EP2392416B1 - Support roller and roller frame comprising same - Google Patents

Description

The invention relates to a support roller according to the preamble of claim 1 and a rolling stand according to claim 6.

Generic back-up rollers are used, in particular, in rolling mills for rolling metallic flat goods, in particular hot or cold strip, fine strip or film. In this case, in a roll stand, which usually has two work rolls and at least two support rollers supporting the work rolls, these products are rolled to the desired strip thickness. Due to the high forces occurring perpendicular to the roll axes there is a deflection of the roll axes, which leads to lack of dimensional stability of the product and undesirable band properties.

In order to reduce this problem, it is known to grind the roller in a symmetrical manner with respect to the center line of the roller so that in the longitudinal section a symmetrical roller profile (Crown) increased in the middle results. The disadvantage here, however, is in particular that regularly the edge regions of the rolling stock of a heavier load depending on the selected crown to "tight" band edges and thus uneven strength properties of the rolling stock over the bandwidth leads.

From the EP 0019 737 A1 It is also known to surround the support roller to form a gap with a roll shell and hydraulically pressurize this gap with pressure. As a result, depending on the load occurring, the crowning of the back-up roll arrangement can be set variably overall (variable crown (VC)). However, this design is technically complicated and therefore expensive.

Based on this prior art, it is the object of the present invention to provide a support roller having a simple and inexpensive to manufacture structure and reduces the loads on the band edge regions.

This object is achieved by a support roller according to the teaching of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

The back-up roll according to the invention intended for use in a rolling mill comprises, in a first manner known per se, two bearing journals and a bale extending therebetween. With the journals, the support roller is rotatable in a frame and optionally driven driven. The bale, which has a substantially cylindrical basic shape, is provided with a non-cylindrical outer contour, which is symmetrical to the center line of the bale and forms a so-called crown as a whole.

In contrast to known spherically ground rollers whose crown has a merely simple curvature, the bale in the region between the center line (ML) and the edge region in longitudinal section in each case two parabolically shaped outer contour regions whose Curvature is in opposite directions, the apex of the curvature of the adjoining the edge region outer contour region to the roll axis and the vertex of the curvature of the adjoining to the center line of the bale outer contour region facing away from the roller. In other words, this means that in particular in the area between the strip edge and the middle between the center line and the strip edge, the roll diameter is lower compared to a conventionally spherically ground roll, whereby the pressure on the rolling stock in this area of the quarter buckles reduced.

Such a support roller is simple and inexpensive, for example by grinding, produced. In addition, the basic roller characteristic is not changed even in a roll grinding, as is the case for example with VC rolls. As has also been shown, the design according to the invention also counteracts quarter buckles and compensates profile errors by an improved rolling force distribution, in particular in the case of narrow strips to be rolled.

In order to avoid in particular inhomogeneities in the bending line of the support roller between the center line of the roller and the edge region, according to a preferred embodiment, the two parabolic regions continuously merge into one another.

A particularly preferred embodiment results when the transition between the two parabolic regions lies midway between the center line and the edge region. As a result, a particularly uniform and homogeneous contour is obtained.

wobei

• y radiale Abnahme
• E Funktionshöhe
• W Ballenlänge
• x 0≤x≤W/4

According to a further particularly preferred embodiment of the invention, the radial decrease of the first parabolic region extending from the roll center towards the edge region is calculated as follows: $$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{-}\mathrm{2}\mathrm{*}\mathrm{e}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

in which

• y radial decrease
• E functional height
• W bale length
• x 0≤x≤W / 4

Where x = 0 corresponds to the roll center. E is the functional height or the so-called Encore, that is the maximum addition to the nominal radius of the roller in the area of the center line (maximum of crowning). This means that the radius of the roller parabolic decreases from the center line to the center between the center line and edge region after the above function. The Encore or the maximum addition is determined in advance for each application, for example by simulation of the rolling process by a FEM calculation.

