Laser-textured working roller for use in a cold rolling mill, and method for producing a laser-textured working roller for use in a cold rolling mill, and cold rolling mill

Abstract

The invention relates to a laser-textured working roller (1) for use in a cold rolling mill, comprising a surface (2) which has a topography (3) comprising multiple longitudinal grooves (3.1) that are juxtaposed in the circumferential direction (U) of the working roller (1), wherein multiple grooves (3.2) juxtaposed over the circumference of the working roller (1) are distributed between each pair of juxtaposed longitudinal grooves (3.1), wherein each of said multiple grooves connects the two juxtaposed longitudinal grooves (3.1) and is arranged in a slanted manner between the two juxtaposed longitudinal grooves (3.1). The invention additionally relates to a method for producing a laser-textured working roller (1) and to a cold rolling mill.

Description

[0001] Laser-textured work roll for use in cold rolling mills and method for producing a laser-textured work roll for use in cold rolling mills and cold rolling mills

[0002] The invention relates to a laser-textured work roll for use in a cold rolling mill, a method for producing a laser-textured work roll for use in a cold rolling mill and a cold rolling mill.

[0003] Work rolls in rolling mills, especially in cold rolling mills for flat steel production, are typically machined before use. Conventional work rolls are usually machined using a grinding process, which imparts a defined roughness to the work roll surfaces. The work rolls are then provided with different textures depending on the application.

[0004] These textures can be applied using, among other methods, the SBT (shot blasting texturing) process, the EDT (electro discharge texturing) process, the EBT (electron beam texturing) process, grinding structures, or the TOPOCROMO (reactor coating) process. These processes involve the application of a stochastic surface topography to work rolls. EP 1 368 140 B1 discloses a corresponding example for EDT. The EBT process also enables the application of a deterministic texture. A completely different process for the application of stochastic as well as geometrically determined, i.e. deterministic, surface topographies is the laser beam texturing (LT) process, in particular using a single or multiple shot, which leads to ablation on the surface of the roll material and thus to the establishment of a surface topography, cf.For example, see EP 0 184 568 B1, JP 56-119 687 A, JP 03-267 319 A, and DE 695 09 883 T2. Depending on the application, the rolls can be finely ground in a grinding process after texturing. After this process, depending on the requirements of the work rolls, they are coated with a metallic protective coating before being (re)used in the rolling stands.

[0005] The background to conventional surface finishing of work rolls is that, by coating the surfaces with a metallic protective layer, they offer improved wear protection with regard to service life, as well as a positive impact on the required (strip) cleanliness. These additional work steps are intended to become obsolete with the new process.

[0006] The object of the invention is therefore, inter alia, to provide a laser-textured work roll for use in cold rolling mills, which has a wear-resistant surface, in particular without using a metallic protective layer.

[0007] The problem relating to a laser-textured work roll for use in a cold rolling mill is solved by the features of claim 1. The problem relating to a method for producing a laser-textured work roll for use in a cold rolling mill is solved by the features of claim 10. The problem relating to a cold rolling mill is solved by the features of claim 11.

[0008] A first teaching of the invention relates to a laser-textured work roll with a surface, wherein the surface has a topography with a plurality of longitudinal grooves running alongside one another in the circumferential direction of the work roll, wherein between each two longitudinal grooves running alongside one another, a plurality of grooves running alongside one another over the circumference of the work roll are distributed, which grooves each connect the two longitudinal grooves running alongside one another and are arranged obliquely between the two longitudinal grooves running alongside one another.

[0009] The topography according to the invention on the surface of the work roll is designed in such a way that rollability is ensured when the topography is used. During the cold rolling process, it is beneficial that (strip) dirt, roll abrasion and / or rolling emulsion are removed in a targeted manner. This can be positively influenced by the arrangement of the longitudinal grooves and grooves between the longitudinal grooves. The longitudinal grooves in the circumferential direction and thus also in the rolling direction of the work roll serve to transport the abrasion from the work roll and / or the strip surface. The grooves between the longitudinal grooves serve to collect the abrasion in order to then transport it in a targeted manner and, due to the oblique arrangement, in the direction of the longitudinal groove(s) in the circumferential / rolling direction, since each groove is connected to at least one longitudinal groove or each groove connects two adjacent longitudinal grooves.In this context, "skew" means that the groove(s) are aligned at an angle other than 90° or 180° to the respective longitudinal groove with which they are connected. At the same time, it was shown that the topography according to the invention on the work roll exhibits comparable wear resistance to standard surfaces. Thus, the work roll according to the invention can be considered a "protective layer-free" and bright-surface work roll.

