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Steel Making

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

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

Tungsten, as an alloy in steel, has been known and used for a...

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

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

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

Piston Pin
The piston pin on an aviation engine must possess maximum res...

Affinity Of Nickel Steel For Carbon
The carbon- and nickel-steel gears are carburized separately...

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

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

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

Cutting-off Steel From Bar
To cut a piece from an annealed bar, cut off with a hack saw,...

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

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

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

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

Molybdenum steels have been made commercially for twenty-five...

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

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

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

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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