Improvements in the Manufacture of Seamless Compound Ingots or Bars and Wire made therefrom.
Year: 1891

page_text: Date of Application, 29th Sept., 1891-Accepted, 7th Nov., 1891
COMPLETE STEULFICATION.
Improvements in the Manufacture of Seamless Compound Ingots or
Bars and Wire made therefrom.
I LEVI LYMAN BURDON of No. 924 Broad Street, Providence in the State of
Rhode Island United States of America, Mechanic 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 :-
In the production of seamless compound ingots, particularly when reduced to
wire, I have sometimes found that the amount of solder, used for uniting the gold
shell or outer portion to the inner or core portion of baser metal, bears too great
a proportion or percentage of the whole ingot, even though the solder itself is rolled
down as thin as practicable and inserted between the surfaces of the shell and core
in the form of a continuous sheet before fusing.
The object of my present invention is to produce ingots (and wire) of the class
just referred to, in which the amount of solder employed is reduced to a minimum.
To that end my invention consists in applying the solder to the interior surface of
the gold shell. This is done by fusing a film of suitable solder over the entire
surface of one side of a comparatively thick disk or flat piece of metal, as gold, or
even plated stock, after which the solder-covered gold or stock is rolled down until
the desired thickness of metal is attained; the piece of stock is then gradually
transformed into a seamless tubular form, at the same time elongating it and
consequently reducing the diameter of the tube. When the tube has reached the
proper size its interior surface will be found to be completely covered with a very
thin layer or film of solder, much thinner in fact than could be practically applied
otherwise.
In making compound ingots I take a piece of base-metal of suitable form and size
and prepare its surface with borax ; I next insert it into the solder-lined seamless
shell or tube of gold, the two snugly fitting together, after which the whole is
subjected to a suitable degree of heat which fuses the solder and unites the shell
to the core. The ingot is then adapted to be reduced to seamless compound wire.
In some of my former Specifications are described ways of making compound
wire, as for example in those under English Patents Numbered 6081, and 6082, of
April 24th, 1888.
In the appended drawing,
Fig. 1 is a sectional view taken longitudinally through the centre of my improved
compound ingot;
Fig. 2 is a similar view of an ingot, one end of the ingot being larger than the
other, or tapering ;
Fig. 3 is a side view of the base-metal core portion;
Fig. 4 is a longitudinal sectional view of the seamless solder-lined gold shell or
tube adapted to be soldered to the core ;
Fig. 5 is a similar sectional view of a solder-lined compound shell, that is a gold-
plated tube having a thin layer of solder covering its inner surface;
Fig. 6 is a transverse sectional view of an ingot having a solid core united to the
solder-lined gold shell;
Fig. 7 is a similar view of an ingot having a hollow core;
Fig. 8 is a cross-sectional view of an ingot having a plated solder-lined shell
united to a base-metal core, and
Fig. 9 represents, in partial section, a piece of wire reduced from my improved
ingot.
In the drawings a designates my improved ingot, or wire, as a whole. The ends 6ª
of the core portion of the ingot may be extended, to facilitate the entrance

