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Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

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

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

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

Heating
Although it is possible to work steels cold, to an extent de...

Crucible Steel
Crucible steel is still made by melting material in a clay or...

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

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

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

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

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

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

A Chromium-cobalt Steel
The Latrobe Steel Company make a high-speed steel without tun...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

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

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

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...

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

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...



Quenching






Category: CASE-HARDENING OR SURFACE-CARBURIZING

It is considered good practice to quench alloy steels from the pot,
especially if the case is of any appreciable depth. The texture
of carbon steel will be weakened by the prolonged high heat of
carburizing, so that if we need a tough core, we must reheat it
above its critical range, which is about 1,600 deg.F. for soft steel,
but lower for manganese and nickel steels. Quenching is done in
either water, oil, or air, depending upon the results desired.
The steel is then very carefully reheated to refine the case, the
temperature varying from 1,350 to 1,450 deg.F., depending on whether
the material is an alloy or a simple steel, and quenched in either
water or oil.



There are many possibilities yet to be developed with the carburizing
of alloy steels, which can produce a very tough, tenacious austenitic
case which becomes hard on cooling in air, and still retains a
soft, pearlitic core. An austenitic case is not necessarily file
hard, but has a very great resistance to abrasive wear.

The more carbon a steel has to begin with the more slowly will it
absorb carbon and the lower the temperature required. Low-carbon
steel of from 15 to 20 points is generally used and the carbon
brought up to 80 or 85 points. Tool steels may be carbonized as
high as 250 points.

In addition to the carburizing materials given, a mixture of 40
per cent of barium carbonate and 60 per cent charcoal gives much
faster penetration than charcoal, bone or leather. The penetration
of this mixture on ordinary low-carbon steel is shown in Fig. 32,
over a range of from 2 to 12 hr.





Next: Effect Of Different Carburizing Material

Previous: Carburizing Material



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