JPH0679315A - Method for leveling roll of cross roll mill - Google Patents

Abstract

PURPOSE:To easily execute proper roll leveling by calculating the difference in rolling reduction from the amount of offset in the horizontal direction of upper and lower work rolls and leveling the work rolls at an arbitrary cross angle by using this value. CONSTITUTION:Difference in rolling reductions when difference between drawing-down forces on the work side WS and drive side DS becomes zero at the plural cross angles of the upper and lower work rolls 1, 2 is measured. The amount of offset in the horizontal direction that is orthogonally crossed with the axial directions of rolls of the upper and lower work rolls 1, 2 is calculated by the formula I from the difference in rolling reduction. The difference in rolling reduction at an arbitrary cross angle is calculated by the formula II from this amount. By using this difference, the work rolls 1, 2 at the arbitrary cross angle are leveled. In the formulas I, II, Hdf: the difference (the amount of leveling) between rolling reductions on the work and drive sides, L: distance between screw-down points on the work and drive sides, theta: the cross angle between the upper and lower work rolls during rolling, delta: the amount of offset of a horizontal axis that is orthogonally crossed with the axial direction of roll of the upper and lower work rolles, Domega: the diameter of work roll, subscript: respective values at each cross angle theta.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll leveling method for a cross roll rolling machine in which upper and lower work rolls are crossed with each other.

[0002]

2. Description of the Related Art In roll leveling of a cross roll rolling mill, a method similar to that of an ordinary four-high rolling mill in which work rolls are not crossed is used.

That is, as shown in FIGS. 4 and 5, immediately after the upper and lower work rolls 1 and 2 are recombined, the lower work roll 2 and the upper work roll 1 supported by the lower backup roll are temporarily brought into contact with each other. , The upper backup roll 3 is reduced by a reduction device to a reduction force P _{W of} about 500 to 1,000 tons.
The pressure is reduced by P _D , and both the reduction amounts X _W , X _D are adjusted so that the pressure difference Pdf = P _W −P _D between the working side WS and the driving side DS at that time becomes zero.

After that, when the upper and lower work rolls 1 and 2 are crossed at a required cross angle θ, as shown in FIG.
The center C in the roll axis direction and the cross point C ₀ coincide with each other to form the working-side roll gap h _W and the driving-side roll gap h _D , and h _W = h _D.

In this way, the working-side roll gap h
_{By making W} and the driving-side roll gap h _D equal, it is possible to roll to a uniform plate thickness on the left and right.

[0006]

However, in a rolling mill equipped with work roll chocks, when the number of times the upper and lower work rolls 1 and 2 are used increases, the dimension between the shaft center and the work roll chock side face (not shown) is increased. When the accuracy decreases and the upper and lower work rolls 1 and 2 are crossed at the cross angle θ, as shown in FIG.
A horizontal shift (hereinafter referred to as offset δ) occurs between ₁ and the lower work roll axis O ₂ in the direction orthogonal to the roll axis direction.

In this case, as shown in the example of FIG. 7, the cross point C
₀ moves from the center C in the roll axial direction to the drive side DS, and the working side cross amount (moving amount) l _w and the working side roll gap h
_W becomes larger than the driving side cross amount (moving amount) l _D and the driving side roll gap h _D.

If the working-side roll gap h _W and the driving-side roll gap h _D become unequal, the difference in sheet thickness between the working-side WS and the driving-side DS (hereinafter referred to as the sheet wedge) will be applied to the rolled material to be rolled. ) Occurs.

[0009] This sheet wedge not only deteriorates the quality of the rolled material but also induces sheet bending, so that the sheet passing property during rolling is deteriorated, and the rolled material meanders and deviates from the center of the rolling mill. , The normal rolling operation becomes impossible.