[0010] Work rolls for cold rolling processes are typically made of metal, for example, they are forged or cast. It goes without saying that the topography is provided axially on the surface of the work roll to such an extent that the flat material to be rolled is covered by the topography across its entire width in the rolling direction.

[0011] The flat material to be cold-rolled is preferably generally a steel flat product in strip form (steel strip). Alternatively, for example, an aluminum flat product (aluminum strip) can also be cold-rolled using the work roll according to the invention.

[0012] Due to their function, the work roll in a cold rolling process must meet different requirements than rolls in skin-pass processes, so-called skin-pass rolls. This ensures, in addition to the aforementioned tasks of removing abrasion and extending service life, a largely slip-free cold rolling process. The topography on the surface of work rolls for the cold rolling process can therefore be precisely adjusted and is not comparable to the topography on the surfaces of skin-pass rolls.

[0013] According to one embodiment of the work roll, the grooves are arranged between two adjacent longitudinal grooves at an angle α, β between 5° and 85°. The "oblique" arrangement of the grooves relative to the longitudinal grooves allows the abrasion accumulated in the grooves to be transported in the direction of the longitudinal grooves. The angle can be at least 10°, 15°, preferably at least 20°, 25°, and in particular a maximum of 80°, 75°, preferably a maximum of 60°, 65°. An angle between 30° and 60° is preferably provided.

[0014] According to one embodiment of the work roll, at least two of the longitudinal grooves running next to one another in the circumferential direction of the work roll are arranged at a distance of between 20 and 2000 pm from one another. In particular, all longitudinal grooves are arranged next to one another in the circumferential direction in such a way that a distance of between 20 and 2000 pm is always provided between each two adjacent longitudinal grooves, in particular from one end to the other end of the surface of the work roll viewed in the axial direction. For example, different distances can also be provided between the longitudinal grooves, which, however, are recurring, in particular from one end to the other end of the surface of the work roll viewed in the axial direction. The distance between two longitudinal grooves can in particular be at least 50 pm, 70 pm, 100 pm and in particular a maximum of 1800 pm, 1500 pm, preferably a maximum of 1200 pm, 1000 pm, 800 pm.Preferably, two, three, four, five, six, or more than six longitudinal grooves form a unit with a defined, in particular identical, distance between the longitudinal grooves forming the unit. Viewed in the axial direction of the work roll, the unit is arranged in a repeating manner and separated by at least one separate longitudinal groove along the axial direction. The distance between the at least one separate longitudinal groove and the one unit or units is defined, and this distance can preferably be greater than the distance or distances, if these should differ within the unit, between the longitudinal grooves forming the unit.

[0015] According to one embodiment of the work roll, at least two grooves running next to one another around the circumference of the work roll are arranged at a distance of between 20 and 1000 pm from one another. Each groove is arranged between two longitudinal grooves and connects them so that abrasion can be removed. The distance between two grooves can in particular be at least 30 pm, 40 pm, 50 pm and in particular a maximum of 800 pm, 500 pm, preferably a maximum of 400 pm, 300 pm, 200 pm. Preferably, two, three, four, five, six or more than six grooves form a unit with a defined, in particular identical distance between the grooves forming the unit, wherein, viewed in the circumferential direction of the work roll, the unit is arranged in a repeated manner and each separated by at least one separate groove along the circumferential direction. The distance between the at least one separate groove and the one unit orto the two units is defined, whereby this distance can preferably be greater than the distance or distances, if these should be different within the unit, between the grooves forming the unit.

