The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1900-05-28

foreign steel plants which first used the
new process.
Steel forgings are comparatively easy
of manufacture and with a good forge
and a slIillfu smithy excellent work can
be turned out at reasonable cost. The
manufacture of steel castings, however,
has been an entirely different matter
and one which has presented great diff
flcuities to both home and foreign en-
gineers. 1t has long been known that
when forgings could be supplanted by
castings of steel and the parts formerly
cast from gray iron cast from steel,
very important advance in the steel in
duStry would be accomplished.
These diftculties have been overcome
by the introduction of the process to
which the hoist and derrick company has
secured rights of manufacture in Minne-
sofa. Steel castings were turned out at
the West side plant on Friday, which, for
a given strength, were one-third lighter
than iron, and of the very best qaulity.
The construction of the plant was kept
a company secret until Saturday, when
an announcement of the successful trial
of the process was made From now on,
all the castings used b ythe- company i'll
places where steel is advantageous, will
be made under the new process. Tie
company pays royalty on the manu-
facture and has exclusive rights TO the
territory embraced within the boundaries
Of the state.
The Tropenas process is The invention
of Alexander Tropenas, of Paris,
famous mechanical engineer and analyti-
cal chemist. Ten concerns in the United
States are operating under permission
from the inventor and st. Paul has no
competition nearer than Milwaukee The
steel castings formerly purchased III the
East for machinery built in the North
west, will now be manufactured in St
Paul and the local firm has appliances
for the manufacture both of all the cast
ings it can use in its own shops. but for
sufficient in addition tC supply the trade
of the entire Northwest.
In the manufacture of steel castings
under the new process, pig iron Of known
ANALYSIS, high in silicon, and low In
phosphorus is used. Minnesota produces
no iron of sufficiently high grade Tor TINS
purpose and that used is secured from
Tennessee mines. An analysis of the
kind of iron necessary furnished by the
engineer who supervised the construction
of the St Paul plant, gives following
specifications:
Silicon, 21s to 31A per cent: carbon, to
40 ner cent; manganese, .05 per cent to
]. 25 per cent; sulphur, .02 per cent to .O6
per cent; phosphorus, % per cent to ~
per cent.
The details Of the manufacture are sim
pie. Iron of the analysis is first placed
into an ordinary cupola furnace. Coke
is used as fuel and the pigs of iron are
dropped in on top. A blast of air is in
troduced at the bottom of the furnace
and in fifteen minutes after good fire
is secured the iron begins to melt. After
being reduced to a molten state, the
iron is drawn off in a ladle and is
ready for the first step in the Tropenas
process.
For the manufacture of steel of prop
critics making it suitable for castings,
what is known as a Tropenas converter
is used. This is a huge receptacle shaped
somewhat like an egg, hung on trunnions
permitting the top to be lowered to the
ground The interior is lined with fire
brick and 1t has no opening except the
chimney vent at the top, through which
the flames escape. The converter holds
between three and four tons of metal
and is of steel construction. It's pecu-
liar feature is an air blast, introduced
horizontally through one of the trun-
Mons on the side.
Into this converter the molten metal is
poured. When ready for the blast the