US1586975A - Mill for piercing billets - Google Patents

Description

June v1', 1926.

8. E. DIESCHER MILL FOR PIERCING BILLETS 3 Sheets-Sheet i Filed August 27 w/vwssses Mam-$143M June 1 1926. 1,586,975

. S. E. DIESCHER MILL FOR PIERCING BILLETS Filed August 27 1923 3 Sheets-Sheet 2 IN VE N 70/? W/TNEGSES Mam June 1,1926; 1,586,975

. s. E. DIESCHER MILL FOR PIERCING'BILLETS Filed August 192s 5 Sheets-Sheet 5 lN VE/VTOE wxrgvesses 5 fiwwflzm gam- 19.03%!

Patented June 1, 1926. v

UNITED STATES PATENT OFFICE...

SAMUEL E. DIESCHER,OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO 8. DIESOHER & SONS, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

MILL FOR PIERGING BILLETS.

Application filed August 27, 1923. Serial No. 659,425.

A form of apparatus forpiercing ingots or billets consists of rolls arranged in such relation that planes coincident with their axes will intersect at anacute angle, said rolls being rotated in the same directions. Rolls so arranged-Will act most eftectlvely if the work-piece is so supported that the axis of the work-piece and a line connecting points on the rolls most closely adjacent, will be in the same plane When the workpieceis in such position, the forces to which it is subjected (the weights of the workpiece and mandrel being disregarded) are equally effective to move the work-piece up or down, and a small movement of the work-piece from such position will bring about an unbalancing of such forces and the billet will be further shiftedf Such iliifting of the work-piece may be prevented by the employment of guides arranged above and below the path of longitudinal movement of the work-piece. Such guides would bear on the work-piece for considerable distance on each side of the zone of action of the rolls, and as the work-piece moves along and also transversely of the (guides, the latter would be quicklyrendere ineffective by reason of wear and excessive heating. And further, such oppositely dlsposed guides are objectionable for the reason that, due to lack of homogeneity of the steel, and the difiiculty in obtaining absolutely uniform temperature at all points on the workpiece, e. g., hard and soft spots, the workpiece is more or less bulged out or enlarged at points along the pierced portions and hence the work-piece might become stuck be-' tween the guides.

In order, to overcome the foregoing and other difficulties encountered, it is the present practice to so mount the rolls that the distance between the most closely adjacent portions of their working faces will be less than the diameter of the work-piece, and the work-piece is so fed between the rolls that its axis is above a horizontal plane passing through the intersection of planes coincident with the axes of the rolls, so that the rolls will exert oppositely acting pressures on opposite sides of the work-piece at points below a longitudinal plane passing through the axis of the work-piece. The tendency of such pressure is to force the billet up wardlyand hence a guide must be employed to hold the work-piece in operative position.

guides in the form of rollers freely rot-ating on an axis parallel or approximately parallel with the axis of the work-piece. The roller so mounted presents little re- -sistance to the rotation of the work-piece but a very considerable resistance to the longitudinal movement of the work-piece. The rolleris made of such a length and is so supported as to bear on the work-piece for a considerable distance on both sides of .56 It is the usual practice to construct these;

a vertical plane passing through the points of contact of the rolls with the work-piece, and hence when a bulge or enlargement formed on the work-piece in the piercing operation, comes in contact with the guide roller, and if the bul e or enlargement is considerable, the wori-piece will be bent and forced down on the mandrel subjecting the latter to injurious transverse strains,

.and militating against the piercing action.

increases as the axis of the work-piece is brought nearer said plane. But as the line of feed approaches such plane the'lifting component of the lateral pressures of the rolls on the'work-piece becomesless'efiective to prevent the dropping down of the work-piece by reason of the weight of the work-piece and mandrel. Hence it iis'the present practice to so adjustthe rolls for a given diameter of billetin such proximity one to the other, that'th'e lifting component of the ressure of the rolls on the workpiece Wlll be in excess of the weight of the work-piece and mandrel and to employ a guide roller to hold the work iece in position to be acted on by the rol s, as hereinafter stated.