[0016] According to one embodiment of the work roll, the longitudinal grooves and the grooves have a depth of between 2 and 40 pm. The depth can be at least 3 pm, 4 pm, 5 pm, preferably at least 7 pm, 8 pm, 9 pm, in order to enable the targeted topography and thus a certain service life of the work roll in the event of unavoidable wear during cold rolling. The depth can in particular be limited to a maximum of 35 pm, 30 pm, or 25 pm. The depth of the grooves can be the same as, but also higher or lower than, the depth of the longitudinal grooves. The depth(s) of the grooves and / or the depth(s) of the longitudinal grooves can also vary from one another. According to one embodiment of the work roll, the longitudinal grooves and the grooves have a width of between 10 and 50 pm.The width can be at least 13 pm, 15 pm, 19 pm, preferably at least 25 pm, in order to ensure, in conjunction with the depth, sufficient absorption volume for abrasion and thus for the corresponding removal during cold rolling. The width can in particular be limited to a maximum of 47 pm, 42 pm, in order to avoid unwanted elevations, particularly in the rolling direction, and thus to avoid near-surface profiling on the flat material to be rolled. The width of the grooves can be the same as, but also greater or lesser than the width of the longitudinal grooves. The width(s) of the grooves and / or the width(s) of the longitudinal grooves can also vary.

[0017] According to one design of the work roll, the grooves can be designed as a curve instead of a straight line.

[0018] According to a second teaching, the invention relates to the production of a laser-textured work roll for use in a cold rolling mill, wherein a work roll to be textured is provided, wherein the surface of the work roll is processed with a laser in order to create a topography on the surface of the work roll, in particular by means of ablation, wherein a topography with a plurality of longitudinal grooves running next to one another in the circumferential direction of the work roll is introduced on the surface, wherein between each two longitudinal grooves running next to one another, a plurality of grooves running next to one another over the circumference of the work roll are provided, which grooves each connect the two longitudinal grooves running next to one another and are arranged obliquely between the two longitudinal grooves running next to one another.

[0019] Devices for carrying out the laser structuring process are state of the art, see also EP 2 892 663 B1, EP 3 172 006 B1 and EP 3 877 112 A1. In this way, it is possible to create a topography on the surface of the work roll which, through laser bombardment, causes ablation, i.e. material removal, on the surface in the area of ​​the impacting bombardment. By targeted adjustment, the laser shots can overlap or be so far apart that an almost initial state remains between the laser shot areas. The areas not hit by the laser bombardment thus form the elevations on the surface of the work roll. To avoid repetition, reference is made to the aforementioned designs of the work roll.

[0020] According to a third teaching, the invention relates to a cold rolling mill with at least three, in particular at least four and at most nine, in particular at most seven, preferably at most five rolling stands, wherein at least one rolling stand has two work rolls according to the invention. Particularly viewed in the process direction, two work rolls according to the invention are provided in at least the second and third rolling stands. The cold rolling mill is preferably a tandem cold rolling mill or a part thereof. Among other things, further systems can also be arranged upstream and / or downstream of the cold rolling mill in the process direction, such as, for example, a continuous pickling line in the upstream section of the cold rolling mill. The arrangement of work rolls in a rolling stand of a cold rolling mill and also the structure and functioning of a cold rolling mill or a tandem cold rolling mill are state of the art.

[0021] An exemplary embodiment of a work roll (1) according to the invention and the corresponding topography (3) is shown in the single Figure 1. Top right, a work roll (1) with a surface (2) and an axis (Z) as well as the axial direction (A) and circumferential direction (U) transverse to the axial direction (A) of the surface (2) of the work roll (1) are sketched. An enlargement on the left in Figure 1 is shown from the small window, schematically depicting a partial plan view of the surface (2) of the work roll (1) with a topography (3). The middle illustration at the bottom of Figure 1 shows a partial section through a longitudinal groove (3.1) or groove (3.2) in order to clarify the determination of the depth (T), which can be between 2 and 30 pm, and the width (B), which can be between 10 and 50 pm. The depth (T) is measured from the highest point of the longitudinal groove (3.1) or groove (3.2) surrounding the elevation on the surface (2) of the work roll (1) and the deepest point in or within the longitudinal groove (3.1) or groove (3.2) introduced into the work roll. The width (B) is determined on the surface (2) between two opposite points at which the curvature or radius, and thus the beginning of the depression of the longitudinal groove (3.1) or groove (3.2), begins. The lower right illustration in Figure 1 shows an alternative to straight grooves (3.2), whereby the grooves (3.2) can be designed as a curve.

