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Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

Annealing Alloy Steel
The term alloy steel, from the steel maker's point of view, r...

For Milling Cutters And Formed Tools
FORGING.--Forge as before.--ANNEALING.--Place the steel in a ...

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

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

Crankshaft
The crankshaft was the most highly stressed part of the entir...

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

Judging The Heat Of Steel
While the use of a pyrometer is of course the only way to hav...

Annealing Method
Forgings which are too hard to machine are put in pots with ...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

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

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

The Electric Process
The fourth method of manufacturing steel is by the electric f...

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

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

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

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

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

The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely nece...



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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