IMPROVEMENTS IN COATING IRON OR STEEL WITH COPPER OR BRASS OR OTHER ALLOYS OF COPPER
Year: 1869

page_text: LETTERS PATENT to George James Hinde, of Wolverhampton, in
the County of Stafford, Manager of Works, for the Invention of
"IMPROVEMENTS IN COATING IRON OR STEEL WITH COPPER OR BRASS OR OTHER
ALLOYS OF COPPER."
Sealed the 22nd May 1869, and dated the 26th February 1869..
PROVISIONAL SPECIFICATION left by the said George James.
Hinde at the Office of the Commissioners of Patents, with his
Petition, on the 26th February 1869.
I, GEORGE JAMES HINDE, of Wolverhampton, in the County of
Stafford, Manager of Works, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN COATING IRON OR STEEL WITH COPPER OR BRASS
OR OTHER ALLOYS OF COPPER," to be as follows:-
My Invention consists of the improvements herein-after described in
coating sheets and articles of iron or steel with copper or brass or other
alloys of copper, by which improvements the coating of the said sheets
and articles is effected at a comparatively low temperature, and the

page_text: difficulties which occur from the high temperatures ordinarily required
for effecting the said coating are avoided.
My Invention is especially applicable to the coating of iron or steel
with copper or brass, but is also applicable to the coating of iron or steel
with alloys of copper other than brass, such as an alloy of copper with
tin or with lead.
I will describe my Invention with reference to the coating of iron or
steel with copper or brass. I clean the sheets or articles to be coated
by any of the well-known pickling or other processes ordinarily employed
for that purpose, and I plunge the sheets or articles into a bath of melted
zinc containing copper in alloy with the said zinc, the quantity of zinc
being so large compared with that of the copper as not to materially
affect the colour of the zinc. From five to six parts by weight of zinc
to one part by weight of copper I find to answer well in practice, but I
do not limit myself to those proportions. After a short immersion of the
iron or steel sheets or articles in the said bath they are withdrawn and
exposed to heat in a muffle or heating chamber sufficiently hot to
volatilize the zinc, and the sheets or articles are allowed to remain in the
said muffle or heating chamber until so much of the zinc has been
volatilized as to leave brass upon the sheets or articles; or when a coating
of copper is required the sheets or articles are allowed to remain in the
muffle or heating chamber until the whole or nearly the whole of the
zine has been volatilized. In order to prevent the sheets or articles from
adhering together or receiving any injury to their coating I prefer before
putting them in the muffle or heating chamber to coat them with a
mixture of finely ground flint and water. This coating when dry protects
the surface of the metal and does not impede the volatilization of the
zinc. After the sheets or articles are removed from the muflle or heating
chamber the coating of powdered flint is removed. The articles are
finished by burnishing or otherwise, and I prefer to pass the sheets that
have been coated according to my Invention through a pair of plain rolls
in order to give smoothness to the coating.
Instead of proceeding in the manner described the sheets or articles to
be coated with copper or brass may first receive a coating of zinc by the
ordinary galvanizing process, or they may be coated with tin or terne
metal before being plunged into the bath of zinc and copper.. A coating
of copper alloyed with tin or an casily fused metal other than zine may
be applied to sheets and articles, of iron or steel by a process similar to

page_text: that already described excepting that tin or the other easily fused metal
is employed in addition to the zinc.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George James Hinde in the Great Scal Patent
Office on the 16th August 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
JAMES HINDE, of Wolverhampton, in the County of Stafford, Manager
of Works, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the. Twenty-sixth day of February, in the
year of our Lord One thousand eight hundred and sixty-nine,. in the
thirty-second year of Her reign, did, for Herself, Her heirs, and suc-
cessors, give and grant unto me, the said George James Hinde, Her
special licence that I, the said George James Hinde, my executors,
administrators, and assigns, or such others as I, the said George James
Hinde, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN COATING IRON OR STEEL WITH COPPER OR BRASS OR OTHER
ALLOYS OF COPPER," upon the condition (amongst others) that I, the said
George James Hinde, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Scal Patent Office within six calendar
months, next.. and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said George James Hinde, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:-
My Invention consists of the improvements hercin-after described in
coating iron or steel with copper or brass or alloys of copper, by which

