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Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

Critical Points
One of the most important means of investigating the properti...

Hardening
The forgings can be hardened by cooling in still air or quen...

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...

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

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

High-carbon Machinery Steel
The carbon content of this steel is above 30 points and is ha...

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

Placing Of Pyrometers
When installing a pyrometer, care should be taken that it re...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Manganese
MANGANESE is a metal much like iron. Its chemical symbol is M...

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

Affinity Of Nickel Steel For Carbon
The carbon- and nickel-steel gears are carburized separately...

Steel Before The 1850's
In spite of a rapid increase in the use of machines and the ...

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

Gas Consumption For Carburizing
Although the advantages offered by the gas-fired furnace for ...



Testing And Inspection Of Heat Treatment






Category: HEAT TREATMENT OF STEEL

The hard parts of the
gear must be so hard that a new mill file does not bite in the
least. Having passed this file test at several points, the gears go
to the center-punch test. The inspector is equipped with a wooden
trough secured to the top of the bench to support the gear, a number
of center punches (made of 3/4-in. hex-steel having points sharpened
to an angle of 120 deg.) and a hammer weighing about 4 oz. With
these simple tools, supplemented by his skill, the inspector can
feel the depth and quality of the case and the condition of the
core. The gears are each tested in this way at several points on
the teeth and elsewhere, the scrap gear being also subjected to
the test. Finally, the scrap gear is securely clamped in the
straightening press shown in Fig. 57. With a 3-1/2-lb. hammer and
a suitable hollow-ended drift manipulated by one of Sandow's
understudies, teeth are broken out of the scrap gear at various
points. These give a record confirming the center-punch tests,
which, if the angle of the center punch is kept at 120 deg. and
the weight of the hammer and blow are uniform, is very accurate.

After passing the center-punch test the ends of the teeth are peened
lightly with a hammer. If they are too hard, small particles fly
off. Such gears are drawn in oil at a temperature of from 300 to
350 deg.F., depending on their hardness. Some builders prefer to have
the extreme outer ends of the teeth drawn somewhat lower than the
rest. This drawing is done on gas-heated red-hot plates, as shown
at A in Fig. 58.



Nickel steel, in addition to all the tests given to carbon steel,
is subjected to a Brinell test. For each steel, the temperature
and the period of treatment are specific. For some unknown reason,
apparently like material with like treatment will, in isolated
cases, not produce like results. It then remains for the treatment
to be repeated or modified, but the results obtained during inspection
form a valuable aid to the metallurgist in determining further
treatment.





Next: Temperature Recording And Regulation

Previous: Affinity Of Nickel Steel For Carbon



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