Process for the Preparation of the " Blanks" necessary for Rolling out Hollow Metal Bodies.
Year: 1898

page_text: Date of Application, 3rd Dec., 1898-Accepted, 22nd July, 1899
COMPLETE SPECIFICATION.
A Process for the Preparation of the " Blanks" necessary for Rolling
out Hollow Metal Bodies.
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:-
66
This invention relates to the production of hollow metal bodies-initial blocks,
rough castings or blanks "of annular or other desired cross section with the
aid of a process such as that described in the Patent No. 21716 of 1894 whereby
the said metal bodies are rolled out-while retaining their seamless character-
and afterwards cut into lengths, to form individual seamless metal pipes or
tubes; or, a number of lengths of varying diameters may be produced and
enclosed the one within the other; or seamless hollow bodies may be produced
having their peripheries solid throughout; or, lastly, compound bodies of any
desired length may be produced, each made up of two or more different metals.
Where it is desired to obtain a single seamless metal tube or pipe, the initial
rough metal body or "blank" may assume the shape of a ring in cross section,
same having a closed-in" or solid periphery of annular or nearly annular
cross section; its outer case or shell being formed of any desirable metal, such
as ingot iron, steel, copper or the like; while within such shell, and concentric
therewith, is a core-piece, consisting either of some material-such as clay, loam
moulding sand, asbestos, &c.-which during the process of rolling will crumble
or become disintegrated and thereby capable of subsequent displacement, leaving
a hollow body; or of some metal, or other material, which, at the temperature the
shell must be brought to for rolling, will either remain plastic (mouldable)-as
litharge or aluminium for example-and may be expelled from the outer shell
by fusion when the rolling process is completed; or which will become liquid,
as for example, in the case of antimony, zinc, lead or tin.
**
In Fig. 1 of the accompanying drawings, I have illustrated in cross section
such body, same having a core a of clay, loam moulding sand, asbestos or the
like and a shell or case of any desired metal; while in Fig. 2 I have shown,
in cross section, an initial body with a neucleus a of litharge, aluminium or
any other metal whose point of fusion is below that of the case or shell b.
In carrying out the invention in the form shown in Fig. 2, i.e., with a core a
of a material possessing a lower fusing point than the metal of the shell b, it is
necessary to separate the core from the shell by an intermediate layer c of clay,
cardboard, asbestos or any other neutral or non-conducting material, so as to
prevent the metal of the shell and the material of the core from slagging (running
into one mass) during the operation-hereinafter described in detail of casting
the initial block.
When the wall of the hollow body is required to be reduced to a minimum in
rolling, the core itself, as illustrated in Fig. 2, may receive the shape of a shell
or tube, or in other words be hollow; in which case its hollow interior may be

page_text: occupied by an inserted piece d of metal identical with or similar to the outer
shell b. When the rolling of the blank is, completed, this insertion d is removed
from the finished article, and may be drawn or rolled into wire, hoop- or angle-
iron, or into a body of any other desired section; or it may be melted down again.
Figs. 3 to 8 illustrate in cross section further modifications of the construc-
tion shown in Fig. 2. Similar letters of reference indicate similar parts to
those pertaining to Fig. 2 and render these several constructions sufficiently
explicit without a fuller description.
In the form illustrated in Fig. 1, the core a may-similarly to the cores of
the modifications shown in Figs. 2 to 8-consist of metal more readily fusible
than that of the shell b; but a layer of neutral or non-conducting material should
be interposed between the core and the shell, as already described.
Initial bodies of any other cross section may be employed, without departing
from the spirit of this invention. The employment of the different cross sections
are for the purpose of facilitating the extraction of the core or cores d after the
blank has been rolled.
Initial bodies or blanks whereof the cross section is such as shown in Figs. 1
to 7-after having been rolled, and after the cores have been removed by fusion,
suction or pressure, or have been knocked out take the shape of simple elongated
hollow bodies or tubes; whereas a blank of the section represented in Fig. 8
results in a series of tubes enclosed the one within the other. Should the core
or cores instead of being removed from the rolled article, be allowed to cool
down, the resulting product will be a body consisting of several combined metals―
such, for example, as copper and ingot-iron, steel and ingot-iron, steel and copper;
steel, ingot-iron and copper, &c., &c.,--whereof the respective sections are arranged
either concentrically with, or symmetrically to, each other. The body thus ob-
tained may then be again heated, but to a lower temperature than before, and
passed through a set of finishing rolls.