[0022] The laser-textured work roll (1) for use in a cold rolling mill, comprising a surface (2), has a topography (3) with a plurality of longitudinal grooves (3.1) running alongside one another in the circumferential direction (U) of the work roll (1). Distributed between each pair of adjacent longitudinal grooves (3.1) are a plurality of grooves (3.2) running alongside one another around the circumference of the work roll (1), each of which connects the two adjacent longitudinal grooves (3.1) and is arranged obliquely between the two adjacent longitudinal grooves (3.1). The grooves (3.2) are arranged between two adjacent longitudinal grooves (3.1) at an angle (α, β) of between 5° and 85°. The angle (α, β) is determined at the connection point of the longitudinal groove (3.1) and the groove (3.2) by an auxiliary straight line (ZI, Z2), which runs parallel to the axis (Z), intersecting the connection point, from which the angle (α, β) between the auxiliary straight line (ZI, Z2) and the groove (3.2) is determined.Alternatively, the angle between the longitudinal groove (3.1) and the groove (3.2) could also be determined. At least two of the longitudinal grooves (3.1) running next to one another in the circumferential direction (U) of the work roll (1) are arranged at a distance (Q) of between 20 and 2000 pm from one another. Two, three, four, five, six or more than six longitudinal grooves (3.1) can form a unit (Y) with a defined, in particular identical, distance (LI) between the longitudinal grooves (3.1) forming the unit (Y), wherein, viewed in the axial direction (A) of the work roll (1), the unit (Y) is arranged in a repeated manner and is each separated by at least one separate longitudinal groove (3.1) along the axial direction (A). At least two grooves (3.2) running next to one another over the circumference of the work roll (1) are arranged at a distance (L) of between 20 and 1000 pm from one another. Two, three, four, five, six or more than six grooves (3.2) can form a unit (X) with a defined, in particular identical distance (Ql) between the grooves (3.2) forming the unit (X), wherein, viewed in the circumferential direction (U) of the work roll (1), the unit (X) is arranged repeatedly and each separated by at least one separate groove (3.2) along the circumferential direction (U).

[0023] In practical tests, two work rolls (1) according to the invention with identical topography (3) were used in a rolling stand of a tandem cold rolling mill to determine their service life and effectiveness, particularly in comparison to standard work rolls. Two work rolls with a deterministic "double-I" topography, created according to the description in EP 2 892 663 B1, were also used as a further reference. Both the work rolls (1) according to the invention and the work rolls laser-textured with "double-I" were not provided with a metallic protective coating, thus they were free of a protective coating.

[0024] In the work roll (1) used according to the invention, three longitudinal grooves (3.1) formed a unit (Y) with an identical spacing (LI) between the longitudinal grooves (3.1) forming the unit (Y). Viewed in the axial direction (A) of the work roll (1), the unit (Y) was arranged in a repeating manner and each separated by at least one separate longitudinal groove (3.1) along the axial direction (A), which was arranged at a spacing (L2) from the adjacent units (Y). Two grooves (3.2) formed a unit (X) with an identical spacing (Q1) between the grooves (3.2) forming the unit (X). Viewed in the circumferential direction (U) of the work roll (1), the unit (X) was arranged in a repeating manner and each separated by at least one separate groove (3.2) along the circumferential direction (U), which was arranged at a spacing (Q2) from the adjacent units (X). The width (B) and depth (T) of the longitudinal grooves (3.1) and grooves were 40 pm and 15 pm. The depth (T) and width (B) were set the same for all longitudinal grooves (3.1) and grooves (3.2). The distances (LI) and (L2) as well as the distances (Ql) and (Q2) were 75 pm and 150 pm and 200 pm and 300 pm. The distance (L, LI, L2, Q, Ql, Q2) is determined in particular from the center of a longitudinal groove (3.1) or groove (3.2) to the center of the adjacent longitudinal groove (3.1) or groove (3.2). The angles (α) and (β) were 30° and 45°. The grooves (3.2) opening into the respective separate longitudinal grooves (3.1) were at a right angle (90°) to each other. (W) indicates the rolling direction of the work roll (1).

