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

Steel Making

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Flange Shields For Furnaces
Such portable flame shields as the one illustrated in Fig. 1...

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

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...

Suggestions For Handling High-speed Steels
The following suggestions for handling high-speed steels are ...

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

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Care In Annealing
Not only will benefits in machining be found by careful anne...

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

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

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

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

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

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

Phosphorus
Phosphorus is one of the impurities in steel, and it has been...

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

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

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

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



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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