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Steel Making

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

Silicon
SILICON is a very widespread element (symbol Si), being an es...

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

Conclusions
Martien was probably never a serious contender for the honor ...

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

The Electric Process
The fourth method of manufacturing steel is by the electric f...

Hardening
Steel is hardened by quenching from above the upper critical....

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

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

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

The Theory Of Tempering
Steel that has been hardened is generally harder and more br...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

Double Annealing
Water annealing consists in heating the piece, allowing it to...

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

Crankshaft
The crankshaft was the most highly stressed part of the entir...



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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