The necessity of adjusting the relative positions of the rolls in accordance with the diameter of the work-piece, rendered it practically impossible to pierce a small workpiece. The adjustment of the rolls into close proximity so reduces the V-shaped space between the rolls inwhich the guide roller must be arranged, that a roller having sufficiently large diameter to sustain the transverse strains to which it must be subjected, cannot be placed in operative position. \Vhen the rolls are so adjusted that the line of feed ofthe work-piece must be outside of the line connecting the nearest points on the peripheries of the rolls, the employment of a guide extending along the workpiece on both sides of the point of reduction necessitates the feeding of-the work-piece above such line and the guide above the work-piece, as if the billet were fed below grammatic elevation showing the relative positions of the reducing. rolls and guide Y the rolls. With rolls so adjusted the line" roller in a mill embodying the invention described and claimed herein; Fig. 2 is a side elevation of the same; and portions of the billet and guideroller being shown in section; and Fig. 3 is a sectional plan view.

In the practice of the invention the reduc in rollsl are'constructed and mounted in suitable manner with their axes-a and 1) arran ed at an angle the one to the other accor ing to rules known in the art, and are adapted to be rotated by any suitable construction of driving mechanism in the same direction. The faces of the rolls operative on the billet are curved transversely or sub? stantially so. In order to avoid the employ ment of two guides or members to maintain the work-piece in position to be pierced, as would be necessary if it were so passed between the rolls that its axis would be in a horizontal plane 0 coincident with the intersection of planes coincident with the axes of the rolls, the latter are adjusted in such relation that the distancebetween points on the operative faces of the rolls lying in said horizontal plane will be sufficiently less than the diameter of the work-piece at the place acted on by the reducing rolls, to prevent the passage of the work-piece laterally between i offeed of the work-piece will be at one side In lieu of employing a guide roller with its axis parallel with the line of feed of. the' work-piece, the invention claimed hereln contemplates the employment of a disc 2 having its axis of rotation at right angles to the path of movement of the work-piece. This disc is secured on a shaft 3 mounted in bearings 4 so arranged that scale dislodged from the work-piece will not lodge on the bearings. This guide is preferably driven as hereinafter described. This guide disc or roll is so arranged as shown in Fig. 2 that its axis of rotation will be in or approximatethe guide roll or disc heretoforeemp'loyed do not bear on the portion of the work-piece being acted on. by the reducing rolls. And further, it isjthe practice in some cases to pierce an ingot as it comes from the mold,

and as such ingotis necessarily tapered from one end to the other 0111 the ends of the guide roller now used wil b'earon the ingot anddue to" the successive increments of feed of the'ingotshaving gradually varying crossmechanisms. In the employment of the im- 'provement described and shown herein the guide roll or disc 2 which is preferably made with a grooved periphery, has its periphery at r the root of said groove corresponding substantially to the transverse curvature of sectional dimensions, the axes of the work v the-peripheries of the reducing rolls so that,

it will conform to the surfaces of the portion of the work piece being acted 'on by the reducing rolls. It will be understood that when reference is hereinafter made to the radius or diameter of the guide roll or disc, the shortest radius or diameter of said roll or disc is meant.

As hereinafter stated, the presence of hard and soft spots in'the billet, due to unequal heating or other causes, will, cause a bulging or enlargement of the periphery of the work-piece, but as such bulging or enlargement cannot occur except after the surface of the work-piece has passed out of contact with the reducing rolls, they cannot have any effect when employing the character of guide roll or disc claimed herein, when the transversely curved faces of the reducing rolls have radii equal to 'the radii of the perimeter of the guide roll, as is the preferred construction, as when said parts are so constructed and relatively arranged.

as hereinbefore stated, the contact of the reducing rolls and guide disc on the orkpiece along the billet are substantially the same.

\Vhile'being operated on by the rolls of a piercing mill, a helical movement is imparted tothe work-piece, i. e., it is moved longitudinally and also rotated. It has been the general practice .to provide a stationary guide to support the work-piece in operative relation to the reducing rolls and the guide was worn away due to the two movements of the work-piece on the guide. In some cases a roller was used in place of the solid guide,-its'axis of rotation being parallel with the axis of the work-piece, but as the direction of rotation of such rollers was at an angle to its longitudinal move-.

ment there would not be any reduction of friction opposing the longitudinal movement of the work-piece. Such a guide roll is cylindrical in form and does not support the work-piece at that portion undergoing reduction by the main rolls of the pierc-.

roll or disc and the work-piece due to the .againstrotation of the work-piece.

rotation of the latter, can be. reduced and if desired wholly eliminated. In this case the relative circumferential speed of rotation of the work-piece and the rotation ofthe guide roll or disc would be such that the speed of the guide roll is greater than the circumferential speed of the work-piece.

Any speed of the guide roll and disc greater than the longitudinal speed of travel of the work-piece tends to cut down friction Also any speed 'of the surface of the guide roll -or disc at a higher rate of movement than that of the longitudinal movement of the work-piece between the reducing rolls would tend to draw the work-piece along.

