US3604239A

US3604239A - Rolling mill and method of removing coating from a work roll of the mill

Info

Publication number: US3604239A
Application number: US813807A
Authority: US
Inventors: Arthur L Moxon
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1969-04-01
Filing date: 1969-04-01
Publication date: 1971-09-14
Anticipated expiration: 1988-09-14

Abstract

A method of treating the working surface of a rolling mill roll on which roll coating accumulates during rolling of work in the mill comprising without removing the roll from the mill flailing the working surface of the roll with flexible elements so that portions of the elements adjacent the ends thereof engage such surface of the roll and by such flailing action rubbing abrasive particles over such surface of the roll and thereby removing at least part of the roll coating accumulated on the working surface of the roll. Further, a rolling mill comprising a roll for acting on work passing in contact therewith, which roll picks up matter from the surface of the work being acted on, and means for removing at least part of such matter from the roll, such means comprising flexible elements and means for mounting the flexible elements for flailing action so that portions of the elements adjacent the ends thereof engage the working surface of the roll, and abrasive particles rubbed over such surface of the roll by the flailing action of the flexible elements.

Description

United States Patent {72] Inventor Arthur L. Moxon Richmond, Va.

[2l] Appl. No. 813,807

[22] Filed Apr. 1, 1969 [45] Patented Sept. 14, 1971 [73] Assignee Reynolds Metals Company Richmond, Va.

Continuation-impart of application Ser. No. 756,183, Aug. 29, 1968, now abandoned.

[54] ROLLING MILL AND METHOD OF REMOVING COATING FROM A WORK ROLL OF THE MILL 19 Claims, 5 Drawing Figs.

[52] US. Cl 72/236, 72/40, 51/289, 51/334, 51/241 [5 l] Int. Cl B2lb 27/04, B2lb 27/06 [50] Field of Search 72/40, 236; 51/334, 251, 254, 49,179, 335, 336, 337, 252, 289, 1, 2, 3

[56] References Cited UNITED STATES PATENTS 3,379,044 4/1968 Kirschner 72/236 Primary Examiner-Charles W. Lanham Assistant ExaminerMichael J. Keenan Attorney-Glenn, Palmer, Lyne, Gibbs & Thompson ABSTRACT: A method of treating the working surface of a rolling mill .roll on which roll coating accumulates during rolling of work in the mill comprising without removing the roll from the mill flailing the working surface of the roll with flexible elements so that portions of the elements adjacent the ends thereof engage such surface of the roll and by such flailing action rubbing abrasive particles over such surface of the roll and thereby removing at least part of the roll coating accumulated on the working surface of the roll. Further, a rolling mill comprising a roll for acting on work passing in contact therewith, which roll picks up matter from the surface of the work being acted on, and means for removing at least part of such matter from the roll, such means comprising flexible elements and means for mounting the flexible elements for flailing action so that portions of the elements adjacent the ends thereof engage the working surface of the roll, and abrasive particles rubbed over such surface of the roll by the flailing action of the flexible elements.

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SHEET t 0F 4 28 I 2 E E Q ARTHUR L. MOXON INVENTOR FIG-5 wt)? HIS ATTORNEYS ROLLING MILL AND METHOD OF REMOVING COATINGFROM A WORK ROLL OF THE MILL This application is in part a continuation of my copending applicationSer. No. 756,l83, filed Aug. 29, 1968, now abandoned.

This invention relatesto a rolling mill and a method of removing coating from a roll of the mill without removing the roll from the mill.

In the hot rolling of metal, it has been recognized that oxide formed on the metal may be transferred to the work rolls as particulatematter, called pickup. In the cold rolling of metal, it is also recognized that particulate matter accumulates on the working surfaces of the rolls. Accumulation of pickup or other particulate matter. results in a roll coating which produces a rough surface on the workpiece, and the deposited coating tends to slough off and become rolled into the surface of theworkpiece. The term roll coating as herein used includes oxide ofthe metal and/or other particulate matter which accumulates on the workingsurfaces of the rolls. As rolling-progresses, the resulting defects are exhibited as streaklike imperfections-in the metaL-Such imperfections in a hotrolled slab or billet persist in the hotrolled strip and subsequently'in the coldzrolled strip if the strip is cold rolled. The imperfections-caused by excessive roll coating cannot be tolerated for usesin which theappearance of the metal is critical.

