US2907151A - Conditioning metal sheets, strip, rod and the like - Google Patents

Description

Oct. 6, 1959 CONDITIONING METAL SHEETS. STRIP, ROD AND THE LIKE Filed Jan. 18. 1954 4 Sheets-Sheet M x E mm w 5 my 2 IPIW 0. v N n u R Oct. 6, 1959 o, PETERSQN 2,907,151

CONDITIONING METAL SHEETS, STRIP, ROD AND THE LIKE Filed Jan. 18. 1954 4 Sheets-Sheet 2 INVENTOR. RUBEN 0. PETERSON TT IZME V6.

Oct. 6, 1959 o, PETERSON 2,907,151

CONDITIONIIING METAL SHEETS; STRIP, ROD AND THE LIKE Filed Jan. 18, 1954 4 Sheets-Sheet 3 PUBIW 0. 76'TER50'N 7 ATTOIZNEYJ.

Oct. 6, 1959 R. OQPETERSON 2,907,151

CONDITIONING METAL SHEETS, STRIP, ROD AND THE LIKE Filed Jan. 18, 1954 4 Sheets-Sheet 4 INVENTOR. Fl/Bf/V OffffiRSflN ATTOPNEKS.

United States Patent CONDITIONING NIETAL SHEETS, STRIP, ROD AND THE LIKE Application January 18, 1954, Serial No. 404,680

18 Claims. (Cl. 51-281) The present invention relating as indicated to the conditioning of metal sheets, strip, rod and the like has more particular regard to means and methods for attaining such beneficiating efiects as the removal of scale and other closely adherent coatings and small slivers, and the rounding of the sharp edges of small pits and scratches, and reducing differences in hardness and associated physical qualities of small adjacent surface areas and small adjacent subsurface component formations, and cleaning and polishing the surface, and reducing surface tension on such articles by brushing action and by the conjoint action, on the surface being treated, of a brush and of auxiliary materials such as abrasive, peening pellets, cleaning and coating materials.

The addition of an abrasive to a brushing operation in order to clean the surface of a metal sheet or like article by an ordinary scouring operation is, of course, well known. Thus, floors have been long cleaned and polished in this manner. It has also been proposed to clean sheet metal plates (see Patent No. 451,263 to Buckman) by similarly supplying an abrasive, e.g. sand, to the surface of the sheet in advance of the application thereto of a rotary brush. However, such simple scouring treatment has not proved effective for the removal of closely adherent oxide coatings, such as heat formed scale, from sheet or strip steel or rod, in order to prepare such metal for further reduction as by rolling or drawing or to prepare the surface of such metal for plating with another metal, such as tin or zinc, or to receive and retain a paint, lacquer, or enamel coating, without employing more costly, objectionable and less beneficial pickling processes.

An aspect of the continuing problem presented, of scale removal by a brushing operation, is evidenced by Patents Nos. 1,440,619 to Noyes et al. and 2,335,196 to Pecsok, which respectively disclose different methods of applying a brush to the surface of a sheet in an endeavor to secure complete scale removal. But other aspects include the removal of small slivers and the sharp edges of pits and scratches which are not removed by prior methods and which when not removed become, upon subsequent rolling, drawing, or the like, the sources of miniature seams and the starting points 'of fractures when an article made from the metal sheet, strip or rod is subjected to stresses of manufacture and use. Also a phase of the problem involves the minimizing of differences in hardness and associated physical qualities of small adjacent surface areas and small adjacentsubsurface component formations, which differences, when permitted to become exaggerated, reduce the facility with which the metal may be worked and reduce some of the desirable qualities of the articles made therefrom. Some commonly used methods and means, such as for example scale-breaking and subsequent pickling to remove the scale, exaggerate such differences and therefore have serious detrimental effects while achieving the main objective.

2,907,151 Patented Oct. 76, 1959 As indicated above, one object of the present inven tion is to combine brushing action with application of an abrasive material in such a manner as will effectually accomplish the removal of scale, small slivers, and other objectionable surface irregularities from metal sheets, strip, rod and similar articles. I have discovered that if such abrasive material be forcibly discharged onto the surface of a sheet simultaneously with the application of a brush thereto or immediately in advance of such application, not only is the cleaning action greatly improved but the power required for brushing greatly reduced. I have further discovered that where, as will be desirable, a rotary brush is employed, such brush itself may be utilized thus forcibly to discharge, by centrifugal action, the abrasive material onto the surface of the sheet without detracting from, but on the contrary greatly increasing, the efliciency of the brushing action proper. v

Independently of such conjoint action of a brush and granular abrasive material, I have discovered that while the effectiveness of brushing action in scale removal may be greatly increased by arcuately flexing the sheet, strip, or rod on the line to which the brush is applied, such scale may be advantageously and completely fractured and considerably loosened and the fragments slightly spaced apart preparatory to being removed by means of power operated brushes, by subjecting the same to a single stretching action. Furthermore, such stretching action has other advantages and benefits. Among these are the reduction of differences -in hardness and associated physical qualities of small adjacent surface areas and small adjacent subsurface component formations, and the slight but important outward turning and spacing apart of the sharp edges of pits, scratches, and small slivers for more advantageous action thereon by direction: ally adjusted abrasive power operated brushes.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out inthe claims, the following de cription and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing: Fig. 1 is a side elevation and Fig. 2 is a plan view of apparatus more or less diagrammatic in character showing an embodiment of the invention designed to stretch thin metal strip preparatory ation removing scale therefrom;

Fig. 3 is a side elevation similar to that of Fig. 1 showing the invention as applied to the removal of scale from elongated work-pieces such as rod or wire;

Fig. 4 is a detail view of the apparatus of Fig. 1 showing a modification in construction;

Fig. 5 is a'plan view of an apparatus similar to that shown in Figs. 1 and 2 but illustrating a different disposition of brushes employed in a sheet beneficiating operation;

Fig. 6 is a side elevation of an apparatus similar to that shown in Fig. 3 but illustrating a different disposition of brushes employed in a wire or rod beneficiating to the brushing operoperation;

Fig. is a side elevation of the mechanism of Fig. 9',

Fig. 11 is a diagrammatic side elevational view of simplified apparatus suitable for employment with relatively thin rrietalstrip; and

Fig. 12 is 'a diagrammatic side elevational view of an assembly suitable for acting upon metal rod and the like in accordance with my invention.

