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   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is lar...

Molybdenum
Molybdenum steels have been made commercially for twenty-five...

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

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

Brown Automatic Signaling Pyrometer
In large heat-treating plants it has been customary to mainta...

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

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

Sulphur
SULPHUR is another element (symbol S) which is always found i...

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Heat-treating Department
The heat-treating department occupies an L-shaped building. ...

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

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

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

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

Air-hardening Steels
These steels are recommended for boring, turning and planing...

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

Pickling The Forgings
The forgings were then pickled in a hot solution of either ni...

Compensating Leads
By the use of compensating leads, formed of the same materia...

Correction For Cold-junction Errors
The voltage generated by a thermo-couple of an electric pyrom...

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...



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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