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Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

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

Reheating for machine ability was done at 100 deg. less than ...

Properties Of Steel
Steels are known by certain tests. Early tests were more or l...

Heavy Forging Practice
In heavy forging practice where the metal is being worked at...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

Nickel may be considered as the toughest among the non-rare a...

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

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

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

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

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

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

Take Time For Hardening
Uneven heating and poor quenching has caused loss of many ve...

Application Of Liberty Engine Materials To The Automotive Industry
The success of the Liberty engine program was an engineer...

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

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

Hardening Carbon Steel For Tools
For years the toolmaker had full sway in regard to make of st...

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

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...



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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