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Steel Making

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

Gas Consumption For Carburizing
Although the advantages offered by the gas-fired furnace for ...

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

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

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

Pickling The Forgings
The forgings were then pickled in a hot solution of either ni...

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

Standard Analysis
The selection of a standard analysis by the manufacturer is t...

The Leeds And Northrup Potentiometer System
The potentiometer pyrometer system is both flexible and subst...

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

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

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

A Chromium-cobalt Steel
The Latrobe Steel Company make a high-speed steel without tun...

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

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

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

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Correction For Cold-junction Errors
The voltage generated by a thermo-couple of an electric pyrom...

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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