Improvements in and relating to the Annealing of Wire, Sheet Metal, and other Metal Articles.
Year: 1890

page_text: Date of Application, 6th Sept., 1890
Complete Specification Left, 5th June, 1891-Accepted, 11th July, 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by CARL FRIEDRICH CLAUS, of Suffolk House,
Cannon Street, in the City of London, Chemist, at present residing at
Wiesbaden, in the Empire of Germany.]
Improvements in and relating to the Annealing of Wire, Sheet
Metal, and other Metal Articles.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co. Patent Agents,
45 Southampton Buildings in the County of Middlesex do hereby declare the
nature of this invention to be as follows:--
My invention relates to the annealing of wire, sheet metal, and other metal
articles.
In the manufacture of wire sheet-metal and other metal articles, by hammering
drawing or rolling or similar treatment the metal frequently becomes too hard to
allow of the hammering, drawing or rolling being continued uninterruptedly till
the manufacture is completed, and the metal therefore, requires to be again
softened or annealed before the working of the same can be continued
satisfactorily.
This annealing is effected by heating the wire, sheet metal or other metal
articles to a temperature at which the ductility of the metal required for the further
working of it is restored; and to prevent oxidation, the process of annealing is
generally carried out in closed vessels such as iron cylinders or boxes. Notwith-
standing this precaution, a film of oxide is usually formed on the surface of the
metal, and hitherto it has been necessary to remove this film by pickling the metal
articles in acids before proceeding further with their manufacture.
Now my invention has for its object to provide for the annealing of the said
metal articles and for the reduction to the metallic state of the superficial film of
oxide formed thercon without the necessity for the use of acids or the like so that
I can dispense altogether with the process of pickling.
The main feature of my said invention consists in passing water gas or hydrogen
gas (free from sulphur, or other suitable gas or vapor through the vessels
containing the metal articles after they have been heated, and in bringing these
gases into contact with the said articles in order to effect the cooling thereof
sufficiently to allow of their removal from the annealing vessels. During this
cooling process any oxide which may have formed on the surface of the metal is
reduced to the metallic state. When the film of oxide on the metals is so thick
that the cooling of the metal articles would take place previous to the reduction
the whole of the film of oxide to the metallic state, I moderate the rapidity of the
cooling by employing the gases in a heated condition during part of the operation,
that is to say, the gases are heated to a temperature not less than that at which
hydrogen is capable of reducing the oxide of the metal state; the final cooling of
the hot metal articles is then effected by means of cold or comparatively
cold gas.
In using water gas for the above described process, it is principally the
hydrogen contained in the same which effects the reduction of the oxide to the
metallic state. If the hydrogen contained in the gases leaving one annealing
furnace has not been sufficiently consumed, the said gases are preferably conveyed
into another annealing furnace in order to use up fully the hydrogen which they
contain. The other chief constituent of the water gas, ri. :-carbonic oxide mostly
passes out of the annealing vessels unconsumed, accompanied by the vapours of
water formed by the action of the hydrogen upon the oxide. Such carbonic oxide
I prefer to use as fuel for producing the heat required for the annealing of further

page_text: quantities of the metal articles. It is for this purpose mixed with air and ignited.
The heating of the annealing pots or boxes and their contents, I carry out either
by conducting the ignited mixture of carbonie oxide gas and air into the heating
flies surrounding the annealing vessels, as is now practised with ordinary fuel gases:
or 1 conduct (by preference) the ignited carbonic oxide gas into the interior of the
annealing chambers so that it comes into direct contact with the metal articles in a
manner resembling the heating of materials in a reverberatory furnace. In applying
the latter method it may be found advantageous to remove by condensation the
water from the carbonic oxide before the latter is ignited. The combustion of the
enrbonic oxide is effected in such a numer that none of the oxygen of the admixed
air remains unconsumed but that on the contrary a part of the carbonie oxida
remains unburnt.