page_text: of the ingot between reducing rolls or other mechanism used for transforming ingots
to wire.
The surface of the ingot consists of a seamless shell c of alloyed gold soldered to
the core other metals, however, may be substituted for the gold. In producing
the shell the metal is cast or rolled out in the form of a flat sheet having
considerable thickness, after which one of its surfaces is covered with solder; after
fusing the solder over said surface the metal is next greatly reduced in thickness
thereby at the same time relatively reducing the thickness of the coating of solder.
Now a disk or blank cut therefrom may by the use of suitably operating plungers
and dies be drawn to a tube-form, having a tapering, cylindrical or other shape
cross-sectionally; the inner surface being lined with the thin unbroken film of
solders.
The thickness of solder as represented in the drawings is greatly
exaggerated. So also are the walls of the shell itself made somewhat thicker than
would be used in ordinary practice.
The core portion b, which is made of base or plating metal usually, is turned off
so as to just fit the interior of the outer shell c. It may be tapering, as shown in
Fig. 2 and having the ends 62 extending beyond the shell, as before stated. The
shell may be prolonged or extended as indicated by dotted lines at m, Fig. 1, for
the purpose of forming a chamber or reservoir m'. This chamber is for holding
loose solder.
In uniting or soldering the shell to the corc, one or both of the adjacent surfaces
are suitably prepared and covered say with borax to promote the fusion of the
sulder. The core bis next inserted into the tube, a pin p fitted into the core
serving to prevent the shell from dropping off during the soldering operation, the
whole being next subjected to the action of heat exceeding the fusing-point of the
solder. I would state that in case additional solder may be required from any
cause it can be supplied from the chamber in¹.
The parts may be suspended vertically in a suitable furnace and revolved while
being acted upon by the heat in order to receive a more uniform treatment.
This manner of producing seamless compound ingots by the employment of solder-
Ined hells e results in a much better grade or quality of seamless compound wire,
because by it the quantity of solder used may be reduced to a minimum. A serious
objection to the use of some forms of seamless soldered wire as heretofore made,
wherein the solder uniting the gold and core has considerable thickness, is that in
insking say rings, chain-links, and other articles therefrom which are to be united
at the abutting ends it is found, particularly when the gold covering is quite thin,
upon subjecting the joint to the influence of heat sufficient to fuse the additional
solder placed on the joint as common in uniting such annular articles, that the
solder from the interior of the wire adjacent to the cut portion melts and runs out,
thereby producing a slight cavity between the core band seamless gold shell c, this
cavity in the process of soldering the joint is not uniformly refilled by the joint-
solder so that the wire at the joint is irregular, sometimes being a little smaller
than the normal diameter and sometimes a little larger. In order to overcome
this defect the workman must possess considerable skill to so finish the joint
that it will not be readily detected. In case the abutting ends of the gold shell
become expanded such expanded portion must be removed, thereby making the
gold very thin if not entirely cutting through it; in the latter event the article
cannot be used. Sometimes the shell of gold at the ends of the ring or link, if
quite thin, become crimped or wrinkled when subjected to heat during the process
of soldering the joint, thereby obviously rendering the article unsuitable for use.
By the employment of wire having the seamless gold shell united to the core
according to iny present improvement the thickness of the solder film is reduced to
a m'nimum, therefore the objections before referred to as inherent in soldered
seamless wire are essentially overcome, and at the same time the percentage of
imperfect work due to the causes above named is practically of no moment.
in lieu of the solder-lined gold shell e shown in Figs. 1, 2, 4, 6, and 7, the shell
may be produced from flat plated or compound stock by fusing solder over the

page_text: reverse or exposed base-metal surface and then by suitable rolls and dies trans-
forming the piece of stock to a tubular form, as shown in Fig. 5, wherein the shell c
has a seamless exterior portion g of gold united or welded to an inner base-metal
portion 6, the latter having its inner surface covered with a minute film of
solder s.
This solder-lined compound shell may be soldered to a solid base-metal
core b, substantially as shown by Fig. 8, or the core may be annular as shown in
Fig. 7.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improvement in the manufacture of seamless compound ingots and wire,
the same consisting in fusing a film of solder over the surface of one side of a flat
piece of fine metal, or plated stock, then by suitable rolls and dies transforming the
blank to a seamless tube having the solder on the inside, then inserting a suitably
prepared core of base metal into the said tube, then subjecting the whole to a
suitable temperature to re-fuse the solder lining of the shell, thereby uniting the
shell and core, and then reducing the ingot to wire.
2. The improved process for making seamless plated stock, the same consisting
in forming a plate, one side of which is covered with solder, into a seamless
tube, inserting a core into the tube and uniting the two together by melting the
solder.
Dated the 10th day of Santamber 1801
LEVI LYMAN BURDON,
Inventor.