Improvements in the Manufacture of Steel.
Year: 1894

page_text: Date of Application, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Steel.
I, CANDIDO DE ESTEVE LLATAS, of 38, Avenue de la Republique, Paris, in
the Republic of France, Engineer, do hereby declare the nature of this invention
to be as follows:-
The invention relates to the manufacture of steel, and has for its object the
production of steel of the highest qualities (such for example as that commonly
known as crucible steel), each quality possessing remarkable uniformity; the cost
of production but little exceeding that of "Bessemer," or "Siemens-Martin
other steel of like class.
"
or
In carrying out my improved method of manufacture, I melt the charge in a
Bessemer or other converter or in a Siemens-Martin or other furnace, and proceed
until the bath is brought to the desired point of purity. Then carbon, manganese
and silicium are separately heated and added in the following proportions to the
molten charge:
From 020 to 030 per cent. of manganese, and from 025 to 035 per cent. of
silicium. There is also added such a proportion of carbon as will, with that
already existing in the metallic charge, bring this element to the proportion of
from 075 to 085 per cent. The heated manganese is first added, and when this has
become thoroughly mixed with the charge and fused the heated silicium is added.
The proportions above set forth are adapted for the production of hard steel, but
where a milder quality of steel is desired the carbon is diminished and the
manganese increased so as to present the following ratios :—
Carbon, from
Manganese, from
Silicium, from
*045 to 055 per cent.,
040 to 050 per cent.,
025 to 035 per cent.
In either of the above cases, the addition of from 012 to 020 per cent. of
aluminium is advantageous, although not essential. Where aluminium is used, it
may be added in the ladle, or in the mould, but if added in the furnace should only
be introduced at the last moment.
Dated the 7th day of April 1894.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Steel.
I, CANDIDO DE ESTEVE LLATAS, of 38bs, Avenue de la Republique, Paris, in
the Republic of France, Engineer, 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 the manufacture of steel, and has for its object the
production of steel of the highest qualities (such for example as that commonly

page_text: known as
"crucible steel "), by a process which may be carried out in a
"Bessemer" or other converter or in a "Siemens-Martin" or other furnace thus
permitting large quantities (such as 10, 20 or 30 tons) to be produced at a single
melting the cost of production corresponding nevertheless with that usually
involved in the manufacture of "Bessemer,'
," "Siemens-Martin' or other steel of
like character.
"
"
In carrying out my improved method of manufacture, I melt the charge in a
" Bessemer or other converter or in a "Siemens-Martin" or other furnace, and
proceed until the bath is brought to the desired point of purity, as regards the
proportion of carbon present (according to the character of the product required).
If the proportion of carbon be lower or higher than that requisite, according to
the formulæ hereinafter set forth, for either hard or soft steel, I may carburize or
decarburize the bath until the proper proportion is reached. In carburizing,
carburetted iron of any suitable kind may be introduced into the bath until the
proper proportion of carbon has been obtained.
When the bath presents, or by carburation or decarburation has reached the
desired condition as regards carbon, the necessary quantities of manganese and o
silicium are added so as to produce a metal which, on tapping, presents the
proportions indicated in one or the other of the formulæ hereinafter set forth.
The manganese and the silicium, before being introduced, are heated to a "cherry
red."
r
When operating with the aid of "Bessemer or other converter, these
may be introduced simultaneously; but when operating with the aid of a
"Siemens-Martin" or other furnace the manganese is first introduced, and, this
having been absorbed, the silicium is added. The siliciumn having been absorbed,
the tapping takes place.
"
""
Whether operating with a "Bessemer" or other converter or a "Siemens-
Martin or other furnace in either of the methods herein before described, the
bath, when tapped, should present the following proportions:-
Manganese,
Silicium,
020 ⚫030
"
""
99
22
"
"
.025 .035
"
2:
For soft steel :
Carbon, from
Manganese,
Silicium,
045 to
•040 -050
055 per cent.,
دو
"
وو
29
⚫025 .03.5
"
"
""
"
In the production of "tool" steel, and, generally, ail kinds of steel which
are not required to withstand concussion, ordinary pig-iron (containing up to
0.13 phosphorus and 0.06 sulphur) may be employed; but for steel required for
manufacture into armour plates, and for other uses where severe shocks have to
be withstood, I employ dephosphorized and desulphurized iron, or iron obtained
from pure or purified ore.
In either of the above cases, the addition of from 0012 to 0.020 per cent. of
aluminium, although not essential, is advantageous, particularly when casting in
sand moulds, as it tends to prevent air-holes. Where aluminium is used, it may
be added in the ladle, or in the mould, but if added in the furnace should only
be introduced at the last moment.
"
or other
By the means herein described, I am enabled to produce at a single melting
5, 10, 15 or more tons (according to the capacity of the "Bessemer
converter or of the "Siemens-Martin" or other furnace employed,) of fine steel of
a quality corresponding with that commonly known as "crucible" steel, but at a
cost little exceeding that involved in the manufacture of low-grade steel. More-
over, steel produced according to my invention, possesses greater toughness than
crucible steel, and, unlike the latter, is homogeneous throughout. It may also be

page_text: readily hardened (from the lowest to the highest degree) without recourse being
had to the repeated operations usually necessary.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
6:
1. The improved method of manufacturing fine steel from pig-iron in a
Bessemer" or equivalent converter, substantially as herein described; same
consisting in bringing the bath to the condition herein specified (if not already so)
as regards the proportion of carbon present, and thereupon adding to the charge
manganese and silicium heated to a "cherry red" and substantially in the
proportions set forth, according to the character of the product required.
2. The improved method of manufacturing fine steel from pig-iron in a
"Siemens-Martin" or equivalent furnace, substantially as herein described; same
consisting in bringing the bath to the condition herein specified (if not already
so) as regards the proportion of carbon present, and thereupon successively
adding to the charge manganese and silicium heated to a cherry red" and
substantially in the proportions set forth, according to the character of the product
required.
"
3. As a new article of manufacture, a high-grade hard steel produced direct
from pig-iron in either of the modes herein described, and containing carbon,
manganese and silicium substantially in the proportions specified.
4. As a new article of manufacture, a high-grade soft steel produced direct
from pig-iron in either of the modes herein described, and containing carbon,
manganese and silicium substantially in the proportions specified.
Dated the 7th day of January 1805