US1951348A - Method of cross-rolling - Google Patents

Description

March 20, 1934. s. E. DIESCHER METHOD OF CROSS ROLLING Filed Sept. 2, 1932 /m g Q pieces introduced between them) Fatented at 20, 1934 PATENT OFFICE 1,951,348 METHOD OF CROSS-ROLLING Samuel E.

Diescher Tube Diescher, Pittsburgh, Pa, assignor to Mills, Inc., Pittsburgh, Pa, a

corporation of Delaware Application September 2. 1932, Serial No. 631,510

SGlaims.

My invention pertains to a method of applying to work-pieces the pressure treatment of cross-rolls (which term is intended throughout this application to include other helically acting rotating members for applying pressure to work- ,--such treatment as occurs, for example, when billets are pierced, pierced billets or other tubes are elongated and reduced in wall thickness, tubes are reduced in diameter, tubes or bars are straightened, etc., by the action of cross-rolls.

According to certain prior inventions which I have made, discs (or, sometimes, a single disc) are mounted in the space between the cross-rolls for engagement at their peripheries with the work-piece. The discs serve to guide the workpiece, and/or to confine the metal of the workpiece as the latter rotates from contact with one cross-roll to contact with the other, as well as to perform other functions which depend, to a certain extent, upon the character of work being performed by the crossrolls. The frictional resistance which the discs exert against rotation of the work-piece, is reduced by rotating the discs in the direction of the progression of the work-piece through the cross-rolls at a speed in excess of that of such progression.

In cross-roll mills employing discs of the character to which reference has just been made, it is often desirable to change the distance separating the discs, or, ii only one disc is used, to change the distance between the periphery of the disc and what may be termed the axis of the throat of the cross-rolls. For example, supposing a tubular work-piece to have been elongated, to produc and wall thickness, at a given setting of the cross-rolls and guide discs,it would be necessary to separate the discs more widely if it were desired to obtain, with the same mandrel and the same setting of the cross-rolls, a tube of the same wall thickness but greater diameter. Similar occasions for varying the distance separating the discs occur in other uses of cross-roll mills employing such discs.

The above-mentioned change of the distance separating the discs has, prior to this invention, presented a difficulty which often could only be overcome by removing the discs from the machine and substituting others of a difierent width. The difflculty arose from the fact that it was often considered necessary to construct and arrange the discs so that they presented peripheral areas, for engagement by the work-piece, which covered substantially as much of the space existing between the cross-rolls as possible. This involved that the edges of the discs came into close proximity with the adjacent cross-rolls, and, since the space between the cross-rolls narrows as the axis of the throat is neared, the discs could 60 not be brought more closely together without coming into contact with the surfaces of the cross-rolls. On the other hand, the discs could not be moved further apart without leaving undesirable spaces between their edges and the surfaces of the cross-rolls.

It is the primary object of the present invention to provide a method of cross-rolling with the use of rotating discs of the above-mentioned character, in which the foregoing difflculty will be obviated. I obtain this object by subjecting the work-piece to the engagement-for guiding, confining or other purposes,of the rotating discs at areas which, in the case of each disc, are nearer to one cross-roll than the other. If a disc is made to engage the work-piece at an area closer to the cross-roll which moves the metal of the workpiece towards such disc than to the other crossroll, I find that the disc will perform its function satisfactorily without engaging the work-piece in the region close to such other cross-roll,--that is, the cross-roll towards which the metal of the work-piece moves from the disc. By this mode of guiding, confining, or otherwise operating on the work-piece, I am enabled to leave space, in 85 the case of each disc, between such disc and that cross-roll towards which metal moves from the disc. This in turn allows the discs to be moved towards and from each other through material distances, while the edge of each disc canahy being o 'm ipofg cam m m meved transversely stillpbe lrept' in close proximity with the cross-roll which moves the metal of the work-piece towards such disc.

The practice of my improved method will be more readily understood from the accompanying drawing, in which,

Fig. l is an end view, of a schematic nature, of a cross-roll mill employing discs of the character mentioned above, the mill being viewed in the direction of the feed of the work-piece therethrough;

Fig. 2 is a section on and Figs. 3 and 4. are fragmentary views, similar to Fig. 1, illustrating the manner of moving the discs for different working conditions.

