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Steel Making

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

It is considered good practice to quench alloy steels from th...

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

Rate Of Absorption
According to Guillet, the absorption of carbon is favored by ...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

The Thermo-couple
With the application of the thermo-couple, the measurement of...

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

ANNEALING can be done by heating to temperatures ranging from...

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

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

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

A combination of the characteristics of nickel and the charac...

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

Preventing Carburizing By Copper-plating
Copper-plating has been found effective and must have a thick...

Temperatures To Use
As soon as the temperature of the steel reaches 100 deg.C. (...

Manganese adds considerably to the tensile strength of steel,...

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

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

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

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

Testing And Inspection Of Heat Treatment


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

Next: Temperature Recording And Regulation

Previous: Affinity Of Nickel Steel For Carbon

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