Those skilled in the art know from experience that only by special treatment of the .rolled product, as by caustic etching or by buffing,- grinding ormachining to remove a surface layer of the metal,. can. the imperfections caused by pickup be completely eliminated. The only practicable way of solving the problem is by intercepting and removing the pickup before it can be. rolled into the work. This means removing pickup or other. matter accumulated on the work roll from the hot rolling .millrollstothe extent that it does not slough off and become. rolled into the surface of the work.

Theproblem .of pickup on hotrolling millrolls has existed and hasbeenvrecognized by those skilled in the art through the years. One solution, but not a practicable one, is to remove and refinish the roll; This means shutting down the mill; and since refinished rolls accumulate roll coating soon after they are put into use the-mill would be shut down a greater part of thetime than it would be operating. Various attempts to removeroll coating from rolls without removing the rolls from the mill have been madeHT he surfaces of the rolls have been ground,-wire brushed and otherwise treated but the results have not-been satisfactory from the standpoint of efficient removal of the pickup. Until. my invention the problem remainedrunsolved and manufacturers of sheet and strip metal could. not economically meet finish specifications of customers.

l have'solved theproblemby'treating the working surfaces of rollingmill: rolls;on,..which roll coating accumulates during rollingof work in themill by,without removing a roll from the miILLflaiIing'the working surface of the roll with flexible elements southat portions I of the elements adjacent the ends thereof engage such surface of the roll and by such flailing action rubbing abrasive particles over such surface of the roll and therebyremoving at least part of the roll coating accumu- Iatedon the. working surface of the roll. I remove from a hot rollingmillroll at leastpart of the pickup accumulated on the working surface of the roll from the surface of the work being acted. on by flailingtheworking surface of the roll as just stated. Thiscan be done while the work is in contact with the workingsurface of the roll or before it enters the mill, or during an interval .between reversing passes through the mill.

The abrasive particles may be fed separately to the roll surface -in position to. be rubbedthereagainst by the flexible elementsbutl prefer to have the abrasive particles carried by the flexibleelements. Theflexibleelements may be in sheet form and.in:a preferred formthey are sheets carrying the abrasive particles like sandpaper, emery paper or emery cloth..The

flailing action is preferably accomplished by rotary movement of the flexible elements which may be carried by a rotating hub positioned adjacent the roll and driven, either in a direction such that the portions of the flexible elements which engage or flail the roll move in the direction of movement of the roll surface or in the opposite direction. Normally I prefer to have the axis of the rotating hub carrying the flexible elements parallel to t c axis of the roll, although in certain cases the axis of the hub may extend transversely of the axis of the roll. I desirably oscillate the flexible elements generally. along the roll to minimize the possibility of scratching rings around the roll by abrasive particles carried by the flexible elements.

The flailing action may be continuous throughout the time the mill is in operation or it may be discontinuous, perhaps being used only on the last one or two passes of a mill in which the work is progressively reduced in a series of passes.

Although the flexible elements may extend the full effective width of the roll face, it is also possible to use narrower elements which traverse the roll face in he course of such oscillation.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof and a present preferred method of practicing the same proceeds.

In the accompanying drawings I have shown a present preferred embodiment of the invention and have illustrated a present preferred method of practicing the same in which FIG; I is an isometric diagram illustrating the working and backing up rolls of a 4-high rolling mill with rotatably mounted flexible flailing means engaging the working surfaces of the working rolls in accordance with my invention;

FIG. 2 is an enlarged diagram illustrating theflailing action;

FIG. 3 is an isometric view illustrating a portion. of the mounting and driving means for the flailing means;

FIG. 4 is a plan view, with a portion cut away, of one of the flailing means and a portion of the mounting and driving means therefor including means for axially oscillating the flailing means; and

FIG. 5 is a fragmentary vertical longitudinal cross-sectional view through a rolling mill having my invention applied thereto.