The power drive'n rotary brushes in engagement with the work will desirably be operated alternately first in one direction and then in another direction for short periods of Certain brush materials work best when they are continually sharpened by alternately operating the brush first in one direction and then in the other. Also, the direction of operation of a brush determines which sides of pits or scratches andco'rresponding sharp edges of which will be most effectively rounded by a given brush. .It is, therefore, desirable to employ several brushes and to have their respective directions of operation so adjusted and periodically alternated as to have their effective operational directions adjusted to several different related angles. The rolls and brushes will be power driven, either by direct motor drive or otherwise as found desirable or convenient, the brushes preferably being rotated rapidly, for example at approximately 3000 r.p.-m. in the case of a 12 in. diameter brush, which will be approximately equal to an average of 9000 f.p.-m. during the useful life of the brush, while the strip of course moves at a much lower speed, relative to the speed at which the contacting brush surfaces travel. Brushes larger than 12 inches in diameter will often be preferred.

Abrasive material may be fed to the power driven rotary brushes in proper'manner for delivery of the abrasive to the working face of the brush where the latter engages the work. In some cases it will be desirable to project such abrasive material forcefully against the work in the region engaged by the brush, and this may be accomplished by introducing the abrasive to the interior of the brush from which it is discharged through the action of centrifugal force. Reference may be had to my co-pending application Serial No. 126,408, filed November 9, 1949, now Patent No. 2,680,938, dated June 15, 1954, where a suitable brush for this purpose is shown and described in -detail.

It is not necessary of'course that all of the particles of abrasive should fall within a defined area on the sheet, but merely that the major portion thereof should do so. In order to catch such particles as may be thrown beyond the desired area, any suitable form of enclosure or guard may be employed. It will be further understood that while reference has been made in the foregoing description of the operation ofmy improved brush to the use of a granular abrasive conveyed by a stream of air, other media, including a suitable liquid, may be employed, such liquid carrying the abrasive being discharged in the same manner. Moreover, for certain purposes the material supplied to the brush for the purpose of thus being centrifugally discharged therefrom may consist wholly of a liquid medium capable of having a beneficiating effect on the surface of the sheet as it is being brushed.

Figs. 1 and 2 illustrate a form of apparatus in which a brush 67 is applied to the beneficiation of the surface of a sheet S which is carried past the brush in flat condition. However, in order to facilitate the removal of scale or equivalent tightly adherent oxide coating from the surface being treated, means are provided whereby the sheet is subjected to a longitudinal stretching operation prior to such brushing operation.

The simple form of apparatus employed for the purpose of illustration comprises there aligned roll stands 68, 69 and 70, such stands being shown diagrammatically only, between the paired rolls 68a, 69a, and 70a, of which the sheet moves continuously in a substantially straight line. Said paired rolls may be drivengin any suitable manner, as by motors 68b, 69b and 70b individually connected with each pair, as indicated in Fig. 2; however, the rate of rotation of the rolls will be regulated so as to impose a definite stretching action on the section of sheet S lying between rolls 68a and 69a while the section lying between rolls 69a and rolls 70a will be subjected only to a normal degree of tension required to hold the sheet approximately in a straight line.

The stretching action imposed on the portion of the strip or sheet S between the pairs of rolls 68a and 69a should be sufficient permanently to deform the strip or sheet so that the scale coating thereon will be fragmented into minute particles slightly spaced from one another and therefore amenable to removal by the action of brush 75. A plurality of such brushes may be utilized as is desirable, and it will also ordinarily be desirable to provide similar brushes to act upon the other surface of the strip or sheet and also on the edges thereof. Since such stretching and permanent deformation of the strip or sheet tends to work=harden the same and render it less susceptible to further stretching, for example, it is found that substantially all of the stretching operation takes place in 'a very short reg'ionimmediatelyxfollowing the rolls 69a where the previously unstretched metal continuously emerges from the grip of such rolls. This feature will be explained in more detail below.

The scale may thus all be removed from the strip or sheet before passage between the pair of rolls 69a, so that the fragmented scale particles will not be impressed into the surface of the sheet by the action of such rolls. The brush67 (or a plurality of such brushes adapted to engage the respective surfaces ofthe sheet) may be disposed mortgage the scale-free surface of the sheet further to beneficiate the same and to perform a polishing operation or the like. A back-11p roll 72 carried by stand 71 is adapted to support the sheet during such brushing operation with the proper degree of pressure, and a similar roll may be employed in conjunction with brush 75. Electric motors such as 73.may be utilized to drive rotary brushes '67 and 75 at the desired speeds as well as cooperating rolls such as 72, so as to avoid any frictional drag between the face of the sheet opposed ,to such latter roll. As previously indicated, the direction of rotation of the brushes may be reversed from time to time, the peripheral speeds of such brushes being very much greater than the rate -of travel of the sheet or strip so that the latter may ordinarily be ignored. Suction boots 74 and 78 may be providerl adjacent brushes 67 and 75 respectively to collect material removed from the surface of the sheet as well as abrasive material which may be added for application thereto by such brushes; The brushing operation which thus removes the scale also removes the minute slivers ordinarily found in the surface of the-metal sheet and tends to blend the sharp edges of other surface irregularities.