wobei

• y radiale Zunahme
• E Funktionshöhe
• W Ballenlänge
• x 0≤x≤W/4

The radial increase of the second parabolic region extending from the edge region in the direction of the roll center is calculated according to a further embodiment as follows: $$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{2}\mathrm{*}\mathrm{e}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

in which

• y radial increase
• E functional height
• W bale length
• x 0≤x≤W / 4

In this case, x = 0 corresponds to the edge of the bale of the roller for this area. This results in a parabolic increase in the radius of the roller from the edge to the middle between the center line and the edge region. This radial increase corresponds in your amount to the radial decrease of the above embodiment, so that, if the outer contour of the roller is made from the edge portions in the direction of the center line taking into account these formulas for both parabolic regions, an overall point-symmetrical design of these two areas results.

The invention further relates to a rolling stand for hot and / or cold rolling of metallic strip, strip and / or film, which can be operated in the one-way or Reversierbetrieb. In this case, this rolling mill has at least one work roll and at least one support roll as described above. However, preferably at least two work rolls and at least two backup rolls according to the invention are provided, each work roll being supported by a support roll.

Finally, the invention relates to a rolling mill with at least two rolling mills arranged one behind the other as described above.

Fig. 1

in nicht maßstäblicher Darstellung in seitlicher Ansicht quer zur Walzenlängsachse ein Ausführungsbeispiel einer erfindungsgemäßen Stützwalze.

In the following the invention is explained in more detail with reference to the drawing showing only one exemplary embodiment. It shows the only one

Fig. 1

not to scale in lateral view transversely to the roll longitudinal axis an embodiment of a support roller according to the invention.

The in the Fig. 1 shown backup roller 1 has two bearing journals 2 and 3, between which the actual roller body 4 extends. The roller body 4 has on both sides of the bearing pins 2 and 3 adjoining edge regions 5 and 6, which do not come into contact with the rolling stock during rolling of the rolling stock. Between the edge regions 5 and 6 extends the bale W, which has a substantially "cylindrical" outer contour. "Essentially cylindrical" means that of the ideal shape of a cylinder deviating outer contour, although according to the invention is not straight cylindrical, the deviations, the so-called crowning or radial elevation, but is numerically low compared to the roll length. For example, a typical backup roll has a length of 1800 mm, while the maximum radial elevation is in the range of a few μm to a few 1/100 mm.

The back-up roll after the Fig. 1 is symmetrical to the centerline ML constructed and has a nominal diameter Dnenn, which corresponds to the ideal cylindrical contour of a roller. The roller 1 has a non-symmetrical outer contour in the form of a crown, which is also arranged symmetrically to the center line ML and forms a crown, which is in lateral view or in longitudinal section through the support roller highest height on the center line ML and the functional height or the "Encore "E represents. This function height is specified as a function of the material to be rolled and the rolling parameters such as stitch loss or the like. In the direction of the edge regions 5 and 6, the radial elevation drops in each case and reaches zero at the ball edges. In other words, the diameter D of the support roller is in the middle D = Dnenn + 2 * E and at the bale edges D = Dnenn.

The area between the center line ML and the edge area 5 - the area between the center line ML and the edge area 6 is designed accordingly - is subdivided into two areas 7 and 8, which in longitudinal section and the view of FIG Fig. 1 each have a parabolically shaped outer contour, with the two outer contours meet exactly in the middle between the ML and the edge region 5 and there merge into each other.

As can be seen from the illustration of FIG. 2, the two regions 7 and 8 are curved in opposite directions. The region 7 has a curvature whose vertex points away from the roll axis, while the curvature of the region 8 is formed so that its vertex points toward the roll axis.

The Indian Fig. 1 represented value y (x) corresponds to the area 8 of the radial increase of the elevation, that is, the half increase of the roll diameter D starting from the nominal diameter D _denote , wherein the value x = 0 is located directly on the bale edge and the roll center is larger.

