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Steel Making

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

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

Carburizing Material
The simplest carburizing substance is charcoal. It is also th...

Heating
Although it is possible to work steels cold, to an extent de...

The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufa...

Hardening
Steel is hardened by quenching from above the upper critical....

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

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

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

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

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

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

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

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

Bessemer Process
The bessemer process consists of charging molten pig iron int...

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

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

The Quenching Tank
The quenching tank is an important feature of apparatus in c...

Lathe And Planer Tools
TO FORGE.--Gently warm the steel to remove any chill is parti...

Mushet And Bessemer
That Mushet was "used" by Ebbw Vale against Bessemer is, perh...



Short Method Of Treatment






Category: HEAT TREATMENT OF STEEL

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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