The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1924-11-12
DIRT IS BLAMED.
IN BREAkAGE
Of PARTS
Cadillac Engineer Explains
Methods Used to Ensure
Sound Metals

Capitalization and breakage, for
merly given as the cause Tor the
failure OF part of a motor car
after a long period OF service, has
become one Of the exploded theories
OF the past. Studies which have
destroyed the old ''crystallization"
theory have also pointed the way
to even greater dependability In
highly stressed parts OF the present
day car, according to Il. A.. Danse,
rnetallurgist Of the Cadillac Motor
Car Company.
Mr.. Danse explains that In ad-
vanced engineering circles the nays-
FERROUS something commonly called
capitalization and hreakage has
been analysed just as medical men
analyze a disease and isolate its
germ and that it is in reality
fatigue" breakage, due to Ina
purity in the metal or some one
other definite defect which can
now be exposed by known labora-
tory and physical tests.
las metals are naturally crystal
line in structure" states Mr.. Danse.
''it is evident that breakage in
service is not due to capitalization.
The metal is a crystalline mass
from the time it Is first melted and
poured. When it solidifies after
melting and pouring, it assumes the
crystalline character; the same as
water solidifies to snow, frost or
ice crystals.
Researches In metallurgy show
that where motor car part fails
in service, the principal cause is
not a mystery at all. II Is usually
Just plain dirt. 1t is impurity so
microscopically fine that without
the most conscientious examination
it defies detection.
1.-THE method Of determining the
cleanliness Of a metal is really
very simple. 1t is merely a pro.
cess of taking infinite pains-ac-
curacy of examination and analysis
to a degree formerly unknown even
in the best OF laboratories.
AT Cadillac every lot Of metal
intended for use in highly stressed
parts of the car must undergo the
most thorough microscopical exam
ination.
THE sample to be examined Is
first polished to degree Of smooth
products. SmoothneSs in highly pol.
ished plate glass or in a piece of
silverware Is crude compared to the
smoothness required in the testing
laboratory.
Take a silver spoon, for ex-
ample. If you are invited out to
dinner tonight and have been lucky
/ in your invitation, maybe there
wwra1l ~ csI -
place, newly polished by the best
Good Housekeeping methods. To
your eye it looks perfectly smooth.
AS 1t passes your lips they also
record perfect smoothness. That
surface under powerful micro.
scope would have ruts and burrows,
lunch room, under this same micro
tains and valleys.
When We prepare this sample
| for examination, we must make
it even microscopically smooth.
Five hours is spent in polishing a
half-inch square Of surface.
This surface is then examined
under a glass magnifying to 100
| diameterS-a task for a busy TWEEN.
ty minutes. One might examine i
in fifteen minutes, but he would
have to slight some areas of the
surface which might contain dirt
inclusions."
The metallurgist was interrupted
by an exclamation, and continued
with a smile, Yes, you can glance
at nickel in an instant and know
that it is a five-cent piece, but II
you really want to see 1t and know
how pure that nickel is, 1t will
take twenty minutes to explore
its whole surface and a, that 500
will cd to hustle
After a thorough visual micro.
scope examination +ne metal is
photographed with n camera which
magnifies from 100 to 1000 diameters
and suspected areas are more close.
| ~ studied.
The structure must be fine in
order to have the strength which