Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-03-03

tageous that where . steel forging can be
finished under the hammer, this should be
done. Doubtless, finishing by means OF
moulds, so as to bring the article rs near to
the ultimate shape required as possible, Is
the besb course to pursue. The hydraulic
press will no doubt play an important part
in this direction at no distant date, though
much has already been done by working IN
this manner under the steam hammer. Inc
writer, for example, remembers the manu-
facture of large screws for holding armor
plates to the sides Of vessels, being CARRIED
on many years ago at the Atlas Works,
Sheffield. These screws, whose thread was
forged under molds, had the original SKIN
of the bar left all over them, the. torgings
being further protected by galvanlzlng.
Polishing Might Simplify Matters.
1t is not forgotten by the writer that
engineers advocate machining not only
so as to obtain the symmetry that is SO
tion is impaired, but also so as to make Vlsl-
BILE any hidden flaws that might be present
in forging. The importance Of this Or
lection is not to be minimized, but apart
from the fact that forging with the tough
skin on and some hidden flaw left might be
preferable to one from which the skin has
been removed, and the flaw "doctored up."
it may be pointed out that in many cases
simple polishing, say, for example, by means
Of the emery wheel, might effect the desired
object without in any material degree weak
ening the strength of the surface protection.
1t can be imagined, at sight of these COM
paratively infusible envelopes, that it would
be quite practicable to weld mild steel and
obtain fbrous product by piling and pass
ing the heated mass through the rolls or
working it under the ha miner.
Nevertheless, according to Mr.. Shelton,
some difficulty appears to have been en-
countered in the attempt to make rivet-bars
in this manner from mild steel-plate cut
tings, possibly not because of any inherent
fault in the method, but because it may not
have been carried out properly, as for ex-
ample, by the introduction of hard pieces in
the piles.
On the other hand, Mr.. Ratliffe, of the
Mersey Forge, it will be remembered, read
a paper before this institute in 1879 where
in he explained how he actually preferred
to roll down his ingots of mild steel into
bars, which he afterward piled to make into
forgings.
Economy in the Process
Not only did Mr.. Ratllffe say that he OBJ
tanned by that means fbrous metal, free
from all crystallization, but also that he
accomplished this desirable result at
considerably less cost than by making
the forgings from large ingots. 1t is not
likely that this economy would follow in
every case, but much would be gained if the
results obtained by the process were to in
duce confidence, and justify its adoption in
cases of awkward forgings, which could be
more easily formed by building up from
bars than by hammering down from a large
mass.
In conclusion, it may be pointed out
how the characteristic to which this
paper refers-namely, the greater fusi-
bility Of the interior of a mild steel bar
as compared with its exterior portion-will
assist operations in the manufacture Of the
Mannesmann tubes. Without asserting
that the phenomenon in question plays an
important part in the process, it is certainly
interesting to note that as the interior of
the bar must be in more pasty condition
than the outside, being nearer it's melting
point, the circumstances, if not actually
conducive to the production of hollow
center, will at any rate offer little opposi-
tion to the forces that induce its formation.