A Process for Manufacturing "Endless" Metal Articles by Rolling or by Rolling and Drawing.
Year: 1898

page_text: Date of Application, 3rd Dec., 1898-Accepted, 14th Oct., 1899
COMPLETE SPECIFICATION.
A Process for Manufacturing "Endless" Metal Articles by Rolling or
by Rolling and Drawing.
I, OTTO KLATTE, of 36, Goethestrasse, Düsseldorf, in the German Empire,
Foundry Manager, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
The first claiming clause to my Patent, No. 21,716 of 1894, is directed to a
process for producing bar, band and wire-like articles, consisting in rolling an
endless" annular metal blank to the required section between one and the same
pair of rolls, the endless form of the blank being preserved, and in then separating
the same into suitable lengths.
In my said previous patent, this process is described only as applied to rolled
goods in the shape of rods, bands or wires, which implies that the initial body
must consist of a solid metal ring which however may be formed by the combina-
tion of a number of concentric rings, each of a different metal, provided that the
final product in all cases presents its full section.
The said process also admits of the production of seamless hollow bodies of
any desired shape from correspondingly formed initial annular bodies. The
method of forming such initial bodies constitutes the subject of my Application
for Letters Patent, dated the 3rd December, 1898, No. 25,579. According to
this method, a core, which may consist of one or more materials, and is of a
circular or oval ring form is encased in the metal from which the desired hollow
body is to be produced.
In carrying out the present invention, it is proposed to produce the desired
body by rolling such an initial body according to any one of the following
processes:
(1.) Assuming the case or shell of the initial body to be formed of ingot-iron
and the core of some such material as litharge or aluminium which, at the
temperature requisite for rolling, will retain its capability of being moulded
and will not materially increase in density, the annular initial body is inserted
in a rolling mill of the type shown in Fig. 1 of the accompanying drawings,
same comprising three rolls set one above the other and differing from that
represented in Figs. 16 and 17 of the drawings to my said previous Patent,
No. 21,716 of 1894, in that the operative surface of each roll provided with
a semi-circular depression a, the object of which is to enable the rolled-out
goods to retain an approximately circular section. In this train of rolls, the
initial body or "blank" is rolled until the operative surfaces of the roll nearly
touch, whereupon the "blank" will have acquired the section indicated in dotted
lines at the upper part of Fig. 1. Inasmuch as the density of the core which
occupies the bore of the shell cannot be increased to any appreciable extent,
the said bore cannot be entirely closed by the action of the roll; in fact, its
volume is the same as in the initial blank, and, accordingly, the relation between
the thickness of wall of the finished hollow body and the diameter of its bore
remains equal to the relation between the thickness of wall of the original shell

page_text: and the diameter of the bore of that shell. The initial section should be made
sufficiently large say from 20 to 25 times larger than the section required for
the finished article-in order that a ring with an inner diameter of 800 milli-
metres and a length of 25 metres, for example, will, after rolling, be from 50
49 60 metres long.
the
It is advisable to divide the task of rolling amongst a number or at least two
treble-roll mills. In the drawings, the latter alternative is supposed to be
adopted, the second treble-roll mill being illustrated by Figs. 2 and 3;
first mill comprising the commencing or preparing rolls, and, the second, the
finishing rolls.
"
"
.
The endless body which, as it leaves the finishing rolls, forms a long endless
loop, is removed from the rolling mill and cut through at one or more points,
whereupon the plastic core is ejected by washing it out or by drawing it out;
or it may be heated until it becomes liquid and then run out; its discharge being
assisted, if necessary, by pressure or suction. The hollow bodies thus obtained
may be rolled over a mandrel or passed through draw-plates in order to impart
to them the desired final section.
If the initial body or blank be a ring whereof the core, through the medium
of cross partitions which form a firmly connected structure with the outer casing,
is divided into a pre-determined number of parts, as indicated at the upper part
of Fig. 3, and if the the finished article be divided at the points where the
partitions are situated, the result will be single seamless hollow bodies closed
at one or both ends. These hollow bodies may, after the removal of the core,
be finished to form receptacles for gases under pressure, projectiles or the like.
By means of the trains of rolls here shown (Figs. 1, 2 and 3) there may
further be rolled a blank which is a compound body comprising a number of
casings formed of core-material and hollow-body-metal alternately.
Figs. 4 and 4 illustrate the method of rolling an initial body of this descrip-
tion in two treble-roll mills. In this case, prior to giving the article its final
form, the individual tubes encased within each other-which may all consist of
the same metal or be each composed of a different metal-must be drawn out
of one another.
1
"
(2.) Where the core of the initial body, as shown in Fig. 1, or the core and
intermediate casings of the initial body, as shown in Fig. 4, is or are not formed
of a material which retains its mouldable property during the rolling operation
as is assumed to be the case in the first example above given-but of a material,
such as antimony, zinc. lead and tin, which, at the rolling temperature will
liquefy, the method to be adopted in rolling must differ according as round or
flat depressions or passes are to be used in rolling. In rolling articles in
rounded passes, the course to be pursued is much the same as that described with
reference to the first example; with this difference, however, that the liquid
core-material, during the rolling operation, follows a flowing motion in the
direction opposite to that in which the rolls work. The reduction of the sectional
area of both the casing and the core, and their increasing length, or in other
words the extent of elongation of the entire hollow body, are in the same propor-
tion as if the core were plastic, as described in connection with the first example.
In rolling blanks through flat passes, any of the mills described in my said
former Patent, No. 21,716 of 1894, may be adopted, see Figs. 5 and 6 for
example; and, in that case, the rolling process should be carried out in the
following manner:-(a.) The initial body, of circular section, is so compressed
in the flat passes of the rolling mill-where these are wider than the diameter
of the said body-that it takes the shape represented in Figs. 5 and 6. Then
the core-material (Fig. 5) forms a flat band while the walls of the casing around
the core-band are practically uniform in thickness. If this body, as it lies flat-
wise in a pass which is limited laterally, be reduced in thickness or depth by
rolling, the width of the slot occupied by the core-band will remain the same;
and furthermore, the width of the matter situated on the sides of such slot will