[0025] Flat steel products in the form of steel strips (coils) were cold-rolled. The longer the service life (coil throughput), the more economical the use of the work rolls. Surprisingly, after only 45 coils had been rolled, the work rolls with the deterministic "double I" topography had to be replaced because the texture had completely dissolved due to stress and wear, particularly since the abrasion in the rolling emulsion was also very high. The standard work rolls and the work rolls according to the invention (1) were removed from the rolling stand after 100 coils had been rolled, and it was found that, thanks to a specifically selected topography (3), the work roll and strip surface properties almost corresponded to the rolling properties and strip surface properties associated with a standard roll surface. The topography (3) was still sufficiently present.

Claims

Patent claims 1. Laser-textured work roll (1) for use in a cold rolling mill, having a surface (2) which has a topography (3) with a plurality of longitudinal grooves (3.1) running alongside one another in the circumferential direction (U) of the work roll (1), characterized in that between each two longitudinal grooves (3.1) running alongside one another, a plurality of grooves (3.2) running alongside one another over the circumference of the work roll (1) are distributed, which grooves each connect the two longitudinal grooves (3.1) running alongside one another and are arranged obliquely between the two longitudinal grooves (3.1) running alongside one another.

2. Working roll according to claim 1, wherein the grooves (3.2) are arranged between two adjacent longitudinal grooves (3.1) at an angle (α, β) between 5° and 85°.

3. Work roll according to one of the preceding claims, wherein at least two of the longitudinal grooves (3.1) running next to one another in the circumferential direction (U) of the work roll (1) are arranged at a distance (Q, Q1, Q2) of between 20 and 2000 pm from one another.

4. Work roll according to one of the preceding claims, wherein two, three, four, five, six or more than six longitudinal grooves (3.1) form a unit (Y) with a defined, in particular identical distance (LI) between the longitudinal grooves (3.1) forming the unit (Y), wherein, viewed in the axial direction (A) of the work roll (1), the unit (Y) is arranged in a repeated manner and in each case separated by at least one separate longitudinal groove (3.1) along the axial direction (A).

5. Work roll according to one of the preceding claims, wherein at least two grooves (3.2) extending next to one another over the circumference of the work roll (1) are arranged at a distance (L, LI, L2) between 20 and 1000 pm from one another.

6. Work roll according to one of the preceding claims, wherein two, three, four, five, six or more than six grooves (3.2) form a unit (X) with a defined, in particular identical distance (Ql) between the grooves (3.2) forming the unit (X), wherein, viewed in the circumferential direction (U) of the work roll (1), the unit (X) is arranged repeatedly and in each case separated by at least one separate groove (3.2) along the circumferential direction (U). Work roll according to one of the preceding claims, wherein the longitudinal grooves (3.1) and the grooves (3.2) have a depth (T) between 2 and 40 μm. Work roll according to one of the preceding claims, wherein the longitudinal groove (3.1) and the grooves (3.2) have a width (B) between 10 and 50 μm. Work roll according to one of the preceding claims, wherein the grooves (3.2) are designed as a curve. Method for producing a laser-textured work roll (1) for use in a cold rolling mill, wherein a work roll to be textured is provided, wherein the surface of the work roll is machined with a laser in order to produce a topography (3) on the surface (2) of the work roll (1), wherein a topography (3) with a plurality of longitudinal grooves (3.1) running alongside one another in the circumferential direction (U) of the work roll (1) is introduced onto the surface (2), characterized in that between each two longitudinal grooves (3.1) running alongside one another1) a plurality of grooves (3.2) extending side by side around the circumference of the work roll (1) are provided, each groove connecting the two adjacent longitudinal grooves (3.1) and arranged obliquely between the two adjacent longitudinal grooves (3.1). A cold rolling mill with at least three and at most nine rolling stands, characterized in that at least one rolling stand has two work rolls (1) according to one of claims 1 to 9. A cold rolling mill according to claim 11, wherein, viewed in the process direction, two work rolls (1) are provided in at least the second and third rolling stands. A cold rolling mill according to claim 11 or 12, wherein the cold rolling mill is a tandem cold rolling mill.

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