Referring now more particularly to the drawings, I have chosen to illustrate my invention as applied to or embodied in a 4-high rolling mill having relatively small diameter working rolls backed by relatively large diameter backing up rolls in which means for removing pickup are applied to the working rolls, although I wish it understood that such means. may be applied to other rolls contacting the material being rolled and/or rolls not contacting the material being rolled, such as the backing up rolls of a 4-high rolling mill.

In the diagram constituting FIG. 1 there are illustrated the working rolls W and the backing up rolls B of a 4-high hot rolling mill for rolling metal such as aluminous metal (aluminum or aluminum alloys), although of course my invention is applicable to the rolling of other metals (ferrous and nonferrous). The rolling mill may be of conventional construction as known to those skilled in the art so description and illustration of the mill details are unnecessary.

Means for removing pickup from the working rolls W of the mill are mounted in the mill for engagement with the working surfaces of the rolls. Such means comprise flexible elements, shown as in the form of sheets S, with means for driving them to flail by the end portions thereof the working surfaces of the working rolls and thus dislodge and remove pickup from such surfaces. In the form shown the sheets S are mounted for rotary flailing action against the working surfaces of the rolls. The sheets S are mounted in groups and secured by their edges to a generally cylindrical elongated mounting member M in the form of a slotted hub having end flanges l-l through which passes a shaft T which projects beyond both ends of the hub M. The hub M carrying the sheets S is fixedly mounted on the shaft T so as in effect to be integral therewith. I shall call each element comprising the hub M with its end flanges-H and the sheets S carried thereby and the shaft T on which the hub is mounted a flailing cylinder, designated F, which is oscillatable axially as a unit along the adjacent working roll W as will presently appear. Each flailing cylinder F is mounted in the mill and driven through its shaft T. It may be driven either in a direction such that the portions of the sheets S which engage or flail the working surface of the roll move in the direction of movement of the roll surface or in the opposite direction.

The action of the flexible sheets S on the working surface of the roll is a rubbing, wiping or slapping action which is perhaps best described by the adjective flailing in contradistinction to brushing action by the ends of brush bristles. The sheets, which extend lengthwise of the roll in contradistinction to a brush bristle which terminates in a point, have their end surface portions for a short distance back from the end edges of the sheets drawn over the roll surface, the rapid succession of sheets thus acting on the roll surface effectively dislodging and removing pickup from the roll surface.

The sheets S may be of any suitable material, suchas paper, cloth or plastic. The sheets must be flexible to have the desired flailing action. Abrasive particles, such as grit or sand, are rubbed over the roll surface by the action of the flailing cylinder. The abrasive particles may be supplied separately, but I prefer that they be carried by the sheets, like sandpaper or emery cloth. The result of such employment of flailing cylinders is effective in removal of pickup from the working surfaces of the rolls.

The shaft T of each of the flailing cylinders F has each of its ends mounted for rotation in a slide 2 slidable in a guideway 2a mounted in the mill housing (see FIGS. 3 and 4). Each slide 2 has an element 3 integral therewith projecting laterally therefrom at the end thereof remote from the flailing cylinder. Beyond the end of each slide 2 is a bracket 4 also mounted in the mill housing carrying a cylinder 5 in which operates a piston having a piston rod 6 connected with the corresponding slide element 3 at 7. Operation of the pistons in cylinders 5 moves the slides 2 and hence the flailing cylinder F toward and away from the corresponding working roll W. Connected with each slide element 3 at 8 and extending through a sleeve 9 carried by the corresponding bracket 4 is a rod 10 having thereon an adjustable stop nut 11, the stop nuts 11 determining the position of the flailing cylinder when fluid is admitted behind the pistons in the cylinders 5 to move the flailing cylinder toward the working roll. The position of each flailing cylinder in relation to its working roll is adjusted by adjustment of the nuts 11 along the rods 10.

