US2040764A - Apparatus for forming tubular blanks - Google Patents

Description

B. BANNISTER APPARATUS FOR FORMING TUBULAR BLANK-S May -12, 1936.

Filed May 1o,v 1955 4 S heets -She eb 1 1760620 02": EEYfli/VT .BH'NN/STE/E,

M I Y his 4170071,?5.

' I APPARATUS FOR- FORMING TUBULAR BLANKS I Filed May 1953 4 Sheet-Shee't- 3 I lmenfor:

BEYfiA/T BANN/ST'EE y- 1 36- B. BANVNISTERU I 2,040,764

APPARATUS FOR FORMING TUBULAR ELANKs I Filed May 10,1935 4 SheetS-Shet 4 g w 5 g 2 -2,- 2 2 Q I I /0 In venfor:

Patented May 12, 1936 UNITED STATES PATENT FFlCE APPARATUS FOR FORMING TUBULAR BLANKS Bryant Bannister, Mount Lebanon, Pa, assignor to National Tube Company, a corporation of New Jersey 2 Application May, 10,, 1933, Serial No. 670,345

the reduction is made attocel p rate the This invention relates to the manufacture of. seamless pipes and .tubes from cast or rolledrounds, and particularly to that procedure in such operations where the solid billet, or work- 5 piece, is pierced, forming a hollow and relatively thick walled tube, although'not limited thereto.

-The usual method of piercing a solid workpiece -for subsequent rolling into seamless tubing of commercial dimensions is to pierce and materially lengthen the same without appreciably changing its diameter. This operation has usually been performed by passing the solid workpiece between a, pair of power rotating, obliquely disposed, barrel-shaped rolls, which rotate and force the work-piece longitudinally over a conical piercing plug, ormandrehwhich is free to --rotate but restricted from longitudinal movereduce rotational friction and act to assist the ment. The workpiece is usually maintained in proper position between the work, or reducing,

rolls by stationary guiding members located above and below the same; These guiding meme bers offer considerable resistance to'both. rota- ,tional and longitudinal movement of'the metal.

improved type consisting of a pair of power actuated guide rolls positioned intermediate the work rolls and with their mid-planes substantially coincident with the longitudinal axis of the mill. These rolls have'a peripheral speed in the direction of and greatly in excess of the axial travel of the work-piece. 7 A

'At present it 'isalmost universal practice to follow the piercing operation by one or more subsequent operations in order to further'reduce the 'wall thickness without changing the diameter and remove marks accruing from the contact of the tubular work-piece with the guide rolls referred to.

It is obviousjto those skilled in the art that the least number of fabricating operations required, consistent, of course, with good and sub- 50 prising a, piercing andelongating operation performed on two separate mill units, and therefore requiring two crews of operators. In producing large diameter pipe, a first, and

second or expanding-piercing, operation is em- 5 ployed preceding the elongation operation. If

In some cases the guiding members are of an work-piece and rotate the same while advancing .of the piercing plug. The elongated parallel porcontact areas substantially adjacent that secwork-piece through the pass, but if they are positioned with their contact areas in-the conventional position; that is, with a line connecting their centers passing through the gorge, or that portion of the pass in which the point of the piercing plug-is disposed, they permit too great an ovality, or distortion, at the outlet end of the pass, and control of the diameter of the work-piece cannot be maintained.

In my co-pending application, Serial No. 667,- 108, filed April 20, 1933, .poweractuated guide rolls are employed in combinationwith metal working rolls to forma, roll pass having converging, elongated parallel, and diverging portions. The converging portion is employed to grip the it forwardly into the elongated parallel portion 0 of the pass. This results in necking-down of the solid work-piece, and is necessary to produce a grip sufllcient to forcethe meta over the point tion of the pass'and the associated piercing plug 5 are so disposed with respect to each other that substantially all of the displacement of metal by the metal working rolls occurs in this section.

The piercing plugof my co-pending applicationreferred this of such curvature and so positioned with respect to the metal workingrolls contact surfaces that the shortest distance between it and the parallel portion of the pass in any transverse section isgreatest at the extreme point of the plug and decreases less rapidly as the section is moved rearwardly in the pass. The I power actuated guide rolls are disposed with their tion of the pass wherein the; last wall reduction ismade. In addition to functioning in combination with the metal workingrolls-to accurately control .the diameter of the pierced work-piece, the guide rolls, positioned as described, present a comparatively flat surface parallel to the cylindr ical portions of the piercing plug, where the last wall reduction is made. 1

. While the comparatively fiat surface presented by the guide rolls effectively guides and assists the work-piece through the outlet end of the pass in such manner as to reduce rotational and longitudinal friction which would occur if the usual stationary guides were employed, they do not actually assist the rotation of the work-piece to the extent desired. It is, of course, obvious thatgin any type of metal working pass extraneous assistance to rotate the work-piece is highly desirable, and due to the unusual number of working contacts occurring in the elongated longitudinal movement through the mill.

