The age-herald. [volume] (Birmingham, Ala.) 1897-1902, 1899-12-04

One hears so much of being purified by
Ere from dross and being purified las by
fire." that the popular mind might easily
conceive stream of pig iron pouring from
a blast furnace as being the highest en-
b1em of purity; yet nothing could be more
erroneous. Common pig iron or cast iron,
as 1t is called, embraces as a rule from
to 10 per cent of impurities; namely, car
bon, silicon, manganese, phosphorus and
sulphur. The impurities or metalloids or
alloys exercise different influences. The
carbon, when combined with the iron,
makes 1t hard and brittle, so that madle-
able iron bars or plates cannot be pro-
duced until this carbon is eliminated, which
is done by the process of pudding. The
Silicon adds f1uidity to the iron and makes
1t as an alloy suitable for use in foundries
for the production of castings, which could
not be made from pure iron alone, which
might indeed be fused to the point of de-
struction without becoming liquid.
1t is necessary, for the production of
steel, not only to remove the silicon and
nearly all the carbon, but also to endeavor
to remove the phosphorus and sulphur,
Which are detrimental qualities without
any of those advantages to offset their
tions, incident to the presence of SILICON
and carbon AS is well known, steel is
vested with such valuable qualities of
greater ductility combined with tensile
strength and, owing to the method of
manufacture, of greater homogeneity and
purity and uniformity of quality, that it's
use for decade past has been limited only
by Its higher price. As, however, successive
Its cost has decreased until, strange to
say, 1t Is now cheaper than iron.
What is steel?
Steel is an artificial compound of pure
iron and carbon. The iron gives the
strength, and the amount of carbon regu-
lates the hardness, toughness and ductiity
OF the compound so that the carbon Is
kept low If a soft and ductile metal is de-
sized for use in boiler plates, hoops, sheets
or wire. 1t is carried some wllat higher for
rails and decidedly higher for tool STEEL.
cutlery and drills.
There are four different methods of maxi
ing steel on a large scale, for we may disre-
gard for the moment the old cement ton
process, where bars of refined iron are
sandwiched with layers of carbon and heat
ed together until the carbon is absorbed by
the iron. We have, however, a return to
first principles in the Harveyizing process
of face-hardening armor plates used our
vessels today, the steel having been first
forged in technically soft" condition,
and afterward hardened by annealing with
carbon in contact with the face, thus giy-
ing a tough back to resist cracks and a
hard face to break up the shot in it's inn
pact
The four main processes are the acid and
basic Bessemer, and the acid and basic
open hearth Both depend upon purifying
the iron by oxygen. The same agent is
necessary that must be breathed twenty
times minute to remove the carbon from
our blood, which would otherwise poison us
in few short hours. to oxidize and render
dnnocuous the organic matter i'm the
streams resulting from sewerage pollution
or to oxfdze and burn up the metalloids In
conjunction with the iron which render 1t
unfit for steel. The four processes, which
are really two subdivided into four, differ
in the method of introducing this oxygen.
The most simple rough and-ready method
of purifying large masses of molten iron Is
the Bessemer process, which consists OF
blowing air by powerful blowing engines
Through a bath of molten iron, the oxygen
in its passage through the metal uniting
with and burning up the carbon, silicon
and manganese. Where there Is much phos-
phorus in the iron, 1t is necessary to make
provision of free lime In the bath, so that
as the oxygen acts as a divorce court in
separating the phosphorus from the iron,
1T may, as 1t rises to the top as Stag, be-
cause of the lighter specific gravity of the
oxide, unite with the lime instead of re-
manning loose and in danger of going back
again to the iron. AS the presence of lime
for this purpose would be inconsistent with
a siliceous lining in the furnace and would
be destructive to it, 1t is necessary in such
cases to line the Bessemer converter with
calcareous material, and ii Is then called
basic Bessemer, and the iron, high in phos-
phorus, which is treated in it is kept ex-
tremey low in silicon, as the presence of
silicon in the pig would be destructive to
the calcareous basic lining of the fur
mace We therefore the irons high in
silicon and low in phosphorus treated in the
siiceous or acid converter, and those high
In phosphorus and low In silicon treated in
the basic converter; but the general prin-
riple of blowing the air through to burn up
the metalloids remains the same.
The entire Bessemer process does not in
yolve more than twenty or twenty-five min
utes, and Is governed by the eye of the man
in charge, who stops it when he judges by
the color of the smoke that the process Is
sufficiently perfect. If he permits 1t to con-
tinue a minute too long, the air, having
burned out the impurities, commences to
burn the iron itself, which causes waste
and financial loss. If he stops minute too
soon, there is too large proportion OF
SILICON or Of phosphorus, as the case may
be. left in the metal. Therefore, the Besse-
tner process, while OF enormous value to
mankind, is yet, compared with an open
hearth process, what may be called trough
and ready"
The open-hearth process, which Is SINH
-vyDn CUIDD M MI cu0INEic