The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1889-02-01

|Iron, This eIabprsse paper uss
WIDER reprinted - The TINE.
ana re viii make bat few
extxxrtSs Concerning the sozzafty 81
the castinSs. Mr.. K,s<p says.
These sDzS0d castings 81 the wnsxe
base alcfse rexlsfesi . we1Znt 81 80
pounds. With erse-feBkh Of per
cent of aluminium added e resisted
So pounds, gain Of 1os pounds. @
about II per cent from this Small
addition The cslsfings appear o.
slightly finer grasrls and the char
aeser OF the crystsliixatson - snne-
shat different. bat the secret OF sne
gsrengtf1 lies IN the closing Of space De-
tween the grains or, n other words
En- the increased SpiidisF OF the cast
ing. No other change Is Dstsceaisis ~
the metal
On the efEe<t 81 the alnminuns on
the Grain, or the changing OF carbon
frors the combined 20 the graphite
state. he says.
bon 20 retain is natural combined
form until the metal Is too thick for
the separated carton 20 escape. but 1t
the sA&&2lk VI NVkzSA2 yA2< 8tA2<-f4AkA
eanses the iron 20 drop portion Of It's
carbon from the combined state. This
liberated carbon takes the graphite
form, and is imprisoned in the other
wise solid IRON The advantage aris-
ing from change of carbon from the
combined TO the grstphitic state at the
instant OF capitalization is that all
carbon thns liberated Ii imprisoned
IL not accumulated in pockets forming
case If liberated while the casting was
vet fluid Aluminium more than any
other element accomplished this. Ii
not only changed white iron 20 gray,
bat seemed st onse 20 change the
whole character OF the metal The
drop of carbon seems 10 be instanfan-
eous. az the instant sH capitalization,
and for this re2sou the time taken in
cooling has little effect In fact. when
the aluminium sbtairts full control of
the caroon it would seem that the
more sudden the cooling the more the
formation Of the graphite. and the
thin portions of the casting are there
fore As gray as the thicker portions.
Take the samples made from the white
iron base. with almost no silicon pres
enf. The base alone gives white bar
full OF blow holes. An addition of
Of one per cent. alumni
mum gives US not only a perfectly
and solid casting, but
the color Is darker and the grain
shows that some OF the carbon has
taken the graphite form. The
thin casting shows this even more than
the heavier bar, showing that the
change occurred suddenly and that
time had but little effect Examining
such bar in turn, we see that each sim
liar addition Of aluminium produces 4
effect, until ut the third
or three-foilrths OF one per
cent. the casting Is gray with no sign
of white, either In the square or in the
thin bar. The set OF tests with the
gray iron base, containing one and
per cent of silicon. shows
that silicon and aluminium work to-
gether in the same direction, and that
q slight addition of aluminium takes
the white out of the casting at once.
giving the same grairi in q thin as in
thick casting. This effect increases as
the aluminium increases, and the in
dications are that at least up to four
per cent. the limit OF our experiments,
the more aluminium, the softer and
grayer the castings.
Further, aluminium causes the car
bon 20 assume the graphite form on
the instant of solidifying. and there
fore the sudden abstraction OF heat
does not imprison the combined car
bon and cause chill. This effect of
Is 10 give uniform grain
for thick and thin castings, and not
allow the GOODNESS OF the mold TO af-
feet the grain.
IL was found that the addition of
aluminium increased the transverse
strength of the iron both under dead
weights and under blows. We see
that the capacity 10 resist impact is in
creased By the addition of aluminium
much more than the capacity to resist
a dead weight, and the test bars made
With the white base are benefited far
more than those made with the gray
base.
Our tests of fiuidiiy are correct as
far as each individual heat is con-
cerned, bat variation may be due 10
the heat of the metal of that par.icu-
lar cast when poured Viewed In q
general way, the indications are that
with the white base, with almost no
silicon. the aluminium has increased
the fiuidity; judging from the series
with the gray base, we would say that,
combined with silicon, aluminium re-
duced the fiuidity, but later tests show
that the aluminium, to very marked
degree, increases the fiuidity.
Our remarks in connection with
shrinkage show that a sharp casting
Is produced by the instantaneous
dropping OF graphite when crystaliiza-
ton takes place, and that ii the iron is
fluid enough 10 till the mold any ex-
ira tiuiditv causes the iron in shrink
ing TO draw away from the mold.
Again, the percentage of aluminium
necessary TO bring about these desir-
able results viii be to small 10 have
much effect upon the fiuidity of the
metal. The fact of the iron giving
sharper and more perfect castings.
caused by the deposition of graphite at
the instant of qualification, might
cause the iron 20 be pronounced more
iiaid, II judged by the appearance of