' Figures 5ancl 6 are views similar toFigure 4,.

Still another object is to provide'means for producing unusually thin walled tubular blanks from solid work-pieces in but a single operation.

A further object is to provide novel means for contacting the wall of a pierced work-piece, throughout the wall reducing section of the pass, thereby permitting it to be of any desired length.

A still further obiect is the provision of novel means for effecting very-great reductions in workpiece cross-sectional area while maintaining a very orderly movement of the metal.

Astill further object is to provide a novel extraneous force having at least an equal helical angle to that of a work-piece progressing through a seamless tube mill.

These and further objects will be apparent after referring to the drawings, in which:

Figure 1 is a plan of the apparatus of the invention with one of the extraneous assisting forces removed and showing the work-piece in section.

Figure 2 is a side elevation of the apparatus showing the work-piece in section.

Figure 3 is a sectional end elevation of the novel metal working pass of the invention taken on the line IIIIII of 1 Figure 1.

Figure 4 is a side elevation of the preferredem- 'bodiment of one of the novel extraneous assisting forces of the invention shown together with a piercing plug and a work-piece in section.

but disclosing modified forms of the apparatus. Figures 7 and. 8 are a plan and elevation, respectively, corresponding somewhat to Figures 1 and 4, but disclosing a modified piercing plug for use when reeling is deemed unnecessary.

Referring more particularly to the drawings.

the numeral 2 designates a pair of barrel-shaped metal working rolls of the cross-roll type, which are disposed with their axes inclined to each other and to the'-axis of the work-piece they of greater length than the diameter of the blank to be processed. V v

Thenovel extraneo'us assisting forces of the invention comprise a pair of substantially cylindrical, power actuated feed rolls 3 which are disposed intermediate the metal working rolls 2 and in a manner somewhat similar to the latter, but with their angles of inclination to the center line of the mill slightly greater than the corresponding inclination of the metal working rolls. These power actuated feed rolls 3, when taken together, provide elongated substantially parallel surfaces 3 and are driven in such manner that these surfaces, which contact with a work-piece progressing between the metal working rolls 2 travel at a speed at least equal to the surface speed of the metal working rolls. The elongated substantially parallel surfaces 3*, of the power actuated feed rolls, are of substantially the same length as the corresponding surfaces 2 of the metal working rolls. The longitudinal feeding tendency resulting from the cross-setting of the power actuated feed rolls 3 is at least equal to the forward feeding tendency of the metal working rolls 2 with equal surface speeds. This difference may, of course, be increased by either increasing the angularity of the power actuated feed rolls 3 or increasing the surface speeds thereof.

A conical piercing plug 5 is provided with a rearward cylindrical portion 5 and disposed between the metal working rolls 2 with its point slightly in the converging portion of the pass defined by the surfaces 2*, and is adapted for rotary movement while mounted on a mandrel bar 6.' 1

Referring to Figures 2 and 5 of the drawings, the feed rolls 3 are shown as provided with rings, or slight corrugations, 4, that are in planes transverse to the axes thereof and extend over a substantial portion of their surfaces. These rings 4 make an impression in the surface of the metal of the work-piece and provide for a more positive contact therewith. I

Inpracticing the preferred embodiment of the invention, the feed rolls 3 are provided with helical threads or corrugations indicated by the numeral, 1. in Figure 4, in order to provide for a greater tendency to rotate the work-piece than wouldbe the case were the rings concentric, as

inFigures 2 and 5. In this form of the invention,

even though the axes of the feed rolls 3 are disposed parallel to the .axis of the work-piece, a very decided rotational and longitudinal feeding tendency will be obtained by increasing the surface speed of the feed rolls above ,that of the work-piece. The angle of the helical corrugations or threads I are regulated to govern the magnitude of the rotational and longitudinal as sisting effect desired. 1

Referring to Figure 3 of the drawings, a pair of small stationary guiding members 8 are profiled to permit-of close proximity to the metal working rolls 2 and the feed. rolls 3 and are disposed to permit'a'small contact area 8 to limit'the lateral bulging of the work-piece as the forward and rearward ends thereof are passing under'the feed rolls.