The general operation of the apparatus last described has been sufliciently indicated in describing the operationof its component parts. It need merely be added that I have found that .by subjecting the sheet, preliminarily to the brushing operation performed by one or more brushes 67, to a stretching operating whereby the sheet is elongated approximately 7%, a fine brightfscahefree and satin finish can be produced by' passing .under a suitable numberiof brushes; and that a lesser degree :of stretching has avery considerable loosening effect on the scale. In the case of steel I have found it desirable to effect arr-elongation of from about 3% to 8%,with about 6%-or 7% usually affording the best results. A single stretching of course serves equally to prepare bothsides of the sheetfor'the subsequent brushing operation and the amount of working ofthe metal involved will obviouslybe very considerably less than that which occurs where the sheetis more or less abruptly flexed first in one direction and then the other, as in the case of conventrend ss leb e kqrs The utilization of such a stretching step to fracture, considerably loosen, and slightly space apart the scale fragments preparatory to power brushing or other surface treatment is not limited to strip or sheets such as have heretofore been particularly referred to, but may be carried on with corresponding advantageous results in the surface treatment of other elongated forms of metal work-pieces such as rod or wire, and in Fig. 3 an arrangement of apparatus is diagrammatically illustrated for thus handling a rod or wire R. The latter, just as in the case of sheets S passes through an aligned series of paired rolls 80, 81 and 82, which will be driven at rates of speed such as to subject the section of the workpiece between rolls 80 and 81 to a definite stretching action and then draw the following section lying between rolls 81 and 82 past opposed pairs of brushes 83 and 84 (only one of the latter appearing in Fig. 3). These brushes and brushes 85 will be positively driven in the same manner as brushes 67 and 75 and may or may not include means for supplying abrasive or other material to the work-piece. The stretching of the rod or wire across its cross-section permanently to elongate the same fractures the scale coating and spaces the resultant minute scale particles for efiicient removal by brushes 85.

The same action so far as regards the loosening of scale or like adherent coating on the work-piece will be produced in the case of such rod or wire as in the case \of sheet S where the degree of stretch to which the work-piece is subjected is of corresponding degree. Asin the case of the apparatus illustrated in Figs. 1 and 2, so in the case of that illustrated in Fig. '3 it will be understood that the number of opposed paired brushes 83, 84 and 85 which are applied to the work-piece may be increased as may be found desirable; also that where more than two such pairs are utilized successive pairs instead of being set at right angles to each other may bedisposed at various intermediate angles so as to insure thorough brushing action around the entire circumference of the work-piece.

The modification illustrated in Fig. 4 relates to the form of rolling support for the work-piece, whether sheet or wire, where it is opposed to brushing action for the purpose of removal of the previously loosened scale or 'for a final polishing step. Instead of a single roll 72 directly opposed to the brush, a pair of rolls 72a may be employed, one located slightly before and the other slightly beyond a line vertical to sheet S and which presses through the axis of the brush.

As previously indicated in the general description of the drawings, Fig. 5 illustrates diagrammatically a modified form of apparatus for the surface beneficiation of a sheet similar to that shown in Figs. 1 and 2. Actually there appears in Fig. 5 only that portion of the mechanism as lies to the right of roll stand 69 in Fig.1, it being understood that the sheet will have been previously subjected to a stretching operation, just as before, in the section thereof that lies in advance of stand 69, i.e. between the two pairs of rolls 68a and 69a. Furthermore, a similar brush'arrangement may be utilized between such pairs of rolls 68a and 69a.

However, inthe modified construction, instead of em ploying one or more transversely disposed rolls 67 or 75, a minimum of at least three and preferably four similar brushes 86, 87, 88 and 89 is applied to the surface of the sheet during its passage. These brushes may be of the same construction as previously described, whereby abrasive or other suitable material will be centrifugally discharged therefrom onto the surface of the sheet at the same time that the latter is being operated upon by the brushes. Furthermore, said brushes, instead of being disposed transversely of the line of travel of the sheet, are disposed in angular relation thereto, the brushes being alternately inclined in opposite directions. As indicated by the direction arrows, brushes 86 and 89 rotate in a 6 clockwise direction and brushes 87 and 88 clockwise direction.

As likewise previously indicated in the general description of the drawings, Figs. 6, 7 and 8 show a modification in the apparatus illustrated in Fig. 3 for beneficiating an elongated metal work-piece such as a rod or wire R. Here again only the portion of the apparatus to the right of the second pair of rolls 81 is shown, but it will be understood that the section of the work-piece lying to the left of said rolls will be subjected to a stretching action such as produced in the apparatus illustrated in Fig. 3 by the difference in rate of rotation of said rolls 81 and the preceding pair of rolls and the arrangement of brushes described below may likewise be utilized in place of the brushes between the pairs of brushes 80 and 81. 4

While the brushes employed to beneficiate the surface of the wire may be employed in fixed opposed pairs, as in the case of brushes 83 and 84 illustrated in said Fig. 3, this may not prove desirable, particularly in treating rod or wire of relatively small diameter, since such opposed brushes would tend to interfere with each other. Particularly after a period of use the brushing surfaces will be worn into transversely concave form, so that the lateral portions of the brushes will overlap and engage with each other. Accordingly, an arrangement of brushes such as shown in Figs. 6, 7 and 8 is preferred, wherein two series of brushes and 91 is employed, it being understood that the number, shown as five in such first series and ten in the second, may be increased or decreased as desired to obtain the best results. But cylindrical rotary brushes having axes arranged transversely of the rod, Wire or like article, and having brushing faces considerably wider than sucharticle, for example fifty times as wide as a one-quarter inch rod, may advantageously be employed by slowly reciprocating such rapidly rotating brush transversely of the rodwhile in brushing contact therewith so as to wear the entire Working face of the brush evenly despite the fact that it is thus operating on a narrow work-piece.

