US3274814A - Rolling mill - Google Patents

Description

E. D. DILLING ROLLING MILL Sept. 27,. 1966 '4 Sheets-Sheet 1 Filed May 25, 1964 Gm g y. mm O INVENTOR. Elmer D. DiHing Agent 3,2 WLM E. D. BILLING Sept. 27, 1966 ROLLING MILL 4 Sheets-Sheet 2 Filed May 25. 1964 INVENTOR. Elmer D. Dil ling Agent Sept. 27, 1966 E. D. BILLING 3,274,814

ROLLING MILL Filed May 25, 1964 4 Sheets-Sheet 3 INVENTOR.

Elmer D. Dilling E. D. DILLING ROLLING MILL Sept. 27, 1966 4 Sheets-Sheet 6.

Filed May 25, 1964 FIGS INVENTOR. Elmer D. Dil ling Agent United States Patent 3,274,814 RGLMNG MILL Elmer 1). Billing, Las Vegas, Nev., assignor to Titanium Metals Corporation of America, New York, N.Y., a corporation of Delaware Filed May 25, 1964, Ser. No. 369,808 13 Claims. (Cl. 7274) This invention relates to rolling metal strip or sheet, and to a rolling mill which will impart improved characteristics to a rolled sheet or strip of metal.

Conventional rolling mills, as is well known, often comprise a pair of working ro-lls which may or may not be backed-up by additional rolls, and a metal sheet or strip is passed between the working rolls to reduce its thickness and thereby also increase its length. Such rolling mills have been found to have several disadvantages. They cannot readily produce rolled strips having absolutely uniform thickness from edge to edge. This occurs because there is inevitably some flexing in the rolls from end to end no matter how strong or rigid they may be designed to be. Inevitably the eifective space between the working roll at their centers is greater than the eifective distances at their outside edges. This produces a strip which is thicker at its center than at its edges, such center thickness being known in the art as the crown."

Another disadvantage of a conventional rolling mill is that the width of strip to be produced is naturally limited by the width of the working rolls. Product-ion of wider strips would be advantageous for those uses where increased width as well as length is desirable.

A further disadvantage of conventional rolling mills is that metal strips passing lengthwise only through the working rolls developes mechanical properties which are orientated according to the direction of rolling. .Thus for example, a long coil of metal strip passing through a rolling mill acquired deleterious properties known as ridgin, roping, and by other special terms, which are, it is believed, imparted by a crystal orientation or alignment of the metal structure along the longitudinal axis of the strip. In production of rolled sheet sections of a relatively small area, the direction efiect of passage through a conventional rolling mill may be to a large extent eliminated by what is known by cross-rolling. This is accomplished by first rolling the sheet section from end to end and then turning it 90 degrees and rolling it from side to side. The second rolling in a direction to right angles to the first eliminates much of the initial directional effects, however, this procedure may leave some residual directional effects from the second rolling. It will be appreciated, also, that the cross-rolling process described must necessarily have a limited application since the length of the sheet (or its longest dimension) cannot be any longer than the width of the working rolls.

Wider rolls can, as must be apparent, provide for pro duction for wider sheets or larger area cross-rolled production. Provision of wider rollers, however, results in increased crown effect because the greater length of the roll span results in greater flexing and larger dimensional difference between the center and edges of the rolled sheet.

The rolling mill of this invention will produce rolled strip of substantially improved uniformity of thickness, that is without crown." The mill will also produce a rolled strip wider than the strip initially fed into the mill. Additionally the mill of this invention will produce a rolled strip which does not have directional properties found in strips rolled with conventional mills.

Summarized briefly, this invention contemplates reducing its thickness by pressing between a platen and a 3,274,8l4 Patented Sept. 2?, 1%36 roller having a thin working edge and which is moved in a path across said sheet or strip workpiece at an angle to its transverse axis. The rolling mill comprises a platen and a rotatable roller having a thin working edge which is adapted to plastically deform and reduce the thickness of a metal strip workpiece against which it is pressed during travel over such a workpiece while it is being drawn across the face of the platen. The path of travel of the working roller is not along the transverse axis of the strip workpiece, but is at an angle to such transverse axis that is diagonally across the strip. Additionally, it is preferred that the path of the working roller be arcua-te, and correspond to an arcuate step on the face of the platen. In a preferred organization a plurality of such working rollers are arranged to travel successive-1y across the surface of the strip workpiece while this is being drawn over the face of the platen.

