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Steel Making

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

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

Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

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

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

This steel like any other steel when distorted by cold worki...

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

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

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

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

Case-hardening Treatments For Various Steels
Plain water, salt water and linseed oil are the three most co...

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

Temperatures To Use
As soon as the temperature of the steel reaches 100 deg.C. (...

Pyrometers For Molten Metal
Pyrometers for molten metal are connected to portable thermoc...

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

Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring tempe...

Knowing What Takes Place
How are we to know if we have given a piece of steel the ver...

The Theory Of Tempering
Steel that has been hardened is generally harder and more br...

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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