Referring to such series of brushes 90, these it will be seen are alldisposed with their axes transverse (preferably at right angles) to the line of travel of the work piece, just as in the case of brushes 83 in the apparatus illustrated in Fig. 3. However, such brush axes instead of being located opposite to each other are spaced suc cessively along such line of travel so that the brushes will successively contact with the work-piece at fairly closely spaced intervals, without interfering with each .other. Furthermore, the axes of successive brushes, while all lying transversely of the line of travel of the work-piece, are inclined relatively to each other, as best shown in Fig. 7. Thus, as the work-piece passes through the series of brushes 90 its entire circumferential surface is subjected to the action of the brushes; in fact the longiin a countertudinally extending areas covered by the successive.

brushes will overlap to a certain extent, thus ensuring uniformity of treatment about the entire circumference of the work-piece. Alternatively, the axes of such brushes may be arranged so that they engage the wire diagonally of the direction of travel of the latter.

While in Fig. 6 all of the brushes 90 are indicated as rotating in the same direction so that the contacting surface of the brush moves oppositely to the direction of travel of the work-piece such direction of travel may be reversed in the case of certain brushes of the series, or preferably a second series (not shown) similar to the one thus illustrated will be employed in which all of the brushes thus rotate in the'opposite direction. Furthermore, as above indicated, the direction of rotation of the brushes may be periodically reversed.

Referring to the series of brushes 91, which will desirably be larger in number than those comprised in the first series, the axes of these brushes are disposed in substantial parallelism with the direction of travel of 'the' work=piece, so that the faces thereof which contact with the latter will be applied crosswise instead of longitudinally. As best shown in Fig. 8, the axes of the successive brushes 82 are spaced circularly about the path of travel of the Work-piece at approximately equal distances, such axes being sufliciently close together so that the longitudinally extending areas of the work-piece respectively affected by the corresponding brushes will overlap at least to some extent and thus ensure complete and uniform treatment of the work-piece about its entire circumference. Here again all of the brushes of the series may rotate in the same direction or certain thereof oppositely to the others, but preferably two series of brushes similar to the one series illustrated will be utilized, the brushes of the second series operating in a reverse direction to those of the first.

Instead of relying on preliminary stretching to crack the scale on the surface of the metal sheet, rod, or the like, a cooling fluid such as water may be delivered to the brush for forceful radial discharge against the heated work. The force of such discharge need not be sufficient actually to remove the scale since the simultaneous action of the brush effectively serves this purpose while the cooling fluid also prevents overheating and deterioration of the brush material. As will be understood, 'work such as steel, for example, will normally be heated above red temperature, for this purpose, being sufficiently hot to ensure fracture of the scale by application of the coolant. The action of the brush material engaging the work also assists considerably in accomplishing such fracture as well as ensuring removal thereof without the necessity of employing very high pressures or excessive volumes of fluid.

While my improved method and apparatus for surface beneficiating metal sheets and the like has been described with special reference to the removal of scale and like closely adherent coatings, no limitation to such particular use is to be implied. Thus, by employing other forms of discrete hard particles instead of granular abrasive, e.g. peening pellets of properly selected size, such method and apparatus may be equally well employed in the peening treatment of sheets and like metal articles.

In pening practice as at present carried out, while the impact of the pellets or shot has the desired effect of relieving surface tensions and otherwise beneficiating the surface of the article being treated, there is at the same timeproduced a disadvantageous effect arising from the presence of the crushed cementite and other constituents of steel. Where the broken fragments of such materials, which are relatively hard, remain on the surface, not only is the peening action interfered with but the surface itself may be permanently marred. However, by combining with the impact action of peening pellets a brushing action such as I am able to obtain, these objectionable prodnets are immediately removed and a much more perfect surface condition obtained.

Where peening pellets are employed, they will of course be fed onto the work-piece by means of the brush so as to be projected therefrom by centrifugal action of the latter in the same manner as the granular abrasive material previously referred to. Furthermore, as has hereinbefore been pointed out, my improved construction of brush and the method involved in its use may be found quite advantageous where instead of thus feeding discrete hard particles through the brush, other kinds of beneficiating materials, e.g. in liquid form, are thus applied to the surface of the article being treated, without carrying any granular abrasive or other additional material.

While the means and method hereinbefore described for centrifugally discharging abrasive or other beneficiat ing material onto the surface being treated, viz. by feeding the same into the interior of a brush rotating at high speed, thence to pass radially outwardly through the stranded brush material, are considered preferable, I have found a like effect may be obtained by supplying such ma- 8 terial at the proper point or points on the surface of such a brush as more fully set forth in my co-pending application Serial No. 126,408, filed November '9, 1949, now Patent No. 2,680,938, dated June 15, 1954.

,The term surface beneficiation as employed herein is to be understood as comprehending any of the several forms of treatment mentioned, e.g. cleaning, polishing, scale removal and relieving surface tension. In addition to the latter, the application of brushing action, with or without the conjoint application of material as described, has been found effective to reduce stress concentration characteristics in the surface of the treated article, where the brushing action is applied in at least four angularly related directions, since by brushing in this manner all of the upstanding edges of so-called craters will be smoothed down, or substantially removed.

The surface irregularities of metal sheets, such as minute craters, have their marginal edges effectively smoothed and rounded by the ends of the brush bristles passing in at least three angularly related directions thereacross. This brushing action, by blending such sharp margins serves to relieve stress concentrations at such points on the metal surface and by the same action reduces susceptibility to corrosion as well as performing the function of cleaning the surface. The ends of the brush bristles have a definite peening, wiping and polishing action which it has been found, however, must be inat least three angularly related directions to be effective on the entire circumference of each'minute surface irregularity. Thus, small slivers raised from the surface of the metal article by a stretching operation as described are likewise most completely removed when thus brushed. The term regularizing is used herein to denote not only such surface beneficiation but also subsurface modifications such as the elimination of hard spots by uniform stretching, and the like.