The annexed drawings illustrates a rolling mill embodying features of this invention and in which:

FIG. 1 shows a general top view of the rolling mill.

FIG. 2 shows a vertical sectional View of the rolling mill of FIG. 1 taken along the line 2-2.

FIG. 3 shows a vertical sect-ion of the rolling mill of FIG. 1 taken along the line 3-3.

FIG. 4 shows, somewhat enlarged, a detail of one of the working rollers of the mill of BIG. -1.

FIG. 5 shows a central vertical section of the working roller illustrated in FIG. 4.

FIG. 6 shows a vertical cross-section of the roller of FIG. 5 taken along the line 6-6.

FIG. 7 shows a detail of the strip guide rolls.

FIG. 8 illustrates the manner in which a strip being rolled by the rolling mill of this invention becomes elongated and additionally increased in width.

FIG. 9 shows a diagram of the movement of metal of the strip being rolled, to explain the mechanics of the process.

Referring now particularly to FIGS. 1, 2 and 3 the rolling mill comprises a supporting structure which is divided into a mill stand base Ill and a reel stand base 12, these bases being pivotably connected by pin 14 so that they may be arranged in desired angular relation. Attached to base 10 are upright members 16 suitably braced by horizontal cross-members 18 and on top of which is securely fastened plate 20. Pastened to the top of plate 20 are a pair of heavy horizontal U-shaped members 22 which, as will be seen more clearly in FIG. 3, are arranged at an angle to each other and which at their tops support cross-plate 24.

Welded to the inner edge of cross-plate 24 is bracket 26 which by means of threaded bushing 28 supports the upper end of shaft 30. Hanging from shaft 350 and rotatably mounted thereon is roller mounting plate 32 on which are fixedly mounted a plurality of radially extending roller mounting blocks 34. Fastened to roller plate 32, and to blocks 34, is ring gear 36. At the outer end of each roller block 34 is mounted a shaft 38 to which is rotatably attached an inner roller 40 and an outer roller 42 and between these inner and outer rollers is mounted a working roller 44, having a relatively thin extending rim or working edge 45.

The Working edge 45 is thin in the sense that its width is substantially less than the diameter of working roller 44 and this would also be thin compared to the edge of a conventional rolling mill roll which is most often substantially longer than the roll diameter. Naturally the path across the strip pressed by working edge 45 would be correspondingly thin. Additional details of the mounting of working roller 44 and the adjustment of inner and outer rollers 40 and 42 will be described hereinafter.

Mounted to one side of one of U-shaped members 22 is support plate 46 on which is mounted motor 48 conven- Q1 tionally connected to reduction gear which drives shaft 52 having on its free end attached pinion 54 which meshes with ring gear 36.

Welded to the upper edges of the lower arms of U members 22 is platen support plate 56 on top of which is fixedly attached platen 58. As will be seen more clearly in FIGS. 3 and 4, platen 58 comprises a heavy piece of metal having a series of steps 68 in its face or upper surface. Steps 60 are arcuate corresponding to portions of the circular paths described by working rollers 44 as will hereinafter be described in more detail.

Welded to the lower edges of the upper arms of U member 22 is backing plate 62 which is provided with an arcuate groove 64 to allow clearance for working rollers 44 as they revolve. The areas of backing plate 62 on either side of groove 64 provide flat bearing surfaces for rollers 40 and 42 as they travel around.

Fixedly attached to base 10 are a pair of uprights 66 into which are journalled shaft 68 of pay-off reel 70 on which is wound a coil of strip 72 which constitutes the workpiece to be rolled. Positioned between uprights 66 and upright members 16 are another pair of uprights 74 into which is journalled shaft 76 of guide roll 78.