[0010]

According to a roll leveling method of the present invention, after setting a work roll in a housing, an upper work roll and a lower work roll are set to a plurality of cross angles, and the respective cross angles are set. The difference between the working-side reduction amount and the driving-side reduction amount at which the difference between the working-side reduction force and the driving-side reduction force becomes zero is measured, and the difference between the respective reduction amounts is used as the upper work roll by the formula (1). An offset amount in the horizontal direction orthogonal to the roll axis direction with respect to the lower work roll is calculated, and the reduction amount difference at an arbitrary cross angle is calculated from the offset amount by the formula (2), and the desired reduction amount difference is used to calculate an arbitrary cross amount. Characterized in that the work rolls at the corners are leveled. δ = (Dω / 2L) · {(Hdf ₂ −Hdf ₁ ) / (θ ₂ −θ ₁ )} ·· (1) Hdf = (2L / Dω) · δ · θ + Hdf ₀ ... (2) where Hdf is the difference between the working-side reduction amount and the driving-side reduction amount (leveling amount) L: The distance between the working-side reduction point and the driving-side reduction point θ: Rolling of the upper and lower work rolls Inside cross angle δ: Offset amount in the horizontal direction orthogonal to the roll axis direction of the upper and lower work rolls Dω: Work roll diameter Subscript: Each value at each cross angle θ

[0011]

[Operation] After setting work rolls by changing rolls, set the cross angle to, for example, 0 ° and / or 0.5 °, and measure the difference in the amount of reduction at which the difference in the reduction force between the working side and the driving side becomes zero. Further, for example, the required cross angle is set to 1 °, the rolling reduction amount is set so that the rolling reduction difference becomes zero, and the leveling amount is measured.

Based on these two measured leveling amounts, the offset amounts of the upper and lower work rolls are calculated by an equation. Since the offset amount in this work roll is always constant, when the cross angle is changed to change the rolling conditions, the leveling amount corresponding to the cross angle is calculated back from the offset amount, and the roll leveling is performed by this leveling amount. to correct.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view showing the concept of a cross roll rolling mill and a roll leveling method, FIG. 2 is a diagram showing a roll leveling position and a roll leveling correction position, and FIG.
FIG. 6 is a diagram showing a reduction amount difference for leveling correction with respect to an arbitrary roll cross angle.

As shown in FIG. 1, after the upper and lower work rolls 1 and 2 have been recombined, the upper and lower work rolls 1 and 2 are supported by the lower backup roll 4 and brought into contact with each other, as in the conventional case. The work side reduction amount X _W and the driving side reduction amount X _D are adjusted so that the difference between the loads P _W and P _D of the work is reduced to zero, and then, for example, at the cross angle θ = 1 °, both the upper and lower workpieces are adjusted. Rolls 1, 2
Cross. At this time, upper and lower work rolls 1, 2
If an offset occurs between the two, the working-side roll gap h _W becomes larger than the driving-side roll gap h _D (see FIG. 7).

This roll gap difference hdf = (h _W -h
_D ) can be expressed by the following equation. hdf = (2Lω ・ θ ・ δ) / Dω (1) where Lω: Work roll barrel length θ: Cross angle δ: Both upper and lower Offset between work rolls Dω: Work roll diameter

At this time, the working side WS and the driving side DS
Leveling amount Hdf = (X _W-X_D) Is
Become. Hdf = (L / Lω) · hdf = (2 · L · θ · δ) / Dω (2) where L: distance between working-side reduction point and drive-side reduction point

That is, the offset amount δ is generated as a pair difference between the pair of work rolls 1 and 2, and is always constant when the upper and lower work rolls 1 and 2 have been recombined. Since L and Dω are also constant, the roll gap difference hdf and the leveling amount Hdf described above eventually change in proportion to the cross angle θ.

Therefore, as shown in FIG. 2, the leveling amounts Hdf, that is, the leveling amount A and the leveling amount B, at which the respective rolling force differences Pdf at the crosses θ = 0 ° and θ = 1 ° become zero are obtained.

