Method and device for structurally conditioning a roll

Abstract

The object of providing a method for conditioning a working roll with which the material properties of a working roll can be set in a process-reliable and uniform manner is achieved by a method in which a roll and at least one pressure tool are rotated relative to each other, in which pressure is applied locally to the roll by means of the at least one pressure tool, comprising at least one pressure element, via the at least one pressure element, and in which a deep rolling process is carried out.

Claims

1. A method for structurally conditioning a roll, in which a roll and at least one pressure tool are rotated relative to each other, in which pressure is applied locally to the roll by means of the at least one pressure tool, comprising at least one pressure element, via the at least one pressure element, and in which the at least one pressure tool is moved relative to the roll with a feed motion in the axial direction of the roll such that pressure is applied to at least one surface section of the roll via the at least one pressure element, wherein a deep rolling process is carried out.

2. The method according to claim 1, wherein a working roll of a roll stand is conditioned for hot or cold rolling of metal strips or foils, in particular metal strips or foils made from aluminium or an aluminium alloy.

3. The method according to claim 1, wherein a surface-removing process is also carried out on the roll, preferably after the deep rolling process.

4. The method according to claim 1, wherein a pressure element is used to which pressure is applied and comprising a rotatable ball or a rotatable cylindrical roller.

5. The method according to claim 4, wherein a ball or a roller with a diameter of 3 to 30 mm or 3 to 16 mm, preferably 6 to 13 mm is used.

6. The method according to claim 1, wherein pressure of at least 100 bar is applied to the pressure element.

7. The method according to claim 1, wherein a feed motion of 0.01 mm to 4 mm/revolution of the roll, preferably 0.1 mm to 0.4 mm/revolution of the roll is used.

8. The method according to claim 1, wherein an increase in the Leeb hardness of the surface of at least 10 HLE is effected in the processed section of the roll.

9. A device for structurally conditioning a roll, in particular a working roll of a roll stand by carrying out a method according to claim 1, with a pressure tool and with means for rotating a roll relative to the pressure tool, wherein the pressure tool comprises at least one pressure element, the pressure element is set up to apply pressure locally on the roll and means are provided for carrying out a relative feed motion of the pressure tool in an axial direction of the roll, wherein the pressure tool comprises a deep rolling tool.

10. The device according to claim 9, wherein at least one means is provided for carrying out a surface-removing process.

11. The device according to claim 9, wherein the at least one pressure element comprises at least one rotatable ball or at least one rotatable cylindrical roller to which pressure can be applied.

12. The device according to claim 9, wherein a pressure source is provided with which pressure of at least 100 bar can be applied to the at least one pressure element.

13. A roll, in particular a working roll for deforming materials, wherein the roll comprises at least one surface section, preferably a roll body which has been treated using a method according to claim 1.

14. The roll according to claim 13, wherein inside the conditioned surface section, the Leeb hardness of the surface of the roll comprises a standard deviation of 15 HLE, preferably a maximum standard deviation of 7.5 HLE.

15. The roll according to claim 13, wherein the roll is designed as a working roll for rolling foils or strips, preferably for rolling foils or strips made from aluminium or an aluminium alloy.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0045] For further configurations of the device and the roll reference is made to the above details regarding the method as well as to the following description and the drawings. In the drawings:

[0046] FIG. 1 shows a schematic representation of a device 2 for carrying out the method,

[0047] FIG. 2 shows a schematic representation of a pressure tool with a pressure element,

[0048] FIG. 3 shows a schematic representation of a working roll, and

[0049] FIG. 4 shows a diagram regarding the difference in hardness achieved under different pressures.

DETAILED DESCRIPTION OF INVENTION

[0050] FIG. 1 shows a schematic representation of a device 2 for carrying out the method. A roll 4 is conditioned with the device 2. A means for rotating 6 the roll 4 is provided which allows the roll 4 to be rotated along a roll axis 8 and thus relative to a pressure tool 10. The pressure tool 10 comprises at least one pressure element 12 wherein pressure is applied locally on the working roll 4 by means of the pressure tool 10 via the pressure element 12. A pressure 14 is applied on the pressure element 12 here which is transferred in the form of a pressure 16 to the roll 4. The pressure can be generated hydraulically or pneumatically.