The shaft T of each flailing cylinder has fixed thereto a sprocket l2. Joumaled in the slide 2 at the end of the flailing cylinder which is adjacent the sprocket 12 is a stub shaft 13 carrying a hub having a single sprocket 14 and a double sprocket 15. A sprocket chain 17 is trained about the sprockets l2 and 14. For each flailing cylinder a driving motor 18 is mounted in the mill whose shaft 19 carries a sprocket 20. A bracket 21 pivoted at 22 and fastenable in adjusted angular positions by a bolt 23 operating in an arcuate slot 24 carries a sprocket 25, and a sprocket chain 26 is trained about the sprockets and 25. The bracket 21 also carries a double sprocket 27 in effect integral with the sprocket 25, and a double-strand sprocket chain 28 is trained about the double sprocket 27 and the double sprocket 15. Thus each motor 18 drives the corresponding flailing cylinder by driving its shaft T.

Fixedly mounted on the shaft T of each flailing cylinder F is a flanged disc 29 which meshes with a circumferentially recessed disc 30 rotatably carried by a shaft 31 connected with a piston rod 32 carried by a piston in a cylinder 33 mounted in the mill. Thus operation of each piston in its cylinder 33 causes movement of the corresponding disc 30 parallel to the axis of the flailing cylinder and since the disc 29 is in mesh with the disc 30 this causes axial movement of the flailing cylinder which carries the sheets S. 'By'such means oscillation of the flailing cylinders axially along the working surfaces of the rolls may be effected obviating circumferential scoring of the rolls.

Excessive flailing of the working surface of a roll may clean and smooth the working surface of the roll to such an extent that slippage occurs between the roll and the work, or between the work roll and adjacent backup roll as in a 4-high rolling mill. Therefore 1 preferably limit the flailing of the working surface of the roll so that at the end of the treatment the working surface of the roll has thereon roll coating sufficient to cause the roll to grip the work during subsequent rolling avoiding undesirable slippage of the roll over the work such as may occur if the roll is completely free of roll coating, but which roll coating is not sufficient to cause any substantial portion thereof to be transferred back to the work from the roll. I find it desirable particularly in a unidirectional continuous mill for hot rolling to perform the flailing treatment of the working surface of the roll at least partly during a period of operation in which the work is in contact with the roll and to discontinue such flailing before the trailing end of the work leaves the roll. This results in a light roll coating on the roll which promotes optimum gripping of the work during subsequent rolling.

The work may be hot rolled in a plurality of passes in contact with the roll being treated (as in a reversing mill) and the flailing of the working surface of the roll may be and desirably is confined to less than all of such passes or can occur during the interval between successive passes. Preferably flailing of the working surface of the roll occurs at least during the final pass.

In a continuous mill, especially a multistand mill for hot rolling, I find it advantageous to discontinue the flailing of the working surface of each work roll before the trailing end of a workpiece leaves the roll and to resume such flailing of the working surface of the roll not earlier than when the leading end of the next workpiece passes into contact with the roll. To obviate return to he work of matter removed from the working surface of the roll I preferably flail the working surface of the roll in a direction to discharge the removed matter away from the work.

While I have shown and described a present preferred embodiment of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

1. In the rolling of aluminous metal to produce sheet of anodizing quality, substantially free of surface imperfections, including a hot rolling operation, the method comprising during said hot rolling of the metal in contact with a work roll flailing the working surface of the roll with flexible elements so that portions of the elements adjacent the ends thereof engage such surface of the roll, providing abrasive particles and by such flailing action rubbing the abrasive particles over such surface of the roll.

