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Steel Making

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

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

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

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...

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

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

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

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

Heat Treatment Of Steel
Heat treatment consists in heating and cooling metal at defin...

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

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

Annealing Work
With the exception of several of the higher types of alloy s...

Compensating Leads
By the use of compensating leads, formed of the same materia...

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

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

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

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

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

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

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



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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