Prior art methods of removing scale have not achieved their major objective of completely eliminating the necessity of a pickling operation, and where it is necessary that absolutely all of the scale be removed it is still standard procedure to employ a pickling step after prior fragmentation and partial mechanical removal of the scale.

While in Figs. 1 and 2 of the drawing I illustrate apparatus suitable for the removal of scale from and the-surface beneficiation of the thinner gauges of strip which are adapted to be relatively readily stretched, a preferred embodiment of my invention is illustrated in Figs. 9 and 10 of the drawing and described below which is adapted to operate successfully on even the heavier gauges and to effect complete removal of scale therefrom.

The employment of breaker rolls and of roller levelers prior to brushing and/or pickling of elongated metal articles such as steel strip and sheet has proven far from satisfactory for a variety of reasons. The relatively sharp reverse bending of the material tends to work-harden the latter excessivelyand the fragmented scale particles may be pressed into the metal surface and such surface scratched and scarred. Stretcher levelers such as are commonly employed to level metal sheet materials, if utilized to stretch a sheet beyond its yield point for the purpose of fracturing a scale coating thereon, do not have a uniform action in thus fragmenting the-scale for later removal by a brushing operation, for example, since, as is well known in the industry, such sheets are of nonuniform hardness, having soft spots and hard spots, so that the total elongation obtained is the result of widely varying degrees of elongation in various portions of the sheet. Consequently, the scale will be found to be readily removable by a subsequent brushing operation in certain areas but will still be closely adherent and impossible of complete removal in other areas. It is a principal object of my invention to provide a method and apparatus which may be relied upon completely to remove the scale from allareas.

Referring now more particularly to Figs. 9 and 10 of the drawing, such figures illustrate apparatus including a back tension unit 130 and a forward tension unit 131 adapted to cooperate tostretch acontinuously advancing metal strip 132 for effective operation thereon by brushing units such as 133 and 134. In the embodiment illustrated, such back tension unit comprises apair of pinch rolls 135 and 136, idler rolls 137 and 138, an intermediate roll 139'and pinch rolls 140 and 141. Both sets of pinch rolls and the intermediate roll 139 are adapted to be driven by the advancing strip 132 and idler rolls 137 and 138 are adjustable (either by screw means or fluid pressure piston-cylinder assemblies) to cause the strip to engage a substantial portion of their peripheries and therefore likewise of the periphery of intermediate roll 139 whereby, in conjunction with the action of the two sets of pinch rolls, a very firm grip may be obtained upon the strip. Consequently, no stretching of such strip will take place until the latter emerges from the nip of pinch rolls 140, 141. The rolls themselves are of relatively large diameter and the flexing of the strip thereby will not be suflicient consequentially to fracture the scale coating.

The forward tension means comprises pinch rolls 142, 143 and 144, 145, both such sets of pinch rolls being driven to advance the strip as is also intermediate roll 146. Idler rolls 147 and 148 are adjustable similarly to idler rolls 137 and 138 to wrap the strip about a substantial portion of the periphery of the intermediate driven roll 146 and also of course, to a lesser extent, rolls 143 and 145.

Such power driven rolls of the forward tension unit 131 may be driven from electric motor 149 through worm gear reducers 150 and 151 and gear reducers 152. and 153. Similarly, the rolls 135, 136, 139, 140 and 141 driven by the travel of strip 132 may be connected in driving relationship to such motor through gear reducers 154, 155 and worm gear reducers 156 and 157. By this arrangement considerable power will be conserved in comparison to an arrangement merely providing braking means for the rolls 135, 136, 139, 140- and 141 to achieve the desired back tension. In other words, while considerable power is required initially to build up tension in strip 132 up to the point where such strip will begin to elongate, once such tension has been achieved itmay be maintained by employment of the drive means above described without the input of additional power except that required to overcome the unavoidable friction and mechanical inefiiciencies of the system. Additional power must, of course, be supplied motor 149 to stretch the strip to the desired degree, such stretching being obtained either by the employment of gearing adapted to drive the rolls of the forward tension unit 131 at a somewhat greater speed than that of the rolls of the back tension unit 130 or preferably by employing rolls in the forward tension unit of slightly greater diameter than the rolls of the back tension unit. Thus, for example, for one analysis of steel we may assume that a tension of 32,000 pounds per square inch must be maintained in strip 132 before any appreciable stretching will occur but that a tension of 45,000 pounds per square inch must be applied in order to obtain a 7% elongation desired. To initiate the operation and provide the requiredtension, a motor of 1000 horsepower may be necessary but once the continuous operation is under way only 300 horsepower will be required, since the power required to supply the 32,000 pounds per square inch tension prior to stretching will be fed back from the back tension unit to the motor. Other means, which may be electric for example, may be employed thus to feed back such power to motor 149 but gearing as above described is preferred to facilitate synchronization of the two units.

In starting the operation a leader strip will preferably first be conducted through the apparatus with the strip to be processed securely welded to the trailing end thereof, the operation being commenced with the leading end 10 of strip 132 just past the nip of pinch rolls 140, 141. Such leader should be selected to be less susceptible to stretching than the strip 132 to be processed so that the stretching tension applied thereon by the apparatus will be effective to stretch strip 132 uniformly through its entire cross-section in a short region immediately beyond the nip of pinch rolls 140, 141. As the strip advances, further stretching will have continued to occur in such localized region only since the previously stretched portion will have been work-hardened by the stretching op eration and therefore less susceptible to further stretching than the portion of the strip continuously emerging from between such pinch rolls.

