equation (7).

Fw = (Tf−Tb) / 2−Q × α / ((Dw + DI) / 2) (7) where the work roll diameter is Dw and the intermediate roll diameter is DI.

  Further, as shown in FIGS. 9A and 9B, the intermediate roll 3 may be variably offset to the outgoing side in the horizontal rolling direction in accordance with the magnitude of the incoming / outward differential tension (Tf−Tb) / 2 ( (See offset amount β in FIG. 9A). As a result, the input / output differential tension (Tf−Tb) / 2 is reduced by the offset horizontal component Fa of the rolling load Q, and the total horizontal force applied to the work roll 2 of the high longitudinal elastic material is reduced. . In FIG. 9B, Fb represents the offset vertical component.

As a result, there is an advantage that the deflection of the work roll 2 can be further reduced.
The total horizontal force applied to the work roll 2; Fw is expressed by the following equation (8).

Fw = (Tf−Tb) / 2−Q × β / ((Dw + DI) / 2) (8) where the work roll diameter is Dw and the intermediate roll diameter is DI.

  Further, in this embodiment, the pair of upper and lower work rolls 2 does not show a structure that shifts in the axial direction, but the work roll 2 may have a structure that can be shifted in the axial direction as follows. In addition, the shift structure of a work roll has a structure shown by patent document 2, for example.

  As shown in FIG. 10, the pair of upper and lower work rolls 2 have tapered roll shoulders 2 a at the roll barrel end positions in the vertical point symmetry direction with respect to the plate width center of the strip 1. Further, bearings (not shown) are attached to the operation side and the drive side of the roll neck portion of the pair of upper and lower work rolls 2. The pair of upper and lower work rolls 2 can be moved in the axial direction by a shift cylinder (not shown) via a drive-side bearing (not shown).

  Next, an edge drop reduction method by shifting the work roll 2 having a tapered roll shoulder 2a will be described below. First, the work roll 2 is provided with a tapered roll shoulder 2a in the direction of vertical symmetry. The distances from the roll shoulder position to the plate edge are represented by δw and δd. In addition, a plate thickness meter (not shown) is provided for measuring the plate thickness at one point or a plurality of points in the vicinity of the plate ends on the operation side and the drive side on the rolling mill exit side.

  If the plate thickness at one point or a plurality of points near the plate end measured on the operation side is smaller than the predetermined plate thickness, the upper work roll 2 is shifted in the roll axis narrow direction. That is, the upper work roll 2 is shifted in the direction of increasing δw. Conversely, if the plate thickness near the plate end portion measured is thicker than the predetermined plate thickness, the upper work roll 2 is shifted in the roll axis wide direction. That is, the upper work roll 2 is shifted in the direction of decreasing δw.

  Further, when the plate thickness at one point or a plurality of points in the vicinity of the plate end portion measured on the driving side is different from the predetermined plate thickness, the lower work roll 2 is similarly shifted to the predetermined plate thickness. Since the work roll diameter can be reduced by the application of the work roll 2 that is originally a high longitudinal elastic material, the rolling load can be reduced by that amount, resulting in a sharp edge of the plate edge called an edge drop that causes a decrease in yield. Thickness reduction can be reduced.

  The combined use of this small-diameter work roll and work roll shift makes it possible to minimize the tapered roll shoulder 2a and the shift positions δw, d, and to roll brittle materials such as electrical steel sheets that are susceptible to cracking. Is particularly suitable. In addition, although this figure has described the mill of FIG. 1 as a representative, the work roll variable offset mill of FIG. 8 and the intermediate roll variable offset mill of FIG. 9 may be used.

  Further, in this embodiment, the pair of upper and lower intermediate rolls 3 have roll shoulders 3a each having a roll diameter decreasing at a roll barrel end position that is symmetrical with respect to the upper and lower points with respect to the plate width center of the strip 1. As shown in the example, the pair of upper and lower intermediate rolls 3 are provided with S-curve roll crowns symmetrical with respect to the plate width center of the strip 1 as shown in Non-Patent Document 1, and shifted in the axial direction. It is good also as a structure to make. In this case, the shape control ability is inferior to that of the 6-stage mill having the roll shoulder 3a, but the shape control ability is superior to that of the 4-stage mill. Further, the work roll shift shown in FIG. 10 described above may be applied to this mill.

  11 is a front sectional view of a four-stage mill showing Embodiment 2 of the present invention, FIG. 12 is a sectional view taken along line XII-XII of FIG. 11, and FIG. 13 is a work roll shift of a four-stage mill showing an application example of Embodiment 2. It is explanatory drawing of.

  The rolling mill of this embodiment is a four-high rolling mill as shown in FIGS. 11 and 12, and a pair of upper and lower intermediate rolls 3 and bearing boxes 15 a to 15 d from the six-high rolling mill of the first embodiment. The bending cylinders 16a to 16d are completely removed. In this case, the plate shape control ability is greatly reduced, but the structure becomes simpler.