page_text: also remain unaltered; but the thickness of the said matter situated laterally
will become equal to the thickness of the whole slotted body lying flatwise, as
reduced by rolling. Now, when the said body is opened out, or drifted, along
its slot in the well known manner, the result will be a hollow body with two ribs
whose thickness will be twice the thickness of wall of the hollow body.
(b.) Where the width of the pass shown in Fig. 5 is only such as to make the
width of the material on the sides of the slot materially less than the thickness
of wall of the casing above and below the said slot, if the body operated upon,
as it lies flatwise, be rolled down until the thickness of wall of the case becomes
uniform around the slot, then, when the slotted body is opened or drifted out,
there will be obtained a hollow body unprovided with any ribs.
Figs. 7 to 11 illustrate the manner in which, from an initial body of, say, a
star-shape in cross section and having a core which will liquefy under the action
of heat, a longitudinally ribbed hollow body may be obtained. The rolling of
these bodies is effected in the usual manner; the roils employed for this purpose
having passes of the form of a half cross. After rolling, the body containing
the core is opened by a mandrel or the whole is rolled on a mandrel.
In fact, hollow bodies in a great variety of forms may be produced by such
means, including, for example, such as present two or a number of hollow spaces
or chambers, either juxtaposed or superposed, and which may serve to form
double gun-barrels, revolver drums and the like. In manufacturing double
gun-barrels the blanks to be rolled must have two cores lying parallel side by
side; while in manufacturing revolver drums, several cores must be arranged
in the blank in positions corresponding with the position of the hollow spaces
in the revolver drum. The blank is rolled in the usual manner and then drawn
over mandrels.
In rolling initial bodies, the cores or intermediate casings of which become
liquid in the process of rolling, such liquid substance is compelled-see Fig. 12-
to take a course opposite to the direction followed by the rolls; the material
being forced back at the point where the initial body enters the pass, and driven
thence to the point of emergence, where it enters between the compressed walls
of the casing. Thus, in rolling blanks of circular section, the blank is extended
proportionately to the elongation and reduction of the thickness of the solid
walls, so that the hollow space cannot resume its original form, but more and
more nearly approximates the form of a flattened oval. This is owing to the
fact that in the part of blank which enters the pass, the material of the soft
core recedes and the solid walls are pressed towards each other. When however
the blank leaves the pass, the space enclosed by the elongated solid walls has
become larger, and therefore the soft material of the core which is driven back
on the other side of the pass can only partly fill out the said space, so that the
blank is only blown out by the mass of the core to the extent of a flattened oval.
It is to be remembered that, although in rolling with a liquid or liquefiable
core, the solid walls of the rolled article are steadily pressed together, there
still remains enough of the liquid metal of the core between the walls of the
body passing through the rolls to render adhesion of the metal walls impossible.
Articles rolled by the method just described with reference to the second
example hereinabove given, are subsequently separated into lengths after their
removal from the rolls, and, upon the core being expelled, are drawn or finished
on a mandrel as the case may be.
(3.) Where the middle portion of the core of the initial body is formed of
hard metal, such as ingot-iron or steel, enclosed in a casing of readily fusible
metal as is supposed to be the case in Figs. 13, 15 and 18-a treble-roll mill
is used, whereof the operative surfaces of the rolls are hollowed out in the manner
shown in Figs. 1 and 2.
Figs. 14, 16, 17 and 19 are illustrations of the configuration which a body
formed in the manner described above will assume in the course of the rolling
process; opposite points of such body being elongated and thinned in the lower