.In Figure 6 of the drawings; one of the feed rolls 3 is shown as having a smooth elongated,

substantially parallel portion 3 In practicing this form of the invention the axes of the feed rolls must, of course, be disposed at an angle to the axis of the work-piece, in order to provide a forward feeding tendency.

In operation, a solid work-piece A is introduced into the converging portion of the pass where it is necked-down" and forced over the point of the piercing plug 5 which is disposed to extend slightly will occurjadjacent the end tion of the pass defined acid-n4 As the metal of the work-piece is displaced between the elongated substantially parallel portions 2" of the metal working rolls 2 and the piercing plug 5', a very substantial reduction in wall thickness will occur. Throughout the porby the elongated substantially parallel surfaces 2'' of the metal working rolls and the piercing plug 5, the elongated substantially parallel portions 3' of the feed rolls will contact with successive increments of the metal of the work-piece as they are fed from the metal working rolls. It will thus be seen that the tangential flow of the metal will be restrained from excessive distortion, or ovality, by the contact areas 3* of the feed rolls and also the small areas 8 of the stationary guide members 8. The

tendency of the elongated ubstantially cylindrical portions 3 of the feed rolls will be to decided: ly assist both rotational and longitudinal move ment of the metal at a greater rate than the corresponding speeds of the work-piece A, with which they are in contact. i v

The metal of the work-piece will next be introduced between the cylindrical portion 5 of the piercing plug and the last area of the elongated substantially parallel surfaces 2' of the metal working rolls while still in contact with the elongated substantially parallel portions 3 of the feed rollss- A very effective reeling action pass beyond where the corrugations or threads cease and the pierced work-piece will emerge therefrom with a finally finished surface but with a slight oval circumference.

The slightly oval circumference of the workpiece is rounded-up between the surfaces 2 of the metal working rolls, from whence it will emerge from the mill in finallyfinished form.

In Figures '1 and 8 of the drawings there is disclosed a modified form of piercing plug which is adapted for piercing operations electively in'-- elongated substantially parallel portions feed rolls tended to be followed by subsequent processing. Underthese circumstances reeling would be unnecessary as waviness in the surface of the work-piece would not be objectionable; Accordingly, the modified form of piercing p u 9 is somewhat similar in design to the plug 5, except that it is not provided with a reeling section. The plug 9 is mounted, on a mandrel bar II and disposed in the same position relative to the metal working rolls 2 and feed rolls 3, as would be the piercing plug 5.

In operation, the work-piece A will be processed exactly as it was when the piercing plug 5 was employed, except that the internal support offered by the plug 9 will cease a short distance before the work-piece encounters the ends of the 3 of the 3. This will have no effect on the wall of the work-piece except that it will not be reeled.

It is to be understood that the novel extrane of this portion of the materially greater ous rotational and longitudinal metal feeding means of the invention the metal working rolls claimed in my co-pending application, Serial No. 677,108, nor is it necessarily intended for use solely in piercing operations, as the foregoing disclosure 9. type of seamless tube mill wherein such substantial displacements of metal are made and numerbe limited exactly thereto, since various modifications may be made without departing from the scope of my invention, as defined in the following claims. a

I claim:

are not limited to use with p is merely intended to I present the invention as used in combination with 1. In a metal rolling apparatus the combination of a mandrel, reducing rolls disposed in cooperative relation with the mandrel to form a pass and cause the blankto bulge laterally away from the mandrel and to move the metal of the blank helically, and blank feeding means including blankengaging' cross-feed rolls located in the pass with their axes extending lengthwise thereof, said feed rolls presenting portions extending lengthwise of the pass for contact with the blank longitudinally thereof to limit bulging of the blank and-to apply extraneous feeding forces to the blank for assisting both the longitudinal and peripheral components of the movement of the metal, said feed rolls being peripherally grooved for furthering the longitudinal component and having their contact surfaces nearest the longitudinal center line of the pass spaced a materially great-' er distance therefrom than the corresponding surfaces of said reducing rollsu reducing portions'materially longer than their individual remaining portions and substantially parallel to each other, and blank feeding means including blank-engaging cross-feed rolls located in the pass with their axes extending lengthwise thereof, said feed rolls presenting portions extending lengthwise of the pass for contact with the blank longitudinally thereof to limit bulging of the blank and to apply extraneous feeding forces to the blank for assisting both the longitudinal and peripheral components of the move- ,ment of the metal, said feed rolls being peripherally grooved for furthering the longitudinal component and having their contact surfaces nearest the longitudinal, center line of the pass spaced a distance therefrom than the corresponding surfaces of said reducing rolls.

BRYANT BANNISTER.

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