page_text: improvements the coating of the iron and steel, is effected at a com-
paratively low temperature and the difficulties which occur from the
high temperature ordinarily required for effecting the said coating are
avoided.
My Invention is especially applicable to the coating of sheets of iron
and steel with copper or brass, or certain other alloys of copper, but is
also applicable to the coating of various articles of iron or steel either
in, a manufactured or partly manufactured state, such as wire, bars, rods,
tubes, and vessels.
My Invention is especially applicable to the coating of iron or steel
with copper or brass, or alloy of copper and zinc, but is also applicable
to the coating of iron or steel with copper alloyed with other metals
than zinc, such as an alloy of copper with tin or with lead.
I will describe my Invention with reference to the coating of iron or
steel with copper or brass. I clean the sheets or articles to be coated
by any of the well-known pickling or other processes ordinarily employed
for that purpose, and I plunge the sheets or articles into a bath of
melted zinc containing copper in alloy with the said zinc, the quantity
being so large compared with that of the copper as not to materially
affect the color of the zinc. From five to six parts by weight of zinc
to one part by weight of copper I find to answer well in practice, but I
do not limit myself to these proportions. After a short immersion of
the iron or steel sheets or articles in the said bath they are withdrawn
and exposed to heat in a muffle or heating chamber sufficiently hot to
volatilize the zinc, and the sheets or articles are allowed to remain in
the said muffle or heating chamber until so much of the zinc has
been volatilized as to leave brass upon the sheets or articles; or when a
coating of copper is required the sheets or articles are allowed to remain
in the muffle or heating chamber until the whole or nearly the whole
of the zinc has been volatilized. In order to prevent the sheets or
articles from adhering together or receiving any injury to their coating
I prefer before putting them in the muffle or heating chamber to coat
them with a mixture of finely ground calcined flint and water. This
coating when dry protects the surface of the metal and does not prevent
the volatilization of the zinc. After the sheets or articles are removed
from the muffle or heating chamber the coating of powdered flint is
removed. The articles are finished by burnishing or otherwise, and I
prefer to pass the sheets that have been coated according to my

page_text: Invention through a pair of plain rolls in order to give smoothness to
the coating.
Instead of proceeding in the manner described the slieets or articles
to be coated with copper or brass may first receive a coating of zinc
by the ordinary galvanizing process, or they may be coated with tin or
terne metal before being plunged into the bath of zinc and copper.
A coating of copper alloyed with tin or an easily fused metal other than
zinc may be applied to sheets and articles of iron or steel by a pro-
cess similar to that already described, excepting that tip or the other
easily fused metal is employed in addition to the zinc.
Having explained generally the nature of my Invention I will
proceed to describe, more in detail the manner in which the same
is to be carried into effect.
For convenience of description I will describe my Invention as applied
to the coating of iron, although it must be understood that both wrought
and cast iron and mallcable cast iron and steel may be coated with
copper, brass, or other alloy of copper by my Invention.
I first make the surface of the iron to be coated perfectly clean. This
I effect either by the process called pickling, that is, immersion of the
iron in dilute sulphuric acid or muriatic acid, a process well understood
and commonly practised, or by mechanical abrasion of the surface by
scouring, filing, turning, or other mechanical operation. I prefer to dip
the cleaned iron into a solution of salammoniac before proceeding to
coat it with the alloy of copper. The iron on removal from the said
solution is coated with a thin film of salammoniac. A solution of one
pound of salammoniac to one quart of water answers very well for this
purpose, but other proportions may be employed.
In making a bath of melted zinc and copper, which I will herein-after
call the coating bath, I melt one part by weight of copper in a crucible
or melting pot, and add thereto five parts by weight of zinc. The melted
metals on being stirred immediately form an alloy, and the coating of
the iron may be effected by plunging it, prepared in the manner herein-
before described, into the melted alloy contained in the crucible or
melting pot in which it is made. I prefer, however, to transfer the
melted alloy into a bath or vessel similar to that used for galvanizing
iron, set in a furnace and heated to a temperature sufficient to keep the
alloy in a state of perfect fusion. Before immersing the iron to be coated
into this coating bath I prefer to throw some salammoniac on the surface