Fixedly attached to base 12 are a pair of uprights 80 into which is journalled shaft 82 of wind-up reel 84. Shaft 82 is driven through variable speed reduction gear 86 by motor 88 which is mounted on plate 90 supported by uprights 92.

As will be seen in FIG. 2 the coil of strip 72 to he rolled is fed from pay-off reel 70 over guide roll 78, over the face of platen 58 where it is rolled and reduced in thickness, as at 94, and re-coiled on Wind-up reel 84.

Referring now particularly to FIGS. 4, 5 and 6, each pair of inner rollers 40 and outer rollers 42 are rotatably mounted on their shafts 38 and between them are rotatably mounted working rollers 44. The space relationship between Working rollers 44 and rollers 40 and 42 is maintained by provision of spacing bushing 96. In FIG. 5 spacing bushings 96 are identical and working roller 44 is spaced midway between rollers 40 and 42, this assembly being that shown in FIG. 1 at 98. In the assembly shovm in FIG. 1 at 100 the inner bushing on shaft 38 has been eliminated and the outer bushing replaced by a longer bushing 96a which locates working roller in its inner position on shaft 38. In the assembly shown in FIG. 1 at 102 the outer bushing on shaft 38 has been eliminated and the inner bushing replaced with longer bushing 96a so that the working roller is maintained in its outer position on shaft 38. Diametrically opposite roller assemblies will be arranged similarly so that the complete organization includes 6 working rollers in opposed pairs, evenly spaced around the periphery of roller mounting plate 32, and spaced radially to correspond with the three arcuate steps in platen 58.

The method of adjusting the vertical position, or bite of working rollers 44 to provide the required pressure of working edges 45 against the strip to be roller will be clear from FIGS. 5 and 6. Shaft 38 is stepped, with the portion on which working roller 44 is journalled (through a suit-able anti-friction bearing) being eccentric as at 104. The interior of shaft 38 is drilled to accommodate partly tapered rod 106 which is treated at its inner end into block 34. Inner roller 40 and outer roller 42 are journalled (through suitable anti-friction bearings) on concentric portions of shaft 38. Washer 108 is interposed between the inner end of shaft 38 and block 34 and outer washer 110 is interposed between the outer end of shaft 38 and nut 112 threaded on to the outer end of rod 106. To adjust the vertical position of working roller 44, nut 112 is loosened and shaft 38 rotated so that the eccentric portion raises or lowers working roller 44 to the desired position. Nut 112 is then tightened to lock the assembly as adjusted. It will be apparent that such adjustment does not disturb the position of inner and outer rollers 40 and 42 which rotate around concentric hub portions of shaft 38.

The action of one of working rollers 44 in rolling metal strip may be best seen in FIG. 4. The strip to be rolled 72 travels across the top or face of platen 58. Working rolls 44 in their three radial positions roll across strip 72 and work the metal between their working edges 45 and steps 60 in platen 58. Each roller assembly as it travels around over platen 58 is maintained vertically by inner and outer rollers 40 and 42 contacting the under surface of backing plate 62 with the working rollers provided with clearance in groove 64, and this assembly thus provides means for pressing the working roller edge 45 against the surface of workpiece strip 72. Platen 58 is welded to the upper portion of the lower arm of U-member' 22 and backing plate 62 is welded to the under surface of the upper arm of this same U-shaped member as previously described. Since U-member 22 is extremely heavy and strong, proper pressure can be exerted between working rollers 44 and platen 58 to cause plastic deformation of feed strip 72 to form a rolled and wider, longer and thinner strip 94. The finished strip 94 is guided in its direction to wind-up reel 84 by side rolls 116 adjustably and rotatably mounted in slots 118 as seen more clearly in FIG 7.