2. A method as claimed in claim 1 in which the working surface of the roll is flailed with flexible sheets.

3. A method as claimed in claim 2 in which the working surface of the roll is flailed by rotary flailing action.

4. A method as claimed in claim 3 in which the working surface of the roll is flailed by rotary flailing action in a direction to discharge the removed matter away from the work.

5. A method as claimed in claim 3 in which the abrasive particles are carried by the sheets.

6. A method as claimed in claim 1 in which the flexible elements are oscillated generally along the roll.

7. A method as claimed in claim 5 in which the flexible elements are oscillated generally along the roll.

8. A method of treating the working surface of a rolling mill roll on which roll coating accumulates during rolling of work in the mill comprising without removing the roll from the mill flailing the working surface of the roll with flexible elements so that portions of the elements adjacent the ends thereof engage such surface of the roll, providing abrasive particles and by such flailing action rubbing the abrasive particles over such surface of the roll and controlling the flailing of the working surface of the roll so that at the end of the treatment the working surface of the roll has thereon roll coating sufficient to cause the roll to grip the work during subsequent rolling avoiding undesirable slippage of the roll over the work such as may occur if the roll is completely free of roll coating, but which roll coating is not sufficient to cause any substantial portion thereof to be transferred back to the work from the roll.

9. A method of treating the working surface of a rolling mill roll on which roll coating accumulates during rolling of work in the mill as claimed in claim 8 including discontinuing such flailing before the trailing end of the work leaves the roll.

10. A method of treating the working surface of a rolling mill roll on which roll coating accumulates during rolling of work in the mill as claimed in claim 8 in which the work is hot rolled in a plurality of passes in contact with the roll and the flailing of the working surface of the roll is confined to less than all of such passes.

11. A method of treating the working surface of a rolling mill roll-on which roll coating accumulates during rolling of work in the mill as claimed in claim 8 in which the work is hot rolled in a plurality of passes in contact with the roll and the flailing of the working surface of the roll occurs at least during the final pass.

12. A method of treating the working surface of a rolling mill roll on which roll coating accumulates during hot rolling of work in the mill as claimed in claim 8 in which flailing of the working surface of the roll is commenced after the leading end of the work passes into contact with the roll and is discontinued shortly before the trailing end of the work leaves the roll.

13. A method of treating the working surface of a rolling mill roll on which roll coating accumulates during rolling of work in the mill and in contact with which roll workpieces pass successively comprising flailing the working surface of the roll with flexible elements so that portions of the elements adjacent the ends thereof engage such surface of the roll, providing abrasive particles and by such flailing action rubbing the abrasive particles and by such flailing action rubbing the abrasive particles over such surface of the roll and thereby removing at least part of the roll coating accumulated on the working surface of the roll, discontinuing such flailing of the working surface of the roll before the trailing end of a workpiece leaves the roll and resuming such flailing of the working surface of the roll not earlier than when the leading end of the next workpiece passes into contact with the roll.

14. A method as claimed in claim 1 in which the flailing of the working surface of the roll occurs at least partly while the work being acted on is in contact with the roll.

15. A rolling mill comprising a roll for acting on work passing in contact therewith, which roll picks up matter from the surface of the work being acted on, and means for removing at least part of such matter from the roll, such means comprising flexible elements and means for mounting the flexible elements for flailing action so that portions of the elements adjacent the ends thereof engage the working surface of the roll, and abrasive particles rubbed over such surface of the roll by the flailing action of the flexible elements, the removing means being shiftable between operative position in contact with the roll and inoperative withdrawn position and stop means being provided for predeterminately positioning the removing means and limiting the movement thereof toward said roll when the removing means are shifted to operative position.

16. A rolling mill as claimed in claim 15 in which the stop means are adjustable relatively to the roll.

17. A rolling mill as claimed in claim 16 in which the flexible elements are sheets.

18. A rolling mill as claimed in claim 17 in which the abrasive particles are carried by the sheets.

19. A rolling mill as claimed in claim 18 in which the sheets are mounted for rotary flailing action.