page_text: of the coating bath, and to introduce the iron to be coated through the
layer of salammoniac on the coating bath. The iron on being plunged
into. and withdrawn from the coating bath will be found to have received
a coating of the alloy. The quantity of salammoniac which I prefer to
throw on the surface of the coating bath previous to the immersion of
the iron varies from a few ounces, to a few pounds, according to the size
of the iron to be coated. As the said salammoniac volatilizes rapidly at
the temperature of the coating bath I prefer to add it to the bath
immediately before the immersion of the iron therein. I also add zinc
to the coating bath from time to time in order to replace that lost by
volatilization.
Although for ordinary purposes I effect the coating in the manner
already described, yet the said coating may be effected upon iron which
has previously received a coating of zinc or of tin, or of tin and lead,
commonly called terne metal. In coating, according to my Invention,
iron which has received a preliminary coating of zinc or tin or terne
metal I proceed in the manner already described, excepting that the
cleaning and immersion in a solution of salammoniac are unnecessary.
When the iron has received a preliminary coating of tin or terne metal
the composition of the coating bath is liable to be affected thereby, the
coating bath becoming charged more or less with tin, or tin and lead,
and the proportion of copper relatively diminished; in such case I add
to the coating bath from time to time small portions of melted copper or
of brass in addition to the zinc added from time to time, so as to keep the
proportion of copper in the bath as nearly as may be the proportion of
one part of copper to five parts of zinc or the other metal or metals.
Where it is wished to coat the iron with an alloy of copper and tin, or
copper and terne metal, I coat the iron first with tin or with, terne metal
in the ordinary manner, and I plunge it into and quickly withdraw it
from the coating bath. In this way the iron is coated with the alloy of
zinc and copper upon the coating of tin or terne metal, more or less of
the said coating of tin or terne metal being removed from the iron
during the immersion in the coating bath; or I add the required
amount of tin or terne metal to the coating bath, and introduce the
uncoated iron therein in the same manner as when a coating of copper
or brass is to be given to the iron. I prefer, however, in all cases where
practicable to use iron without any preliminary coating, and to make the
coating bath of the exact composition which it is wished the coating to

page_text: be given to the iron shall have previous to the heating process herein-
after described. The preliminary coating of zinc or tin or terne metal
is principally useful where small articles or articles of complex form are
to be coated with copper or alloy of copper. In such cases there is no
risk of the coating failing in any part through oxidation of the iron or
steel, as sometimes happens when the iron or steel has not received a
preliminary coating. The iron after immersion and removal from the
coating bath is coated with a thin coating of the zinc and copper alloy,
or when the iron has been previously coated with tin or with 'terne metal
the coating contains besides zinc and copper a portion of tin or terne
metal. The coating on the iron after removal from the coating bath
much resembles a coating of zinc, being of a nearly white color, and
giving little or no indication by its colour of the presence of copper. I
will herein-after call the iron in this stage alloy coated iron. I next
proceed to volatilize so much of the zinc of the alloy coated iron as to
produce a coating of brass or copper, or copper more or less alloyed with
zinc, in the following manner :-I place in a vessel of convenient size
and shape a mixture of ground calcined flint and water mixed to about
the consistency of cream, and I immerse the alloy coated iron in the
said mixture and immediately withdraw it therefrom. A coating of flint
and water adheres to the said iron. This coating is quickly dried by the.
application of heat on or in a stove, or in any other convenient manner.
The alloy coated iron thus coated with dried calcined ground flint is
then placed in a conveniently shaped annealing box or vessel of iron or
other refractory material. The alloy coated iron placed in the annealing
box or vessel is covered by another box or vessel somewhat smaller, but
of the same shape, inverted in the larger box or vessel, the space between
the sides of the smaller box or vessel and those of the larger box or
vessel being filled with dried calcined powdered flint. The box or vessel
containing the alloy-coated iron is then placed in an annealing muffle
and heated until it is at a bright red heat throughout. About twenty
to thirty minutes exposure to this heat is usually sufficient to volatilize
so much of the zinc of the alloy coated iron that an alloy of copper and
zinc in the proportions in which they form brass is left on the iron. By
prolonging the time of exposure to heat more zinc is volatilized, until
eventually the whole or nearly the whole of the zinc is driven off, and a
coating of pure or nearly pure copper is left on the iron. To volatilize
the whole or nearly the whole of the zinc about two hours exposure of
the alloy coated iron at a bright red heat is usually sufficient. Where

