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Steel Making

Hardness Testing
The word hardness is used to express various properties of me...

SULPHUR is another element (symbol S) which is always found i...

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

The Modern Hardening Room
A hardening room of today means a very different place from ...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

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

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Manganese adds considerably to the tensile strength of steel,...

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

The Packing Department
In Fig. 56 is shown the packing pots where the work is packe...

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

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

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

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

Drop Forging Dies
The kind of steel used in the die of course influences the he...

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

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

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

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

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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