On the other hand, for the region 7, y (x) corresponds to the radial decrease of the elevation, that is, half the decrease of the roll diameter D from the diameter at the centerline ML of the roll D _ML = Dnenn + 2 * E, where the value x = 0 immediately the center line is and becomes larger towards the edge of the roll.

$$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{2}\mathrm{*}\mathrm{E}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

For the areas 7 and 8 the following relationship applies: $$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{-}\mathrm{2}\mathrm{*}\mathrm{e}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

$$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{2}\mathrm{*}\mathrm{e}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

Example:

• Nenndurchmesser = Dnenn
• Encore E = 50 µm
• Ballenlänge W = 1800 mm
• y (x) = radiale Überhöhung

Bereich 7: x Punkt y(x) Durchmesser 0 1 0 D_nenn + 100 µm W/8 2 -0,125E D_nenn + 87,5 µm W/4 3 -0,5*E D_nenn + 50 µm Bereich 8: x Punkt y(x) Durchmesser 0 6 0 D_nenn W/8 5 0,125*E D_nenn + 12,5 µm W/4 4 0,5*E D_nenn + 50 µm The following table of values describes a back-up roll according to the invention with the following parameters:

• Nominal diameter = Dnenn
• Encore E = 50 μm
• Bale length W = 1800 mm
• y (x) = radial elevation

Area 7: x Point y (x) diameter 0 1 0 D _nominal + 100 microns W / 8 2 -0,125E D _nominal + 87.5 microns W / 4 3 -0.5 * E D _nominal + 50 microns Area 8: x Point y (x) diameter 0 6 0 D _nom W / 8 5 0.125 * E _Nominal D + 12.5 microns W / 4 4 0.5 * E D _nominal + 50 microns

Claims (8)

1. A backup roll for use in a rolling mill, featuring two journals and a roll body that extends between the journals and has a non-cylindrical outer contour that is realized symmetric to the center line of the roll body,
   characterized in
   that the roll body (W) respectively features in a longitudinal section in the region between the center line (ML) and the edge region (5, 6) two parabolically shaped outer contour regions (7, 8) with opposite curvature, wherein the apex of the curvature of the outer contour region (8) situated adjacent to the edge region (5) points to the roll axis and the apex of the curvature of the outer contour region (7) situated adjacent to the center line (ML) of the roll body points away from the roll.
2. The backup roll according to Claim 1,
   characterized in
   that the two parabolic regions (7, 8) continuously transform into one another.
3. The backup roll according to Claim 2,
   characterized in
   that the transition between the two parabolic regions (7, 8) lies in the center between the center line (ML) and the respective edge region (5, 6).
4. The backup roll according to one of Claims 1 to 3,
   characterized in
   that the radial reduction (y) of the first parabolic region (7) extending from the roll center (ML) in the direction of the edge region (5, 6) is calculated as follows: $$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{-}\mathrm{2}\mathrm{*}\mathrm{E}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

   

   
   wherein
   y radial reduction
   E functional height
   W roll body length
   x 0 ≤ x ≤ W/4.
5. The backup roll according to one of Claims 1 to 4,
   characterized in
   that the radial rise (y) of the second parabolic region (8) extending from the edge region (5, 6) in the direction of the roll center (ML) is calculated as follows: $$\mathrm{y}\left(\mathrm{x}\right)\mathrm{=}\mathrm{2}\mathrm{*}\mathrm{E}\mathrm{/}{\left(\mathrm{W}\mathrm{/}\mathrm{2}\right)}^{\mathrm{2}}\mathrm{*}{\mathrm{x}}^{\mathrm{2}}$$

   

   
   wherein
   y radial rise
   E functional height
   W roll body length
   x 0 ≤ x ≤ W/4.
6. A roll stand for hot-rolling and/or cold-rolling a metallic strip, thin strip and/or foil in the one-way mode or in the reversing mode, featuring at least one working roll and at least one backup roll according to one of the preceding claims.
7. The roll stand according to Claim 6,
   characterized in
   that at least two working rolls and at least two backup rolls are provided.
8. A rolling mill with at least two successively arranged roll stands according to one of Claims 6 and 7.

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