An operation of elongating and reducing the wall thickness of a tubular blank, to produce a seamless tube, has been selected for illustration. The blank A, upon a mandrel B, is fed to a pair 110 the line lI-1I of Fig. l;

or crose= rolls 12, 13, between which are mounted a pair of discs, 1e, 15, which engage the workpiece one on each side thereoi. These discs are rotated in the direction of the arrows (Fig. 2), that is, in the direction 05; the progression of the work-piece through the cross-rolls, at a peripheral speed in excess of the longitudinal speed of such progression of the work-piece. The portion of the work-piece which is, at the moment, in the throat of the cross-rolls is designated A and the portion thereof which has been elongated is designated A.

From the arrows on Fig. 1, it will be seen that the cross-roll 12 is moving the metal of the workpiece towards the disc 14, while the cross-roll 13 is moving the metal towards the disc 15. In the practice of my invention, I cause the guiding, confining or other engaging action of each disc to occur to a greater extent on the side of its periphery adjacent the cross-roll which is moving the metal towards it than on the other side, that is, in the case of the disc 14, more on the side of its periphery adjacent the cross-roll 12 than on the side adjacent the cross-roll 13. While allowing one edge of each disc to be placed in close proximity with the cross-roll which is moving metal towards the disc, this permits a considerable space to be left between the other edge of such disc and the other cross-roll, thereby pro vidlng room for movement of the discs in a transverse direction as an incident to a movement towards each other.

The periphery of each disc is of a curved transverse contour so chosen that the metal coming to the disc from the adjacent cross-roll will be properly deflected and directed towards the cross-roll towards which the metal moves from the disc. Such contour may conveniently, though not necessarily, be that of the arc of a circle, of a diameter larger than that of the largest article that will be produced, which has its center beyond a plane central of, and parallel with, the disc. Considering a disc as positioned so that its periphery is spaced from the axis of the throat of the cross-rolls by a distance somewhat larger than the greatest distance that will be required (for that disc) in practice, and as being placed with one edge of its periphery in close proximity with one of the cross-rolls, as described above, the contour 01' the periphery of such disc may be that of a circle drawn about the axis of the throat of the cross-rolls as a center.

The mahrnerhrwhich the work-piece is engaged by the discs, and the different positioning of the discs which is thereby made possible, will be readily understood from Figs. 3 and 4. Fig. 3 shows the cross-rolls as set, with respect to the mandrel B for producing an elongated tube of a given wall thickness. The diameter of the elongated tube will be controlled by the position of the discs 14, 15, which are shown as widely separated, so as to produce a tube of relatively large diameter. The separation of the discs is somewhat exaggerated, however, in the figure for ease of comparison with Fig. 4. Taking, for instance, the disc 14, it will be noted that this disc is engaging the work-piece at an area nearer to the cross-roll 12 than to the cross-roll 13, that a material space is left between the edge of the disc and the cross-roll 13, and that the edge 14a of the disc is in close proximity to the cross-roll l2,-so that the disc immediately intercepts and deflects the metal as it moves from the crossroll 12, and no space exists between such crossroll and the edge of the disc into which the metal might tend to flow. The space between the disc and the cross-roll 13 provides room for the disc to be moved further in towards the axis of the throat of the cross-rolls, permitting the disc to be moved transversely towards the cross-roll 12 (so as to avoid contact of its edge 14a with the cross-roll 12 when the disc is thus moved further in towards the axis of the cross-roll throat). Fig. 4 shows the same setting of the cross-rolls with respect to the mandrel B, giving a tube of the same wall thickness as before. However, the discs are placed more closely together, to produce a tube of smaller diameter. To bring the discs into the closer position, they are moved so as to approach each other and also transversely as is indicated by the dotted lines a continuing the edge 14a of the disc 14 in the two figures, and the dotted lines b continuing the edge 15a of the disc 15.

I claim:

1. The method of treating work-pieces by means of cross-rolls, which includes applying to the work-piece, between the cross-rolls, at an area nearer to the cross-roll which rotates the workpiece toward the pressure member than to the other cross-roll, the engaging pressure of a member moving in the direction of the longitudinal progression 01 the work-piece through the crossrolls at a speed greater than that of such progression.

2. The method of treating work-pieces which includes subjecting a work-piece to the action of a plurality of cross-rolls and simultaneously applying to the work-piece, intermediate the cross-rolls, the engaging pressure of a member having its engaging surface disposed nearer to the cross-roll which rotates the work-piece toward the pressure member than to the other cross-roll, and moving in the direction of the longitudinal progression of the work-piece through the cross-rolls at a speed greater than that of such progression.

3. The method of treating work-pieces which includes subjecting a-work-piecetatlfaction of a plurality of cross-rolls and simultaneously SAMUEL E. DIESCHER.

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