A plurality of brushing units such as 133 and 134 will preferably be located intermediate the two units and 131 to afford rapid abrasive brushing action on the surfaces of the strip subsequent to the stretching of the latter to remove the minute slightly spaced particles of scale together with the usual tiny slivers and other sharp edged surface irregularities. The surfaces of the strip will thus be cleaned and smooth prior to passage between the rolls of forward tension unit 131 and such surfaces will not be damaged by pressing of such scale particles, slivers, etc., therein through action of the rolls of such latter unit.

The brushing units may comprise stands carrying relatively large diameter short trim brushes 158 and 159 adapted to be driven at fairly high speeds, as for example a surface speed of 9000 feet per minute. Such brushes will preferably be disposed with their axes angularly related to the direction of travel of the strip and means such as piston-cylinder assemblies 160 and 161 may be provided to reciprocate the units carrying such brushes transvversely of the strip to ensure uniform wear of the brush face. Adjustable back-up means 162 and 163 will also desirably be provided to hold the strip with a'properly regulated pressure against such brushes. The desired abrasive brushing action may be obtained by the employment of relatively hard wire brush bristle material,

for example, or by supplying suitable abrasive for application by'brushes utilizing less hard bristle material. While a slight peening action is desirable, as by impelling such abrasive by action of the brushes, this will be considerably less than that obtained in conventional shot blast or equivalent procedures employed in the past in an attempt to remove scale from metal strip. The extreme peening action of prior art abrasive blasting procedures has tended both to embed particles of abrasive in the metal surface and also to cause excessive work-hardening of the surface having a detrimental effect on subsequent reduction as by rolling and manufacturing operatrons.

After treatment in accordance with my invention, the metal surface will be found to be of much more uniform Knoop hardness than when the scale has been removed by conventional pickling procedures. Furthermore, the scale is removed in a dry state and may be salvaged for employment as an abrasive or for reduction as with hydrogen for employment in powder metallurgy, and the making of pigments and the like. The brushing, moreover, relieves surface strains and regularizes the surface, thereby eliminating hardspots while the preliminary stretching vregularizes the internal formations and together the two act so that subsequent reduction by rolling is facilitated. It is found, in fact, that considerably greater reduction may thereafter be achieved before annealing becomes necessary. Similar brushes may be disposed to engage the rangement of back tension and forward tension means which has been found to be quite sufiicient to afford a non-slip grip on the strip. A three high roll stand comprising rolls 164, 165 and 166 may be utilized as the back tension unit with the strip wrapped therearound as illustrated and firmly gripped in the nip of rolls 165 and 166. A similar set of rolls 167, 168 and 169 is utilized as the forward tension unit with the strip gripped in the nip of rolls 168 and 169. Such strip will also preferably be gripped between rolls 1'64 and 165 and between rolls 167 and 168 with sufficient tension being maintained on the strip as it comes from the uncoiler, for example, to ensure snug engagement with roll 164 and sutficient tension being maintained on the strip as it leaves roll 167 passing onto a roll stand or coiler, for example, to maintain the strip in snug engagement with such latter roll. A plurality of brushing units diagrammatically indicated at 170 and 171 will, of course, be provided to engage the respective surfaces of the strip similar to those of Fig. 9 and drive means interconnecting the back tension and forward tension units may likewise be utilized in the same manner as in the Fig. 9 embodiment. The operation will be generally as above described with no consequential stretching or slipping of the strip taking place prior to emergence of the latter from the nip of rolls 165 and 166, whereupon the stretching will immediately take place as such strip emerges therefrom.

Now referring more particularly to Fig. 12 of the drawing, the apparatus there diagrammatically illustrated is adapted especially for the stretching of rod and wire and removal of scale therefrom in a relatively simple manner in accordance with the principles of my invention. Several turns of the rod 172 are taken around roll 173 and gripped by cooperating pinch roll 174 so that no elongation will take place prior to the emergence of such rod from the nip of such rolls. A capstan 175 serves as the forward tension means and the rotation of the pinch rolls is regulated relative to the drive for such capstan to develop the necessary tension to provide the desired elongation. A cooperating pinch roll (not shown) may be utilized in conjunction With capstan 175 similar to roll 174 but is ordinarily not required since the tension in the rod passing to take-up reel 176 will be suflicientto give such capstan a strong purchase. Furthermore, since the progressiveelongation of the rod will take place in a short region extending from the nipof rolls 173 and 174 to the previously stretched portion of the rod (often a distance of only 4, to /2 inch, depending on the thickness of the material, rate of travel, physical characteristics, etc.) there will be no further elongation or slippage of .the stretched rod as it passes around the capstan.

A number of brushes such as 177 may be arranged to engage the rod about its entire periphery to remove scale and beneficiate the metal surface, such brushes being disposed as shown in Figs. 6-8 for example, or preferably with their axes of rotation :at acute angles tothepath'of travel of the rod so that a diagonal brushing action is achieved. Abrasive brush material or applied abrasive will be utilized .for best scale-removing action and the brushes operated at high speedssuch as 9000surface feet per minute.

A die, indicated at 178, may be positioned in advance of capstan 175 but subsequent to such brushes in the path of travel'of the rod to-reduce the latter. Brushingof the metal surface and,-more particularly, brushingofthe same portions of such surface in several different angularly related directions, not only affords certain benefits above explained but also provides a very finely cross-hatched .surface having an enhanced ability to retain the usual lubricants and drawing compounds whereby unusually great reductions may be obtained-in a single pass, as when subsequently rolling strip or drawing :rod.

Whether stretching strip or rod, the localized region in .which such stretching continuously takes place makes it .-possible;to obtain the necessary uniformity so that all portions of the article, both surface and cross-section, will receive the same treatment. The opportunity for substantial variation in the degree of stretch achieved in different local areas is eliminated so that not only will all of the scale be rendered susceptible to removal by the'brushing operation but also the metal will have been worked uniformly through its cross-section, much facilitating later rolling and other operations thereof. Quite frequently the length of such region where the stretching thus continuously takes place may be only about one-eighth of an inch long, although of course extending across the entire width of the article.

