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December, 1925
is cracked along a line, between the two arrows. Filing
and etching of this part of the billet surface revealed
a crack as shown in Fig. 5. An attempt was
made to remove the crack with a hollow chisel, but
this proved to be unfeasible on account of its depth.
A hole was then drilled and the crack found to be
deeper than one inch. A careful inspection of the
same section did not reveal any further signs of cracks.
Subsequently the billet was slowly brought up to die
forging temperature. As soon as pressure was applied
under a steam hydraulic press, cracks appeared on
three sides of the examined section, similar to wha'c
had been experienced on the billet mentioned previously.
The failure of the second billet doubtlessly
confirmed the supposition concerning the inherent
defect, responsible for the failure of the first one.
It seems strange that only the last two of 20 billets
failed, but this fact is easily explained, considering
that the last billets were those of highest carbon content,
in other words the most susceptible to develop
cracks.
The cause of the cracks was explained as follows:
After forging the ingot in the steel works it was exposed
to rapid cooling. The temperature decreased
rapidly at the corners, but they were prevented from
shrinking by the hot material with the greater volume
inside. When the center of the billet was cooling
off, the corners formed a rigid frame and thus prevented
the inner material from contraction. If there
had been hair cracks in the ingot, they would have
been noticed during the first forging operation.
From these considerations it may be concluded that
with proper treatment, especially when cooling and
heating, these troubles would have been avoided.
Research Committee Receives Reports
An all day session of the Joint Research Committee
on the Effect of Temperature on the Properties
of Metals, sponsored by the American Society of
Mechanical Engineers and American Society for
Testing Materials, was held recently at the Cleveland
Hotel, at Cleveland, under the chairmanship of Mr.
G. W. Saathoff.
A report was made by the Sub-Committee on Procurement
of Materials, headed by Mr. H. J. French,
indicating that manufacturers are eager to co-operate
by suplying the necessary materials for physical tests.
A supply is on hand of three types of steel. These
are to be properly heat treated and machined to standard
test specimen shapes and distributed to the cooperating
laboratories. Other materials can be obtained
from manufacturers when needed, upon the
request of the committee.
A report was presented by the Sub-Committee on
Specifications for High Temperautre Tests. This
sub-committee, headed by Mr. L. W. Spring, submitted
devised forms of specifications for short and
long time tests, which had been discussed at the precedeing
meeting. These specificiations, as adopted,
are now in proper form to be released to the co-operating
laboratories. They are accompanied by the
sample log sheets and stress-strain diagram sheets.
for the guidance of all co-operators, so that reports
from various co-operators will be uniform and can be
compared directly as received.
Forging-Stamping-Heat Treating
435
The Sub-Committee on Co-operating Laboratories,
headed by Mr. C. T. Malcolm, reported that practically
all the laboratories addressed expressed a desire
to co-operate in these investigations to the limit
of their facilities and personnel. The report indicates
that between 20 and 30 laboratories are already
equipped to handle high temperature tests, and practically
all of these have offered the use of their
facilities.
Twelve of these laboratories were selected for the
first group of high temperature tests and the material
on hand will be distributed to them when heat
treated and machined, with the tentative standard
specifications, so that they may proceed with the
active work on these materials.
The present set of tests is for the determination
of the tensile properties of these metals under elevated
temperatures. The committee discussed plans contemplating
contemporary work on other physical
properties of metals at high temperature such as
fatigue phenomena, corrosion, erosion, etc. This work
will be allotted to other co-operating laboratories than
those working on the present group of tests.
The plans were formulated for a survey to obtain
reports from users of metals concerning their experiences
in finding suitable materials for use under severe
service conditions involving abnormal temperatures,
either above or below normal.
The need of an organized attack on this problem
was convincingly attested at this meeting by the
reports which indicated the large number of laboratories
which have already worked on these problems,
by willingness of all parties to contribute information
and to co-operate in the investigations, and by the
fact that the committee already has been consulted
by the users of metals who are in need of information
on this subject in connection with their manufacturing
processes.
Measuring Gases in Metals
Metallurgists have realized for some time that the
presence or absence of gases in steels and cast irons
has an important effect upon the properties of the
metals. Just what this effect is or how to measure
the gases housed in the metal content have been difficult
matters to fathom. The Bureau of Standards, at
Washington, claims to have arrived at a method of
determining accurately the amounts of oxygen and
hydrogen in metals. The analysis, it is said, will
disclose 1/1000 of a gram of oxygen and 1/10,000 of
a gram of hydrogen in 100 grams of iron or steel. A
sample of the metal is sealed inside a fused-silica tube,
the tube is evacuated, the sample is melted in a high
frequency induction furnace, and the gases are collected
and weighed. A complete description of the
process is to be published soon in one of the bureau's
scientific papers.
Great Machinery Sales Building
Machinery dealers are buying space on a co-ope_ative
basis, the investment to be used for the erection
of a 21 story machinery mart across from the new
Union Station, Chicago, 111. The estimated cost is
$8,500,000 and the rentable floor space will be 800,000
square feet. Plans have been drawn by Graham, Anderson,
Probst & Wrhite, 80 East Jackson Boulevard,
Chicago.