Where the blanks to be operated upon, instead of being a ring with an un-
broken core, is a ring with a core having interstices or breaks, with a core which
is divided into a number of bodies (or lengths) with a filling of suitable material
inserted therein, as illustrated in Fig. 9 or in Fig. 10, the final product will be a body
which by cutting it in certain points may be divided into a corresponding number
of individual seamless hollow articles, each with a bottom wall at one or both
ends. The bodies thus obtained may subsequently be finished in the shape of,
say, carbonic acid receivers containers for high pressure gases, projectile shells
and the like. The blank, as shown in Fig. 9 has a core composed of hollow
balls wherein is a filling a of clay, loam, moulding sand or other suitable
material which, during the process of rolling will crumble so that it can be
readily extracted by knocking, tapping or other means through a hole in the
shell b. Or when the filling a is a metal, it may be removed from the shell b
by fusion. Instead of perforating the shell 6 it may be divided into halves,
the filling a being thereupon scraped out.
In the one case a seamless hollow body having only one small aperture is
obtained, which body may be applied to very different purposes such as con-
tainers for high pressure gases, explosives, etc., as previously indicated-than
would be practicable in the other case wherein two tray-shaped seamless half-
shells are obtained and which may be applied to any required purpose to which
such half-shells may be found suitable. It will be understood that the form of
the balls will be altered after the blank has been rolled and that they will
become elongated or vary in shape according to the form of the rolls employed.
The blank shown in Fig. 10 is similar to that just described with reference
to Fig. 9, the bodies being in the form of hollow closed cylinders as dis-
tinguished from that of hollow balls.
The casting of the initial body or blank may be performed by either of two
methods.
Assuming, by way of example, that the object is to produce a blank of the

page_text: section shown in Fig. 8; in which case the casting operation is performed in
the manner illustrated in Figs. 11 and 12, viz:-A base plate, block or pedestal e
is provided whereof the upper side is formed with a cavity e; a central per-
foration or recess being formed therein for the reception of the central solid core d
of the initial blank. Concentrically with this recess or perforation, are a
number of annular recesses which may be produced by turning, or otherwise,
for the reception of the outer cores a which are disposed around the said central
core d. The diameter of the cavity e is approximately equal to that of the
blank which it is desired to cast.
Now, in the first place, the core d is placed in the central recess or perforation,
the several casings 6 (previously obtained by any known process of founding,
rolling, stamping or pressing) being then placed the one within the other around
the said core d, in such a manner that their lower ends rest upon the projecting
surfaces between the annular recesses in the cavity e' as illustrated in Fig. 11.
The material whereof the cores other than the central core d are to be formed
is then poured into the spaces between the several casings b and central core d.
Such material occupies the lower annular recesses e² in the pedestal e, but is
not, however, allowed to rise quite to the full height of the casings b. A pillar
or rod of a section such as represented in Fig. 8 will thus result, whereof the
cores, at the upper end, present a number of annular concentric recesses, with
a central aperture, and, at the lower end, a number of corresponding annular
concentric projections as also the projecting central solid core d. The upper
end of this rod or pillar might thus be termed the negative end, and the lower,
the positive end.
Two such rods are next bent each into a semi-circle, and the positive end of one
rod joined to the opposing negative end of the other rod, or a single rod may be
bent until its extremities meet, as at f in Fig. 13; so that, in the former case,
an annular body composed of two parts, and in the latter, an annular body com-
posed of one part divided with only one point of junction, is obtained.
as
This annular body is now placed in a bi-part "chill" of any known construction,
such, for example, as that shown in Figs. 14, 15 and 16, which represent, respec-
tively, a partial section and side elevation, a section taken on the line - in
Fig. 14, and a plan; the said annular body being so centred in the "chill"
to be surrounded by a uniform space. This centring is effected by means of
screws (Fig. 15) whereof the inner ends are furnished with pins or studs h
for engaging with the exterior surface of the annular body. These pins or studs
are of the same material as that of the outer casing b which now remains to be
cast.
