The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1903-11-28
FoR "THE UNION"
THE MANUFACTURE OF STEEL.
The Melting Of Ore in the Blast Furnace and tn
Manufacture of Iron.
BY JOHN s. LoNeNEcKEB, JR.

The process of making steel begins
by making iron from ore. This is
done in furnace called blast fur
mace. This furnace is filled with a
mixture of coke, iron ore and line-
stone, and superheated air is blown
in at the bottom through openings
called "tuyeres. A portion of the
coke is burned by the oxygen in the
air, and serves to keep the furnace at
a high temperature, while another
portion is employed in robbing the
iron ore of its oxygen. The point
where the air enters the furnace is
called the Zone of fusion" and is
the hottest point in the furnace. The
high temperature at this point quick
1y completes all reactions, the ore is
reduced, the earthly impurities unite
with the limestone and are fused into
Stag, while the metallic iron is melted
and collects in the hearth below the
tuyeres. The metal so produced is
not pure iron, for during the process
of melting it absorbs certain elements.
1t takes carbon from the coke and sill
con from the ash of the coke. Sui
phur is also present in small quanti-
ties. This is not wanted, but there
is seldom less than .o2 of I per cent,
while there may be rs of per cent,
or even more. The amount of silicon
and sulphur present depend upon con-
ditions in the furnace, and may be
controlled by the furnaceman. There
is one other element, phosphorus,
which is universally present, over
which he has no control. Whatever
amount is present in the fuel and ore
will show in the iron. Pure iron it
self is very hard to melt, and is soft,
tough and malleable, both hot and
cold. The elements described change
its character completely in three diff
ferent ways: Ist, 1t becomes more
fusible. I'd, 1t becomes more brit
tile. sd, 1t cannot be forged either
hot or cold. The iron in this condi-
tion is known as pig iron and is the
foundation Of the iron and steel in
dustry.
THE MAKING OF WROUGHT IRON.
Wrought iron is made by melting
pig iron In contact with iron ore, and
burning out the silicon, carbon and
phosphorus, leaving metallic iron.
This iron when taken from the fur
mace is in a pasty condition, and is
mixed with Stag, making honey
comb Of iron, with each cell filled
with melted lava or Stag. This honey
combed material is squeezed and roll
ed until most of the Stag is worked
out and the iron is welded together
into a compact mass, called "muck"
iron. This muck iron is heated to a
welding heat and rolled again, giving
clean iron, which is the wrought iron
of commerce.
A DEFINITION OF STEEL.
By the term steel is meant the NAL
leable compounds of iron made in the
Bessemer converter, the open-hearth
furnace, or the cruc1Dle.
THE BEsSEMER PROCESS.
The Bessemer process consists of
blowing cold air through liquid pig
iron. Sometimes the iron is brought
from the blast furnace while fluid,
and sometimes is melted in the cupo-
las. The Bessemer process is divided
into two sub-processes The acid
and Basic processes.
THE ACID BESSEMER PROCESS.
In the acid process, the air passing
through the iron, burns the silicon
and carbon, and the heat caused by
their combustion is sufficient to not
only sustain the "bath" in liquid
state, but to increase its temperature,
necessitating an addition of scrap as a
cooling agent. The burning of the
silicon furnishes great amount of
heat, while the burning of the carbon
furnishes very little. 1t is therefore
necessary for the iron used to con-
tain enough silicon to raise the tenn
perature to point where the steel
will remain fluid. In the acid Besse-
mer process it is necessary to have
iron containing I per cent. or more OF
silicon.
When the silicon and carbon are
all burned, manganese is added in
order that the steel shall be tough
while hot and be able to stand the
distortions of the rolling mill. IF
soft steel is wanted the maganese is
obtained by using ferro-manganese, a
rich alloy, containing about SO per
cent. manganese, while if hard steel
is wanted, spieleg iron containing
about II per cent. manganese is used.
For every ten tons of steel about one
ton of spiegel is added, and this gives
enough manganese to make it roll
we'll, and at the same time gives
enough carbon to confer the necessary
hardness. The resulting steel is pour
ed into a 1adle, and the Stag being
very light, floats on top. The steel
is then tapped from the bottom, the
separation of metal and Stag being
perfect. In the acid process there
can be no removal of phosphorus or
sulphur, and as no steel is allowed to
contain over Il of I per cent, the
iron used cannot contain more than
this allowable amount. This process
is the cheapest method of making
steel that has ever been discovered.
The lining of the acid Bessemer con-
verter is of silicious rock or clay.
THE BASIC BEsSEMER PROCESS.
The Basic Bessemer process is SIM
liar to the acid Bessesmer process, be-
ing based on the fact that if cold ali