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Steel Making

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Preventing Decarbonization Of Tool Steel
It is especially important to prevent decarbonization in such...

Phosphorus
PHOSPHORUS is an element (symbol P) which enters the metal fr...

Connecting Rods
The material used for all connecting rods on the Liberty engi...

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

Annealing
There is no mystery or secret about the proper annealing of d...

Process Of Carburizing
Carburizing imparts a shell of high-carbon content to a low-...

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

Hardness Testing
The word hardness is used to express various properties of me...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

The Forging Of Steel
So much depends upon the forging of steel that this operation...

Annealing Of Rifle Components At Springfield Armory
In general, all forgings of the components of the arms manufa...



Fatigue Tests






Category: COMPOSITION AND PROPERTIES OF STEEL

It has been known for fifty years that a beam or rod would fail
at a relatively low stress if only repeated often enough. It has
been found, however, that each material possesses a limiting stress,
or endurance limit, within which it is safe, no matter how often
the loading occurs. That limiting stress for all steels so far
investigated causes fracture below 10 million reversals. In other
words, a steel which will not break before 10,000,000 reversals
can confidently be expected to endure 100,000,000, and doubtless
into the billions.

About the only way to test one piece such a large number of times
is to fashion it into a beam, load it, and then turn the beam in
its supports. Thus the stress in the outer fibers of the bar varies
from a maximum stretch through zero to a maximum compression, and
back again. A simple machine of this sort is shown in Fig. 10,
where B and E are bearings, A the test piece, turned slightly
down in the center, C and D ball bearings supporting a load
W. K is a pulley for driving the machine and N is a counter.





Next: Hardness Testing

Previous: Impact Tests



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