The effect of the action of working rolls 44 is shown in FIG. 8. A workpiece strip 72 is plastically deformed by the machine, the edges of the working rollers following tracks 114 across its surface. These tracks 114 as described are arcuate and correspond to steps 60 in the top surface of platen 58. Also due to the positioning of feed roll 70 and platen 58 workpiece strip 72 is arranged so that tracks 114 cross its surface on a diagonal, that is at an angle to the transverse axis thereof, considering an arcuate path as having an average direction along a straight line corresponding to its chord. Deformation of strip 72 therefore occurs progressively along paths or tracks 114 and roller 44 is caused to press the strip 72 between its working edge 45 and platen 58 to produce a thinner but wider as well as longer sheet 94. The arcuate paths of the deforming wheel edges are advantageous to avoid crown in the rolled sheet. With such an arcuate deformation path excess metal in thicker crowned portions of the feed strip can be re-distributed to an extent crosswise as well as lengthwise of the strip so that a completely crown free rolled sheet 94 can be produced.

FIG. 9 is an idealized representation of the action of a single roller operating over an average track across a strip. It is shown to explain the mechanism by which a feed strip is rolled to thinner gauge and at the same time to greater width, and also explains the new angular direction of progress of the rolled strip compared to the feed strip before rolling. Referring now to FIG. 9 the feed strip is shown at 72 and the rolled strip at 94 with the average or straightened path of the working roller (or rollers) at b. Considering a particle of metal at a, when the strip 72 is rolled it will, because of progression of the strip across platen 58, move in the direction of 0 along the path ac. Due, however, to the fact that the material at a is being also rolled and reduced the strip becomes elongated in a direction at right angles to the path of the working roller or as shown in FIG. 9 from c to d. The resultant of these two movements and indicating the actual strip movement and direction will be ad on the FIG. 9 diagram. Thus it is seen that the direction and width of the rolled sheet is principally determined by the degree of reduction under which the working roller or rollers and the angle of the average working roller travel path.

In operation of the rolling machine of this invention the bite of working rollers 44 is adjusted by suitable rotation of eccentric shafts 38 and setting by tightening nuts 112. This is arranged so that the distance between the edge of the front working rollers as at 102 and the corresponding surface of platen 58 is set to give the re quired rolled metal thickness. Then mill stand base 10;

and reel stand base 12 are arranged at the required rolled metal thickness. Then mill stand base and reel stand base 12 are arranged at the required relative angle (pivoted on pin 14) so that the strip to be rolled 72 will pay off reel 70 and the rolled sheet will align with and wind on wind-up reel 84. The ratio of reduction gear 86 is set so that the rate of progression of strip 72 through the mill will be such that the degree of reduction arranged will result in the desired width and direction of movement of the rolled strip, with the paths of travel of edges 45 of working rollers 44 being adjacent and successive across strip 72.

With the settings on the mill arranged, a coil of strip to be rolled is placed on pay-off reel 70 and led over platen 58. Preferably, initially a tail is welded onto the strip end to start the proper angular direction of the rolled strip and this is led over wind-up reel 84. Then motor 48 is started to rotate roller and support plate 32 and causing working rollers 44 to move successively across the strip on platen 58 and, simultaneously, the reduced sheet, following the tail, is wound on wind-up reel 84.

It will be apparent that the settings on the rolling mill of this invention can be adjusted to provide desired width and thickness of rolled sheet within certain limits. The width increase cannot ordinarily be more than about 50 percent greater than the original sheet width due to mechanical limitations in wind-up reel angles and structural design problems.

The angle of the average travel path of the working roller or rollers can be varied from about 10 degrees to about 70 degrees to the transverse axis of the sheet strip. The average travel path can be considered to be the chord of an arcuate path and the central or middle of several such paths, if employed. Less than a 10 degree angle will not produce an appreciable increase in strip width. Apparatus to employ an angle of greater than about 70 degrees is difficult to design mechanically, the rolled strip take-off angle is excessively great, and design limitations become serious.