When the desired metal is eventually cast into the space between the exterior
surface of the annular body and the inner wall of the "chill," an initial annular
body or blank having a seamless and jointless outer periphery, such as illustrated
in Fig. 13 will result; which may be finished either in accordance with the
process for rolling endless or seamless articles," described in Patent No. 21716
of 1894 or in an universal "-roll, or an angle-roll mill.
44
"
The casing b, which is cast into the "chill" in the last instance, in this case
forms one piece with the outer shell 6 of the rod, as shown in Fig. 11.
The other method whereby the blank may be prepared is as follows:-
The core d is cast in the shape of a ring-ingot-iron, steel or any other suitable
metal or material being used for the purpose or a round ingot iron or steel bar,
produced in the well known manner the heat employed in producing it being
made use of if necessary in the subsequent stages of the operation-is bent into
the shape of a ring the butt-ends of the round bar, which are thus brought
close to each other, being either left open or firmly connected in any suitable
manner.
Around such bar ring, it being placed in a "chill" of the shape represented in
Figs. 14 to 16 and of adequate dimensions, readily fusible metal is cast to form
the outer case or shell; and the body thus obtained, after being allowed to cool

page_text: down, is further encased in a sheet or layer c of clay, cardboard, asbestos.or the
like.
Having arrived at the present stage the article under operation, is again placed
in a "chill
of slightly larger size and the first casing b cast around it, from
which, by subsequent rolling, a thin tube or pipe or a narrow hollow body may be
formed; and so on; until a blank of the requisite size is obtained, which, in its
turn, may be rolled out as before.
It will be seen that in carrying out the first method of preparing the initial
body or blank no non-conducting intermediate layers such as care required,
since, in accordance with that method the bodies, which will melt but with com-
parative difficulty, exist before the readily fusible bodies; whereas, in the case
of the second method, according to which metal not so readily fusible is cast
around bodies capable of melting more readily, the omission of such intermediate
layers is not advisable, if it be desired to prevent the materials which form the
several casings, from running together into one mass (or slagging).
When the annular body or blank has been finished it is cut into pre-determined
lengths. In the case of a blank produced by the casting process first described,
it should be cut at the point f (Fig. 13) indicated by a mark which shows through
the outer casing b; while in the case of a blank produced by the second method,
the point at which such blank is to be cut through may be determined at will.
Owing to the "endless" (closed in) form of the blank, the core-material is
displaced by the compressed casings of the hollow bodies in a direction opposite
to the motion of the rolls; by such means receiving a compulsory circular motion,
that is to say, the core-material is forced from the part where the blank becomes
interposed between the rolls to the part (on the opposite side of the rolls) where
such blank leaves the said rolls. Accordingly, the walls of the hollow bodies of
the blank in process of being flattened by the rolls are again forced out upon
leaving the rolls, by the core-material which is being forced through the bodies,
and so on the repeated operation of rolling subsequently bringing the bodies
to completion. As will be understood, the extent of the resumption of shape of
the bodies will depend upon the degree of elongation as the result of the action of
the rolls, and, similarly, the increase in the volume of the hollow bodies.
Where round or nearly round articles are to be rolled out, the section of the
core becomes reduced in the same proportion as the thickness of the casings or
shells; and in the case of a liquid core, the same effect of the motion of the core
molecules will be observable as in the case just described.
Blanks, whereof the outer casings are formed of brass, and whose cores are a
readily fusible metal-such, for example, as lead, tin or antimony-may be rolled
cold, after having been previously annealed.
The relation between the thickness of the cores a and d (i.e. both the hollow
and solid cores), and the thickness of the shells or casings b constituting the
walls of the hollow bodies to be produced, may vary in many ways according to
the desired shape of the finished article. In point of fact this relation of thick-
nesses, whatever it is, remains constant from the beginning of operations on
the initial blank until the rolled article is finished, since-as experiment has
shown the diminution in the thickness of the material during the rolling pro-
cess is always precisely uniform throughout the sectional area of the blank.
