The Republican. [volume] (Oakland, Md.) 1877-current, 1889-03-09
MALLEABLE IRON.
The Simple Process of Two Cen turtles Ago |
Successfully Revived.

Successfully Revived.
The process by which iron is made
malleable is a simple but expensive
one. 1t has commanded favor among
iron-workers, however, by reason OF
the remarkable tensile strength and
ductility which it imparts to the other
wise refractory material and renders 1t
as firm as cast-iron and as enduring as
the wrought metal, so that it can be
fashioned into any form by the molders
art. not possible with wrought 1ron'
But once annealed it is useless, as is
wrought iron. for any purpose that re-
quires remelting, for, although that
can be done, the absence of carbon de-
stroys fusibility, making necessary SO
great heat that it is almost impracti-
cable.
The ore is first selected with view
to obtaining that which is as nearly as
possible free from sulphur, pyrites and
phosph orus, as those foreign elements
would preclude malleability. Then the
fuel for smelling must be free from
sulphur. Only charcoal is available.
Even this must be produced with great
care. Twenty-Five kilns, each with a
capacity of about 700 cubic feet; will
afford a supply for furnace of twenty
eight tons daily capacity. The wood is
cut and placed in the kilns before
seasoning is allowed. Albumen and
vegetable matter are detracted by g.
sort of roasting, which allows no flame
to reach the wood, which process re-
quires seven days. The ore is then
pulverised, and, with a proportion of
limestone, is charged into furnace in
layers alternated with charcoal. A
strong air blast then induces tenn
perature of from 10000 to $1,000,
that melts the mass. The limestone
fuxes-that is, it being lighter than
the molten iron, combines with the
impurities which, with the iron proper,
made up the ore, and rising is drawn,
off, leaving the iron free The latter is
then cast into pigs or small, rough
bars.
Then the essential process for con-
verting into malleable really begins.
Up to this point the pigs are very
excellent quality of cast iron. 1t is
again subjected to heat of 10000 for
time sufficient to make evanescent a
major portion of the carbon. Just
enough only of this carbon is extracted
not to destroy feasibility.
Directly from this second process the
molten iron is poured into molds,
which give the desired form in which it
is to be used. The castings are then
cleaned and dipped into acid to re-
move external impurities. 1t is then
packed into iron boxes with iron oxide.
The boxes are then sealed Theoretically
and packed into an oven. This is
bricked up so closely as to be air-proof,
and the anneal;ng process begins. This
requires high constant temperature
for seven or eight days, or until the re-
naming carbon has united with the
oxide and passed off as carbonic acid
gas.
The walls are then torn down, the
boxes removed, the surface impurities
worn off by revolving in a slowly turn.
ing box, and the castings are sent to
the stamping room. At this point, the
degree of temper is so intense that,
were the castings cool, slight shock
would jar them into thousand pieces.
Malleable iron is manufactured wholly
to order, however. They are now
heated to cherry red, and each piece
is put in the lower half of die, which
fac smile of the pattern wanted, is
secured to a massive anvil. The CORE
spending half is fastened to a drop
hammer, which descends and perfects
the design. The force of this blow is
so great that it would dissolve ordinary
iron into a shower of sparks. The
great impediment to the extensive use
of malleable iron is the expense neces-
sary to its production. But, ultimately,
this is more than offset by long life of
the product, which is practically indie
structible. 1t can not be broken, and
if bent will readily reassume its form
by few well-directed blows on the
anvil. From this it derives it's name
malleable being the property that al
lows a thing to be worked under the
hammer without injury to the fiber.
Besides. the same pattern can be made
of one-half the weight of iron that
would be required of ordinary cast
metal and will afford even creator
firmuess. 1t will be but short time,
[ believe, until it will wholly supercede
cast-iron for the commonest uses.-W.
w. Culver, in st. Louis Globe Demo-
crat.
Headlight for Locomotives.