An Improved Method of Preparing Metal and Metal Articles for Stamping and Drawing in Dies.
Year: 1896

page_text: Date of Application, 16th Jan., 1896-Accepted, 28th Mar., 1896
[Communicated from abroad by RUSSELL AND ERWIN MANUFACTURING CO., of
New Britain, Connecticut, United States of America.]
An Improved Method of Preparing Metal and Metal Articles for
Stamping and Drawing in Dies.
1, LEONARD DOIG, of Russell & Erwin Manufacturing Company, of Brook's
Wharf, Upper Thames Street, in the City of London, 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 :-
This invention relates to improvements in the method of preparing metal and
metal articles for stamping or drawing in dies, and the main object of the said
improvements is to provide the metal with a coating during the annealing process
which will prevent oxidation of the metal and also facilitate the operation of
stamping or drawing the metal in dies.
In the accompanying drawing
Figure is a vertical longitudinal section of a furnace suitable for use in
carrying out my improved process.
Figure 2 is a transverse section of the same.
Figure 3 is a central longitudinal section of a vessel suitable for holding the
metal to be treated, the middle portion of the vessel being broken out.
Figure 4 represents a sheet metal disc such as may be treated by my process,
and
Figure 5 is a sectional view of a cup shaped object formed from said disc.
A designates the heating chamber which may be of any desired length and is
preferably provided with a rising and falling door B at the front extending for
substantially the whole length of the furnace. The furnace shown is arranged for
consuming oil, the hydrocarbon burners being set in the port holes 9. The smoke
flue D is under the heating chamber and may communicate with a chimney by any
suitable exit as at 10. C designates a vessel which I prefer to make in the form
of a long cylinder having a suitable removable cap or cover at one end. This
cover may be secured to the vessel by means of screw threads as at 7 Figure 3
and may be advantageously provided with some means for example the
projections 8, 8, for the application of a wrench or lever to facilitate screwing
and unscrewing it. I prefer to provide the cover with a small pipe 11 for use as
hereinafter described and to let said pipe project through an opening 12 at one end
of the heating chamber.
Any form of sheet metal or blanks, or articles that have been partly formed of
sheet metal and which are to be again stamped, struck up, or drawn by means of
dies, as for example, discs as shown in Figure 4, or cup shaped blanks, or partly
formed articles as shown in Figure 5, the surfaces of which are substantially free
from scale are thoroughly coated or smeared with an oleaginous substance as oil or
grease and then placed in a suitable vessel such as C, which is closed except at
some small vent such as the pipe 11. These vessels which may be nearly as long
as the heating chamber can be conveniently rolled into the said chamber through
the opening at the front when the door is raised. In Figure 2 the broken circles
indicate three such vessels lying side by side in the heating chamber. They are
here subjected to heat to make them and their contents red hot for as long a time
as may be desired, as in ordinary annealing processes. The oil on the articles or

page_text: metal in the vessels C is in part converted into gas under the influence of the heat
and as the gas expands it flows out through the vent, or if air is commingled with
gas in the vessel, a flow of air and gas passes out through said vent and thereby
an excessive pressure in the vessel is avoided. The flow. through the vent
continues as long as the heat increases. The oil when thus heated leaves a smooth
carbonaceous coating on the articles or metal resembling lamp black. After being
heated for the requisite time for annealing the metal, the vessels or cylinders are
removed and cooled. In the operation above described the metal is annealed
simultaneously with the production thereon of a coating which protects the surface
from oxidation and which also acts as a lubricant in the subsequent operation of
stamping or drawing. As soon as each vessel or cylinder is removed I connect it
with a gas supply, for instance any pipe leading to the ordinary gas main, by
means of a rubber tube which can he slipped on the small pipe 11, whereby as the
gas within the vessel shrinks in cooling, gas from the gas main will flow in and thus
exclude the free ingress of air. I sometimes provide the small pipe 11 with a
stop cock which is closed during the removal of the cylinder from the heating
chamber, so that what little shrinkage of gas there may be while transferring the
vessels from the heating chamber to their place of cooling will not draw in as
much air as would be the case if the stop cock were not employed. But even if
air docs enter the vessel, as it generally will to some extent, the carbonaceous
coating, previously formed, protects the metal and avoids the oxidizing effect of
the air.
In subjecting the metal to further operation in dies as for example, drawing the
disc Figure 4, into the cup like blank Figure 5, the carbonaceous coating instead
of being a detriment, serves as a lubricant to protect the dies and to facilitate the
operation without causing any injurious effects whatever on the metal. Oil may
be used in connection with the carbonaceous coating when subjecting the metal to
the stamping or drawing operation.
The metal to be heated may be sineared with oil or grease (for the express
purpose of being coated with oil) as is frequently the case when cutting it into
thape, or when partially forming it up, or other working, and this coating of oil if
left on the metal will generally be found sufficient for the purpose of my process.
If it is desired to again anneal for further drawing in dies a piece of work that
has been operated upon it can be again treated as hereinabove described and so on
as many times as may be desired. Whatever means may be taken to exclude the
air from the vessel when the latter is cooling, or whether or not any means for
excluding the air is made use of, the beneficial effect of the carbonaceous coating in
stamping and drawing the metal after annealing is the same, and such coating is
always formed prior to cooling the vessel.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
The method of preparing metal or a metal article for stamping or drawing in
dies which method consists in coating the metal or metal article with an oleaginous
substance, then heating it in an enclosing vessel which in combination with the
expulsive action of the gas given off by the coating material (which gas is allowed
to escape from the enclosing vessel) substantially excludes the flame and com-
bustion products of the heating medium, thereby simultaneously annealing the
metal and producing thereon a smooth protecting and lubricating carbonaceous
coating, substantially as described.
3000
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C.; Agents for the Applicant.