All that is necessary is to see that the relation of thicknesses of the core and
the casing, respectively, is not reduced to unduly narrow limits, as otherwise
the continued rolling may cause the walls of the hollow bodies to come into con-
tact with each other, or the space between them to be reduced to an invisible
degree.
The several casings 6 need not consist of the same metal, but may each be
formed of a different metal. For example, the first may be of copper, the second
of steel, the third of ingot-iron, &c., or each casing itself may consist of two or
more metals.
As core-material, oxygenized earths, salts and oxides, mixed with coal-dust,

page_text: and gas-generating substances generally, may be employed, if desired; in which
case there will be evolved in the interior of the rolled bodies according to the
proportion of oxygen contained in the core-material selected-high-pressure gases
which will assist the above mentioned forcing out of the bodies.
For the central core, a glass block, or a block (or body) of suitable slag, may
be adopted; such a core being considered as equivalent to any solid core or piece
of solid metal.
Where earths, salts, oxides, glass or slag are employed in the formation of
the core, such core is bored or knocked out after it has effected its purpose by
means of suitable tools such as spiral drills.
After cutting open the annular body and removing the cores the hollow bodies
obtained-such as tubes, for example-are worked into the final shape desired
«
by being rolled over a mandrel or by being drawn.
The removed core-material may be utilised in subsequent operations.
Also, where the object is to produce flat hollow bodies, the core may be formed
of a strip of wood leather, asbestos, clay or any other suitable substance, or
of a mixture of such substances, or of metal covered with a layer or coating of
such substance or substances. Such cores will either burn to ashes in the process
of rolling, or be pulverised, and may therefore in either case be readily removed
after rolling.
By the means herein described an almost infinite variety of hollow bodies-
such, for example, as so-called double barrels or revolver barrels-also hollow
bodies with ribs, &c., &c., may be produced.
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 method of preparing rough casts or "blanks for
subsequent rolling into hollow bodies or into bodies having a combination of
several different metals, same consisting in forming a bar or rod composed of
one or more suitable materials into a ring, such ring being placed in a mould,
fitted with a casing (such as 6), and the metal for forming the hollow bodies to
be rolled cast around such ring.
2. In the production of bodies by the method characterised under the first
claiming clause, the simultaneous production of a number of hollow bodies;
consisting in encasing or enclosing cylinders, such as b, of various dimensions,
formed of the materials which are eventually to constitute the hollow or compound
bodies, as the case may be, within each other, with intermediate spaces into
which suitable core material a or d as the case may be, is cast; the bar or rod
thus obtained being then bent into the desired form and furnished with a seamless
homogeneous casing of suitable metal formed by casting the same around the
cylinders in a bi-part chill or any other convenient mould.
3. The hereindescribed alternative method of producing a number of hollow
bodies, same consisting in casting in a bi-part chill around a ring-shaped or other
core, such as d, a homogeneous layer, such as a, of a metal having a lower fusing
point than the metal b whereof the hollow bodies are to be formed, such layer
being then enclosed in a layer such as c formed of a neutral or a fire-resisting
material; the body thus obtained being then placed in a bi-part chill of larger size
and a metal, such as 6, fusible with difficulty cast around the same; these
operations being repated until an annular initial body (or blank) of the desired
sectional area is obtained; from which body, after it has been rolled out, the
cores are removed in any well-known manner, by simply melting such cores, or,
if necessary, by first melting them and then drawing them out or expelling them
by suction, or by pressure.
4. The hereindescribed means for producing hollow bodies, same consisting
in filling a series of hollow bodies, such as b, with either a fairly fusible or a
readily fusible core such as a and, after the initial body or blank has been

page_text: finished by the rolls and freed from the core (as described), converting the same
into closed seamless hollow bodies by dividing them centrally into a number of
seamless chambers, each provided with a base.
5. The hereindescribed further means for producing hollow bodies, same con-
sisting in the employment of a core comprising a strip of well-known neutral or
non-conducting substance or substances, such as earth, sand, ashes, wood, leather,
asbestos, clay or the like, or a strip of metal covered or coated with such sub-
stance or substances, which become either carbonized or pulverised and are capable
of being readily removed from the hollow body. after rolling.