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Steel Making

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

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

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

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

For Milling Cutters And Formed Tools
FORGING.--Forge as before.--ANNEALING.--Place the steel in a ...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

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

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

PHOSPHORUS is an element (symbol P) which enters the metal fr...

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

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

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

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

The Electric Process
The fourth method of manufacturing steel is by the electric f...

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

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

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

Furnace Data
In order to give definite information concerning furnaces, fu...

Hardening Operation


Hardening a gear is accomplished as follows:
The gear is taken from the furnace by the furnaceman and placed in
the lower die, surrounding the centering jaws, as shown at H in
Fig. 62 and C in Fig. 63. Air is then turned into the cylinder
D, and the piston rod E, the die carrier B, the top die F
and the expander G descend. The pilot H enters a hole in the
center of the lower die, and the expander G enters the centering
jaws I, causing them to expand and center the gear C in the
lower die. On further advance of the piston rod E, the expander
G is forced upward against the pressure of the springs J and
the upper die F comes in contact with the upper surface of the
gear. Further downward movement of the dies, which now clamp the
work securely, overcomes the resistance of the pressure weight
K (which normally keeps up the plunger A), and the gear is
submerged in the oil. The quenching oil is circulated through a
cooling system outside the building and enters the tempering machine
through the inlet pipe L. When the machine is in the position
shown, the oil passes out through the ports M in the lower plunger
to the outer reservoir N, passing to the cooling system by way of
the overflow O. When the lower plunger A is forced downward,
the ports M are automatically closed and the cool quenching oil
from the inlet pipe L, having no other means of escape, passes
through the holes in the lower die and the grooves in the upper,
circulating in contact with the surfaces of the gear and passes to
the overflow. When the air pressure is released, the counterweights
return the parts to the positions shown in Fig. 63, and the operator
removes the gear.

The gear comes out uniformly hard all over and of the same degree of
hardness as when tempered in an open tank. The output of the machine
depends on the amount of metal to be cooled, but will average from
8 to 16 per hour. Each machine is served by one man, two furnaces
being required to heat the work. A slight excess of oil is used
in the firing of the furnaces to give a reducing atmosphere and
to avoid scale.

Next: Carburizing Low-carbon Sleeves

Previous: Temperature Recording And Regulation

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