After the temperature has been reached which is necessary to anneal the articles,
the current of ignited gas is diverted or shut off from the annealing chamber and
the current of water-gas or hydrogen gas is conducted into the said chamber in order
to reduce the oxide formed on the surface of the said articles again to the metallic
state, and after that to cool the said articles sufficiently for removal from the
annealing vessels. The process is then repeated in the manner above described.
Before the water-gas or hydrogen gas is conducted into the annealing vessels for
the purpose of cooling the articles, it is necessary to displace any atmospheric air
which may be contained therein in order to prevent explosions, I accomplish this
result by passing a portion of the product of combustion of the carbonic oxid.
through the annealing vessels before admitting the above named gases,
1 also adapt the above described method of annealing and of treating wire and
sheets of metal for making the process of drawing and rolling a continuous one.
Dated this 6th day of September 1890,
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to the Annealing of Wire, Sheet-
metal, and other Metal Articles.
1. HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co.. Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 :-
My invention relates to the annealing of wire, sheet-metal and other metal
articles.
In the manufacture of metal articles, such as wire or sheet-metal, by hammering,
drawing, rolling or similar treatment, the metal frequently becomes too hard to
allow of the hammering, drawing or rolling being continued uninterruptedly till the
manufacture is completed, and the metal, therefore, requires to be again softened or
annealed before the working of the same can be continued satisfactorily. This
annealing is effected by heating the wire, sheet-metal or other metal articles to a
high temperature and then allowing the same to cool, whereby the ductility of the
metal required for the further working of it is restored; and to prevent oxidation,
the process of annealing is generally carried on in closed vessels, such as iron
cylinders or boxes. Notwithstanding this precaution, a film of oxide is usually
formed on the surface of the metal, and hitherto it has been necessary to remove
this film by pickling the metal articles in suitable acids before proceeding further
with their manufacture.
Now my invention has for its object to provide for the annealing of the said
metal articles and for the reduction to the metallic state of any superficial film of
oxide that may be formed thereon, without the necessity for the use of acids or the
like, so that I can dispense altogether with the process of pickling.

page_text: I have discovered that, by cooling the heated metal articles by means of water-
gas or hydrogen-gas, I am enabled to very effectually prevent the formation of, or
remove any film of oxide on the surface of the said articles, and also to greatly
expedite the process of annealing, as the cooling of the metal articles is effected
by my process in a much shorter period than is practicable by the ordinary
process.
The main feature of my said invention, therefore, consists in passing water-gas or
hydrogen-gas (free from sulphur) through the vessel or vessels containing the
metal articles, after the latter have been heated to a suitable temperature, and thus
bringing these gases into contact with the heated articles until the same are
sufficiently cooled to allow of their removal from the annealing vessel or vessels.
During this cooling process, any oxide which may have formed on the surface of
the metal is reduced to the metallic state. When the film of oxide on the metals
is so thick that the cooling of the metal articles would take place previous to the
reduction of the whole of the film of oxide to the metallic state, moderate the
rapidity of the cooling by employing, during the first part of the operation, gases
heated to such a temperature as will ensure the reduction of the oxide of the metal;
the final cooling of the hot metal articles is then effected by means of cold or
comparatively cold gas.
In using water-gas for the above described process, it is principally the hydrogen
contained in the same which effects the reduction of the oxide to the metallic state.
If the hydrogen contained in the gases leaving one annealing furnace has not been
sufficiently consumed, the said gases, after having served for cooling the annealed
articles in this furnace, are or may be conveyed into another annealing furnace in
order to use up fully the hydrogen which they contain. The other chief con-
stituent of the water gas, viz.-carbonic oxide, mostly passes out of the annealing
Tessel unconsumed, accompanied by the vapours of water formed by the action of
the hydrogen upon the film of oxide. Such carbonic oxide I prefer to use as fuel
for producing the heat required for the annealing of further quantities of the metal
articles. It is, for this purpose, mixed with air and ignited. In some instances, I
use hydrogen-gas first for cooling metal articles in one or more of the annealing
vessels, and then for heating further quantities of metal articles in other annealing
vessels, the said gas being mixed with a small proportion of air and ignited. The
heating of the annealing pots or boxes and their contents, I carry out either
by conducting the ignited gas into the heating flues surrounding the annealing
vessels, as is now practised with ordinary fuel-gases; or (by preference) I conduct
the ignited gas into the interior of the annealing chamber, so that it comes into
direct contact with the metal articles in a manner resembling the heating of
materials in a reverberatory furnace. In applying the latter method, it may
be found advantageous to remove, by condensation, the water from the carbonic
oxide before the latter is ignited.