[0051] The pressure is applied on the roll 4 only locally at the contact point to the pressure element 12. A means for moving the pressure tool 10 relative to the roll 4 is provided which moves the pressure tool 10 with a feed motion 18 at least along a section of the roll 4 wherein pressure is applied to the section of the roll 4 via the pressure element 12.

[0052] A section of the roll 4, for example the roll surface or the mounting surface is thus successively conditioned with a very high pressure 16 by the common rotational movement and the feed motion 18. The conditioning of a roll 4 combines setting the surface hardness by a cold work hardening of the edge layers and setting the residual stress into the depth of the material. At the same time, a particularly smooth and uniform surface is provided. These properties are achieved in a homogenous and process-reliable manner via the conditioned section. In addition, a surface-removing process can, in principle, be carried out with the device 2 on the roll 4. Preferably, in this case a surface-removing process, e.g. grinding or milling, can be carried out with the device 2 on the roll 4 after the conditioning in order to prepare the surface of the roll for carrying out subsequent rolling processes.

[0053] FIG. 2 shows a schematic representation of a pressure tool 10 with a pressure element 12 to illustrate the principle, as they can be used in a method or a device 2 described here. The pressure element 12 is designed as a ball and is arranged in a housing 20. The pressure 14 is provided by a hydraulic device, which is not represented here, and is transferred in the housing 20 to the pressure element 12 with a fluid which comprises for example a grinding emulsion as the lubricant.

[0054] While the pressure 14 acts on a larger surface of the pressure element 12, a very small contact surface is defined for the roll 4 by the diameter of the ball-shaped pressure element 12 whereby the local pressure 16 exerted on the roll 4 can be significantly higher than the pressure 14 which applied to the pressure element 12.

[0055] he surface hardness by way of a cold work hardening of the edge layers and setting the residual stress into the depth of the material is carried out by a deep rolling process using the pressure tool 10.

[0056] FIG. 3 shows a schematic representation of a roll 4′ which is designed here as a working roll of a roll stand and has been conditioned with a method according to the invention. The working roll 4′ comprises a roll body 22, a pin 24 and a pivot point 26 as regions with different functions.

[0057] The roll body 22 comprise a roll surface which is usually in direct contact with the material to be rolled in the case of working rolls. The structure of the roll body 22 is thus particularly important for the rolled product such that setting surface hardness and residual stress by conditioning the roll body 22 is advantageous.

[0058] Surfaces on the pins 24 can also lend themselves to conditioning. For example, the surfaces 24a to 24f can serve as mounting surfaces, individually or in combination and thus setting of surface hardness and residual stress can be carried out by conditioning. The same applies for the pivot point 26.

[0059] In principle, any sections of the surface which are subject to corresponding structural requirements can be conditioned. Substantially the entire surface of the working roll 4′ can also be conditioned.

[0060] Test series were carried out on different working rolls in order to examine the effect of the method or the device with respect to the surface hardness. The working rolls were set up to roll foils or strips made from aluminium or aluminium alloys. The Leeb hardness of the surface was measured on already used and newly-smoothed working rolls prior to and after conditioning. In order to determine the Leeb hardness, the measuring device with the designation Eqotip 2 (R) with an impact body E was used, as sold on the application date by the company, Proceq SA (R).

[0061] The pressure on the pressure element was varied from 100 bar to 400 bar in a first test series on different sections of the roll body and the Leeb hardness according to DIN 50156 was measured at three positions. A roll body with a diameter of 13 mm was used as the pressure element and a feed motion of 0.2 mm/revolution with a rotational speed of 125 r/min. The results of this test series are recorded in Table 2 and FIG. 4.