The radius of the circle of which the work rollers travel path is an arc, may vary from about 1 to 5 times the width of the strip workpiece being fed through the rolling mill of this invention. If the arc circle radius is less than equal to the strip width the curvature of the arcuate path across the strip will become so great that points on the path deviate excessively from a straight line or average path of travel. If the arc circle radius is greater than 5 times the sheet strip width, then the curvature of the working roller path becomes so nearly fiat and straight that effective re-distribution of rolled metal along an arcuate path to reduce or eliminate crown, is substantially lost.

The thickness reduction possible according to the instant invention will be of an order comparable to that obtainable by other metal working methods. Generally this is determined more by the character of the metal being worked than the working machine design. Properties such as ductility, rate of work hardening and other characteristics often limit the percentage reduction that can be obtained in one operation, without annealing. Lesser reduction amounts in the range of 40 to 50 percent are probably more common particularly for harder and stronger metal, for example steel.

In the case of the example illustrated in FIG. 8 the increase in width of rolled strip 94 over feed strip 72 is 33 percent. The angle of the average chord of arcuate paths 114 is 45 degrees to the transverse axis of sheet strip 72. The radius of the circle of which the average of paths 114 is an arc, is three times the width of sheet strip 72. With the bite of working rollers 44 adjusted so that the final thickness reduction is 50 percent the rolled strip 94 will be 50 percent longer and 33 percent wider than feed strip 72, not counting end losses and normal variations.

Production of rolled sheet or strip according to this invention is advantageous in several important aspects. It provides, first, a method of producing a rolled sheet or strip that is wider than the feed strip and, second, it provides a method for production uniform thickness strip or sheet that is without the crown that normally characterizes the product from conventional rolling mills. Third, strip of improved properties can be produced.

Deforming the sheet or strip by plastic flow along a diagonal path produces a rolled product wider than the feed. This occurs because the metal is caused to thin and flow along the deforming roller path which because of its diagonal dimension becomes a longer base line 7 (even though still angled) for the rolled product. A diagonal rolling path is in a sense a partial cross rolling; in other words the feed strip is being to some extent elongated widthwise as well as lengthwise.

Production of wide strip is important and particularly since the process herein described will produce crownfree wide strip. Ordinary rolling mills, designed for wide strip production invariably encounter increased crown forming difficulties because of the greater tendency for deflection of their longer rolls.

As important, or even more important, than the capability of wide sheet production is the effect of the rolling process of this invention on the mechanical properties of the product strip. Metal products when rolled unidirectionally, as in a normal strip process, acquire undesirable properties resulting from this unidirectional working. Such effects can be manifest by ridging or roping in the rolled strip which terms are used to describe a longitudinal waving or grooving of a strip when stretched during fabrication, such waves or grooves being characteristically parallel to the rolling direction. They may extend as long stringers down the length of a section of strip. Sheets of metal, having length not much greater than width are often processed by cross-rolling. The sheets are rolled lengthwise then crosswise to neutralize the effect of one direction rolling. While this works well with products having the length to width relationship of sheet, it cannot be applied to strip whose width may be reasonably small but whose length as coiled may be hundreds or thousands of feet or may even be measured in miles. Of utmost significance therefore is that the rolling of strip according to this invention can produce the beneficial effect of cross-rolling in a strip whose length is immaterial because the diagonal path of the deforming rollers moves progressively along a strip of any length.

It is advantageous to rotate the working roller -assemblies continuously in a plane parallel to the surface of the strip being worked. This results in the working rollers moving across the strip successively in one direction only and provides easier handling of the strip at its take-off angle since it is subject to side pressure from one side only. Additionally, the continuously moving working rollers can move at constant speed across the strip and are not subject to starting and slowing speed variations as might occur with a reciprocating, back and forth, working roller movement. The mechanical construction involved in arranging a continuously rotating working wheel assembly is also simpler and easier to maintain.

