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

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

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

Surface Carburizing
Carburizing, commonly called case-hardening, is the art of pr...

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...

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

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

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

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

Hardening
The forgings can be hardened by cooling in still air or quen...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

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

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Conclusions
Martien was probably never a serious contender for the honor ...

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

Preventing Cracks In Hardening
The blacksmith in the small shop, where equipment is usually ...

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...



The Packing Department






Category: HEAT TREATMENT OF STEEL

In Fig. 56 is shown the packing pots where
the work is packed. These are of malleable cast iron, with an internal
vertical flange around the hole A. This fits in a bell on the
end of the cast-iron pipe B, which is luted in position with
fireclay before the packing begins. At C is shown a pot ready
for packing. The crown gears average 10 to 12 in. in diameter and
weigh about 11 lb. each. When placed in the pots, they surround
the central tube, which allows the heat to circulate. Each pot
contains five gears. Two complete scrap gears are in each furnace
(i.e., gears which fail to pass machining inspection), and at
the top of front pot are two or more short segments of scrap gear,
used as test pieces to gage depth of case.



After filling to the top with compound, the lid D is luted on.
Ten pots are then placed in a furnace. It will be noted that the
pots to the right are numbered 1, 2, 3, 4, indicating the position
they are to occupy in the furnace.

The cast-iron ball shown at E is small enough to drop through
the pipe B, but will not pass through the hole A in the bottom
of the pot. It is used as a valve to plug the bottom of the pot
to prevent the carburizing compound from dropping through when
removing the carburized gears to the quenching bath.

Without detracting from the high quality of the work, the metallurgist
in this plant has succeeded in cutting out one entire operation
and reducing the time in the hardening room by about 24 hr.

Formerly, the work was carburized at about 1,700 deg.F. for 9 hr. The
pots were then run out into the yard and allowed to cool slowly.
When cool, the work was taken out of the pots, reheated and quenched
at 1,600 deg.F. to refine the core. It was again reheated to 1,425 deg.F.
and quenched to refine the case. Finally, it was drawn to the proper
temper.





Next: Short Method Of Treatment

Previous: Heat-treating Department



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