These functions can be attained by rotating-the guide rolls at a speed so related to the speed of rotation of the work-piece that the peripheral speed of the guide roll is approximately one-half the peripheral speed of the work-piece divided by the sine of the average angle of the helix of feed of the work piece through the pass.

When the relationship of speed between reducing rolls and the guide roll or disc is such as set up in the above formula, then the friction between the work-piece and theguide has been totally eliminated or there are neither circumferential nor longi tudinalfrictions incurred by the work-piece m tigating against its passage through the mill. However, it would be understood that this entire matter is one of diverting the friction between the work-piece and the guide roll into a useful effect instead of a detrimental one. That friction which ordlnarily occurs against rotation and longitudinal travel of the work-piece, is by this method wholly confined to longitudinal friction between the work-piece and the guide roll, when the speeds areas set up in the formula, and since the guide roll travels faster than the work-piece in the longi-' tudinal direction, it now assists the workpiece through the mill instead of retarding it aswas the case in all constructions heretofore. A speed of the guide roll in excess of the formula given herein will of course result in a further assistance of the piece through the mill; As any speed of the guide roll above the speed of the -longitudi- 'nal travel of the billet will help in the forward movement of the billet as above stated, then under the conditions of pressure exerted on the billet by the guide roll and the excess speed of the guide roll over the longitudinal travel of the billet, the power used in driving the guide roll expends itself inheat on the surface of the billet. By speeding up the guide roll even in excess of the formula given, where all matters of friction both against its transverse and longitudinal movement are satisfied, the temperature may be brought to such a point as to bring about a welding heat on the surface of the work-piece over the extent of its reduction, and the circumferential travel bringing the heated parts in working position under the reducing rolls at the BIS welding temperature will definitely close" these cracks. I

In the preferred practice the guide roll will be positively driven and maybe given any desired speed regardless of the circumferential movement of the reducing rolls which affect the rotation and the rate of feed of the work-piece, such rate of feed being dependent on the angle between the planes of rotation of the reducing rolls and the axis of the work-piece.

It is characteristic of the mill shown and described herein that the guide disc or roll piece is small and as all other portions of the surfaces of the guide roll form heat radiating surfaces the guide roll canv be made of such diameter as to prevent any material heating of said guide roll when operating the mill. I

When employing a guide disc or roll, with its axis of rotation at right angles to the direction of longitudinal movement of the work-piece, its strength to resist the pressure of the work-piece thereon will be proportional to the diameter of the supporting shaft. As the latter is arranged entirelyto one side, i. e., above or below the rolls, it can be made of any desired diameter. As the guide disc or roll can be made of a thickness less than the diameter of the work-piece to be pierced, then very small work-pieces can be operated on in the improved mill.

When the reducing rolls are made of the same diameter and have the same peripheral speed, the vertical resultant of the lateral pressures of the two rolls on the workpiece as well as the amount of displacement which takes place in piercing or other factors will be equal, but if the peripheral speed of one roll is increased, the resultant pressure of the'guide roll will be affected. As for example, an increase in the peripheral speed of the right hand roll in Fig. 1 will supplement the action of the vertical component of the pressures of said rolls to prevent the billet from moving upward and hence the billet maybe fed on a line nearer the horizontal plane a. It will be understood that the increase in peripheral speed may be attained by increasingthe speed of one of two rolls of the same diam eter or by making one of the rolls of a greator diameter than the other-and rotating the rolls at the same speed.

It will be observed that the tendency to shift the position of the work-piece by an increase in the peripheral rate of one of the rolls, will operate in the direction of rotation of such roll; as for example, an increase in the peripheral speed of the right hand roll in Fig. 1 would tend to move the workpiece down supplementing the vertical com? ponent of the lateral pressures on the workpiece and the weight of the work-piece and mandrel. If however, the peripheral sped of the left hand roll be increased, the effect of such increase will be to counteract to a greater or less degree dependent on the increase in peripheral speed, the combined action of the vertical component and the weight of the work-piece and mandrel,-

thereby decreasing the. pressure of the work-piece on the guide roll. As the action.v

of increasing the peripheral speed in a direction away from the supporting or guide roll would tend to shift. the work-piece from between the rolls, great care should be exercised in using such a construction.