By utilizing the gases in the manner above described, I considerably reduce the
cost of the process.
The combustion of the gas is effected in such a manner that none of the oxygen
of the admixed air remains unconsumed, but that, on the contrary, a part of the gas
remains unburnt. I find it advantageous to admit sufficient air to ensure the
burning of about one-fourth of the entire quantity of the gas, and to leave a laige
excess of the gas unconsumed to prevent re-oxidation.
After the temperature has been reached which is necessary to anneal the articles,
the current of ignited gas is diverted or shut off from the annealing chamber, and
the current of water-gas or hydrogen-gas for cooling is conducted into the
said chamber in order to reduce again to the metallic state any oxide that may
be formed on the surface of the said articles, and also to cool the said articles
sufficiently for removal from the annealing chamber. The process is then
repeated in the manner above described.
I find it advantageous, in carrying on my process, to employ a continuous
or endless series of annealing vessels, which are so connected with each other

page_text: and with apparatus for the supply of water-gas or hydrogen-gas, that the gas
can be allowed to pass through one or more of the annealing vessels, after the
articles therein ave been heated to the required temperature, and the gas ean then
be mixed with air, ignited and conducted through or around other vessels of the
series for the purpose of heating the articles therein, and, after these articles are
sufficiently heated and those in the first vessel or vessels have been cooled, the
water-gas or hydrogen-gas for cooling can be shut off from the latter vessels and
almitted to those in which the metal articles have just been heated by the ignited
gases. The annealed articles are then removed from the first vessel or vessels
which are re-charged with other articles to be annealed, and these articles are then
hented by the ignited gases and subsequently cooled as above described. The
process can thus be carried on in a continuous manner. Suitable devices of any
well-known description should be provided for admitting air in regulated quantities
for admixture with the gases, for the purpose above specified.
By my improved process, I provide not only for preventing the formation of, or
removing any film of oxide on the surface of the articles to be annealed, but also for
cooling the articles more expeditiously than by the ordinary process. I am, there-
fore, enabled to effect the annealing of the articles in much less time than is
practicable by the ordinary process,
Before the water-gas or hydrogen-gas is conducted into the annealing vessels for
the purpose of cooling the articles, it is necessary to displace any atmospheric air
which may he contained therein, in order to prevent explosions. I accomplish this
result by passing a portion of the products of combustion of the carbonic oxide
through the annealing vessels before admitting the above named gases.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed as communicated to
ne by my foreign correspondent, I wish it understood that I am aware that it has
been proposed to introduce into the annealing chambers a non-oxidizing gas, such
as the ordinary illuminating gas, for the purpose of preventing oxidation of
the metal articles, and I, therefore, do not claim generally the employment of
a non-oxidizing gas for this purpose; but I am not aware that it has ever
been proposed to cool the heated metal articles by means of a current of water-gas
or hydrogen-gas as hereinbefore described; and I claim :—
First. In the annealing of metal articles, the herein described method or process
of cooling the said articles and removing therefrom any oxide that may be formed
thereon, by passing water-gas or hydrogen-gas through the vessel or vessels
containing the said articles, after the latter have been heated to a suitable
temperature.
Second. In the annealing of metal articles by a process such as I have
hereinabove described, the utilization of the gases whereby metal articles have
been cooled in one annealing vessel. for the heating of further quantities of
such articles in another annealing vessel, in such a manner as to leave a large
excess of the gas unconsumed, substantially as hereinbefore described and for the
purposes specified.
Third. The modification of my invention wherein the annealing of the metal
articles is carried on in a continuous manner by means of an endless series of
anuealing vessels, substantially as herein before described.
Dat this 5th day T1001
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.