page_text: and upper passes alternately, while the solid central body is drawn out at the
same time. The sectional outline follows somewhat the contour of the human
eye. When the desired reduction in the sectional area of the blank has been
effected, one of the rolls-say the upper one-is raised, to relieve the upper part
of the blank from pressure; while the lower pass still maintains a moderate
pressure until the inner solid body is liberated from the "grip" which compresses
it on the two sides which are not acted upon by the rolls forming the lower pass.
In this case, as in previous instances, the article which is being rolled receives
from the operative surfaces of the rolls of the treble-roll mill which extend at an
angle to the axial line of such rolls a slow rotary motion about its own axis.
The finishing process is here the same as in the preceding examples. The
hard ingot-iron or steel core, after being removed from the blank, is further
rolled or drawn out into bands, flat, round or square bars, or wire, in the usual
manner.
(4.) Where the initial body or blank presents a flat shape from the first, see
the dotted outlines in Fig. 20 two treble-roll mills are employed in rolling, as
illustrated in Figs. 21, 22, and 23, the passes of which are formed as shown.
The outlines shown in Fig. 20 serve to illustrate the gradual reduction of the
sectional area of the initial body as it is operated on by the rolls. In this case
pressure is brought to bear upon the top and bottom rolls, not in the downward
and upward directions only, but also from the sides; such pressure being pro-
duced by the aid of compressed air, by a suitable fluid, or by lever or other
mechanism adapted to transmit the top and bottom pressure to the sides of the
adjustable rolls. It may be further mentioned in this connection that lateral
pressure may be exercised also in the manner just described in the treble-roll
mills represented in Figs. 1, 2, 4, 4, 5 and 6; the central roll being permanently
or non-adjustably supported in its bearings. By such means uniform pressure
is exercised upon the blank in the upper pass bb and in the lower pass cc, until
it acquires the requisite shape, while room for lateral enlargement is left in the
side portions above and below.. Thus, the section of the blank is reduced in a
continuous manner until the desired outline is reached; while a further simul-
taneous result is that the material situated on the sides of the core is drawn down
to the thickness of wall which the finished article is required to present in a
similar manner to the main portions of material whch extend over the flat sides
of the core, the width of the core itself undergoing no appreciable variation
although it becomes reduced to the substance of a mere line.
In all other respects the rolling process is as previously described.
In opening out the flattened hollow bodies, the usual mandrel or drift is
employed, after the flat article has been divided into lengths or sections; or the
hollow bodies thus opened out may be rolled or drawn to the desired final shape
on a suitable mandrel.
The process covered by the 1st Claim of the Patent No. 21,716 of 1894 and the
process hereinabove described may be modified, moreover, by drawing out the
endless annular body, with or without a core, to the desired final shape imme-
diately after rolling, i.e., before cutting it up into sections.
Thus, in drawing the rolled body, its "endless" shape is retained; the great
advantage of this method over that which consists in drawing the goods after
rolling and dividing, so that each piece presents two ends, being, that the
necessity for repeatedly subjecting the goods to the action of the draw-plate
or plates is obviated.
The draw-plates should be made up of two or more parts, capable of being
brought closer together until the desired shape is attained; the parts being moved
towards or from each other, by any suitable means such as a pressure fluid,
weights, springs, screws, lever-mechanism or the like.
Preferably, two draw-plates instead of only one should be employed; and
these should be so arranged that the joints, resulting from their subdivision into
parts, are placed in a "cross-bond" relation to each other; by which means the

page_text: formation of a seam will be effectually avoided. The aperture in the draw-plate
may be circular, semi-circular, oval, triangular, square, polygonal or of any
other shape such as serrated or ribbed.
As soon as the endless body has been drawn to its final shape it is cut through
and if it contain a core, this is removed. A plastic core may be forced, drawn
or washed out, and one that will liquefy under the action of heat may be simply
allowed to run out of the hollow article; or it may be got rid of by pressure
or suction.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim:
―:
1. The herein described process of manufacturing endless rolled hollow bodies
of any desired form; same consisting in furnishing the endless annular body
with a removeable core of a plastic or liquefiable material, the said core serving
as a mandrel for the annular body during the rolling process, substantially as
set forth.
2. The herein described process of manufacturing endless rolled and drawn
articles; same consisting in drawing the said endless annular body, with or with-
out a core, after rolling, but before being cut into sections or lengths, to the
desired final shape; substantially as herein described and whereby the repeated
operations by the draw-plate or plates are avoided.
Toad : 9.1
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