page_text: large annealing boxes are employed a longer exposure to heat is required',
and where a very high temperature is employed the zinc is volatilized
more rapidly.
If the iron that has been coated is in the form of bars, rods, or plates
and it is desired to have a smoother surface than it has when taken
from the muffle or heating chamber it is passed through rolls, the
adhering ground calcined flint having been previously washed or
brushed off. The iron may be softened if required after being rolled by
subjecting it to a dull red heat. The coated arm is then scoured with
sand and water and rapidly dried by heat in or on a stove or other
means. When manufactured or partly manufactured articles are coated
by my Invention and it is wished to make the coated surface smooth,
this is effected by the process of burnishing, planishing, spinning, or other
mechanical treatment, as is well understood. When wire has been
coated according to my Invention it may be drawn in the same manner
as brass wire is drawn and annealed during the drawing process. If the
wire is to be worked into manufactured articles in a hard state it must not
be annealed after the final drawing; but if it is required to be used in
a softened state it must be annealed after the final drawing. By using
the proportion of zinc to copper in the coating bath, herein-before
described, or thereabouts, I avoid many difficulties that arise in
attempting to coat iron with copper or brass directly, as the mixture
of copper and zinc that I use is very fusible, and can be kept melted by
the application of heat in an iron vessel in the same manner as molten
zinc. By the use of a coating of powdered flint to the alloy coated iron
previous to the volatilization of the zinc the surfaces of the coated iron
are prevented from touching each other in the pans or vessels, and the
coated surface is less oxidized or tarnished than when the alloy coated
iron is without the coating of powdered flint. Although I prefer to use
calcined powdered flint for the purpose described, yet I do not limit
myself thereto, as other finely divided substance may be employed, and
although I prefer to give the, alloy coated iron a coating of powdered
flint or other matter previous to introducing it into the muffle or heating
chamber, yet the use of the said coating of powdered flint or other
matter may be dispensed with in carrying my Invention into effect, and
other methods resorted to of keeping the sheets or articles apart during
the volatilization of the zinc.

page_text: in which the same is to be performed, I wish it to be understood that I
do not limit myself to the precise details herein described, as the same
may be varied without departing from the nature of my Invention; but
I claim as my Invention, the improvements herein-before described in
coating iron or steel with copper or brass or other alloys of copper,
that to say, coating iron or steel with copper or brass by giving to
the said iron or steel a coating of an alloy of copper and zinc, the
proportion of zinc in the said alloy being so great that the said alloy
differs but little in fusibility and other physical characteristics from zinc,
and afterwards volatilizing by heat the zinc of the said alloy cither
wholly or in part, and thereby leaving upon the said iron or steel a
coating of copper or brass, substantially as described.
Also the modifications described with reference to the coating of iron
or steel previously coated with tin or terne metal, and the modifications
described when it is wished that the final coating shall contain in
addition to copper or copper and zinc, tin or terne metal.
Further, the use of a film of powdered calcined flint or other finely
divided substance for protecting the alloy coated iron or steel from injury
and oxidation during the volatilization of the zinc or other volatile metal
contained in the coating.
In witness whercof, I, the said George James Hinde, have here-
unto set my hand and seal, this Twelfth day of August, in the
year of our Lord One thousand eight hundred and sixty-nine.
Witness,
JOSEPH JONES,
Wolverhampton.
GEORGE JAMES HINDE. (L.S.)