It is preferred in the practice of the invention claimed herein to feed the Work piece between the reducing rolls'so that its axis will be below a horizontal plane 0 and coincident with the intersection of planes a and b coincident respectively with the axes of the reducing rolls for the reason that in such case the weight of the work-piece and mandrel will operate to prevent the workpiece from being forced laterally through the narrowest space between the rolls and hence it is possible to so space the rolls for a given diameter of work-piece that the axis of the billet when being fed through the rolls will be closely adjacent to the plane 0,

thereby increasingthe reducing efficiency of the rolls. As for example, under the present practice it has been found expedient to so feed the work-piece that its axis will be for a four-inch diameter work-piece about one and a quarter inches above the plane 0 so that the lifting effect of the vertical com ponent ofthe pressures of the rolls on the work-piece will be largely'in-excess of the weight of the work-piece and mandrel. But by arrangin the line of feed that the axis of the worIz-piece will be below the plane 0, the weight of the work-piece and mandrel and the vertical component of the pressures of the rolls operate together to prevent the upward movement of the workpiece from between the rolls, the work-piece may be so fed between the rolls that its axis is not more than three quarters of an inch below the plane 0. r

I claim herein as my invention:

1. In a piercing mill the combination'of reducing rolls adapted to act on the workthan the diameter of the solid and pierced portions of the work-piece and having its axis of rotation at an angle to the direction of movement of the work-piece.

3. In a piercing mill the combination of reducing members and guiding member adapted to bear on the portion of the workpiece having a diameter less than the diam eters of the solid and pierced portions of the work-piece, the portion of the guiding member-bearing on the work-piece moving in a direction parallel'with the axis of the workpiece.

4. In a piercing mill the combination of reducing members arranged in operative relation one to the other and having the surfaces operative on the work-piece, trans- Ill versely curved, and a rotating guiding member adapted to support the work-piece in position to be operated on by the reducing members, the radius ofthe guiding member being substantially equal to the radii. of the transversely curved surfaces of the reducing rolls.

5. In a piercing mill the combination of reducing rolls adapted to act on the workpiece in a helical direction, and having curved operative faces and a guiding member having its axis of rotation in a plane at an angle to the line of feed of the work-piece to be pierced and adapted to bear on the portion of the work-piece being acted on by the reducing rolls, the radius of the guiding member being substantially equal to the radii of the curved surfaces of the reducing rolls. a

6. In a piercing mill the combination of reducing rolls adapt-ed to act on the workpiece in a helical direction, a guiding member having its axisof rotation in a plane at an angle to the axis of the work-piece and adapted to bear on the portion of the Workpiece being acted on by the reducing rolls, and means for rotating the guiding member so that the surface in contact with the workpiece will move in the direction of longitu-' dinal-Inovement of the work-piece.

7. In a piercing mill the combination of reducing rolls adapted to act on the workpiece in a helical direction, a guidin memher having its axis of rotation in a plane at an angle to the axis of the Work-piece and adapted to bear on the portion of the workpiece being acted on by the reducing rolls, said guiding member being so arranged relative to the reducing rolls that its bearing on the work-piece will be below a horizontal plane coincident with the intersection of planes coincident with the axes of the reducing rolls, and the portion bearing on the work-piece will move in a direction of the longitudinal movement of the work-piece.

8. In a piercing mill the combination of rolls having transversely curved reducing surfaces and a rotating guiding member, the radii of the transverse curvature of the re ducing rolls and the guiding member being substantially equal.

9. In a piercing mill the combination of reducing members and a guiding member having its peripheral surface moving in the direction of the work-piece being operated on, the radius of such surface being substantially equal to the radii of the-surfaces of the reducing rolls and arranged to so support the Work-piece being reduced that its center line will lie in a plane outside of but parallel with a horizontal plane coincident with the point of intersection of planes coincident with the axes of the reducing rolls.

10. In a piercing mill, the combination of reducing members having their axes in planes at an angle one to the other; and a guiding member so arranged that its point of contact with the work-piece will move in thedirection of the longitudinal movement of the workpiece and having a rate of rotation relative to that of the work-piece that the peripheral speed of the guiding member is approximately that of the circumferential speed of the work-piece divided by the sine of the angle of the helix of feed of the work-piece.

11.; In a piercing mill'the combination of reducing members and a guiding member having its peripheral surface moving in a directionof the workpiece being acted on, the radius of such surface being substantiallyequal to the radii of the surfaces of thereducing rolls and arranged to so support the work-piece being reduced that its center line will lie in a plane outside of but parallel with the line of intersection of the planes coincident with the axes of the reducing rolls and the narrowest portion of i the pass between the said reducing rolls.

In testimony whereof, I have hereunto set

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