The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1889-02-01
SILICA II SHRINKING.
4 new Process Requiring No
Special Plant



The silica process IN the m2nufae
tire Of iron and steel seems 70 be zp
prozcAsng the stage Of actual trial on
. commercial scale. In pamphlet re
Gently issued by the eornpxay which
controls the process We find the state
menf made that I'll os the largest man
ufAetaring establ sshnenfs IN the EuI
ed States have taken license TO use thu
process and are preparing 10 go reg
uIariy to running on IL at "a earsi
day Ii II further said that the silica
process II q simple and novel Use q
comparatively pure silica teiOZt a.
helper IN the manufacture OF superio'
iron and steel. It needs no speeial
slant nor any addition& machinery
and IL Il not ccafsned 70 any particular
DEPARTMENT OF the iron industries, bus
II & applicable 20 ali other processes
far the production Of east iron.
wrought iron. steel and cast steel
IL e claimed for this process that IL
makes ar acid Stag, and removes the
oxide OF Iron. Il lessons the amount OF
carbon ia the iron: promotes the for
nation Of graphite carbon. and an
taxonizes the formation OF com bined
carbon; changes the hard. white irons
into soft, tough gray irons: liberxfes
the ocefadeti gases. leaves the molten
metal quiet in bath, ladie OF fnoId. and
renders the product comparatively
free from porosity helps the elimina-
ton oil sulphur aud phosphorus: il
diminishes the tendency 70 shrinkage
and cracking in castings. leaves the
castings cleaner when they come frpfn
the mods. dIminishes fall one-fhird
the quantity Of ferro-manganese used
IN sfeei-snaking; augmeufs the electri-
cal conLnctiyity OF steel wire, and IL
increases the tensile and resilient
strength Of iron and steel
Under the date of Sept. 20, ISIS, Mr.
+. Is. johnson, professor OF civil en-
cheering Of Washington University.
reports 10 the president OF the Mullins
Sificased Iron & Steel Company, the
results of tests on cast iron made By
him for that company. He says: The
specimens we're brought 20 me IN the
rough, being ~ in. in diameter ard
some IL ia. long. They were turned
down at the laboratory under my di-
recfaon. AMI tested on q Richie 10, 600.
fAyti8}a hrrk4tSE fxt3Atf8tr vi VIZ 1AtE1b
improved pattern. The working
qualities OF the metal we're observed
and sts appearance on the fractured
sgFfacQpoted. All tests and eoiRpu-
tations were Eaaaie by me personally.
With very few exceptions, was ig-
norant OF the source and composition
OF the specimens. Fsifher did | know
which were siiicated and which not,
until after the tests were completed.
No record of this information was
kept by me, however, and you have
to-day sent me the information which
alone enables me Ia classify the results
into .'silicateds' and 'non-siiicated. .
and also 10 determine which tests
were on identical mixtures.
NY tests and examinations have
been directed to the following proper
ties of the iron. Internal structure,
working qealities. tensile strength and
residence.
The siiicated iron shows a remarka-
bic uniformity of structure across the
section, being close and firse-grained
throughout X appears more dense
and more free from blowholes and
from the spongy structure generally
found az the centre of thick castings.
II tested for specific gravity. or density
I believe IL would show greater weight
per cubic foot than ordinary cast iron.
It's structure would also lead one to
predict q less shrinkage In cooling than
ordinary iron. and II this il the case,
then the internal strains which are
caused by this excessive shrinkage,
would be proportionateiy reduced. If
IL should prove 10 be true that the
shrinkage Is very much less than il Is
in other irons. ~ | am inclined "a
think is the ease. then one very serious
objection TO the use of cast iron in
heavy masses, and in complicated
forms, is removed
Almost withoutexeertion the silica
ted specimens have worked well in the
lathe. They have been soft and tough,
many OF them remarkably so. With
the exception Of a few mixtures of car
wheel iron, which would be ciassed as
hard" all the silieated specimens
submitted to me have possessed prae-
ficaily perfect working qualities.
1c3ssile Strength lie made in all "A
tests Of tensile strength, 43 of which
were on silieated cast iron and 81 on
Eon-silieated iron. In only II eases
were the mixtures identical, except for
the siiieated treatment. In the other
instances the siiicatea process was an.
piled TO cheaper mixtures. and the
products compared with the stanaar,,
OUTPUT Of the foundry. These tssf
specimens are said to have come frorn
Is different foundries.
A fair COMPARISON of results. Ia show
the effect Of the process. can only he
made. therefore. between the silisatn.l
and -silicated mixtursSs wbisI,
were otherwise identical. comnarinp
the results Of these. we obtain the fol.
lowing averages. the tensile strength
being given in pounds per square inch
silt Soo.
Gated. silieete.l
No. of tests. ......,....,.-.......... IA "A
Average tensile strength 1900 20.72l
s.s strength ..'..,... l.ass s,Sa
=. sa'sns Ill.,. is''ee io'e,N
me sIeaest Increase OF strength
wa i'ouh is.sio 70 $3.50, or an IN
eIesss 81 - yer cent lhe least IN
e.ease VI ssfshgtn was from @S,oe 10
~ssoso' or m ING tease 81 , per cent, as
.esuss vi siss silIsa'ea treatment, the
MIXTURES osherWlse remaining the
same.
hNsf'sisfs.~, ne fesslience, or spring
Oh metal y Us hhitity 10 resist a
snoSA or otONs ~ II not simply Its
sueng'hs pnt its ability 10 dis
tort under Q bsow without break