FIG. 3 shows these results as a relationship between the cross angle θ and the leveling amount Hdf. This figure shows the leveling amount at any cross angle,
It can be expressed by the following equation. Hdf = (2Lδ / Dω) · θ + Hdf ₀・ ・ ・ ・ ・ ・ ・ ・ (3)

The gradient 2Lδ / Dω in this equation is obtained by the following equation as the gradient of the straight line connecting the two points A and B. 2Lδ / Dω = ΔHdf / Δθ = (Hdf 2 -Hdf 1) / (θ 2 -θ 1) ··· (4)

The offset amount δ between the upper and lower work rolls can be expressed by the following equation. δ = (Dω / 2L) · {(Hdf ₂ −Hdf ₁ ) / (θ ₂ −θ ₁ )} (5)

As described above, the offset amount δ is always constant in the pair of upper and lower work roll groups, so that the leveling amount at an arbitrary cross angle can be calculated by the following equation. Hdf = {(Hdf ₂ −Hdf ₁ ) / (θ ₂ −θ ₁ )} · θ + Hdf ₀ (6) Here, the leveling amount when Hdf ₀ : θ = C

As described above, the upper work roll 1 and the lower work roll 2 are crossed at the required cross angle θ, and linear correction is performed by the leveling amount Hdf obtained above, and the work side roll gap h _W and the drive side roll gap Roll leveling is performed so that the difference from h _D becomes zero.

When the cross angle θ is changed to change the rolling specifications such as the plate thickness, plate width, material of the rolled material or to control the plate wedge during rolling, the cross angle θ is predetermined according to the changed cross angle θ. The leveling amount is adjusted to Hdf, and roll leveling is performed.

[0025]

According to the present invention, at a plurality of cross angles,
When measuring the leveling amount at which each rolling force difference becomes zero, the offset amount is calculated from this leveling amount, and the roll leveling is performed by back-calculating the leveling amount at any cross angle from this offset amount, thereby setting the work roll. It is possible to easily calculate the offset amount, and it is possible to easily and properly perform the roll leveling regardless of what cross angle is adopted or the cross angle is changed.

Therefore, it becomes possible to roll the strip material without the plate wedge, the quality and yield are improved, and the rolling stripability is improved, so that the misroll is eliminated and the productivity is improved. Further, the roll leveling work can be automated, and the leveling intervention operation by the operator becomes unnecessary, so that the labor can be saved.

[Brief description of drawings]

FIG. 1 is a front view showing a concept of a cross roll rolling mill and a roll leveling method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a reduction force difference and an amount of leveling at an arbitrary cross angle.

FIG. 3 is a diagram showing a leveling amount for leveling correction.

FIG. 4 is an explanatory diagram showing a conventional roll leveling method.

FIG. 5 is a diagram showing a leveling position in a conventional roll leveling method.

FIG. 6 is an explanatory diagram showing the relationship between the intersecting state of the upper and lower work rolls and the roll gap amount when there is no offset between the upper and lower work rolls.

FIG. 7 is an explanatory diagram showing a relationship between an intersecting state of upper and lower work rolls and a roll gap amount when an offset occurs.

[Explanation of symbols]

1 Upper work roll 2 Lower work roll A Leveling position B Leveling correction position DS Drive side WS Work side h _D Drive side roll gap h _W Work side roll gap P _D Drive side roll down force P _W Work side roll down force X _D Drive side roll down Amount X _W Working side reduction amount θ Cross angle δ Offset amount Hdf Leveling amount

Claims (1)

[Claims] 1. A work roll is set in a housing, and then an upper work roll and a lower work roll are set to a plurality of cross angles, and a difference between a working-side rolling force and a driving-side rolling force at each cross angle. The difference between the working-side reduction amount and the driving-side reduction amount is zero, and the horizontal direction orthogonal to the roll axis direction of the upper work roll and the lower work roll is calculated from the difference between the respective reduction amounts according to equation (1). Is calculated, the difference of the reduction amount at an arbitrary cross angle is calculated from the offset amount by the formula (2), and the work roll at an arbitrary cross angle is leveled by the difference of the reduction amount. Roll leveling method for cross roll mill. δ = (Dω / 2L) · {(Hdf ₂ −Hdf ₁ ) / (θ ₂ −θ ₁ )} ·· (1) Hdf = (2L / Dω) · δ · θ + Hdf ₀ ... (2) where Hdf is the difference between the working-side reduction amount and the driving-side reduction amount (leveling amount) L: The distance between the working-side reduction point and the driving-side reduction point θ: Rolling of the upper and lower work rolls Inside cross angle δ: Offset amount in the horizontal direction orthogonal to the roll axis direction of the upper and lower work rolls Dω: Work roll diameter Subscript: Each value at each cross angle θ