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Steel Making

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

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

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

Heat Treatment Of Lathe Planer And Similar Tools
FIRE.--For these tools a good fire is one made of hard foundr...

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

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Making Steel Balls
Steel balls are made from rods or coils according to size, st...

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

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

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

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...

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

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

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

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

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

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

Connecting Rods
The material used for all connecting rods on the Liberty engi...

Short Method Of Treatment


In the new method, the packed pots are
run into the case-hardening furnaces, which are heated to 1,600 deg.F.
On the insertion of the cold pots, the temperature naturally falls.
The amount of this fall is dependent upon a number of variables,
but it averages nearly 500 deg.F. as shown in the pyrometer chart,
Fig. 61. The work and furnace must be brought to 1,600 deg.F. Within
2-1/2 hr.; otherwise, a longer time will be necessary to obtain
the desired depth of case. On this work, the depth of case required
is designated in thousandths, and on crown gears, the depth in
0.028 in. Having brought the work to a temperature of 1,600 deg.F.
the depth of case mentioned can be obtained in about 5-1/2 hr. by
maintaining this temperature.

As stated before, at the top of each pot are several test pieces
consisting of a whole scrap gear and several sections. After the
pots have been heated at 1,600 deg.F. for about 5-1/4 hr., they are
removed, and a scrap-section test-piece is quenched direct from
the pot in mineral oil at not more than 100 deg.F. The end of a tooth
of this is then ground and etched to ascertain the depth of case.
As these test pieces are of exactly the same cross-section as the
gears themselves, the carburizing action is similar. When the depth
of case has been found from the etched test pieces to be satisfactory,
the pots are removed. The iron ball then is dropped into the tube
to seal the hole in the bottom of the pot; the cover and the tube
are removed, and the gears quenched direct from the pot in mineral
oil, which is kept at a temperature not higher than 100 deg.F.

Next: The Effect

Previous: The Packing Department

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