An Improved Process or Means for Manufacturing Tubes without Seam out of Cold Wrought Iron and Steel or other Metals, said Tubes being Specially Applicable for Gun Barrels, Hollow Transmission Rollers, Fire Tubes of Steam Boilers, and the like.
Year: 1887

page_text: Date of Application, 9th Apr., 1887.
Specification Accepted, 15th July, 1887.
An Improved Process or Means for Manufacturing Tubes without
Seam out of Cold Wrought Iron and Steel or other Metals, said
Tubes being Specially Applicable for Gun Barrels, Hollow
Transmission Rollers, Fire Tubes of Steam Boilers, and the like.
We, WILHELM VON FLOTOW, Major and Director, (Manager) of the Konigliche
Gewehr und Munitionsfabrik, of Werdengasse, Danzig, Germany, and HERMANN
LEIDIG, Engineer of the Konigliche Gewehr und Munitionsfabric, of 81 Breitgasse,
Danzig, Germany 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 novelty of this Invention for manufacturing seamless tubes from wrought iron
and steel consists in the employment of a short hollow piece of steel or iron of round
section, or which has been made cylindrical either by boring or by the processes of
casting, welding, or rolling, (see Figure 1 of the annexed Drawings).
This piece after it has been made smooth on the outer and inner surfaces by turning
and boring, or by hammering and surfacing, is forged at one end, as shown at
Figure 2, conical or also cylindrical until it is of a diameter somewhat smaller than
that of the tube to be produced, it is then arranged upon a cold mandrel or chuck in a
cold condition, and afterwards fixed in the crosshead of the screw gear so that it is by
means of a matrix brought by degrees to the proper diameter with relation to the size
of the drift.
.
Figures 3 and 4 show part of the head of a cold-metal-drawing bench. These
Figures show the matrix or die m through which is stuck the tube (which is about
to be drawn) with the forged fore part e. In the inside of the tuber is seen the or

page_text: drift d. The back end of said drift is fixed in the adjusting screw g which is carried
in the standard or support b, and the other end has an enlarged portion v which is
passed into the inner diameter of the tube to be drawn.
When the fore part of the tube is gripped by the devisable crosshead s, the two
screw spindles o and p (see Figure 4) are revolved and these by means of the cross-
heads draw the piece of tube through the matrix or die m and over the fixed
drift d.
When the machine is sufficiently strong in construction a matrix or die of such a
diameter can be used so that at one drawing tubes may be diminished in their
thickness 01 and 1 m/m and over.
In drawing tubes in brass and copper it does not matter in which direction the
material is stretched and contrary to the present process of manufacturing steel and
wrought iron tubes from plates said plates being made somewhat of the required shape
by rolling first near the edge and then from the cavity or bowl originated by the first
operation drawn out and perfected by degrees it is in this process necessary to
consider the direction of the fibre of the material which is preserved and the material
worked out to the smallest part in the direction of the fibres during the rolling out of
the materials.
On the other hand it follows that by not drawing out over a drift, which together
with the drawn out cup or bason shaped piece is at the same time moved through the
matrix; but over a fixed drift, against which the material presses or squeezes itself in
the operation of drawing, there is a working out and rolling together of the small
particles not only on the outer wall of the tube but also on the inner wall.
The drift d (see Figure 3) can be so adjusted with respect to its length by means of
the screw that the enlarged portion and the narrow portion or neck of the
matrix m come together and thus there follows a stretching of the material on the
outside and inside of the tube at the same time.
In drawing in several operations when a short cylindrical piece of metal is to be
drawn out into a long and thin tube, the drift next applied is of a somewhat smaller
diameter, while the preceding drift over which the tube was forcibly drawn through
the machine, can only again be employed with the expenditure of proportionally
greater power. In such a case the size of the hole in the piece of metal to be operated
upon is larger than after it has undergone the process of manufacture into a tube.
This new process is applied with advantage to such steel and wrought iron as is
formed of a number of pieces manufactured together. The superiority consists in the
matrix and drift being very kind to the metal under operation so that the tubes are
not split by the process.
In the application of the invention to the manufacture of transmission rollers there
is an important saving in material and workmanship as also in the production of fire
tubes for steam boilers.
Gun barrels and conical tubes generally will be made on a mandrel, conical in
shape, the tube being drawn in gradations as indicated by the numbers 1, 2, 3 and so
on in Figure 5. With the first matrix the tube will be drawn the whole of its length,
with the the second matrix it is forced to 2 and only to the spot marked 2 with the
third to the spot marked 3 and so on.
The little graduations which originate through the varying diameter of the matrix
are later on easily equalized by the inclination and smoothing of the tubes.
As a modification of the tube end represented by e another form may be employed
as shown at B in Figure 6. In this case no hole is made through the whole length of
the piece of metal to be operated upon but one part is made to take the form of a peg
or projection, or a separate bolt with a head may be used as in Figure 7. But we do
not limit ourselves to the particular shapes illustrated which it is obvious are only of
secondary importance.

page_text: Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
1. The method of drawing tubes, hollow transmission rollers and boiler tubes in
wrought iron and steel from a short piece of the hollowed material which is drawn
through a die or matrix and over a fixed opening out tool or drift, by which means
the said piece is stretched and worked out as hereinbefore described.
2. The manufacture of gun barrels and other like conical tubes out of wrought iron
and steel whereby the tube is drawn by graduations through matrices or dies of
various diameters and a little only at a time, said tubes being reduced to a
smooth condition by scouring or otherwise surfacing as hereinbefore described.
Dated this Oth 1:1 1007
perfectly