The stretching operation not only fractures and spaces the minute scale particles to facilitate removal of the latter but furthermore such particles are thus formed and distributed in a manner uniquely adapting them to serve as abrasive for surface beneficiation of the article when subjected to the action of the brush.

The pressure applied on pinch rolls 140, 141 and 142, 143 to grip the strip may be on the order of A to /2 that which would be required to effect a reduction in thickness of the strip, while pinch rolls 135, 136 and 144, 145 may exert a pressure on the order of V2 rolling pressure to ensure that the arcuate contact with the intermediate rolls 139 and 146 will be effective. Additionally, if desired, the pressure of rolls 144, 145 may .be made suflicient to effect actual reduction of the strip, thereby serving two purposes very economically. Reduction at this stage is facilitated because the strip will be under a degree of back-tension and also because such strip will have been regularized both at its surface and through its cross-section by the preceding operations. It may be noted that the rolls about which the strip is flexed should be of sufficiently large diameter that the outer surface of such strip will not be stretched beyond its yield point by such flexure.

The term bristle" as used herein and in the claims, of course, includes hard Wire and like filamentous material, as noted above.

This application is a continuation-in-part of my .00- pending application Serial No. 221,906, filed April 19, 1951, now Patent No. 2,666,282, dated January 19', 1954, which is in turn a continuation-in-part of my application Serial No. 668,391, filed May 9, 1946, in turn a continuation-in-part of Serial No. 632,831, filed December S, 1945, and .Serial No. 437,648, filed April 4, 1942; and also of my co-pending application Serial No. 126,408 (Patent No. 2,680,938), filed November 9, 1949. Such applications Serial No. 437,648; 632,831; and 668,391

have been abandoned without prejudice in favor of application Serial No. 221,906 (Patent No. 2,666,282). Reference may also be had to my co-pending application Serial No. 404,431, filed January 18, 1954-, now Patent No. 2,757,486, granted August 7, 1956, disclosing and claiming a method and apparatus for surface beneficiating metal strip or the like by flexing the same and brushing the concave surface thereof.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of thelfollowing claims or the equivalent of such be em- I ployed.

2. In a method of surface beneficiating an elongated hard metal article such as a steel sheet or rod, the steps of bristle brushing such surface in at least four angularly related directions, with a plurality of high speed cylindrical rotary brushes having brush bristle material engaging the work, and traversing such article relatively to such brushes to obtain each of such varied brushing actions over such surface whereby minute surface irregularities are blended by the brush bristle material to produce a relatively smooth surface.

3. The method of surface conditioning a metal surface which includes the steps of continuously advancing such surface, blending minute surface irregularities by high speed bristle brushing of the full width of such moving surface in at least three diiferent directions with rotary brushes having brush bristle material engaging the work and simultaneously forcefully projecting abrasive material against such moving surface within the immediate areas being subjected to such brushing action.

' 4. In a method of surface beneficiating an elongated metal article such as a metal sheet or rod the steps which comprise stretching the surface being-treated to fracture non-metallic surface scale encrustations, and then bristle brushing the same portions of such surface in at least three angularly related directions with a plurality of power driven rotary brushes having brush bristle material engaging the work to remove such scale and smooth out surface irregularities of the metal. Y

5. In a method of surface beneficiating an elongated metal article such as a metal sheet or rod the steps which comprise stretching the surface being treated beyond the yield point of such metal permantly to deform such surface and thereby to fracture non-metallic surface scale encrustations, and then bristle brushing the same'portions of such surface in at least three angularly related direction with a plurality of power driven rotary brushes having brush bristle material engaging the work to remove such scale and smooth out surface irregularities of the metal.

6. The process of de-scaling elongated metal articles such as steel strip and the like which comprises continuously advancing such scale-coated strip, continuously gripping such advancing strip uniformly thereacross in a narrow transverse region to resist advance thereof at greater than predetermined speed, continuously applying tension to such advancing strip in the direction of travel thereof, and in a straight line from the point of release of such gripping action, suflicient to stretch such strip beyond its yield point uniformly across its cross-section in a short region immediately following the point-of emergence from the region of exertion of such gripping force to fracture such scale into minute separated particles, the portion of such strip which has already passed such short region having already been stretched and therefore work-hardened so that it is less susceptible to further stretching than the following portion of such strip newly arriving in such region, and subjecting such permanently stretched strip to high-speed abrasive rotary bristle brushing action by a rotary brush having hard brush bristle material engaging such strip to remove such scale particles therefrom prior to reaching the point of application of such tension.

7. The method of permanently stretching elongated articles such as steel strip and rod which comprises advancing such article longitudinally, gripping such article uniformly by back-tension means, gripping both sides of such article with forward tension means, applying a straight-line pull by such forward tension means on such article directly where thus gripped by back tension means sufiiciently permanently toelongate such article, further advancing such article, and further stretching such article in like manner, such further stretching taking place in the region between the trailing end of the already stretched portion and the point of emergence of such article from the grip of such back-tension means.

8. The method of permanently stretching elongated metal articles such as steel strip and rod which comprises gripping sucharticle uniformly between pinch rolls, continuously advancing such article therebetween, controlling the rotation of such rolls to limit the rate of advance of such article at this station, and exerting a uniform, direct continuous pull on such article where released from such pinch rolls suficient to stretch said article from about 3%lto about 8%, such stretching taking place uniformly of the cross-section of such article in a short region immediately following emergence of such article from the nip of such rolls only and between such nip and the preceding already stretched, and therefore work-hardened, portion of the article.

