Polynesian., 1856-11-29
Che 11olnnesian.
TFrom the London Saturday Review.J
A New way to make Steel.

the British Association that paper would be read
on new method of converting cast into malleable
iron without the use of fuel, the intelligence was
received by many with smile of increduty, and
not few practical men, went to the meeting of
Section e., expecting TO be entertained by the Wis
Ionary schemes OF some ingenious but idle enthu-
Isiast Their expectations were utterly falsiied.
Conviction was forced upon minds from which no
ready assent could have been hoped /; a great in
vention was ucidly and unostentatiously PROFOUND
ed and men who went prepared for exhibition
of temerity, if not of folly, remained to express
their concurrence in the graceful tribute of admi
ration paid by MIR. Nasmyth to one of the greatest
discoveries of the age. Every one felt after hear
ling Mr.. Bessemer's paper, that, if any reliance
could be placed upon the facts stated to the Asso-
citation, new era at hand in all those numer-
Gus and important branches of manufacturing in
dustry which concern the working of wrought iron
and steel. Without further reference to the paper
communicated to the Association, we will now de-
scribe what we have seen at Mr.. Bessemer's prem
ises at Baxter House, leaving our readers to say
whether we have oyerstated the Importance of the
subject.
| 1t is necessary to premise that common cast iron
contains somewhere about or D per cent. Of car
bon, well as n variable quantity of silicum and
other earthly bases phosphorus and sulphur The
object of every process for making maleable iron
is the separation and removal of these foreign sub
stances. The best malleable iron contains about
I2 per cent. of carbon; but the process of eXtrac
ton is difficult and expensive The fusibility of
iron depends upon the quantity of carbon present !;
and no commercially available method has till now
been discovered by which iron, after parting with
very large proportion of its carbon can be brought
to remain In state more nearly approaching fusion
than that of pasty mass Steel is produced from
iron from which the carbon and other impurities
have been extracted, by tedious and costly pro-
cess, the object of which is the restoration of
Of thp
have removed. Steel contains according to the
purposes for which 1t is wanted from rather more
than l2 per cent. to rather less than per cent. of
carbon. Malleable iron-or iron comparatively
free from carbon-is usually produced, in this
country, in the following manner
The melted iron, extracted from the oEs in the
smelling or blast furnace Is out into bars few
feet in length, technically termed pigs. These
pigs, when cold, are removed from the sand mods
into which they run, and transferred to a sec
ond furnace, called the - finng furnace" where
they are again reduced TO a state of fusion; and
finally, the mass thus produced is placed Ill third
furnace, where it undergoes the process of pud-
ding. Omitting all matters Of detail, the essen
tial part of this operation is the reduction of the
iron TO pasty mass. which Is stirred and rolled
about by the workman until large ball. 'bloom,"
of iron, weighing from 60 to 20 pounds, is conglo
merated at the end of the rod with which he works.
and is Judged to be in fit state for the final pro-
cess 1t is then Withdrawn from the fire, and taken
to Il tilting hammer and pair of squeezers, or
to a Nasmyth's steam forge, where it is subjected
to a very heavy pressure, and quantity of melted
/ Stag and refuse, mixed with the puddled iron,
squeezed out For the purpose of our present COM
parison we need follow tile process no further.
/ Other methods of producing maeable iron direct
ly from the are in use In various parts of the
/ Continent but they are extremely expensive, re-
quire a rich ore and very pure fuel, are only ap-
n 10 md
large Percentage-in some cases from 40 to so per
cent-Of the metal
| OF all our more important mechanical operations.
perhaps pudding is the most imperfect and unsat-
isfactory. 1t is very expensive, both from the
quantity of fuel consumed (which is about equal to
the weight of metal treated) and the nature
of the labor required. During the recent hot
weather it was found necessary to stop nearly all
the Stafordshire pudding furnaces-two men hav-
ing fallen dead at their work. The result is the
production of iron so far from being chemically
pure that it is astonishing how much we have been
able to effect with so imperfect material. From
the immense demand for iron which has prevailed
for some years past and the stimulus that has thus
been given to the production of Increased quantity
the quality has very seriously dcteriorated. The
difficulty experienced by the Government during
the last war III procuring iron of quality suitable
for the purposes of warfare is too well known TO
need more than passing reference.
Mr.. Bessemer's experiments have been conduct
ed upon the pig-iron. He proposes that, for the
purposes Of manufacture, the sm"tcd iron, as it
leaves the blast furnace, shall be run Immediately
into the converting vessel presently to be descrb
ed but for the purposes of experiment, it has been
more convenient to melt down pigiron, as the net
al is much sooner reduced to a state of fusion.
The experiment. therefore, takes up the process at
the point at which the metal is ordinarily placed in
the fining-furnace. 1t must be remembered how
fbat rod h,,b
ventlon is to do away with the consumption of fuel
required for this intermediate process. The'' con-
veTting vessel" where the change of the melted
metal from ordinary cast iron to maleable iron or
steel is to take place, consists, externally, of
cylinder of iron, surrounded, near the bottom, by
hollow ring-an annular pipe, in fact-of the same
metal, communicating with five small "tuyere"
pipes, placed at equal distances round the cylinder
These pipes are carried through the outer and in
ner structure of the vessel and each of them en-
teEs the chamber within, near the junction of the
side with the floor, by an aperture about three
eights of an inch in diameter protected by coat
ing of the best fre-cay. The external cylinder is
lined with thick lining of fire brick, and the in
terna structure consists OF two chambers, STORIES
communicating by small cylindrical opening in
the center. The lower chamber, into which the |
melted iron is introduced, is a simple cylinder
the upper chamber has floor inversely arched so /
that any melted metal forced up through the open
ing from the lower chamber may trickle back again.
and the roof is in the shape Of cupola OF dome. /
Two apertures few inches square, placed oppo- |
site each other, between the floor and the top of
this chamber, communicate with the external air.
a powerful blast, worked by small engine, can
be let into the hollow ring which grds the outer
cylinder, and thence, of course, enters the lower
chamber through the tuyere pipes. A hole atthe |
bottom of the chamber, secured in the usual man
ner furnishes the means of tapping the vessel and
running off the produce into the mouds nrenared |