As pointed out previously, crown in met-a1 strip is caused by deflection of rolling mill rollers. Crown can be reduced in metal sheet by cross-rolling but not generally eliminated since the cross-rolling operation will leave a crown effect of its own. Additional longitudinal rolling cannot eliminate crown in a strip line because the metal flow is always in a generally longitudinal direction, that is parallel to the direction of rolling. In a crowned strip the metal is thicker at the center than at the edge and plastic flow must be induced from the center of the strip toward its edges to re-distribute the excess metal in the crown. This can be accomplished simultaneously with strip rolling and lengthening according to the process of this invention, and occurs because the arcuate travel paths of the deforming rollers work the metal transversely as well as longitudinally. At every point in such an arcuate path direction and space is provided for flow of excess crown metal.

I claim:

1. A method for reducing the thickness and increasing the width and length of a metal strip which comprises; passing said metal strip over a platen and working said strip to reduce its thickness by pressing against said platen with a thin edge working roller which is moved in successive, adjacent paths diagonally across said strip at an angle to the transverse axis thereof.

2. A method according to claim 1 in which the diagonal paths across said strip are arcuate.

3. A method according to claim 2 in which the working roller is continuously rotated in a circular path in a plane parallel to that of the surface of said strip and moves in successive adjacent paths diagonally across said strip as said strip is passed over said platen.

'4. A method according to claim 2 in which the diagonal arcuate paths across said strip have curvature corresponding to an arc of a circle of radius from one to five times the width of the strip.

5. A method according to claim 1 in which the angle of said paths is from degrees to 70 degrees to the transverse axis of said strip.

6. A method according to claim 1 in which the said Working roller is moved diagonally across said strip in only one direction.

7. A method according to claim 1 in which a plurality of working rollers are employed.

8. A rolling mill comprising (a) a platen,

(b) means for drawing a metal workpiece progressively across the face of said platen,

(c) a rotatable working roller having a thin working edge, and,

((1) means for pressing and moving said working roller diagonally across the surface of said workpiece in a path at an angle to the transverse axis thereof while said workpiece is being drawn over the face of said platen.

9. Apparatus according to claim 8 in which the diagonal path across said workpiece is arcuate.

10. Apparatus according to claim 9 in which said platen has an arcuate step across its face corresponding to the arcuate path of the working edge of the working roller.

11. Apparatus according to claim 8 in which the means for pressing and moving said roller across the surface of said workpiece comprise:

(1) a member in the form of a horizontal U with said platen supported on the upper surface of lower arm of said member,

(2) a backing plate attached to the underside of the upper arm of said member,

(3) a roller mounting plate rotatably mounted having at least one roller mounting block attached to its periphery,

(4) inner and outer rollers rotatably mounted on said roller block on opposite sides of said working roller which is also rotatably mounted on said roller block,

(5) means for adjusting the distance between the bottom of the Working edge of said working roller and the top edges of said inner and outer rollers, and,

(6) means for rotating said plate ina plane parallel to the surface of a workpiece being drawn across the surface of said platen so that said workpiece is worked between said working roller edge and said platen with said working roller being pressed into working contact with said workpiece by the edges of said inner and outer rollers in contact with said backing plate.

12. Apparatus according to claim 11 in which a plurality of working rollers are arranged evenly spaced around the periphery of said roller mounting plate.

13. Apparatus according to claim 11 in which a plurality of said working rollers are mounted on said roller mounting plate.

References Cited by the Examiner UNITED STATES PATENTS 148,643 3/1874 Annandale -49 2,069,496 2/1937 Kessler 80-19 3,192,756 7/1965 Cartwright 72-216 CHARLES W. LA'NHAM, Primary Examiner.

H. D. HOINKES, Assistant Examiner.

Claims (1)

1. A METHOD FOR REDUCING THE THICKNESS AND INCREASEING THE WIDTH AND LENGTH OF METAL STRIP WHICH COMPRISES; PASSING SAID METAL STRIP OVER A PLATEN AND WORKING SAID STRIP TO REDUCE ITS THICKNESS BY PRESSING AGAINST SAID PLATEN WITH A THIN A EDGE WORKING ROLLER WHICH IS MOVED IN SUCCESSIVE, ADJACENT PATHS DIAGONALLY ACROSS SAID STRIP AT AN ANGLE TO THE TRANSVERSE AXIS THEREOF.

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