9. The process of de-scaling and regularizing scalecoated elongated metal articles such as steel strip and "rod which comprises continuously longitudinally advancing such article, gripping such advancing article umdenly releasing such grip in a uniform.manner transversely of such article, exerting a regulated straight-hne pull on such'article at a second station -to advance such article at such second station at a predetermined rate greater than the rate at such first station and sufiicient permanently to stretch such article in a short region 1mmediatelyfollowing its release at such first station, and subjecting such stretched strip to high-speed abrasive bristle brushing action to remove the scale fractured by such stretching prior to reaching the forward tension applying station. 1

10. The process of de-scaling and regularizing elon gated metal articlessuch as steel strip and rod which comprises continuously advancing such article between pinch rolls firmly and uniformly gripping the same, such article having a smooth scale coating thereon, regulating the rotation of such rolls to limit the rate of advance'of such article at this station, applying a forward tension pullon such article at a point beyond such rolls suflicient to stretch such advancing article beyond its yield point to fracture such scale coating and permanently space the resultant minute particles adhering to -the surface of'such article, such stretching continuously taking place substantially entirely in the short straight line region the same, regulating the rotation of such. rolls to limit the rate of advance of such article, continuously applying a forward tension pull on such article at a point beyond such rolls sufiicient to stretch such advancing article beyond its yield point to fracture such scale coating and space the resultant minute particles adhering to the surface of such article, such stretching continuously taking place substantially entirely in the short region between the point of emergence of such article from the nip ofsuch rolls and the previously stretched portion thereof, and then subjecting such advancing stretched strip to high-speed abrasive, bristle brushing action in at least three angularly related directions.

12. The process of regularizing elongated metal articles such as steel strip and rod which comprises continuously longitudintally advancing such article, applying a backtension grip on such advancing article, applying a forward tens-ion pull on such article at a point beoynd such application of back-tension suflicient to stretch such advancing article beyond its yield point, regulating such back-tension grip .to prevent any permanent stretching and slipping of such article at any point prior to "final release of such back-tension grip thereon, and subjecting such stretched article to high-speed bristle brushing action in a plurality of angularly related directions.

13. The process of regularizing elongated metal articles :such as steel strip and rod which comprises continuously longitudinally advancing such articles, applying a backtension grip on such advancing article, applying a forward tension pull on such article at a .point beyond such application of back-tension sufficient to stretch such advancing article beyond its yield point, regulating such back-tension grip to prevent any permanent stretching adn slipping of such article at any point prior to abrupt 'final release of such back-tension grip thereon, and subjecting such stretched article to high-speed bristle brushing action by a rotary brush having hard brush bristle material engaging such strip with application of granular abrasive material thereto to enhance the action of such brushing.

14. The process of de-scaling and regularizing an advancing elongated metal article which comprises continuously, progressively, and uniformly stretching such article beyond .its yield point in a short region bounded by the plane passing through the respective axes of opposed rolls gripping the same and a preceding previously stretched portion thereof, and then abrading the stretched surface of such article in a plurality of directions before further altering such surface by other con- ,tacts.

15. The process of de-scaling and regularizing an advancing elongated metal article which comprises continuously, progressively, and uniformly stretching such article beyond its yield point in a short region bounded by the plane passing through the respective axes of op posed. rolls gripping the same and a preceding previously stretched portion thereof, and'then abrading the stretched surface of such article in a plurality of directions by means of a plurality of rapidly revolving cylindrical :rotary bristle brushes before altering such surface by other contacts, and periodically reversing the direction of rotavtiionof such brushes.

'16. The process .of de-scaling elongated metal articles such as steel strip and the like which comprises continuously advancing such sca1e-coated article, gripping :such advancing article uniformly across its width and substantially uniformly longitudinally thereof progressively along its length at a first station to regulate such advance of such article to a predetermined speed at such station, exerting a regulated pull on such article at .a

second station to advance such article .at' such second station at a predetermined rate greater than the rate at such first station and sufficient permanently to stretch .the intervening portion of such article to separate such scale into minute particles, and subjecting .the surface 5 of such stretched article to high-speed abrasive bristle 16 brushing action to remove such scale particles from the same. t

17. The process of regularizing elongated metal articles such as steel strip and the like having surface blemishes such as slivers and scratches which comprises con tinuously advancing such article, gripping such advancing article uniformly across its width and substantially expose the edges of such scratches, and subjecting the surface of such stretched article to high-speed abrasive bristle brushing action by a rotary bru h having hard brush bristle material engaging such strip to reduce such surface blemishes.

18. The process of descaling and beneficiating the surface of an elongated metal article which comprises progressively and uniformly fracturing the scale on the surface vof said article and then abrading the surface of such article in a plurality of dilferent directions by means of a plurality of rapidly revolving rotary brushes having brush bristle material engaging such article before altering such surface by other contacts, and periodically reversing the direction of rotation of such brushes.

References Cited in the file of this patent UNITED STATES PATENTS 82,780 Wooster Oct. 6, 1868 89,313 Holmes Apr. 27, 1869 197,242 Betz Nov. .20, 1877 293,011 Hall et al. Feb. 5, 1884 451,263 Buckman Apr. 28, 1891 492,099 Nelson Feb. 21, 1893 781,087 Legnard Jan. 31, 1905 869,478 Broderick Oct. 29, 1907 1,410,117 Pool Mar. 21, 1922 1,556,261 Stoddard Oct. 6, 1925 1,884,791 McCrery Oct, 25, 1932 1,978,681 MacGregor Oct. 30, 1934 2,105,637 Davis Jan. 18, 1938 2,176,939 Woolford Oct. 24, 1939 2,200,593 Coddington May 14, 1940 2,218,913 Hughes et al. Oct. 22, 1940 2,221,348 Hershey et al. Nov. 12, 1940 2,666,282 Peterson Jan. 19, 1954 2,680,938 Peterson June 15, 1954 FOREIGN PATENTS 49,730 Germany Nov. 22, 1889 France Oct. 10, 1927 sums. .4-

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