  In this embodiment, the pair of upper and lower work rolls 2 do not show a structure that shifts in the axial direction. However, as shown in FIG. It is good also as a structure which has the taper-shaped roll shoulder 2a in the point position of a roll trunk | drum of a point symmetry direction, respectively, and can shift to an axial direction. According to this, edge drop can be reduced with a simpler structure.

  In the application example, the pair of upper and lower work rolls 2 each have a tapered roll shoulder 2a at the position of the roll barrel end in the vertical point symmetric direction with respect to the center of the width of the strip 1, and the axial direction An example of a shiftable structure is shown, but the upper and lower pair of work rolls 2 have S-curve roll crowns symmetrical with respect to the upper and lower points with respect to the center of the width of the strip 1 as shown in Non-Patent Document 1. A structure may be provided and shifted in the axial direction. In this case, the shape control capability is superior to the four-stage mill shown in FIG.

  Further, when the small diameter work roll rolling mill of the present invention is applied to a tandem rolling mill, as shown in FIG. When applied to a single stand, strong reduction is possible by a small diameter work roll made of high longitudinal elastic material. The final stand, NO. When applied to 4 stands, a thin plate can be rolled by a small diameter work roll of a high longitudinal elastic material. Of course, you may apply the small diameter work roll rolling mill of this invention about all the stands. Thereby, a thinner and harder material can be rolled. In this figure, as a small diameter work roll mill of the present invention, a 6-stage mill is shown as a representative, but a 4-stage mill can be similarly applied.

DESCRIPTION OF SYMBOLS 1 Band plate 2 Work roll 3 Intermediate roll 4 Reinforcement roll 5a, 5b Pass line adjusting device 6a, 6b Hydraulic cylinder 7a, 7b Housing 13a-13d Work roll bearing box 15a-15d Intermediate roll bearing box 17a-17d Reinforcement roll bearing box 14a ~ 14d Work roll bending cylinder 16a ~ 16d Intermediate roll bending cylinder

Claims (3)

A pair of upper and lower work rolls for rolling the metal strip, a pair of upper and lower intermediate rolls for supporting the work roll, and a pair of upper and lower reinforcing rolls for supporting the pair of upper and lower intermediate rolls. In a 6-stage rolling mill that does not have a supporting roll inside and outside the rollable sheet width,
The work roll is driven, and the work roll is made of a material having a high longitudinal elastic modulus whose ratio with the longitudinal elastic modulus of the conventional material having a longitudinal elastic modulus of 21,000 kg / mm ² is K = 1.2 to 3.0. A rolling mill characterized in that the minimum roll diameter of the work roll is between the minimum diameter upper limit Dmax1 and the minimum diameter lower limit Dmin1, and these are expressed by the following formula.
Minimum diameter upper limit Dmax1 = D4max × B / K ^(1/4)
Here, D4max; upper limit of minimum diameter of work roll with conventional plate width of 1,300mm: φ380
B; Board width (mm) / 1,300mm
K: Ratio of high longitudinal elastic material to conventional material
(Longitudinal modulus of high longitudinal elastic material / longitudinal modulus of conventional material (21,000kg / mm ² ))
Minimum diameter lower limit Dmin1 = D4min × B / K ^(1/4)
Here, D4min; Minimum work roll minimum diameter of conventional plate width 1,300mm: φ180 It consists of a pair of upper and lower work rolls for rolling metal strips and a pair of upper and lower reinforcing rolls for supporting the work rolls, and is a four-stage type having no support rolls inside and outside the roll width of the work rolls that can be rolled. In the rolling mill,
The work roll is driven, and the work roll is made of a material having a high longitudinal elastic modulus whose ratio with the longitudinal elastic modulus of the conventional material having a longitudinal elastic modulus of 21,000 kg / mm ² is K = 1.2 to 3.0. A rolling mill characterized in that the minimum roll diameter of the work roll is between the minimum diameter upper limit Dmax1 and the minimum diameter lower limit Dmin1, and these are expressed by the following formula.
Minimum diameter upper limit Dmax1 = D4max × B / K ^(1/4)
Here, D4max; upper limit of minimum diameter of work roll with conventional plate width of 1,300mm: φ380
B; Board width (mm) / 1,300mm
K: Ratio of high longitudinal elastic material to conventional material
(Longitudinal modulus of high longitudinal elastic material / longitudinal modulus of conventional material (21,000kg / mm ² ))
Minimum diameter lower limit Dmin1 = D4min × B / K ^(1/4)
Here, D4min; Minimum work roll minimum diameter of conventional plate width 1,300mm: φ180   A tandem rolling mill in which a plurality of rolling mill stands are arranged, wherein at least one of the rolling mills according to claim 1 or 2 is provided.

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