TABLE-US-00002 TABLE 2 Pressure Hardness Hardness Hardness (bar) Pos. 1 (HLE) Pos. 2 (HLE) Pos. 3 (HLE) Δ HLE 100 Beforehand 806 815 811 6 Afterwards 814 818 819 200 Beforehand 817 816 820 18.3 Afterwards 836 837 835 300 Beforehand 816 814 815 29.3 Afterwards 842 844 847 400 Beforehand 811 807 819 39.6 Afterwards 850 855 851

[0062] It can hereby be noted that the conditioning effects a uniform increase in the hardness. The increase of the Leeb hardness in FIG. 4 is plotted as a function of the pressure. An increase of 10 HLE can be expected from approximately 150 bar with a 13 mm ball. Increases of at least 25 HLE or at least 35 HLE are also possible. With an identical ball at 400 bar of pressure, an increase of approximately 40 HLE was introduced.

[0063] Subsequently, conditioning of the roll body likewise with a 13 mm ball was carried out on two used working rolls with the designations F87 and F88 with a pressure of 400 bar. The Leeb hardness prior to and after the conditioning is recorded in Table 3 for three measuring points, the position of which is indicated in relation to the roll body edges.

TABLE-US-00003 TABLE 3 Hardness Hardness Hardness Hardness Hardness Pos. Pos. Pos. Pos. Pos. Rotational 200 500 800 1200 1500 Working speed Duration mm mm mm mm mm roll (r/min) (min) (HLE) (HLE) (HLE) (HLE) (HLE) F87 125 64 Beforehand 823 813 814 818 815 125 64 Afterwards 848 842 841 842 837 F88 200 40 Beforehand 818 817 822 828 828 200 40 Afterwards 848 844 847 846 845

[0064] In this test series also a notable increase in the surface hardness, with which the working rolls are re-conditioned for different usage purposes, was determined.

[0065] In order to examine the distribution of the generated hardness over the conditioned surface, the Leeb hardness was determined at different positions a-q of the conditioned roll body. The first position a was in this case spaced 25 mm from the roll body edge. The distance between the further positions was respectively 100 mm. This was respectively carried out on the circumference at four different angular positions P1 to P4, between which the working roll was respectively rotated by 90°. The results thereof are recorded in Table 4, together with the calculated standard deviation of the Leeb hardness by the average value. The unit of hardness here is also HLE.

[0066] The values from table 4 show that a particularly uniform structure of the working roll was provided with the conditioning. For working roll F87, the standard deviation of the Leeb hardness was under 15 HLE. For the working roll F88, a standard deviation of below 7.5 HLE was even achieved.

TABLE-US-00004 TABLE 4 a b c d e f g h i j k l m n o p q SD F87 P1 840 849 849 848 850 950 851 851 849 848 847 844 845 845 847 851 842 13, 8 P2 839 854 850 852 853 851 852 850 852 851 849 848 849 847 848 848 841 P3 825 851 851 854 843 848 850 839 839 850 850 843 849 850 849 850 839 P4 848 848 857 855 856 855 855 855 851 850 849 850 850 848 845 831 823 F88 P1 828 834 839 849 849 843 843 847 848 848 848 843 848 848 847 844 842  5, 6 P2 840 842 845 844 842 845 840 840 839 840 842 844 843 844 834 829 827 P3 829 830 849 849 849 851 849 843 848 844 843 841 845 844 842 849 845 P4 847 846 847 846 843 844 836 849 848 848 849 850 850 846 847 844 842

[0067] In a further detailed test series, the different method parameters for the ball diameter d of the pressure element, the pressure and the feed motion were varied. The rotational speed was here maintained constant with 160 r/min.

[0068] Based on this test series, preferred parameter ranges could be established which condition the rolls particularly advantageously. These can be used irrespective of the rotational speed. The ranges are combined in Table 5 as a function of the desired hardness in A HLE.

TABLE-US-00005 TABLE 5 Δ HLE d ball (mm) Pressure (bar) Feed motion (mm/r) 10  3-10 100-160 0.2-0.3 20  3-10 250-330 0.2-0.3 25 10-16 220-290 0.2-0.3 30 10-16 300-380 0.3-0.5 35 10-16 320-400 0.2-0.3 40 10-16 350-450 0.2-0.3

[0069] The effect of the conditioning on two working roll pairs was also further examined which stood out with complaints in relation to pattern imprints in the rolling process. After conditioning these working roll pairs with the described method and subsequently grinding the roll surface, the working roll pairs could be operated without complaints in relation to the imprinting of surface patterns by material overlaps.

[0070] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0071] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0072] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.